Week 5 Flashcards

Question

Acute tubular necrosis:

Answer 1

ischemic ATN is one of the most common causes of acute kidney injury in hospitalized pt ATN can be caused by decreased renal perfusion due to severe hypovolemia, shock or surgery The **straight proximal tubules (PCT)** and the **thick ascending limb of Henle's loop** located in the _outer medulla_ are the most commonly affected portions of the nephron. (predom the medulla since they have a low blood supply even in nl conditions -pct uses a lot of energy with ATP transport) clinical pres: inc serum creatinine, inc BUN, norm bun/cr rationoliguria, **muddy brown casts**

Answer 2

Sludge formation is a known precursor to stone formation, particularly cholesterol stones and may be complicated by biliary colic, acute cholecystitis, cholangitis, and pancreatitis. Gallbladder functions to actively absorb water from bile. Hypomotility cases bile concentration, which promotes bile precipitation and accumulation of viscious biliary sludge that predisposes to gallstones formation and bile duct obstruction

Answer 3

pigment gallstones can be brown to black and arise from conditions that increase the amt of unconjugated bilirubin in bile. brown stones -- asc w/ biliary tract infections (microbes producting B-glucoronidases) black stones -- setting of chronic hemolytic anemia (SCD), and increase enterocyte cycling of bilirubin (Crohn disease)

Answer 4

hyponatremia, hyperkalemia, hyperchloremia, non-anion gap metabolic acidosis

Answer 5

23PBG is an organophosphate created in erythrocytes during glycolysis The production of 2,3 BG is increased when oxygen availability is reduced, as occurs in chronic lung disease, heart failure, and chronic exposure to high altitudes elevated 2,3 BPG dec hemoglobin O2 affinity allowing the release of more O2 in the peripheral tissues 2,3 BPG binds to deoxygenated HB, between 2 beta chains, decreasing the affinity for oxygen (binding pocket increased in positive charge to allow for binding)

Answer 6

most often due to inversion of a plantar-flexed foot, ankle is stablized laterally by the **ant inferior tibiofibular, ant talofibular, posterior talofibular and calcaneofibular ligaments** the lateral ligaments are weaker and are injured more often than the medial ligaments most common ankle sprains involve only the **ant talofibular ligament** and present with pain, ecchymosis at the anterolateral aspect of the ankle

Answer 7

inhibition of mycolic acid synthesis side effects: neurotoxicity (give vitamin B6/pyridoxine), hepatotoxicity, could cause drug induced SLE reaction (*SHIPPE*) [mycolic acids are essential for proper cell wall structure and virulence factor synthesis-sulfatides, wax D, cord factor; without the mycolic acids, they canot create proper cell walls or divide--also it is what allows them to be acid fast as they retain the carbolfuchsin dye and resist decoloration by an acid alcohol decolrizing agent]

Answer 8

**Schwann cell-derived tumors** that typically arise from the **vestibular portion of the vestibulocochlear nerve (CN VIII)** and are commonly located at teh cerebellopontine angle (between teh cerebellum and lateral pons). Patients present with **_ipsilateral_** **unilateral sensorineural hearling loss** and **tinnitus** due to impairment of the _cochlear_ portion of the nerve. Damage to the vestibular component may also result in vertigo, dysequilibrium and nystagmus. most are unilateral but recall that bilateral acoustic neuromas are frequently seen in pt with neurofibromatosis type 2.

Answer 9

IN insulin sensive skeletal and adipose tissue, GLUT4 is the insulin-sensitive transporter; it is sotred in cytoplasmic vesicles, thus when insulin is present, GLUT 4 is incorporated into the cell membrane --\> inc # of transporters, inc # of glucose uptake = carrier mediated transport stereoselective and preferentially catalyze the entrance of D-glucose rather than L-gluc

Answer 10

\> 1 month duration of clinical features * intrusive thoughts, nightmares, flashbacks, avoidance of trauma reminders, hypervigilance and sleep disturbance* tx: trauma-focused CBT anti-depressants (SSRIs, SNRIS) [less than 1 month, more likely to be acute stress disorder- sx may remit within 1 month or progress to PTSD after this time]

Answer 11

corticosteroids have the strongest and most predictable effects on the inflammatory component of asthma inhaled corticosterods form teh cornerstone of chronic therapy for pt with persistent astham and can reduce the # and severity of acute asthma exacerbations (futicasone) pronounced anti-inflammatory effects on the respiratory epithelium used for chronic mgmt (inhaled) and acute exacerbations (systemic) inhibit the formaiton of inflammatory mediationrs (cytokines, prostaglandins, leukotrienes) implicated in bronchial asthma reduce leukocyte extravasation induce apoptosis of inflammatory cells within a few weeks --\> significant reduced airway inflammation; decrease amt of mucus produced by goblet cells further educing airway obstruction

Answer 12

condition characterized by chronic airway inflammation and edema leading to bronchial wall thickening and remodeling. Hyperinflated lungs, airway mucus plugging, cellular infiltration of bronchial wall airflow can be compromsied by airway hyperresponsiveness adn increased bronchoconstriction, which occurs in acute asthma exacerbation

Answer 13

folate antagonist structually similar to folic acid and competitively and irreversibly inhibits DHF reductase, which inhibits the formation of THF after entering the cell, MTX udnergoes polyglutamation, which prevents the movement of MTX out fo teh cell, resulting in intracellular accumulation of MTX for later use Tetrahydrofolate is an integral precursor of DNA synthesis; inhibited folic acid and DHF polyglutamate will accumulate in cells

Answer 14

is composed of multiple cystic edematous hydropic villi as a result of trophoblast proliferation serial measurements of **B-hCG** should be performed following evacuation of a hydratidiform mole! \*\*persistently elevated or rising levels may signify the development of an *_**invasive mole** or **choriocarcinoma!**_*

Answer 15

_preductal_ coarctation of the aorta (note diminished femoral pulses) bicuspid aortic valve

Answer 16

characterized by gradual deterioration in graft function **at least 3 months** post-transplant in absent of other events sx: _worsening hypertension, progressive rise in serum creatinine, proteinuria with normal urinary sediment_ pathogen: graft endothelial damage, *low-grade cellular and humoral immune response directed against alloantigens* --\> **obliterative fibrosis** intimal thickening and scattered mononuclear infiltration of the surrounding tissues --\> renal ischemia and chornic inflammation causing shrinkage of the renal parenchyma with tubular atropy and interstitial fibrosis

Answer 17

minutes to hours PREFORMED antibodies agasint graft in recipeints circulation morphology: gross mottling, cyanosis, arterial fibrinoid necrosis and capillary thrombotic occlusion

Answer 18

usually \<6 months exposure to donor antigens induces humoral and cellular activation of naive immune cells **Humoral**: C4d deposition, neutrophilic infiltrate, necrotizing vasculitis **Cellular**: lymphocytic interstitial infiltrate and endothelitis

Answer 19

Aneurysmal compression of oculomotor nerve --\> takes out the parasympathetics since the efferents are superficial early: dilated pupil and loss of accomodation late: ptosis and opthalmoplegia Diabetic opthalmoplegia --\> central infarction, affects teh somatic nerve fibers but spares peripheral parasympathetics (thus pupil ok!) down and out position (unopposed CN IV, CN VI since CN III is out!) normal sized, reactive pupil ptosis (paralysis of levator palpebrae)

Answer 20

**collection of squamous cell debris** that form a **round pearly mass** behind the tympanic membrane can be congenital or may occur as an acquired primary lesion or following infection, trauma or surgery of the middle ear. They can cause hearing loss due to erosion into auditory ossicles Primary are due to chronic negative pressur ein the middle ear causing retraction pockets in the tympanic membrane that become cystic -- as squamous cell debris accmulates -\> cholesteatoma formed secondary -- occur after squamous epithelium migrates to or is implanted i the middle ear **commonly cause painless otorrhea**, can produce lytic enzymes and are often discovered when they **erode through the auditory ossicles causing conductive hearing loss** \*\*despite what the name implies, cholesteatomas do not contain any lipid or cholesterol components\*\*

Answer 21

anticonvulsant works by blocking voltage gated sodium channels clinical use: partial and generalized seizures (except status epilepticus), is also effective for bipolar disorder AE: steven johnson syndrome (\<10 % body involvement) or toxic epiderma necrolysis (\>30% body involvement) -flu like symptoms, flollwed by extensive cutaneous and mucosal lesions; **lesions are characterized by epidermal necrosis and subepiderma bullae**

Answer 22

Lamotrigine carbamazepine phenobarbital (?) phenytoin ethosuximide (?)

Answer 23

depends on renal plasma flow and GFR FF = GFR / RPF on avg, aprox 1/5 of the plasma that passes through the glomerulus capillaries is filtered into bowman's capsule DEC RPF --\> DEC GFR --\> *_reducing distal tubule sodium delivery_* this _stimulates secretion of renin and increased angiotension II production_ --\> angio II preferentially _constricts the efferent glomerular arteriole_ --\> i**ncreasing hydrostatic pressure** in the glomerular capilaries and attempts to maintain the GFR (autoreg) -- the decrease in GFR is thus less pronounces than the decrease in RPF --\> increasd in FF

Answer 24

one of the most common congenital long-QT syndromes autosomal RECcessive other presentation: **congenital neurosensory deafness** QT-interval prolongation predispose to syncopal episodes and possible sudden cardiac death due to torsades de pointes / inherited disorder of myocardial repolarization, typically due to ion channel defects; increased risk for sudden cardiac death (k+ ??) vs: *_Romano-Ward Syndrome_*, autosomal Dominant, but a pure cardiac phenotype with no deafness involved

Answer 25

cardiac auscultation reveals a nonejection, midsystolic click and mid to late systolic murmur of mitral regurg. MVP is most often casued by defects in mitral valve connective tissue proteins that predispose to myxomatous degeneration of the mitral leaflets and chordae tendinae click due to sudden tensing of the chordae as they are pulled taut by the ballooning valve leafest murmur due to malaligment of the valve margins during systole Squatting increases venous return and LV volume --\> help bring the leaflets in a more normal anatomical position and thus delaying onset of click and the murmur shortes/disappears murmur disappears with squatting (note HCM also disappears with squatting but no midsystolic click will be heard!) MVP coudl be primary sporadic characterized by myxomatous degeneration of connective tissue secondary - inherited connective tissue disorders, including marfan's, ehler's danlos syndrome and osteogenesis imperfecta \*\*myxomatous lesions are characterized by proliferation of spongiosa of the valve leafets, fragmentation of elastin fibers with increase in mucopolysac adn type III collage deposits

Answer 26

Aspirin or clopidogrel (irreversibly block P2Y12 component of ADP receptors on the platelet and prevents platelet aggregation) with pt who are intolerant of aspirin

Answer 27

the splenic flexure and rectosigmoid junction lie between regions of perfusion of major arteries. These watershed areas are susceptible to ischemic damage during hypotensive states, esp in patients underlying arterial insufficiency (ie-ischemic colitis 0 sx: abdominal pain adn bloody diarrhea following complicated surgery) colon receives blood from teh marginal artery/artery of drummond, an anastomic system of arteries that is in turn supplied by the SMA and IMA distal colon also receives blood from the internal iliac artery noncolusive ischemic coudl occur at the marigins of anastomic distributions less commonly occlusive ischemic can also be caused by thromboemnolic or atheroembolic events impaired profusion --\> ischemia and necrosis; complications includa cidosis, spepsis, grangrene, performaiton colonscopy --\> pale mucosa and petechial hemorrhages

Answer 28

cystic tumor in teh cerebellum of a child most likley to be a pilocytic astrocytoma biopsy will show a well-defined neoplasm comprised of **spindle cells with hair-like glial** **processes** that are *_associated with microcysts_* these cells are mixed with **Rosenthal** fibers and **granular eosinophilic bodies**

Answer 29

**erythrocytes** - since they lack mitochondria **Liver** - lacks the enzyme succinyl CoA-acetoacetate CoA transferase (thiophorase), which is required to convert acetoacetate to acetoacetyl CoA 12-18 hours of fasting, bodys glycogen sotres are depleted and glyconeogenes is requires to maintian blood gluc levels -- if fasting continues, body limits its relaince on gluconeo in an effort to conserve protein and seorts instead to ketone body synthesis generated in the liver from FA and yield energy when converted to acetyl coA in the mitochondria of target cells

Answer 30

Ectoderm --\> epidermis mesoderm --\> dermis melanocytes --\> neural crest cells

Answer 31

Infection of the medial face, sinuses (ethmoidal or sphenoidal) or teeth may spread through the valvess facial venous system into the carvenous sinus --\> carvenous sinus thrombosis **2° to pituitary tumor mass effect, carotid-cavernous fistula, or cavernous sinus thrombosis related to infection.** typical presentation: h/a, fever, proptosis, ipsilateral deficits in CN III, IV, VI, and V (opthalmic and maxillary branches) THINK: nerves that control extraocular eye + V1 and V2, cavernous part of internal carotid also here \*CN IV is the most susceptible to injry Blood from eye and superficial cortex ---\> cavernous sinus --\> internal jugular vein

Answer 32

REVERSIBLE, adaptive response to chronic irritation, such as smoking the normal columbar epithelium is replaced by sw epithelium in the lungs, which is more resistant to irritaiton but has reduced mucociliary clearance (increased risk for injuries) etaplasia also occurs with Barrett esophagus, in which esophageal squamous epithelium is replaced by columnar epithelium in response to chronic acid exposure

Answer 33

Cerebellar ataxia Telangiectasias (superficial, _blanching_ nest of capillaries) INC risk of sinopulmonary infections Also inc risk of hematologic malignacies and **causes an immune deficiency consisting of both cell-mediated and humoral dysfunction** (*_primarily IgA deficiency_*, increasing risk for infections of upper and lower airways) Autosomal Recessive due to a mutation of **ATM** gene (Ataxia Telangiectasia Mutated) - **gene responsible for _DNA break repair_** \*\*hypersensitive to X-ray radiation that causes multiple chromosomal breaks\*\*

Answer 34

Immunodeficiency resulting from a defect in expression of HLA class II antigens on the surface of antigen presenting cells MHC II is needed to present foreing anteigen to T cells to elicit a cell mediated AND humoral response (**because T cells must first activate B cells to mature and undergo class switch)**

Answer 35

IN RER: 1. synthesis -translation of collagen alpha chains = preprocollage usually GLY-X-Y where X and Y are prolines/lysinnes 2. hydroxylation - **req vitamin C / scurvy** 3. glycosylation and formation of hydroxyline resides, formation of procollage via hydronge and disulfied bonds (triple heliz 3 alpha chains) -- if probs fomring tirple helix = **osteogensis imperfecta** 4 exocytosis outside in fibroblast: 5. proteolytic processing - cleavege of disulfied bonds --\> insoluble tropocollagen 6. crosslinking - reinforcement by covalent lysine-hydroxylysine cross linkage by **copper containinglysyl oxidase - ehlers-danlos syndrome, menkes dz**

Answer 36

**Menkes disease** - X linked connective tissue dz caused by impaired copper absorption and transport defect due to defective menkes protein ATP7A --\> decrease activity of lysyl oxidase (copper is a necessary factor) --\> brittle/kinky hair, growth retardation and hypotonia **Wilsons dz** = autosomal recessive defect in ATP 7B, leads to copper accumulation

Answer 37

**_in fed state -_**-\> increase amt of ATP --\> inhibits is**ocitrate dehydrogenase** (isocitrate --\> alpha-ketoglutarate) --\> increased citrate levels --\> citrate leaves the mitochondrial via citrate shutle, cleaved by ATP citrate lyase to make acetyl CoA --\> malonyl-Coa **via acetyl-coA carboxylase** (CO2 + biotin) --\> fatty acid synthesis **malonyl coa inhibits carnitine acyltransferase**, which is part of the carnitine carrier that shuttles fatty acyl-coa into the mitcondria. this inhibition prevents the transfer of acyl groups into the mitocondria, thus functions to preven thte breakdown of newly synthesized fatty acids.

Answer 38

most commonly caused by autoantibodies against **postsynaptic nicotinic acetylcholine receptors (striated muscle)** ---\> blockade of the receptors active site, receptor internalization and dedegration, and damage to the motor endplate due to complement fixation --\> decrease number of functional acetylcholine R --\> DEC available cation channels --\> reduction of end-plate potential following acetylcholine release --\> threshold potential not reach = muscle cells do not repolarize = no contraction NL absolute refractory period BUT actual synaptic concentrations of acetylcholine are UNAFFECTED (unlike botulism or lamber-eaton syndrome)

Answer 39

typically involved a cholinesterase inhibitor, an immunosuppresive agent and/or *_thymectomy_* cholinesterase inhibitors example pyridostigmine common side effect is GI symptoms due to excessive cholinergic stimulation of the gut could give **scopolamine**, **hyoscyamine** (**_selective_ _muscarinic_ acetylcholine R antagonist**) that will reduce the effects of cholinesterase inhibitors at muscarinic R (ie- GI) *_without affecting the one on skeletal muscles since its nicotinic R!_*

Answer 40

low-molecular wt heparin that fxns like heparin (enoxa**parin)** in that it binds and activates anti-thrombin III (AT III) --\> binds to factor Xa and stops factor Xa from converting prothrombin to thrombin DUe to its fewer molecules, LMWH acts primarily on factor Xa, not thrombin *low molecular wt heparins are more effective at blocking AT III than thrombin/IIA directly.*

Answer 41

RF: pre-existing psychiatric disorders, hopelessness and impulsivity, previous attempts/threats, divorced/separated, elderly white man, unemployed/unskilled, physical illness, fam hx, fam discord, access to firearms (individuals with access have3x risk of suicide _completion_ as sucide by firearm is asc with higher fatality rates vs other methods --\> where direct intervention can help!), substance abuse protective factors: suicide support/family connectedness, pregnancy, parenthood, religion adn participation in religious activities

Answer 42

the piriformis passes through the greater sciatic forament and is involved with external hip rotation. muscle injury or hypertropy can compress the sciatic nerve in the foramen 00\> The sciatic foramen - pelvic opening for structures of the lower limbs divided into greater and lesser by the sacrspinous ligament piriformis originates on the anterior aspect of the sacrum and occupies most of the psace in teh greater sciatic foramen --\> inserts on teh greater trochanter of the femur

Answer 43

SEL strep group B E. coli listeria

Answer 44

Resistant to penicillin-binding proteins: listeria (not covered by 3rd degree cephalosporins), MRSA, enterococci No cell wall: atypicals - mycoplasma, chlamydia

Answer 45

LIsteria is a gram-positive facultative intracellular organism that is able to avoid phagocytosis and spread intracellularly (actin rockets!) **requires cell-mediated immunity** humoral response does not play a role --\> listeria is most common among pt with deficient cell-mediated immunities such as infants and those receiveing chemotherapy, or HIV positive, pregnant women **Tx: ampicillin** **NOT covered by third gen cephalosporins**

Answer 46

accessory nipples ie- polythelia, supernumerary nipple due to failure of involution of the mammary ridge asympto may well or become tender during inc hormones occur anywhere along the embryonic milk line btw axilla and perineum bilateral in 50% findings: hyperpig, epidermal thickening, pilsebacous structure of montgomery areolar tubercles, smooth muscle bundles, possib mammary glands and multiple ducts

Answer 47

solar lentigines = "freckles" aka ephelides.. increased melanin production by melanocytes solar lentigo = increased proliferation of melanocytes themselves both hyperpigmented and flat but solar lentigines are often larger and occur in adults

Answer 48

partial agonist of 5HT1a receptor nonbenzo anxiolytic used to treat general anxiety disorder NO muscle relaxant or anticonvulsant properties (vs benzos) NO RISK dependence ok with alcohol (vs benzos and barbs) not useful for acute anxiety or tx panic disorder due to its SLOW ONSET OF ACTION (clinical response is up to 2 weeks)

Answer 49

= different mitochondrial genomes within a single cell (each cell has tons of mitochondrai, and defects in their own genome may occur in any # of mit within the cell) variable clinical expression in affected members, due to the coexistence of distinct verisions of mitochondrial genomes in an individual cell severity often directly related to the proportion of abnormal to normal mitochondria within a pt cell \*think about when a mitochondrial dz; ie- presence of lactic acidosis and ragged skeletal muscle fibers ~ myopathy (recall mitco responsible for ATP production, thus tend to cause lactic acidosis nad primarily affect tissues with the highest metabolic rates!)

Answer 50

when both members of a chromosomal pair are inherted from one parente, which causes problems due to genomic imprinting ie) although most often due to chromosoal deletions, uniparental disomy can also cause prader willi and angelmann syndromes due to loss of expression of maternalparental imprted components of a critical region of chrom 15

Answer 51

anti-fribinolytic agent that inhibits plasminogen activators and to a lesser degree antiplasmin activity helps achieve hemostasis when firbinolysis is the casue of bleeding

Answer 52

contains only cold-soluble proteins (Factor VIII, fibrinogen, vWf, vitronectin) vs fresh frozen plasma contains all the coag factors

Answer 53

adenosine rapid acting drug with a half-life of only less than 10 seconds acts by slowing the conduction through the AV node by HYPERPOLARIZING the nodal pacemaker and conducting cells Also, drug used for _chemical_ stress test! side effects: flushing, chest burning(due to bronchospasm), hypotension and high grade AV block

Answer 54

Also known as **hereditary motor and sensory neuropathy (HMSN).** Group of _progressive_ hereditary nerve disorders related to the **defective production of proteins involved in the structure** and **function of peripheral nerves or the _myelin_ sheath.** Typically _autosomal dominant_ inheritance pattern and associated with _scoliosis_ and _foot deformities_ (high or flat arches). often present with weakness of foot dorsiflexion due to involvement of the common peroneal nerve

Answer 55

superior gluteal nerve injury most often caused by peliv trauma or iatrogenic damage occuring during hip surgery or buttock injections (superior medial) the superior gluteal nerve innervates the gluteus medius, gluteus minimus and tensor fasciae latea muslces --\> fucntion to stablized the pelvis and abduct the thigh weakness --\> pelvis will sag towards the unaffected/contralateral side when the pt stands on the affected leg to compensate for the hit drop (gluteus medius lurch)

Answer 56

innervates muscles responsible for flexion of the thigh at the hip (iliacus and sartorius) and extension of the leg at the knee (quads) Also supplies sensory innervation ot the skin on the anterior thigh and medial leg injury ---\> **knee buckling and loss of patellar reflex**

Answer 57

--\> impairment thigh adduction and medial thigh sensory loss

Answer 58

innervates the muscles in the posterior comparment of the thigh (hamstrings) subsequently divides into the tibial and common fibular/common peroneal nerves --\> motor and sensory innervation to the leg and foot TIP and PED

Answer 59

**Autosomal recessive** Deficiency of neutral amino acid (e.g., **_tryptophan_**) transporters in _proximal renal tubular cells_ and on _enterocytes_ --\> neutral aminoaciduria and 􏰂absorption from the gut --\> tryptophan for conversion to niacin --\> pellagra-like symptoms (diarrhea, dementia, dermatitis). Treat with high-protein diet and nicotinic acid. \*\* Niacin is made from tryptophan (which is essential!!) Labs: aminoaciduria, restricted to the neutral amino acids Note- the urinary excretion of proline, hydroxyprolife and arigine remians unchanged - impt to differentialte hartnup from other causes of genearlized aminoaciduria as fanconi syndrome tx: nicotinic acid or nicotinamide and high protein diet generally results in significant improvement of symptoms * Recall - Na+-dependent transporters in PCT reabsorb amino acids.*

Answer 60

essential amino acid and precurosf for nicotinic acid (--\>niacin), serotonin and melatonin

Answer 61

is maximal in states of accelerated carbohydrate metabolism b/c it acts as a cofactor for the enzyme transketolase in the pentose pathway

Answer 62

characterized by chronic fatigue, dyspnea, difficult concentrating and evidence of hypoventilation (partial pressure of carbon dioxie \>45 mmHg while awake) in an obse person! it is one of hte important causes of hypoxemia with a normal alveolar to arterial oxygen gradient

Answer 63

nl: 5-15 mmHg hypoxemia wiht a normal Aa gradient indicates that both the alveolar and the arterial partial pressure of oxygen are low this can occur with: alveolar hypoventilation or inspiriration of air at high altitude

Answer 64

Glycogenolysis and gluconeogenesis First 12-18 hours: glycogenolysis first step: breakage of 1-4 glycosidic linkage to form glucose-1-hosphate Once the glycogen stores become depleted: gluconeogenesis becomes the major process used by the body to keep blood glucose levels within the normal range oxalocacetate --\> phosphoenolpyruvate one of the steps

Answer 65

monosaccharide (remember that monosacs can be absorbed directly and don't need to be degraded) absorption is NOT affected by exocrine pancreatic insufficiency, and can be used to differentiate between pancreatic versus mucosal causes of malabsorption

Answer 66

exocrine pancreas has significant secretory reserve and \>90% of the glandular tissue must be destroyed before a patient wil develop clinical malabsorption can use the D-xylose test to observe if malabsorption is occuring without the pancreatic enzyme or if it due to the brush border

Answer 67

AVP attaches to its membrane receptor V2 --\> acts on G2 --\> AC --\> increase cAMP --\> inc protein kinase A --\> phosphorylation of aquaporin 2 vesicles, to increase the # of aquaporin 2 channels in the apical membrane --\> increasing H20

Answer 68

Aka space constant = measure of how far along an electrical impuse can proproage / distance at which the og potenital decreases to 37% of its original amplitude DEC can be due to: decrease of myelin (fxn is to increase membrane resistance to decrease the charge dissipation and thus increasing length constant - ie like an insulation); myelinaiton also decreases the time constant (time it takes for a charge in the membrane potential to achieve 63% of the new value; reduction in time constant = faster / decrease membrane capacitance)

Answer 69

During decent of teh testes (located in the peritoneal cavity and sub decend into the scrotum before birth), the testes are accompanied by an envagination of the peritoneum = processus vaginalis, which is suppose to oblieterate after descent is complete failure --\> persistent connection btwn the scrotum and the peritoneal cavity through the inguinal canal if the opeing is small --\> fluid leakage --\> hydrocele (transillumination of the scrotum, and scrotal ultrasound reveals fluid surround the affected testicle) if large --\> could allow for pasage of abdominal organs, an indirect inguinal hernia develops [indirect hernias are common in children, as they pass through teh deep inguinal ring, are covered by internal spermatic fascia and are located lateral to the inferior epigastric blood vessels] hydroceles and indirect inguinal hernias both can present as an asymptomatic scrotal mass that increase in size during valsalva maneuvers

Answer 70

characterized by difficulties with key academic skills (reading, writing, math - it could be in only one subject, does not have to be all ), resulting in performace well below expectations for age level children commonly display symptoms of axiety, inattention or hyperactivity when under stress. If a child is showing these symptoms a learing disorder should be ruled out (need to rule out intellectual disability, hearing, vision orneurological disoder)

Answer 71

testosteron: development of internal male genitalia (except prostate), spermatogenesis, male sexual differentiation at puber (muscle mass, libido) DHT: developmet of external male genitalia, prostate, male-patter hair growth; also amplified effects of testosterone due to high affinity for testosterone receptors T --\> DHT requires **5alpha-reductase** **male pseudohermaphorditism** could occur if 5alpha-reductase type 2 deficiency (type 2 is predom found in genitals, where type 1 is found in postpubercent skin) small phallus with hypospadias are common

Answer 72

Candidemia- candida can colonize teh catheter, and the lipid emulsion in the parenteral nutrition solution is thought to promote the growth of some candida sp Candida dispaly psudeohyphae with blastocondida most susceptible to echinocandis and nearly always to fluconazole

Answer 73

group of heme-containing proteins that are responsible for the majority of drug metabolism, predom in the liver but also found in the gut and elsewhere various CYP exitgenerally deactivate drugs and faciliate excretion from the body by improving water solubility, and also metabolize certain compounds to their acrive forms Polymorphisms: genes could alter their expression/activity three impt: poor, intermediate, rapid

Answer 74

1. Toxic shock syndrome 2. staph scalded syndrome 3. gastroenteritis (usually mayonnaise containing products, heat stable exotoxin that causes rapid-onset nausea, vomiting and abdominal cramping)

Answer 75

X-linked recessive deletion of the dystrophin gene (structural protein of muscle fibers and its absence casues muscle fiber destruction = myonecrosis) on light microscopy - variation in muscle fiber shape and size, regenerating fibers and increased amounts of connective tissue are seen on light microscopy disease onset: 2-5 years muscles of the proximal lower extremities, back adn peliv and shoulder girdles are affected first look for: abulation difficulties, gower sign, calf pseudophypertropy (calf muscles hypertropy initially but later replaced by fat and connective tissue/**fibrofatty),** asymmetric weakening of the paraspinal muscles --\> kyphoscoliosis wheelchair bound by 12 scolisosi progresses rapidly due to muscle imbalance and body positional changes --\> complicated by restricted pulmonary function (dec vital capacity and total lung capcity)

Answer 76

tumor suppressor genes, involved in repair of double-stranded DNA breaks mutations results in genetic instability, predispoding cells to an increased risk of malignancy transformation Both BRCA mutations are inhereted in AUTOSOMAL DOMINANT manner with VARIABLE PENETRANCE 70-80% lifetime risk for developing BCA, 40% of developing ovarian (\> BRCA1)

Answer 77

mu-opioid receptor, blocks the rewarding and reinforcing effects of drugs... used for: **alcoholicim**, show to reduce craving and ok to be initiated while the pt is still drinking **heroin -** Long-acting opioid antagonist used for relapse prevention _once detoxified_

Answer 78

wilson's disease aka- hepatolenticular degeneration autosomal recessive mutaiton of ATP7B gene --\> impaired cellular transport of cooper --\> decrease incorporation into ceruloplasmi, reduced biliary copper excretion --\> copper accumulation in liver, brain and eyes --\> injury by binding to sulfhydryl groups of cellular protines sx: hepatic, neurologic, psychiatric, kayer-fleishcer rings low ceruloplasmin, elevated transaminase antidote: D-penicillamine (contains free sulfhydryl group and functions as a copper chelator)

Answer 79

Reaction formation is a defense (immature) mxn in which an individual transforms unacceptable feelings or impulses into teh extreme opposite (ie-being a sex addict then becoming a nun)

Answer 80

diabetes mellitus diabetes insipidus (central/nephrogenic) primary polydipsia (PP)

Answer 81

psychological disorder characterized by increased intake of free water --\> usually pt have hyponatremia with low initial urine osmolarity w/large volume urine osmo increases after water depriviation but there is not additional increase in urine osmolarity with vasopressin injection tx: restriction of water intake

Answer 82

usually asmpto recurrent sinopulmonary and GI infections asc with other AI diseases **anaphylaxis during transfusion (potentially fatal! IgE mediated)** dx: low or absent serum IgA levels, nl IgG and IgM levels pt can form IgE antibodies to IgA (anti-IgA antibodies) due to failure of B cells to differentiate inot IgA-secreting plasma cells

Answer 83

causes hereditary angioedema that can be triggered by transfusions. affected pt have angioedema but DO NOT have urticaria or wheezing

Answer 84

ex- terazosin, doxazosin --\> decrease in systemic vascular resistance reflex increase heart rate used for symptomatic BPH side effects: orthostatic hypotension -- lightheadedness and syncope due to cerebral hypoperfusion upon standing

Answer 85

--\> increase release of NE from peripheral nerve terminals -- increase blood pressure and heart rate

Answer 86

NMS is an adverse reaction to anti-psychotic medication characterized by severe **"lead-pipe" rigidity, hyperthermia, autonomic instability, and mental status changes** ***Fever*** **Fever, Encephalopathy, Vitals unstable, Enzymes inc, Rigidity of muscles** **potentially life-threatening adverse reaction to neuroleptics (antipsychotics)** \*\*although symptoms overlap with those of serotonin syndrome, pt wtih NMS do not exhibit hyperreflexia and clonus characteristic of serotonin syndrome

Answer 87

SSRI + any additional drug that will increase the serotonin hyperthermia, confusion, myoclonus, cardiovascular instability, flushing, diarrhea, seizures. Treatment: cyproheptadine (5-HT2 receptor antagonist).

Answer 88

hemorrhagic, because there is dual blood supply to the lungs

Answer 89

typically results from a massive rupture of a intervertebral disk that is capable of compressing two or more of the 18 spinal nerves roots of the cauda equina but can occur due to any trauma or space-occupyin glesion of hte lower vertebral column these nerve roots provide the senosry and motor innervation of most of the lower extremities, the pelvic floor and the sphincters sx: low back pain rading to one or both legs saddle anethesia loss of anocutaneous reflex bowel and baldder dysfunction (S3-S5) loss of ankle-jerk reflex with plantar flexion weakness of the feet

Answer 90

dihydropyridine **-dipines** **h/a, flushing, dizziness, peripheral edema** effective anti-hypertensive agents commonly used as monotherapy or in combination with other agens for treatmetn of hypertension pt get peripheral edema due to its preferential dilation of precapillary vessels (arteriolar dilation), which leads to increased capillary hydrostatic pressure and fluid extravasation into the intersititum vs ARBs and ACE inhibitrs cause post-capillary venodilation adn can normalize teh increasd capillary hydrostatic pressure, reducing risk for peripheral edema in pt taking CCB

Answer 91

genomic imprinting = phenomenon in whcih an offsprings genes are expressed in a parent manner it is caused by DNA methylation, an epigenetic process in which genes can be silenced by attaching methyl groups to cytosine residues in the DNA molecule enzyme: DNA methytransferase, uses S-adenosyl-methionine (SAM) as the methyl group donor - modify gene expression without altering the genetic code cytosine methylation is also used, as a means that the genes expressed are parent-specific (ie-parent is methylated/imprited so that only the mother's is expressed)

Answer 92

the phenomenon in which the allel of one gene affects the phenotypic expression of alleles in another gene

Answer 93

Vitamin A maintains orderly differentiation of specialized epithelia, inclduing the mucus-secreting columnar epithelia of the ocular conjunctiva, respiratory and urinary tracts adn pancreatic adn other exocrine ducts **it can also cause squamous metaplasia of such epithelia to a keratinizing epithelium, when a deficiency state exits!**

Answer 94

"can't make new blood cells properly" ## Footnote **Carbamazepine, Methimazole, NSAIDs, Benzene, Chloramphenicol, Propylthiouracil**

Answer 95

bone marrow failure due to hematopoietic stem cells (CD 34+) Histo: hypocellular marrow filled with fat cells adn amrrow stroma causes: autoimmune, infections (parvo, EBV), drugs (carbamazepine, chloramphenicol, sulfonmides), exposure to radiation or toxins (benzene, solvents) clinical findings: pancytopenia and sx associated w/it anemia thrombocytopenia leukopenia dx: biopsy showing **hypocellular** bone marrow composed mainly of fat and stromal cells

Answer 96

**dystonia:** _sustained_, unvoluntary muscle contractions, force certain parts of the body int abnl, sometimes painful movements or postures; affect single muscle or group of muscles or entire body (cervical dystonias = spasmodic torticollis - most common focal dystona; blepharospams - involuntary, forcible closure of the eyelids, writers cramp) **myoclonus -** _sudden, brief,_ sometimes shock-like muscle contraction. both physiologic ( hiccups, hypnic jerks when falling asleep) or pathological (epilepsy, creutzfeldt-jakob dz) **cogwheel -** resistent to passive extension/flexion on a parkinsonian limb **bradykinesia-** slow movement, parkinson **chorea-** involuntary muscle activity that flows from one muscle group to another; appear fragmented or jerkey; pt may display a dancing gait; huntington dz- **hemiballism-** flinging of hte limbs (arms and/or leg) on one side of the body; occurs due to contralater injury in or near the subthalamic nucleus

Answer 97

hand hygiene

Answer 98

MS = AI demyelinating disease of teh CNS that typically presents in young women age \<50, with neurologic deficits disseminated in time and space. A common initial manifestation of MS is optic neuritis, MRI findings - include white matter lesions scattered through the brain and/or spinal cord with a predilection for hte subcortical periventricular regions involves autoimmune response (T cell and antibody-mediated) targeting oligodendrocytes and myelin in the central nervous system --\> release of cytokines that promote infiltration of destructive macrophages/microglia and leukocytes, be cells play a role as most pt have oligoclonal immunoglobulin bands in teh CSF--\> myelin destruction--\> slowed nerve conduction with neurologic deficits!

Answer 99

infection with high risk HPV strains (16, 18) \*\*strongest\*\* hx of STI early onset of sexual activity (before 18- 2x) multiple or high-risk sexual partners immunosuppression (INC esp w/HIV!) history of vaginal or vulvar cancer low socioeco status tobacco use (note-alcohol does NOT inc for cervical although it does for breast ca)

Answer 100

yeast that has antiphagocytic polysac capsule, its major virulence factor methenamine silver stain -- narrow based buds india ink -- capsules appear clear mucicarmine -- capsules appear red affects immunocomp transmitted via respiratory route, most commonly preesnts with subacute or chronic meningoencephalitis; lung disease cause pneumonia like symptoms, including cough with scant sputum production, pleuritic chest pain, dyspnea and hempotysis chest x-rays are nonspecific dx-identify in sputum, bronchoalveolar washing or tissue sampling

Answer 101

diastolic heart failure is caused by decreased ventricular compliance LVEDP- increased LVEDV- normal LV ejection fraction - normal / near nl \>50% *in the setting of increased LV filling pressures* due to conditions that **decrease LV compliance:** impaired myocardia relaxation (ie-from ischemia) inc intrinsic ventricular wall stiffness (amyloid deposits) Inc LV wall hypertrophy (long stanidng HTN), impairing myocardial relaxation and increase intrinsic wall stiffness *LV diastolic pressure-* determined by blood volume in the lV cavity and compliance of the LV, reduced ventricular compliance --\> increased LVEDP at teh same LVED volumes; this casues a shift in teh pressure-volume curve that goes upward and to the left as diastolic dysfunction worsens, LVEDP continues to rise as the heart attempts to maintain a near normal stroke volume and CO...decompensation occurs when the increased LVEDP (transmitted to teh left atrium and pulmonary veins) casues PE and dyspnia...cardiac reserve also diminished as teh stiffened ventricle becomes less effective at accomondating incread blood volumes, limiting the ability of frank-starling mxn

Answer 102

systolic HF is caused by primary decrease in myocardial contractility rather than ventricular compliance. as a result, systolic HF is characterized by reduced LV ejection fraction \<50% along with progressive chamber dilation with, increased LV volume increased LVEDP

Answer 103

overuse injury of the secondary ossification center/apophysis of the tibial tubercle common key pain in young adolescentatheltes after recent growth spurt presents with pain and swelling at the tibial tubercle, the insertion point of the patellar ligament...patellar ligament conects the tibia to the patella, which in turn is connected to the quad muscles

Answer 104

aneuploidies TRISOMY 21 + others

Answer 105

multiple gestations incorrect date anencephaly neural tube defects (NOT spina bifina oculta) ventral wall defects (omphalocele, gastroschisis) Multiple gestations

Answer 106

in the quadruple screen, LOW AFP and unconjugated estriol levels associated with DS w/INCREASE h-HCG and inhibin A chromosome 21 nondisjunction occurs during **oogenesis** and is significantly associated with advanced maternal age; could also result from an unbalanced Robertsonian translocation, during which the entire long arm of one chrome 21 is translocated to the long arm of an acrocentric chromosome, thus individuals have 46 chromosomes but one with a long arm.

Answer 107

myeloproliferative disorder characterized by uncontrolled erythrocyte production. Virtually all patients with polycythemia vera have a mutation in JAK2, a **non-receptor cytoplasmic tyrosine kinase** associted with the erythropoietin receptor --\> constitutivea activation of its kinase domain, resulting in clonal proliferation of myeloid cells clinical presentation: nonspecific systemic symptoms, aquagenic pruritus, facial plethora, splenomegaly other conditions include peptic ulcer dz (due to alt mucosal blood flow due to increased viscosity- recall that blood helps to buffer the acidity), gouty arthritis (higher red cell turnover --\> inc uric acid) labs: increased erythrocyte mass, thrombocytosis, leukocytosis and low erythropoietin levels other erythorcyte indices are usually normal

Answer 108

Protease inhibitors reversibly inhibit viral protease, an enzyme responsible for HIV polyprotein cleavage to form mature viral proteins NEVER USED as monotherapy side effects: fat distribution! 1. Lipodystrophy --\> buffalo hump, with central obesity and peripheral wasting 2. hyperglycemia --\> increased insulin resistnace and may lead to diabetes 3. inhibition of cytochrome P450 (ritonavir)

Answer 109

On exposure from sunlight, &-dehydrocholesterol (provitamin D) in the skin absorbs uvB rays --\> opens the B ring of 7-dehydrocholesterol, forming previtamin D3, which then undergoes thermal isomerization to form Vitamin D3 D3 hydroxylated in the liver to 25-hydroxyvitamin D --\> 1,25 hydroxyvitamin D

Answer 110

1. cholecystectomy 2. Medical tx: hydrophilic bile acids (ursodeoxycholic acid) --\> reduce biliary cholesterol secretion and increased biliary bile acid concentration --\> gallstone dissoluation by _improving cholesterol solubility_ (high rate of recurrence)

Answer 111

1. adrenal medulla- stimulated by sympathetic cholinergic preganglionic neurons (ACh on a nicotinic R) 2. eccrine sweat glands pre and post innervated by cholinergic innervation (pre = ACh on nicotinic R / post is ACh on muscarinic R)

Answer 112

--\> progressive weakening during contraction could indicate NMJ pathology (MG) and/or abnormally rapid muscle fatigue due to some restriction / fibrosis or disease

Answer 113

trapezius serves to elevate, rotate and stabilize the scapula innervation: CN XI

Answer 114

antigens are presented to cytotoxic CD8+ T lymphocytes on MHC I Structure: heavy chain and B2 microglobulin location: all nucleated cells fxn: present antigen to cd8+ T cells type of antigens: viruses, tumor proteins antigens are processed in the cytoplasm (RER and golgi app); **_endogenously_** synthesized! Antigen is presented (first signal), activating CD8+ T cell via B7/CD28 second signal --\> apoptosis of the presenting cell

Answer 115

antigens are presented to cytotoxic CD4+ T lymphocytes on MHC II Structure: beta and alpha polypep chains (+invariant chain) location: APCs (b-cells, macros, dendritic, langerhans) fxn: present antigen to cd4+ T helper cells type of antigens: bacterial antigens phagocytosed, digested by lysosomes within which antigen binds MHC II Antigen is presented (first signal), activating CD4+ T cell via B7/CD28 second signal --\> activated and produces cytokines

Answer 116

children - metaphysis of long bones (due to slower blood flow and capillary fenestrae in the region) adults - vertebral body

Answer 117

AVP: hemophilia A (increase circulating factor VIII) type 1 Vonwillebrand (increases endothelial secretion of vWF) Pressor -- central diabetes insipidus, noctunral enuresis (bindsV2 receptors in rental tubular cells, leading to increased aquaporin channels, increased water reabsorption and decreased urine output)

Answer 118

vWF and factor VIII produced in the endothelial cells

Answer 119

the excess risk in the exposed population that can be attributed to the risk factor ARPexposed = 100 x [(rel risk -1)/RR]

Answer 120

Directly inhibit Xa examples- rivaroxaba, apixaba prolong both aPTT and PT with NO effect to TT

Answer 121

demyelinating syndrome of the peripheral nerves characterized by ascending muscle weakness and paralysis

Answer 122

defined as mean pulm arterial pressure \> 25 mmHg at rest follows a 2 hit hypothesis: an abnormal BMPR2 (auto dom) gene acts as the first insult and predisposes to **excessive endothelial and smooth muscle proliferation** A second insult (drugs, infections, channeld defects..) is then thought to activate the dz process: increase endothelin, decrease prostacyclin, decreased NO--\> resulting in vascular remodeling, elevated pulmonary vascular resistance and progressive pulmonary hypertension clinica pres: dyspnea, fatigue, can be heard as an accentuation of the second heart beat; eventualy leads to right ventricular failure (cor pulmonale) which can present with exertional angina, elevated JVP, hpatic congestion and peripheral edema

Answer 123

pentose phosphaste pathway - fxn is to generate teh reducing agent NADPH, which is then essential to reduce oxided gluthaione, that will then convert hydrogen peroxide --\> water G6PD: NADP+ --\> NADPH Gluthione reductase: oxidized gluthione --\> reduced glu

Answer 124

cholesterol gallstones Fibrate medications (fenofibrate, gemfibrozil) INHIBIT cholesterol 7alpha-hydrxylase, which catalyzes the rate limiting step in the synthesis of bile acids Reduced bile acid production results in decreased cholesterol solubility in bile--\> super saturate and favors the formation of cholesterol gall stones also upregulate LPL, resulting in increased oxidation of fatty acids

Answer 125

Hirschsprung dz is a result of abnl migration of neural crest cells druing embryogenesis. these cells are the precurosors of ganglion cells of intestinal wall plexi since neural crest cells migrate caudally, the RECTUM is always involved

Answer 126

hepatocyte necrosis (cellular swelling and cytoplasmic emptying / balloon degeneration), apoptosis with mononuclear infiltration in severe cases, adjacent lobules are interconnected with swaths of dead hepatocytes called bridging necrosis hepatocyte apoptosis is characterized by cellular shrinkage adn nuclear fragmentation with intense eosinophilia (councilman bodies), likely caused by mitochondiral oxidative damage

Answer 127

erythrocyte sedimentaiotn rate or C-reactive protein - nonspecific but highly sensistive and almost always highlly elevated in GCA --\> then must undergo temporal artery biopsy for definitive diagnosis

Answer 128

Valproate - used for seizure prophylaxis and bipolar disorder blocks voltage-gated sodium channels adn enhaces GABA synthesis and release. As an anti-convulsant, valproate effectively treats absence (2nd line), myoclonic (DOC) and generalized tonic-clonic sezures.

Answer 129

single lesion of urticaria which is classically described as an erythematous papule/plaque with central pallor a bee sting is a hypersensitivity type I release of histamine and heparin + other vasoactive mediators occurs when tehre is IgE crosslinke and degranulation on mast cells and basophils --\> increase local vascular permeability, but can also cause systemic vasodilation, bbronchoconstriction and inflammation leadsin to anaphylactic shock and potential death (there must have been a primary exposure that allowed for class swithching to IgE, that in which subsequent exposure results in degranulation)

Answer 130

cytokine produced by macrophages and mast cells functions to signalf or apoptosis of tumor cells and activation of inflammatory cells such as CD4+ T lymphocytes, neutrophils, fibroblasts, endothelial cells and hematopoietic stem cells elevated in inflammatory conditions can be elevated in type IV hypersensitivity rxn

Answer 131

1. pyruvate dehydogenase cofactor, gyclolysis --\> TCA pyruvate --\> acetyl-CoA 2. alpha-ketoglutarate dehydrogenase, TCA ketoglutarate --\> succinyl 3. branched chained alpha ketoacid dehydrogenase, essential for catabolism of brancehd chain amino acids (lecuine, isoleucine, valine) 4. transketolase, enzyme of the pentose pathway pathway ribulose 5P (from glucose) --\> glycolysis intermediates deficiency - LOW baseline erythrocyte transketolase activity but increases after the addition of thiamine pyrophosphate \*ensure to give thiamine supplemenation with glucose infusion; if not, acute cerebral damage could occur

Answer 132

of fatal cases / total # of people with disease

Answer 133

blood flow per minute the circulatory system is a continuous circuit and therefore the volume output of the left ventticle must closely match the output of the right ventricle This balance is necessary to maintian continuous blood flow through the body and exits both at rest and during exercise

Answer 134

Tetrodotoxin is a potent neurotoxin found in pufferfish functions by blocking the VOLTAGE GATED SODIUM CHANNELS in nerve cell membranes -- inhibits passive transport of sodium

Answer 135

recall CN III innnervates: all except superior oblique and lateral rectus fxn: adduction, depresison, elevation and external rotation _Lesion findings:_ eye deviated doward and laterally, diagonal diplopia, dilation of pupil and loss of accomodation, ptosis

Answer 136

Sulfonylureas bind to their receptors on pancreatic beta cells to inhibit the ATP-dependent potassium channels --\> alters cell's resting potential, allowing calcium influx and leading to exocytosis of insulin --\> insulin secretion oby beta cells independent of blood gluc levels thus, high risk of hypoglycemia risk.. risk increase with exercise, missed meals, chronic malnourshiment, organ dysnfuction or after a hospital admission all 2nd gen sullfonylureas are equally as effective to lower blood glucose levels BUT they have different durations of action Glyburdie and glimerpiride are long acting, and a higher incidence of hypoglycemia, espeically in the lederly! vs: glipizide is short acting thus lower incidence of hypoglycemia

Answer 137

alpha-glucosidase inhibitor --\> decrease intestinal glucose absorption and blunts the postprandial rise in serum glucose not associted with significant hypoglycemia

Answer 138

dipeptidyl peptidase 4 (DPP-4) inhibitor that decrease glucose utilization by peripheral cells and incerase beta cell insulin release effect is glucose-dependent!! thus effect diminishes as glucose levels approach normal --\> no big risk of hypoglycemia

Answer 139

Binds to PPAR-γ nuclear transcription regulator --\> increase insulin sensitivity by increasing glucose untilization and decreasing glucose production in adipose, muscle and liver. have been associated with CARDIAC side effects (HF) but do not cause significant hypoglycemia

Answer 140

embrypathy: congeital malformations (heart, neuro tube defects) placental vasculopathy: asphyxia, growth restriction, polycthemia increased fetal insulin: macrosomia, hypertrophic cardiomyopathy, hypoglycemia after birth (beta cell hyperplasia and hyperinsulinism --\> increasd fat deposition and enhanced fetal growth, resulting in macrosomia; req frequent feedings or parenteral glucose to prevent hypoglycemia and subsequent neurologic injry - most of the time, the hyperplasia willl resolve over time) Caudal Regression Syndrome Transposition of Great Vessels

Answer 141

Thiazides increase calicum reabsorption through 2 mechansims: 1. inhibit the Na+/Cl- contransporter on the apical side of the distal convulouted tubel --\> decrease intraceullar sodium --\> activated the basolater na/ca antipoter, whcih pumps Na into the cell and Ca out --\> decrease intraceullar caclium concentration, enhances teh lumina calcium reabsorption across the apical membrane 2. hypovolemia induced by thiazides increases Na+ adn H2O reabsorption in the proximal tubule, leading to a passive incrase in paraceullar calcium absorption --\> thiazides can help prevent stone fromation be decreasing urine calcium excretion indicated in pt with nephrolithiasis secondary to hypercalciuria adn contraindicated in hypercalcemia

Answer 142

Chronic rejection of lung transplant mostly affects the small airways, causing bronchiolitis obliterans. It is charactetrized by first a lymphocytic inflammation and destruction of the epithelium of the small airways subsequently, fibropurulent exudate and granulation tissue are found in the lumen of the bronchioli, which ultimately results in fibrosis, scaring and the progressive oblietration of small airways

Answer 143

aka: undifferentiated/oat cell CA 10-20% of malignant lung tumors strong association with smoking usually centrall located arises from primitive cells of hte basal layer of the bronchial epithelium ligh microscopy: round or oval cells with scant cytoplasm and large hyperchromatic nuclie; may resemble lymphocytes but typicall larger can form sheets or cluters, abundat mitosis could be seen to have secretory granules in cytoplasm immunohistochem stains are frequently positive for **neuroendocrine markers** (chromogranin, neuron-specific enolase, synaptophysin)

Answer 144

massive myoctye hypertrophy predominately affecting the septal region myofiber dissary (irregular arrangement of abnormally shaped myocytes with bizarre nuclei and areas of increased connective tissue)

Answer 145

Primary: muscle weakness, cardiomyopathy, hypoketotic hypoglycemia, elevated muscle triglycerides MCAD deficieny: hypoglycemia, hypoketotic hypoglycemia deficient synthesis of ketone bodies (acetoacetate) in the liver, decrease ATP generation from FA in cardiac and skeletal myocytes

Answer 146

Overlying skin retractions such as dimiling slignal invovlement of suspensory ligaments of teh breast (cooper ligament) --\> causing fibrosis and shortening, leading to traction on teh skin with distortion in breast contour most commonly with invasive breast carcinoma presenting with an irregularly shaped adherent breast mass

Answer 147

causes dull visceral pain at the umbilicus due to afferent pain fibers entering at the T10 level in the spinal cord. Progressive inflammation in teh appendix irritated the pareital peritoneum and abdominal wall to cause more severe somatic pain shifting from teh umbilicus to McBurney point. -- rebound tenderness is a "peritoneal sign"

Answer 148

isattributing one's own uncoscious, undesired thoughts or feelings to another person who does not actuall have them "a son is upset his parents are getting a divorce but he believes they are upset with him Projection is an immature defense mxn involving the malattribution of one's unacceptable feelings or thoughts to anothe rperson who does not actually have them vs displacemet = redirecting unacceptable thoughts, feelings and impulses inteded for one person to a more neutral person (if the son was mad at his sibling)

Answer 149

high lipophilicty high volume of distribution high CNS penetration

Answer 150

Reassortment only occurs in segmented viruses! Capable of genetic shifts via this mechanism it involved teh exchange of entire genomic segments --\>epidemics or pandemics; more dramatic process than the point mutations responsible for genetic drift ReCombination undergo Crosing over all viruses

Answer 151

orthomyxovirus reoviruses bunyaviruses arenavirues

Answer 152

second most common brain neoplasm in children located in the cerebellum, often times in the vermis and consist of small, blue cells like other PNET (primitive neuroectodermal tumors- sheets of small cells with deeply basophilic nuclie and scant cytoplams, abundant mitoses) tumors medulloblastomas are poorly differentiated and have a bad prognosis \*\*sheest of primitive cells with many mitotic figures\*\* undifferentiated and aggressive tumors clinical pres: gait instability, limb ataxia - symptoms of cellular involvement, increased intracranial pressure (morning headaches, vomiting lethary)

Answer 153

Linezolid (used to tx infections caused by gram-positive bacteria, particularly vancomycin-resistant enterococcus and methicillin-resistant S. Aureus) has MAOI activity thus can precipitate serotonin syndrome when used cocomitantly with an SSRI Serotonin syndrome is characterized by a triad of autonomic instability, alt metal status, neuromuscular irritability MAOI or non-antidip with MAOi activity (linezolid), with serotonergic med: SSRI, serotonin-NE reputake inhibitor or TCA

Answer 154

excessive exposure to UVA wavelenths and is characterized by epidermal atropy with flattening of rete ridges additionally, there is d**ecreased collagen fibril production** and **upregulation of matrix metalloproteinases (including collagenases) --\> increased degradation of collagen** **and elastin in the dermis** atrophic dermis and _increased collagen crosslinking_, along with desiccation of the stratum corneum, produce the characteristic wrinkling of photoaged skin

Answer 155

middle geniculate artery injuries are characterized by rapid-onset hemarthrosis and knee swelling

Answer 156

gestational trophoblastic disease A complete mole usually results when an empty ovum (no x, no y) is fertilized by a haploid sperm --\> then there is duplication of the paternal genetic complement resulting in characteristic 46,xx genotype (YY has not been observed; and less commonly 2 sperm can fertilize an empty ovum to create a 46, XY) - no fetal structures - composed of large, edematous, disorderd chrionic villi that appear grossly as clusters of vesicular structures "bunch of grapes" - high b-hCG, due to trophoblastic hyperplasia - ultrasound demonstartes a central heterogenous mass with multiple cystic areas and is classically described as a "swiss cheese" or "snowstorm" pattern rf: gestational age, prior molar pregnancy, prior miscarriage or infertility

Answer 157

produced by helper T cells adn stimulates growth of CD4+ and CD8+ T cells and B cells. activates NK cells and monocytes increased activity of T cells adn natural killer cells is thought ot be responsible for IL2's anticancer effect on metastatic melanoma and renal cell CA.

Answer 158

high-O2 affinity hemoglobin mutations reduce the ability for hemoglobin to release oxygen in the tissues --\> low perfusion of the kidney, stimulate to increase erythropoietin synthesis, which results in a compensatory erythrocytosis that helps maintain oxygen delivery

Answer 159

Ebstein anomaly is characterized by apical displacemet of hte tricupsid valve leafets, decreased volume of the right ventricle and atrilization of the right ventricle caused by gestation use of lithium lithium is used to treat bipolar disoder, acute mania, hypomania, bipolar and unipolar depression

Answer 160

neutropenia incidence increased when co-administered with zidovudine or trimethoprim-sulfamethoxazole

Answer 161

competitively bind iron present in heme protiens, with a higher affinity than oxygen --\> carboxyhemoglobin any remaining site opened for oxygen to bind will have increased oxygen affinity --\> leftward shift of oxygen dissociation curve, impeding oxygen delivery to tissues. CO can also bind cardiac myoglobin --\> imparied use of oxygen and decrease cardiac output CO binds cytochrome oxidase, inhibiting aerobic metaboilsm adn exacerbating tissue hypoxia tx: high-flow or hyperbaric oxygen therapy

Answer 162

First-generation antihistamine are signed to relieve allergic symptoms BUT have can have prominent side effects due to blockade of other receptors, includign alpha-adrenergic, serotonergic and cholinergic receptors anticholinergic effects on the ocular ciliary muscle impair accomodation and cause blurring of visison for close objects

Answer 163

ciliary muscle attaches to the lens via the zonular fibers contraction of the muscle reduces tension of the fibers --\> allowing the lens to becoe more spherical and increase its refractive power ciliary muscle is under teh parasympathetic control from teh Ediner-Westphal nucleus/ciliary ganglion light comes in, synapses on the pretectal nucleulus --\> synapses on each of the edinger-westphal nucleus --\> ciliary ganglion to synpase on ciliary muscle inhibting the parasympathetic agents limit accomodation adn cause blurring of vision for close objects (pupillary sphinceter also receives parasympathetic innervation from teh edinger-westphal nuclues -- pt on antimuscarinic agents may have mydriasis/pupillary dilation as well

Answer 164

pudenal nerve provides motor and sensory innervation to the perinal region it originates from ventral rami S2-S4 and passes between the piriformis and coccygeus muscles as it exits the pelivs through the greate sciatic foramen, then reenters the pelvis near teh ischial spin through the lesser sciatic foramen prior to dividing into its termianl branches sensory branches innervate the external genitalia as well as teh skin around the anus and perinuem motor branches innervate the peliv floor muscles as wellas teh external urethral and anal sphinceters \*\*vulnerable to stretch injury, due to its curved course around the ischial spine\*\* sx: fecal and urinary incontinence, perineal pain and sexual dysfunction

Answer 165

Lower abdominal arteries followed by the coronary arteries, popliteal arteires, internal cartoid arteires adn the circle of willis

Answer 166

may develop elevated plasma levels of citrate (a substance added to store blood)...citrate chelated calicum and mangesium, and may reduce their plasma levels --\> **paresthesias**

Answer 167

due to molecular mimicry: anti-group A strep antibodies attach host antigens on cardiac and neuronal tissue approx 2-4 weeks acter acute pharyngitis clinical featuers: JONES critera Joints - migratory arthritis O - pancarditis, mitral regurg N -nodules E- erythemam margiatum S -sydenham chorea anti-group A strep antibodies (anti-M protein, anti-N-acetyl-beta-D-glucosamine) cross react and attack cardiac and CNS antigens prevent with promt treatment of strep pharyngitis w/**penicillin**

Answer 168

almost all increase cerebral blood flow --\> could result in increased ICP other impt effects of inhalation anesthetics are myocardia depression, hypotension, respiratory depression and decreased renal function

Answer 169

confounding = exposure-disease relationship is muddied by the effect of an extraneous factor that has correlations with boht the exposure and the disease; it can result in the false association of an exposure with a disease * confounding effects can be negated by running separeate analyses for the smokers and non-smokers - both have an RR close to 1; larege pvalues suggest small difference in RR from the null value is due to chance alone --therefore the RR disappears an dno true association (**stratified analysis**)* * ie) increased alcohol use is associated with increased smoking, and perhaps not alcohol alone leads to increase in bladder cancer in people who use alcohol* Effect modification results when an external variable positively or negatively impacts the observed effect of a risk factor on disease status -- stratified analysis will reveal a significant difference in risk between the stratified groups p-values \>0.05 ie) smoking would modify the effect of alcohol consumption on bladder cancer

Answer 170

Lung absences usually have a presentaiton of indolent symptoms, fever, night sweats, wt loss and a cough productive of foul-smelling sputum (indiciative of anaerobes); usually there is a vacitary lesion with identifiable air-fluid level on imaging RF: anything that increases aspiration risk - alcoholism, drug abuse, seizure disorder, stroke, dementia, prolong anesthesia, severe neurologic diseases MOA: 1) oropharyngeal aspirations most common cause - watch for mixed aerobic and anaerobicm oral flora in the absecess (peptostreptococcus, prevotella, bacteroides, fusobacterium sp) anything that is associated with increased aspiration puts ppl at riks, loss of consciouness or dysphagia 2) lung abscess may occur as a complication of bacterial pneumo. predisposing facotrs - immunocompromised, old age, nderlying chornic lung disease; necrotizing pneumonias are usually nosocomial and caused by A. aureus, E.coli, Klebsiella, pneumo and pseduo 3) in with septicemia or infectious endocarditis,

Answer 171

temporal - granulomatous inflammation of the media both invovle arterial vessesl of different sizess and locations (aorta and proximal aortic arterial branch invovlement vs more distal carotid artery branch invovlement, respectively) and have diff clinical presentaitons they both have common pathologic morphology: granulomatous inflammation of the media

Answer 172

agenesis of the sacrum and occasionally lumbar spine and experience resultant flaccid paralysis of hte legs, dorseflexed contractures of the feet and urinary incontinence can range from isolated anal atresia --\> sirenomelia rare 1:60,000 births related to poorly controlled maternal diabetes

Answer 173

can cause craniafacial abnormalities, psoterior fossa CNS defects, auditory defects and abnormalities of the great vessels (similar to those in DiGeorge Syndrome)

Answer 174

blanching of a vein into which NE is being infused together with induration and pallor of the tissues surrounding the IV site are signs of NE extravation **NE leak causes intense alpha 1 receptor mediated vasoconstriction, which can lead to local tissue necrosis** Necrosis can be prevted by infiltration throughout the affected area with 10-15 cc of sodium chloride solution containing 5-10 mg of phentolamine mesylate, an alpha receptor blocker --? must be given within 12 hours of extravation to be effective \*\*phentolamine / other alpha receptor blockers lead to vasodilation, countering the alpha1 receptor mediated vasoconstriction of NE \*beta receptor activation will not be effective because these receptors are not found in subcutaneous tissue blood vessles as compared to alpha 1 receptors; beta are more likely found in striated muscle, renal and mesenteric vascular beds

Answer 175

In the lungs = haldane effect oxygenation of Hb promoates teh dissociation of H+ from Hb; this shifts teh equilibrium towards the formation of CO2 --\> CO2 is released from RBC at the lung (chloride shift IN!) In the periphery = bohr effect increased hydrogen from the tissue metaolism shfits curve to the right, unloading O2

Answer 176

thiazide diuretics NSAIDS (except aspirin) ACE inhibitors toxicity: ACUTE - GI, late neurologic sequela CHRONIC - confusiong, agitation, ataxia, tremors/fasiculations

Answer 177

results from trauma to teh sterociliated hair cells of the organ of corti. acoustic refelx normally dampens the effects of loud noise by causing the stapedius and tensor tympani muscles to contract, which lessens the responsiveness of hte ossicles to sound. HOwever, prolong noise exposure can cause distortion or fracture of the sterocilia due to shearing forces against the tectorial membrane. High frequency hearing is lost first, reglardss of the freq of teh sound causing the damage [hearing loss due to the auditory nerve is most commonly due to an vestibular schwannoma; pt develop high freq sensorineural hearing loss, but symptoms are usually unilateral]

Answer 178

dendritic cells found in the skin that act as professional antigen presenting cells they are derived from the *_myeloid cell line_* and they possess characteristic **racquet-shaped intracytoplasmic granules** known as **Birbeck granules**

Answer 179

COnduct disorder, the problem behaviors are more severe and agressive. In conduct disorder, often there is physical aggression or cruelty towards people or animals, destruction of property or the typical pattern of stealing or deceit seen in conduct disorder. Think of violations of the basic rights of other sseen in conduct disorder ODD, may precede the development of conduct disorder and increases the risk of adult antisocial behavior, impulse-control problems, substance abuse, anxiety and depression. pattern of angry/irritable mood, argumentative anddefiant behavior for more than 6 months oppositional behaviors must be excessive compared to normative age-apprpriate behaviors and observed during interactions with individuals other than siblings

Answer 180

1. Toxo give pyrimethamine and sulfadiazine (+leucovorin/folinic acid) or use clindamycin if sulfa drug hypersensitivity 2. Primary central nervous system lymphoma **diffuse, large-cell non-hodgkin lymphoma of B-cell** origin that usually cocurs as a late complication of HIV infeciton; EBV is identified in almost all cases + EBV polymerase PCR in CSF is diagnosis

Answer 181

Hypernatremia and pedal edem are rarely observed in PH due to the phenomenon of **aldosterone escape** The high aldosterone levels lead to increased intravascular volume and therefore cause increased renal blood flow with resulting **pressure natriuresis and augmented release of ANP** --\> results in increased sodium excretion by the renal tubules, which limits net sodium retention and prevents the development of overt volume overload and significant hypernatremia.

Answer 182

serum TSH (often times will rise before low thyroid hormone level is seen) important exception - TSH will not be elevated in pt with secondary or tertiary (central) hypothyroidism. Central hypothyroidism is uncommoon an dpt usually have other clinical features that suggest hypothalamic or pituitary dysfunction symptoms of hypothyroidism: fatigue, bradycardia, wt gain, constipiation, slowed relaxation of deep tendon reflexes

Answer 183

fever, rash, methemoglobinemai dapsone also can put oxidative stress on the body ,so G6PD levels should be checked before administrating dapsone in order to prevent hemolytic anemai in pt with this enzyme deficiency

Answer 184

1. infections 2. drugs - dapsone, antimalarials, TMP-SMX 3. diabetic ketoacidosis 4. favos, (ingestion of fava beans) note: anemail, reticulocytosis, jaundice and dark urine can occur; red cell fragments, microps

Answer 185

Osteoporisis is characterized by decrease bone strengt from low bone mass and microarchitectural deterioration of bone tissue but normal bone mineraliztion. Increased susceptibility to fragility fractures (minimal to no trauma). in primary osteoporosis (not caused by a medical disorder), **serum calcium, phosphorus and parathyroid hormones levels are NORMAL!**

Answer 186

beign tumor composed of blood vessels, smooth muscle adn fat bilateral renal angiomyolipomas are assocaited with tuberous sclerosis (autosomal dominant)

Answer 187

Methimazole and propylthiouracil DEC teh formation of thyroid hormones via i**nhibition of thyroid peroxidase**, the enzyme responsible for both *_iodine organification and coupling of iodotyrosine_* PTU also decreases the peripheral conversion of T4 -- T3

Answer 188

DNA pol I: - proofreading: 3'-5' exonuclease activity - DNA repair: 5'-3' polymerase activity - RNA primase removal: 5'-3' exonuclease activity DNA pol II: - DNA repair: 5'-3' polymerase activity DNA pol III: - DNA synthesis: 5'-3' polymerase activity - proofreading: 3'-5' exonuclease activity ONLY

Answer 189

Meiotic nondisjunction (95%) - extra copy of chrome 21 present in every cell; based on maternal age Unbalanced translocation/robertsonian - all or part of additional chrome 21 attached to another chrome; high if balanced translation is presnet in one parent Mosaicism - some (not all) cells have an extra copy of chrome 21; nondisjuntion event in early embryonic life; based on maternal age

Answer 190

when a person receives 2 copies of a chromosome from teh same parent and no copy from the other parent

Answer 191

most toxic antifungal med most dangerous toxicity is nephrotoxicity -- due to both a decrease in glomerular filtration rate adn direct toxic effects on the tubular eipthelium --\> anemia (dec erythropoietin production), electrolyte abormalities such as hypokalemia, and less often hypomagnesmi due to an increase in the membrane permeability of the distal tubule hypokalemia --\> weakness and arrhytmias ECG findings in hypokalemia include T wave FLATTENING, ST seg depresison prominent U waves, premature atrial and ventricular contractions. Profound hypokalemia can cause ventricular tachycardia or fibrillation

Answer 192

Intestinal type: forms solid mass that projects into the stomach, composed of glandular forming cubodial or columnar cells Diffuse carcinoma - linitis plastica, infiltrates teh stomach wall and displays signet ring cells on light microscopy

Answer 193

-micin's are the amingoglycoside drugs bacteria could form resistance by aminoglycoside-modifying enzymes that transfer different chemical groups (acetyl groups, adenyl groups, phosphate groups) to AGs molecule outside the bacterium, decreasing the ability of the AG to bind to ribosomes and exert its antimicrobial effects - it is acquired resistance mediated by plasmids or transposons NOT chromosomally mediated

Answer 194

Unit of analysis is POPULATIONS not individuals the frequency of a given characteristic and a given outcome are studied using population data! useful to generate hypotheses but should not be used to make conclusions regading indivudals within these populations (ecological fallacy)

Answer 195

Start with cohort studies in which participants are followed over time, and those participates who develop an outcome of interest become cases for a case-control study

Answer 196

caused by secretion of parathyroid hormone-related protein (PTHrP), closely resembles PTH at the bioactive amino-terminal region. PTHrP causes increased bone resorption and decreased renal excretion of calcium - no focal bone lesions - very servere, serum calicum levels are usually higher than in primary hyperparathyroidism alone - complications: polyuria, nephorlithiasis, GI and neuropsychiatric symptoms 80% of malignancy-induced hypercalcemia tumors: squamous cell cancers ( lung, head, neck, esophagus) renal and bladder ovarian and endometrial breast CA [can also occur in CA pt due to ostelytic bone mets, excess prod of 1,25-hydroxvit D or rarely ectopic PTH secretion]

Answer 197

latex agglutination test detects polysach capsule antige of Crypto, used for diagnosis India ink staining of CSF shows round or oval budding yeast culture (sabouraud's agar) Methenamine (GMS), mucicarmine stains of tissue tx: amophtericin B + flucytosine (acute meningitis) Fluconazole for lifelong prophylaxis \*\* C. neoformans casues meningoencephalitis in HIV+

Answer 198

Vitamin B7 essential for **carboxylase** enzymes CO2 carrier impt role in carboyhydrate, lipid and AA metabolism deficiency sx: nonspecific, changes in mental status, myalgias, anorexia, chronic dermatologic changes such as macular dermatitis; can also develop metabolic acidosis as a result of increased conversion of pyruvate to lactic acid associated with excess ingestion of avidin, found in egg whites

Answer 199

fluid filled cavity in the liver + fevers, chills, right upper abdominal paint --\> heaptic abscess In UNDERdeveloped countries -- relatively high incidence, primarily caused by parasitic infections (Entamoeba histolytica - scending from teh colon through the portal venous systmem since its a foodborne parasite, echinococcal) In DEVELOPED countires, hepatic absceens are uncommong, caused by bacterial infection (S. aureus via hematogenous spread, gram negative bacilli from enteric route/ascending cholangitis, mixed aerobic and anaerobic flora from penetrating trauma)

Answer 200

**AVOID when possible benzodiazepines, antihistamines and sedating antidepressants for the use of insomnia in the elderly due to their adverse effects.** For initial mgmt: non-pharacologic intervents - sleep hygiene, CBT Pharmacologic can be considered shorte term - **Ramelteon** (melatonin agonist, bind to melatonin R in the suprachiasmatic nucleus - sale for older adults!)

Answer 201

peptide framgent that is bound the the MHC II antigen binding site acts to guide the molecuing during sortin gin the golig and occupies the site until teh molecule enters an acidified endosome where it can bind foreing porinte. FUsion of the vesicle contianing MHC Class II to the acidified phagolysosomes contianign foreign antigen molecule leads to the degradation of the invariant chain and loading of antigen onto the MHC class II [withouth lysosomal acidification, antigen processing in associated MHC class II antigens won't occur, and the MHC class II would be unable to bind antigen and thus bind TCR for activaiton]

Answer 202

occurs when the neural tube fials to fuse in the region of the anterior or posterior neuropores @4th week This leads to a persistent communication betwen the spinal canal and amniotic cavity leakage of alpha-fetoprotien and acetylcholinesterase occurs, which allows for prenatal diagnosis of NTDs **_HIGH AFP_ and _Acetylchonlinesterase_ appear in amniotic fluid adn also elevated in maternal serum** **both used for prenatal diangosis of NTDS**

Answer 203

Down's syndrome and other chromosomal abnormalities down = afp is down

Answer 204

decreased calcium increased serum PTH (secondary hyperparathyroidism) decreased phosphorous (dec absorption @ GI and increased secretion @ kidney due to PTH) sx: bone pain, muscle weakness

Answer 205

vasoconstriction of efferent arteriole (up to an exent) --\> increased hydrostatic pressure in the gomerula capillaries --\> INC GFR FF always increases with increasing efferent arteriole constriction! efferent arteriolar constriction also reduces renal plasma flow RPF FF = GFR / RPF \*\* note when RPF is so low, that is secondary to SEVERE efferent arteriolar constriction, the flow becomes so slow that there is an increase in capillary hydrostatic pressure and capillary oncotic pressure begins to oppse --\> substantially increased capillary oncotic pressure results in an overall decrease in GFR

Answer 206

**protein: 1 g --\> 4 calories of energy** **carbohydrates: 1 g --\> 4 calories of energy** **fat: 1 g --\> 9 calories of energy**

Answer 207

Enkephalins, endorphins, dynsorphins are endogenous opioid peptides part of our body's natural sysmte, released in response to noxious stimuli and bind to different opiod receptors to allow physiologic modulation of pain Different types... beta-endorphis is one that is dervied from proopiomelanocortin (POMC) recall that this is a polypeptide repcursor that goes through enzymatic cleavage and modification to produce not only beta-endorphins but also ACTH and MSH *there may be a close physiological relationship between teh stress axis and opioid system*

Answer 208

agitation, disorientaiton, pharyngospasm and photobonia --\> coma, death w/ nonspecific, flu-like prodrome, followed by an acute neurologic syndrome taht includes agitation, persistent fever, variable consciousness, photophobia, and painful spasms with swallowing and/or inspiration pharyngeal muscle spasms --\> dysphagia dysphagia + hypersalivation due to autonomic dysfunction "mouth foaming" generalized FLACID paralysis and coma follow the acute neurologic phase, with most pt dying within 2 weeks of becoming comatose rabies are SS RNA virsues envelped by a bullet shaped capuse- which is studded by glycoprotein spikes that bind to nicotinic acetylcholine receptors. bding to acetylcholine R on peripheral NS axons and travel retrograde to the central CNS \*\*once the sxs of rabies encephilits appear, post-exposure prophylais is no longer effective\*\*

Answer 209

**Heteroplasmy** - variable degrees of severity dependent on the variablity of the distributio ofmitochondrail between the daughter cells; exclusively inherited from one's mother Mitochondrial syndromes: - leber hereditary optic neuropathy --\> bilateral vision loss - Myoclonic epilepsy with ragged-red fibers --\> myoclonic seizures and myopathy associated with exercise; skeletal bipsy shows irregular shaped muscle fibers / ragged red fibers - mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS): sezisure disorder with stroke like episdoes + neurological deficits; muscle weakness, inc lactate levels at rest and post-exercise

Answer 210

human placental lactogen (hPL) decreases maternal fatty acid stores and increases maternal serum glucose in order to provide adequate glucose to the growing fetus. The actions of hPL result in physiologic insulin resistance in the latter half of pregnancy - usually seen second and third trimesters due to shunting of carbohydrate metabolism toward supplying glucose and amino acids to fetus **- insulin resistance isn primarily due to action of hPL aka chorionic somatomammoropin, a peptide hormone secreted by the syncytiotrophoblast** insulin resistance leads to increased gluocse levels in maternal circulation - glucose can freely cross into fetus and is continuously consumed for fetal energy maternal lipolysis and protelysis are also increasd by hPL hPL also stimualtes pancreatic beta cell insulin porduction --\> gestational diabtes mellitus results when the pancreatic funciton is not sufficient to overcome the pregnancy-related icnrease in insulin resistance \*\*gestational diabetes is more accurate third trimseter doen via orgal glucose

Answer 211

The ureters pass posterior to the gonadal vessles within the retroperitoneum (water under the bridge) and **anterior to the common/external iliac arteries to reach the true pelvis**-- within the true pelvins, the ureters lie antoerior to the internal ilial artery and medial to the gonadal vessels. The uterine artery crosses over teh anterior surface of the ureter (water under teh bridge)

Answer 212

glucose enters beta cells by facilitated diffusion via glucose transport 2 - (glucose + glucokinase --\> G-6-P) undergoes oxidative phosphorylation --\> increases ATP ATP --\> binds to ATP-sensitive K+channel (K+ in normalluy exiting the cell) --\> CLOSES CHANNEL --\> decreaes K+ efflux =\> membrane depolarization --\> opening of VG-calcium channels --\> increased calcium --\> exocytosis of insulin

Answer 213

**Vitamin B6 ---\> active form pyridoxal 5' phosphate via pyridozine phosphokinase** --\> pyridoxal 5' phosphase is a co-factor for **gamma-aminolevulinic acid (ALA)** synthase, which is the first enzyme that catalyzes the rate limiting step in heme synthesis \*\***isoniazid** is a direct inhibitor of the activation of vitamin B6 --\>sideroblastic anemia microcytic hypocrhomic anemia iron is transported to developing erythrocytes that are developing but cannot form heme, thus iron accumulates around the nuclues --\> ring siderblasts pyridoxal 5' phosphate is a co-factor for numerous enzymes thus it can also lead to: dermatitis, stomatitis, neuropathy, confusion

Answer 214

schizoid = longer, detached, unemotional schizotypal - eccentric, odd thoughts, perceptions and beavhior; magical thinking, superstitiouness and odd perceptual disturbances that are sub-threshold for a psychotic disorder; do not experience the persistent, fized delusions or frank hallucinations seen in schizophrenia. rarely sustain close interpersonal relatioships due to excessive social anxiety that does not diminish with familiarity

Answer 215

first line: **carbamazepine** others: baclofen, valproic acid - not first line!

Answer 216

Due to the fact that the virion-encoded RNA-dependent RNA polymerase has **NO proofreading 3' --\> 5' exonuclease acivity** --\> *_many errors during replication_* *_variant strains differ primarily at hypervaribale genomic regions, such as those encoding glycoproteins;_* **Prevents host antibodies from mounting an effective immune response**

Answer 217

Best are antimuscarinic agents and antihistamine with antimuscarinic action perception of motion and orientation is determined by input from the vestibular, visual and somatosensory systems -- conflicting info from teh 3 cause --\> motion sickness integration of tehse sensory pathway occurs in the **vestibular nuclei** via muscarinic M1 and histaminic H1 neurotransmission side effects: **blurry vision, dry mouth, urinary retention and constipation**

Answer 218

= find positive predictive value \*PPV varies with disease prevalance (unlike specificity and sensitivity)

Answer 219

RIght drains directly to the IVC Left drains first to the left renal vein then the left real vein IVC

Answer 220

Kaposi sarcoma typically presents as blue-violet or brownish skin plaques on the extremities and mucous membranes of HIV-positive patients. This tumor arises from **primitive mesenchyma cells** and is strong associated with **HHV8**

Answer 221

readioactive material such as iodine-131 can be released into the environment following nuclear reactor accidents, breach of contaimnet waste disposal or atomic bomb blasts... non reactive radioactive iodine is preferentaily taken up and concentrated within the thyorid gland -- an lead to hypothyroidism and thyroid carcinoma give POTASSIUM IODINE prophylactically to protect the thyroid from excessive accumulation of radioactive 131I competitively inhibits thyroid uptake of radioactive iodine isotopes and is often administered following nuclear accidents to protect the thyroid and prevent development of radiation-induced thyroid CA (prevents from entering thyroid follice cells - large increases in serum iodine levels also inhbit iodine organification Wlff-chaikoff effect and reduce thyorid hormone releease

Answer 222

The best and most reliable auscultatory indicator of the degree of mitral stenosis is the A2-opening snap interval (becomes shorter because atrial pressures increase with severity; measurement of transvalvular pressure gradients via 2D doppler echocardiograph is a means to diagnose MS severity) shorter intervals = more severe stenosis other auscultatory findings can include diastolic rumbling murmur with presystolic accentuation due to left-atrial contraction

Answer 223

enlarged cells with basophilic or eosinophilic *_**INTRANUCLEAR** inclusion bodies_* sx: odynophagia (pain with swallowing) or dysphagia (difficulty swallowing) and can be accompanied by fever or buring chest pain if CMV esophagiits [think of immunocompromised pt]

Answer 224

small cell lung CA, breast, ovarian and uterine CA Etiology: Anti-Yo, anti-P/Q, anti-Hu antibodies sx: progressively worsening dizziness, limb and trucal ataxia, dysarthria and visual disturbances + cerebellar symptoms due to an immune response agasint tumor cells that cross-reacts with purkinje neuron antigens --\> acute-onset rapid degeneration of teh cerebellum *paraneoplastic cerebellar degeneration is diagnosed clinically after exclusing other conditison since antibodies are not always detectable*

Answer 225

presentation: intracranial, GI, cutaneous, umbilica and surgical site BLEEDING etiology: LOW vitamin K stores at birth (poor placental transfer, sterile guyt, low content in breast milk), neonatal liver cannot use vitamin K efficienty (usually vitamin K is given at birth because of those reasons! but parents could refuse and could lead to this!)

Answer 226

essential co-factor for gamma-glutamyl carboxylase, enzy responsible for conversion of glutamyl residues for gamma-carboxyglutamates. Carboxylation is critical for the function of clotting factors II (prothrombin), VII, IX, X as it allows for the creation of calcium-binding sites. THe calicum binding sites attract the clotting factors to negatively charged phospholipds on platelets and endothelial cells, encouraging coagulation and thrombin formation

Answer 227

ACE inhibitors then ARBS reduce the risk of CKD ACE inhibitrs additionall raise levels of bradykinin (by blocking ACE, which normally degrades bradykinin), thus inhibition leads to increased levels of bradykinin and substance P --\> nonproductive cough (not seen in ARBs)

Answer 228

live attenuated vaccines generally produce stronger immune response than killed by acting as a persistent stimulus that better activates helper and cytotoxic T cells THsu live attenualted orgal vacciens generate a much more robus oropharyngeal and interstial mucosal IgA response thatn intramusucalr inactivates vaccines [oral sabin vs inactivates Salk]

Answer 229

SECRETORY IgA is the major ab associated with mucosal immunity upon exposure to antigen, B cells fond in Peyer's patches and mesenteric lymph nodes become activated and preferentially migrate to the lamina propria underlying the interstinal mucosa --\> become fully differentiated plasma cells that begin to synthesize IgA dimers (linked by J chain)...IgA dimers then bind the polymeric immunoglobulin receptor (plgR) found on teh basolateral

Answer 230

Modafinil non-amphetamine stimulant MOA is is not well described but it is thought to enhance dopaminergic signaling Amphetamines are second line agents due to their sympathomimetic side effects (HTN, arrhythmia, psychosis) and risk for dependence

Answer 231

TLS developes due to rapid cell turnover and high sensitivity to chemotherapy. When a large amount of cells are destroyed --\> ions, such as potassium, phosphorous, uric acid (a metabolite of tumor nucleic acids) are released into the serum and are then filtered by the kindey... Uric acid is soluble at physiologic pH but precipitates in acidic environment --\> lowest pH in the nephron is at the distal tubules and collecting ducts thus tehse are the segments of the nephron that can become obstructed by ric acid crystals --\> obstructive uropathy and actue renal failure Prophylaxis: urine alkalinization and hydration allopurinol can be used to reduce uric acid production during breakdown of tumor cells

Answer 232

tumors of **PARAFOLLICULAR CALCITONIN-secreting C-CELLs** spindle shaped cells in an amorphous background 80% sporadic, 20% familial (MEN 2 syndrome) germline **RET** *_proto-oncogenes codes for a membrane-bound tyrosine kinase receptor_* involved in cell cycle regulation

Answer 233

Activating mutations at the KRAS gene lead to constitutive activation of the epidermal growth factor receptor (EGFR) pathways, promoting increased cell proliferation adn growth tumors harboring these mutations are resistant to chemotherapy with anti-EGFR drugs (cetuximab, panitumumab)

Answer 234

inhibiting MATURE osteoclast-mediated bone resportion chemical structure similar to pyrophosphate and attach to hyroxyapatite binding sites on bony surfaces - thus osteoclast that resorb the bone take up the bisphosphonate and are unable toa dhere to more bony surfaces to continue resorption - decrease osteoclast activity - induce osteoclast apoptosis - decrease teh development/recruitment of osteoclast precursor cells slow bone loss and some pt may experience small increase in bone mineral density

Answer 235

MG - fluctuating weakness that WORSENS over the course of the day and most often involved the extraocular and bulbar (chewing, dysphagia) muscles --\> decreasing force of muscle contraction with repetitive stimulation [most pt have thymic abnormalities which may appear as an anterior mediastinal mass on chest imaging] Lambert-eaton: presents with proximal extremity weakness that IMPROVES with USE [small cell lung CA due to antibodies direct agasint presynaptic calcium channel, which causes reduced acetylcholine release]

Answer 236

a type of pneumoconioses, mostly asymptomatic but can present with dyspnea on exertion and productive cough 10-20 years after initial exposure Distinguished by calcification on the rim of hilar nodes (eggshell calcificaiton) and birefringent silica particles surrounded by fibrous tissue on histology

Answer 237

**LINEAR RATHER THAN SPIRAL** development during septation of the truncus arteriosus of the aorticopulmonary septum in utero, resulting in an anteriorly positioned aorta connected to the right ventricle and a posteriorly positioned pulomnary artery connected to the left ventricle --\> pulmonary and systemic circulations are abnormally separated and exist as 2 paralel circulations incompatible with life unless other connection ie)PDA

Answer 238

NL: PT, aPTT and platelet count with PROLONG BLEEDING TIME example: uremic toxins accumulate due to significant renal dysfunction -- impairing platelet aggregation and adhesion --\> qualitative platelet disorder