Pathophys Miscellaneous Flashcards
What is hyperkeratosis and give at least one skin condition it occurs in?
Increased thickness of stratum corneum
-> psoriasis
What is parakeratosis and give at least one skin condition it occurs in?
Hyperkeratosis with RETENTION OF NUCLEI in the stratum corneum
-> psoriasis
What is hypergranulosis and give at least one skin condition it occurs in?
Increased thickness of stratum granulosum (Granular layer, 3rd layer)
-> lichen planus
What is spongiosis and give at least one skin condition?
Epidermal accumulation of edema fluid in intercellular spaces (will see spaces between stratum spinosum)
-> occurs due to allergic inflammation, especially eczema (atopic dermatitis) or allergic contact dermatitis
What is acantholysis and give at least one skin condition?
Separation of epidermal cells, especially in the spinosum layer (acantho = spiny, like spur cells in hematology)
-> Pemphigus vulgaris
What is acanthosis and give at least one condition?
Hyperproliferation of epidermis leading to increased spinosum layer
- > acanthosis nigricans -> thickened skin
- > acanthosis also occurs in psorasis
What type of inflammation is most specific for multiple sclerosis?
Perivenular inflammatory infiltrates with autoreactive T cells and macrophages. This occurs due with breakdown of BBB, but not destruction of the blood vessel. #919
How do OCPs work and how do they affect your risk of ovarian cancer?
Work by giving exogenous supply of estrogen -> FSH release by the pituitary is inhibited. Thus, the follicle never develops and cannot be stimulated. LH surge never occurs because estrogen supplied is not high enough to induce this positive feedback mechanism.
Ovarian surface epithelial cancer risk is decreased because less ovulation -> less rupture of ovary surface.
What is the function of the Purkinje cells of the cerebellum?
Only cell involved in the output of the cerebellar cortex
- > they are inhibitory “PurkINje” to the deep nuclei of the cerebellum
- > when the deep nuclei are not inhibited, that send glutamate neurons out of the cerebellum
What are the three structures which communicate with the cerebellum called / where do they hook up? What is the most inferior one also called?
Superior cerebellar peduncle - Attaches to midbrain
Middle cerebellar peduncle - attaches to pons
Inferior cerebellar peduncle - attaches to medulla. Also called the “restiform body”
What is the juxtarestiform body?
Axons which run from the vestibular nuclear complex (at the junction of rostral medulla / caudal pons) to the vestibulocerebellum / spinocerebellum (involved in regulation of vestibular system).
Called juxtarestiform because it runs near the ICP (“restiform body”).
What are archicerebellum, paleocerebellum, and neocerebellum also called? Their function?
Archi = vestibulocerebellum, the oldest one. Includes fastigial nucleus as well as flocculonodular lobe and uvula. Maintains equilibrium with medial most trunk muscles + help from LVST/MVST of vestibular system.
Paleo = Spinocerebellum -> includes globose and emboliform nuclei, coordinates trunk and proximal limb flexor activity thru red nucleus / rubrospinal
Neo = Lateral zone -> includes dentate nucleus, projects to VL thalamus to synergize skilled movements of digital / appendicular muscle
What portion of the hypothalamus primarily control the parasympathetic vs sympathetic nervous system?
parasympathetic -> chills you out and cools you down. Think A/C -> Anterior nucleus of the hypothalamus
Sympathetic is just the opposite -> heats you up when active. Posterior nucleus of hypothalamus.
What will stimulating the anterior vs posterior hypothalamus do?
Anterior -> cools you down. Stimulates vasodilation / sweating (parasympathetic)
Posterior -> heats you up. Stimulates vasoconstriction, shivering (sympathetic)
How does melatonin and the suprachiasmatic nucleus work?
Exact mechanism is unknown, but generally the SCN projects to the pineal gland via norepinephrine. It’s rate of firing dictates melatonin release, which feeds back on the SCN to inhibit its firing. Higher melatonin levels = lower firing rate of SCN to other nuclei = decreased wakefulness. A major afferent to the SCN is also light.
What are the waveforms on EEG in wakefulness, Stage 1 NREM, Stage 2, stage 3, and REM sleep?
Awake, eyes open - Beta (concentrating) Awake, eyes closed - Alpha Stage 1 - Theta / alpha Stage 2 - Spindles and K complexes within Theta background Stage 3 - Delta (slow wave) REM - Beta
BATS Drink Blood
What’s the mnemonic for the layers of the spermatic cord?
ICE tie
Internal spermatic fascia = transversalis fascia derived
Cremasteric muscle and fascia = internal oblique
External spermatic fascia = external oblique
Internal / external mean deep / superficial inguinal ring
How is cranial nerve 3 affected differently if damaged due to ischemia vs compression?
PANS fibers controlling pupillary reflex and accommodation are on outside
Motor fibers controlling LPS / muscles are located centrally.
Ischemia - i.e. diabetic nephropathy -> central motor fibers affected first. Eyes will be down and out with normal pupillary reflex / accommodation
Compression - periphery affected first -> initial loss of pupillary constriction before down and out gaze. I.e. due to Posterior communicating artery aneurysm or uncal herniation.
What type of brain hemorrhage does cerebral amyloid angiopathy typically cause?
Lobar hemorrhages, especially in the elderly. These are intraparenchymal hemorrhages located more superficially in the cortex, especially in the occipital lobes #499
Can an optic tract lesion cause a pupillary light reflex defecet?
Actually yes -> there will be a RAPD showing “dilation” on flashlight test when the light is shone in the eye contralateral to the lesion since photoreceptors on the nasal side contribute disproportionately to the reflex
How does Hep A often present in adults?
Often presents as prodrome of fever and anorexia, followed by jaundice symptoms that make it mimic extrahepatic cholestasis (i.e. dark colored urine, acholic stools, icterus)
What liver disease of middle age women often presents with xanthelasmas / xanthomata? What’s the pathognomonic finding in the liver?
Primary biliary cholangitis
Florid duct lesion (granuloma due to intralobular bile duct destruction) is pathognomonic
What is the cause of obstructive atelectasis and how will it appear on CXR?
Causes include:
- Foreign body obstruction
- Obstruction by bronchial secretions / exudate, i.e. asthma, chronic bronchitis, bronchiectasis
Obstruction needs to be COMPLETE to collapse the lung, the absorption of the air behind the block
CXR -> tracheal deviation towards the affected side since volume is lost.
Progressive loss of air -> loss of radiolucency -> progressive opacification of lung on CXR.
What is the numeric definition of pulmonary hypertension and what gene causes inherited PAH?
mean pulmonary arterial pressure > 25 mmHg at rest.
BMPR2 mutation (bone morphogenic protein receptor 2) -> inactivating mutations will cause vascular smooth muscle proliferation -> normal function is to inhibit proliferation
What is the constellation of symptoms in tuberous sclerosis? Include CNS and renal findings as well
Hamartomas:
Cardiac rhabdomyoma
Angiofibromas - connective tissue hamartomas of face
Ash-leaf spots - hypomelanotic lesions seen by wood’s lamp
mental retardation
renal angiomyolipoma - often biolateral causing renal failure #6
Shagreen spots - CT hamartomas seen on trunk
Ungual fibromas - nailbed tumors
Subependymal giant cell astromacytomas
What are the features of von Hippel Lindau disease?
Chromosome 3, VHL gene deletion (tumor suppressor)
Hemangioblastomas, especially in cerebellum
Angiomatosis - especially cavernous
Bilateral renal cell carcinomas
Pheochromocytomas (VHL and RET (MEN2), as well as NF-1 associated with this)
What are the three types of melanocytic nevi and how does this explain how they appear?
- Junctional - at the DEJ
- Compound - both extension into dermis + DEJ involvement (compound)
- Intradermal - extension into dermis leads to the nevus becoming raised. Also flesh-colored due to loss of DEJ component. #11502
What germ layers are the meninges derived from?
Dura - mesoderm
Arachnoid - neural crest
Pia - neural crest
What is often the earliest sign of hypothyroidism and what are its clinical features?
Delayed / slow relaxing deep tendon reflexes (think of generalized slowing seen in hypothyroidism) and hypothyroid myopathy
- > proximal muscle weakness and ELEVATED creatinine kinase from breakdown of fast twitch muscle fibers
- > implies there is some actual muscle DAMAGE going on
What is myoedema which can be seen in hypothyroid myopathy? How is this type of myopathy definitively told apart from steroid myopathy?
Myoedema - sustained contraction of the muscle groups around where it is percussed due to impaired reuptake of Ca+2 into SR, due to generalized slowing.
Hypothyroid myopathy - elevated CK due to muscle damage (inflammatory)
Glucocorticoid myopathy - CK will be normal due to muscle loss being strictly for gluconeogenesis. (atrophy)
What histologically characterizes dermatitis herpetiformis and where does it appear?
Microabscesses containing fibrin and neutrophils at dermal papillae types due to IgA deposition
-> coalesce to form blisters in tips of involved papillae
anti-gliadin antibodies are reacting with epidermal transglutaminase
Appears on the extensor surfaces
What is the mechanism which is thought to underlie Functional Hypothalamic Amenorrhea?
Decreased circulating leptin levels suppress GnRH
What way does the iliopsoas rotate your leg?
Externally rotates it, since it inserts very inferomedially on the lesser trochanter, contraction of the muscles will cause the leg to undergo external rotation
What are the most common cardiovascular symptoms of ankylosing spondylitis?
Ascending aortitis -> can lead to aortic regurgitation due to dilation of the aortic ring
What is one big way to tell primary glioblastoma apart from a metastatic brain cancer?
Metastases tend to be well circumscribed since they are a foreign tissue in the brain -> get walled off.
Also there are frequently multiple lesions in metastases.
Where does phrenic nerve irritation refer to?
Diaphragmatic irritation (i.e. lung cancer, or gallbladder pain) refer to shoulder -> C3-C5 nerve roots (phrenic) refers to supraclavicular nerve (C3/C4) -> #647
Where are most craniopharyngiomas?
Often suprasellar, since the oral ectoderm is at such an angle that the tumor tends to appear above the pituitary.
Idk man just look at a brain
What are common presenting symptoms of giant cell arteritis?
- Polymyalgia rheumatica symptoms - hip / shoulder achy pain
- Jaw / tongue claudication - specific
- Headache
- Amaurosis fugax - “fleeting darkness” - transient, painless monocular vision loss
What is the cause of vitiligo?
Complete autoimmune destruction of melanocytes. They will be completely absent in macules and patches.
What is bronchioalveolar carcinoma and how does it present? What does the epithelium look like?
Adenocarcinoma in situ - presents as hazy infiltrates similar to pneumonia on CXR. This is a standalone carcinoma which may represent part of a progressive to invasive adenocarcinoma
May present as bronchorrhea - copious amounts of watery sputum from mucinous discharge of AIS.
What does the epithelium of bronchioalveolar carcinoma look like?
Epithelium is tall, columnar cells often containing mucin, which line the alveolar septae (apparent thickening of alveolar walls). Alveolar architecture is preserved (vs invasive adenocarcinoma).
What vasculitis is commonly associated with wrist / foot drop?
Eosinophilic granulomatosus with polyangiitis (Churg-Strauss) -> CNS / PNS involvement is common due to ischemic damage to the epineural blood vessels secondary to vasculitis damage
Remember this condition is also associated with necrotizing granulomas, asthma, sinusitis and peripheral eosinophilia
What is the cause of Meniere’s disease and what is the triad?
Increased endolymphatic pressure. Triad:
Tinnitus
Vertigo
Progressive sensorineural hearing loss
Tinnitus / vertigo are generally episodic
How is BPPV told apart from Meniere’s disease?
BPPV is NOT associated with tinnitus / hearing loss, and episodes are generally briefer, brought on by head movement
What are the risk factors for pigment gallstones?
- Chronic hemolysis -> increased biliary excretion of conjugated bilirubin, and a small percentage always becomes unconjugated. Obv higher risk of forming stones with more bile produced.
- Biliary tract infections -> microbial deconjugation of bile acids
- Gallbladder hypomotility -> thickens bile
What are the two morphological types of pigment stones? What causes them? Are they radio-opaque or translucent?
Black - occur in chronic hemolysis -> majority are radio-opaque from complexing with calcium. Multiple and smooth. Think “black is white” baby!!
Brown - occur in biliary tract infections -> soft and soapy, radiotranslucent
What is the most common type of cholecystitis and its pathogenesis?
Calculous cholecystitis - obstruction of neck of gallbladder via a stone = retention of bile, gallbladder distention, chemical damage via buildup of bile, and vascular compression in the wall (venous congestion since veins are more compressible, causing hemorrhagic infarct overtime)
What are the risk factors for the less common type of cholecystitis (acalculous)?
Critically ill patients - occurs without stone, due to hypomotility or hypoperfusion
- > Cystic duct obstruction by concentrated bile with excessive reabsorption due to dehydration and hypomotility
- > poor vascular perfusion (during shock)
- > bacterial infection -> sepsis can seed the gallbladder which has bile material which is not moving
What non-pericarditis / cardiac tamponade conditions can cause pulsus paradoxus and why?
Conditions which require the generation of a highly negative intrathoracic pressure in order to try to breathe can do this -> increase bloodflow to the lungs while decreasing LV preload during inspiration
Examples:
Severe croup (obstructed airway)
Obstructive sleep apnea
Asthma
What is microvesicular vs macrovesicular fatty change and which is more common?
Microvesicular - implies active turnover of fat globules, as fat normally coalesces overtime to form large droplets. A much more ominous finding, as in acute fatty liver of pregnancy, or Reye syndrome.
Macrovesicular - far more common, implies stable fat accumulation in hepatocytes, as would be seen in alcoholism, kwashiorkor, chronic hepatitis C, etc.
What is the cause of congenital torticollis and how will the patient present?
8325
Generally due to birth trauma or malposition of the head in utero (i.e. due to macrosomia or oligohydramnios). Baby will present not wanting to turn the head towards the affected side (SCM is contracted and holding the head turned away). SCM is often seen bulging on ipsilateral side.
What are the complications of PNH?
- Aplastic anemia - associated with destruction of bone marrow stem cells via complement. Pancytopenias.
- Thrombosis - platelets and RBCs lack CD55 (decay accelerating factor, due to loss of GPI anchor) -> increased release of hemoglobin which damages endothelium, and other procoagulant factors from platelets -> thrombosis, especially portal vein (Budd-Chiari).
- Increased risk of AML
- Iron deficiency anemia from hemolysis
What causes SSPE / what will be seen in CSF?
Measles virus which cannot leave the cells properly -> accumulating nucleocapsids in neurons and progressive neurodegeneration
In CSF, patients will have anti-Measles antibodies as an oligoclonal band #910
What are the skin layer findings of psoriasis?
1117
Hyperkeratosis, parakeratosis (increased thickness and nuclei in corneum) -> hyperparakeratosis
Thin stratum granulosum (hypogranulosis)
Acanthosis -> increased spinosum (due to increased mitotic activity of basal layer)
What are Auspitz sign and Monro microabscesses of psoriasis?
Munro microabscesses - spongiotic clusters of neutrophils in superficial dermis and hyperparakeratotic epidermis
Auspitz sign - elongated rete ridges of dermis with thinned dermis superiorly = easy bleeding.
What is pituitary apoplexy?
Pituitary apoplexy - can be used as an umbrella term encompassing acute pituitary insufficiency due to necrosis or hemorrhage. Sheehan syndrome may be considered a subset of this.
Other authors have it mean acute hemorrhage into the pituitary gland, leading to pituitary insufficiency
How does hemorrhage into the pituitary usually present, and what must it be differentiated from?
Usually presents in the setting of a pituitary tumor (esp. prolactinoma, most common), which weakens blood vessels -> rupture and hemorrhage
Will show sudden onset acute adrenal insufficiency, severe headache, visual impairment due to compression from expanding blood pool (CN3 palsy, bitemporal hemianopsia)
Must be differentiated from anterior communicating berry aneurysm, which also presents with an awful headache and CN3 involvement, but will not show preceding prolactinoma symptoms.
How does estrogen affect thyroid hormone levels?
772
Will increase TOTAL T4 by increasing TBG synthesis, but has no effect on free T3/T4 since the transient decrease in free T3/T4 levels will be compensated for by increased secretion to maintain euthyroid.
What is the function of the JG cells and what are they?
Modified smooth muscle cells of the AFFERENT arteriole, release renin when stimulated by macula densa or B1 adrenoceptor
What cells release erythropoietin?
Interstitial fibroblasts of the peritubular capillary bed of the kidneys, in response to hypoxia.
What is the significance of the cold agglutinins seen in Mycoplasma and what other conditions can they be present in?
They generally occur due to molecular mimicry -> clump blood when it is cold (i.e. in extremities, or held in cold test tube).
Since the IgM antibodies are binding erythrocytes, may cause a hemolytic anemia in some patients (autoimmune hemolytic anemia).
-> also occurs in mononucleus (EBV-related) and CLL.
IgM, Mycoplasma, Mononucleus = MMM
What is the primary usage of hydralazine?
Can be used:
- Acutely to manage hypertensive crisis
- Longterm for management of complicated hypertension (in combination with a beta blocker and a diuretic)
- In combination with nitrates for heart failure - in those with contraindications to ACE inhibitors (bilateral renal artery stenosis, C1 esterase inhibitor deficiency), especially African Americans.
Who is hydralazine contraindicated in and why?
Contraindicated in those with coronary artery disease / angina -> arteriolar vasodilation triggers a reflex tachycardia to maintain blood pressure -> increased work on heart.
This also explains why some of the side effects include fluid retention -> sympathetic release will cause activation of the RAA system.
What is the primary cardiovascular drug which causes angioedema and why?
ACE inhibitors.
Angioedema refers to the acute, localized subcutaneous / submucosal edema caused by increased vascular permeability. This is because ACE is also responsible for the breakdown of bradykinin -> increased vascular permeability.
Why are ACE inhibitors contraindicated in C1 esterase inhibitor deficiency?
C1 esterase inhibitor is required to breakdown kallikrein.
Unregulated kallikrein will continue converting HMW kininogen to bradykinin -> high circulating levels of bradykinin
Only other enzyme which breaks down bradykinin is ACE. If ACE is inhibited -> gg you have tons of bradykinin and angioedema.
What is one major way to determine a child has eczema and not dermatitis herpetiformis?
Dermatitis herpetiformis almost NEVER happens in children!!!!!!@!@!@!!@@@!@!!@!@!@!@!@!@
What happens to GFR and filtration fraction when you constrict the efferent arteriole?
Filtration fraction increases and GFR INCREASES!
What actually drops is the renal plasma flow.
Filtration fraction = GFR / RPF
How does constriction of the afferent arteriole affect filtration fraction?
Keeps it relatively constant, since the loss of hydrostatic pressure from dropping renal plasma flow will be matched by a drop in GFR.
What do Stanford type A and Stanford type B aortic dissections usually occur?
Type A - sinotubular junction of the Ascending aorta -> sinotubular junction = junction of aortic sinuses and the tube of the aorta proper
Type B - Descending aorta - usually just distal to the left subclavian artery (last branch of aortic arch)
Other than eosinophilia, how do you tell apart the granulomas caused by Sarcoidosis vs Churg-Strauss syndrome?
Sarcoidosis - Non-caseating granulomas
Churg-Strauss - Caseating granulomas
What viruses predispose you to aplastic anemia?
- Hepatitis B virus
- EBV - infects B cells
- HIV
- Parvovirus B19 - pure red cell aplasia
What is the inheritance pattern of hereditary angioedema and what complement levels will be low? Symptoms?
Autosomal dominant - lack of C1 esterase inhibitor (inhibits the activated C1s subunit which cleaves C4)
C4 levels will be low.
Symptoms -> episodes of swelling (angioedema) all over the body
What hormones are required for development of internal and external male genitalia? What condition does the latter relate to?
Internal genitalia - requires testosterone, includes seminal vesicle, epididymis, ejaculatory duct, and vas deferns
External male genitalia - Requires dihydrotestosterone includes penis, scrotum, and prostate. Thus 5alpha reductase deficiency will result in ambiguous external genitalia until puberty when testosterone levels ride
What hormones are required for development of internal and external female genitalia?
Internal - Requires NO hormones, just a lack of MIF which would be present from Sertoli cells if testes were present. Includes Fallopian tubes, uterus, and proximal 1/3 of vagina.
External - Requires estradiol. Includes distal 2/3 of vagina, labia, and clitoris
What will the genitalia for a female with placental aromatase deficiency?
Lack of estrogen synthesis -> failed external genitalia development, with increased testosterone levels (also explains why virilization of mother occurs).
Normal internal genitalia (i.e. uterus), normal ovaries, but ambiguous external genitalia generally with clitoromegaly due to increased androgens.
What happens to a male with placental aromatase deficiency?
Generally asympatomatic, except they will grow very tall (lack of estrogen closing of the physeal plates) and increased risk of osteoporosis (lack of stimulation of osteoprotegerin).
What’s the best way to tell Cryptococcus infection from Toxoplasmosis in HIV?
Crypto - tend to be really tiny “soap bubble” lesions which are uniform (not ring-enhancing) all over the brain, and far rarer than toxoplasmosis in HIV patients. Typically crypto causes meningitis
Toxoplasmosis - tend to be multiple ring-enhancing lesions, most common in HIV. (Followed by primary CNS lymphoma).
What is the best way to tell Toxoplasmosis from primary B cell lymphoma in HIV? How is the latter diagnosed?
Toxoplasma - will always be multiple lesions
Diffuse B cell lymphoma - if solitary, this is nearly diagnostic. However, it can be multiple ring-enhancing lesions just like Toxo. In this case it’s pretty hard to tell them apart. For diagnosis, EBV titers will be positive.
What is the mechanism by prostate surgery can cause bleeding? Will D-dimer be elevated?
Prostate surgery causes the release of UROkinase -> a plasminogen activator which activates plasmin to start degrading fibrin.
Since this causes primary and not secondary fibrinolysis (i.e. fibrinolysis occurring after DIC or a major injury), D-dimer will not be elevated since the clots will not have had time to enlarge. Fibrin split products will still be elevated.
What causes decorticate vs decerebrate posturing?
Red nucleus is excitatory to flexors of upper extremities
Decorticate -> loss of UMN inhibition of red nucleus (lesion above red nucleus) -> increased upper extremity flexion
Decerebate -> loss of red nucleus to upper extremity flexors -> loss upper of extremity flexion -> extension
Extension occurs because lateral vestibulospinal tract no longer receives descending cortical inhibition, but excitation remains intact because the vestibular nucleus complex is at the junction of the pons / medulla. #11574
What is adenomyosis and how do you differentiate it from endometrial hyperplasia?
Extension of endometrial tissue into myometrium (like endometriosis but in myometrium).
Vs. endometrial hyperplasia, adenomyosis will be PAINFUL, and there will be a normal gland:stroma ratio. Endometrial hyperplasia shows abnormal gland proliferation.
How can hypoperfusion worsen lactic acidosis, aside from the fact that decreased oxygenation inhibits oxidative phosphorylation?
Decreased perfusion to liver -> inability to use lactate to make glucose
When do the symptoms of congenital hypothyroidism typically appear and what are they?
Usually not for 1-2 weeks after birth due to placental transfer of T4
Include: Constipation, lethargy, hypotonia, umbilical hernia, macroglossia, and large anterior fontanelle
What happens to urea clearance in the presence of vasopressin?
It decreases -> in order to increase the osmolarity of the interstitium, urea is resorbed in the medullary collecting duct.
What makes chronic graft rejection in the lungs so unique?
Most graft rejection - i.e. kidneys is due to CD4 mediated hypersensitivity reaction to VASCULAR structures.
Chronic graft rejection in the lungs causes bronchiolitis obliterans -> dyspnea and wheezing due to fibrosis and destruction of the small airways (bronchioles). #534
What is the immune response to intracellular bacteria (i.e. Listeria)?
Bacterial antigens are expressed on MHC, and cytotoxic T cells induce lysis of host cells which contain these bacteria, exposing them to the antibody / complement system.
Cytotoxic T cells also secrete IFN-y to stimulate maturaiton of macrophages to help kill their intracellular pathogens.
What problems does pyruvate kinase deficiency cause? What type of RBCs will be seen and what will happen to the spleen?
PK deficiency -> decreased ATP to maintenance the Na/K ATPase
-> echinocytes (burr cells) are seen on RBC peripheral smear - smaller and more evenly spaced than acanthocytes.
Spleen will have red pulp hyperplasia (due to increased digestion of RBCs by RE system)
How will a newborn present with pyruvate kinase deficiency? What happens to the O2 carrying capacity in these infants?
Present with Hgb with decreased affinity for oxygen -> due to upstream buildup of 2,3-BPG
Newborn presents with hemolytic anemia due to increased clearance of RBCs / echinocytes from the spleen
What would be an example of a few conditions that cause passive splenic congestion?
- Portal hypertension
- Congestive heart failure
- Splenic vein thrombosis
- > backup of blood in the spleen
How do you tell apart GVHD and transplant rejection?
GVHD - skin, liver, and GI tract are commonly attacked by donor T cells
Transplant rejection - only the grafted organ will be damaged
What are the differential effects of a left vs right frontal lobe lesion?
Left (dominant) - apathy. My dominant feeling is that I don’t care about this useless fact
Right - disinhibition
Are the parasympathetic fibers at the center or the outside of CN3?
Just remember that PARAsympathetic is at the PERIphery
- > parasympathetic on outside
- > Affected first by compression (i.e. tumor)
- > Affected last by ischemia (i.e. diabetes)
What effect does pH have on citrate levels?
Low kidney proximal tubule pH (where citrate is reabsorbed) is associated with increased absorption of citrate
Proximal tubule pH will be low during:
1. Systemic acidosis
2. Distal RTA -> systemic acidosis with failed acidification of distal tubule
-> NOT proximal tubule acidosis
https://www.ncbi.nlm.nih.gov/pubmed/2841871
What effect does hypocitraturia have on kidney stones?
Hypocitraturia -> increased stone formation
- > citrate is needed in the urine as a divalent anion to complex with the divalent cation Ca+2 to prevent its formation
- > low citrate allows precipitation of calcium oxalate stones, which you will remember is ASSOCIATED with low pH at previously described
-> cystine / uric acid crystals are directly caused by low pH (treat with acetazolamine)
Why can a high sodium diet precipitate calcium stones?
Na / Ca are reabsorbed together
-> more Na+ left to be excreted in the tubule results in hypercalciuria
Does a low calcium diet prevent kidney stones?
NO!
Calcium is needed to bind oxalate in the GI tract
If calcium is not present -> too much oxalate absorption -> hyperoxaluria -> kidney stones
Why do patients remain euvolemic in SIADH or psychogenic polydipsia? What is meant by euvolemia?
Euvolemia = ECV is normal (Rossi is correct)
Body will respond to water retention by increasing ANP/BNP -> increases urinary Na+ secretion to keep ECV normal -> still relatively more water, especially in the ICF.
-> euvolemic hyponatremic. #1379
What is the most common cause of bladder outlet obstruction in male infants? What causes it?
Posterior urethral valve:
Wolffian duct abnormality which leads to a membrane remant in the posterior urethra of males -> urethral obstruction.
What are the complications associated with posterior urethral valves?
Obstruction can cause hydronephrosis and oligohydramnios prenatally. Also, to push against the obstruction, the bladder wall can become thick.
What are two causes of polyhydramnios due to increased urine output?
High cardiac output due to:
- Anemia
- Twin-twin transfusion syndrome - (AV malformation pumping blood into twin’s circulation, increased cardiac output to compensate.)
- > increases GFR by increasing renal blood flow -> increased urine production
How do you tell if superior vena cava syndrome is due to a pancoast tumor or a mediastinal mass?
If it is due to a pancoast (superior sulcus) tumor, it will much more likely occur with other symptoms due to being at the apex of the lung, i.e. hoarsness, Horner syndrome (stellate ganglion compression), brachial plexus deficits, etc
Mediastinal mass - usually presents with SVC syndrome without any other accompanying pancoast symptoms
What is a cholesteatoma and what are the common complications?
Overgrowth of desquamated keratin debris in the middle ear
Often produces lytic enzymes which degrade ossicles -> conductive hearing loss
Middle ear discharge is also a common complaint.
May be congenital or arise secondary to chronic negative pressure on the tympanic membrane which induces cyst formation inside. #11628
Is it greater excitatory or inhibitory neurotransmission that promotes hepatic encephalopathy?
Inhibitory - increased GABA levels
Remember this in two ways:
- Benzos / sedatives precipitate coma / worsening of altered mental status
- Ammonia is going to convert glutamate -> glutamine, impairing excitatory neurotransmission.
How do you tell maternal DIC apart due to amniotic fluid emboli vs placental abruption?
Amniotic fluid emboli - associated with hypotension / shock
Placental abruption - associated with hypertension (since that’s what causes it)
What is Good syndrome? How does it present?
Hypogammaglobulinemia in the setting of Thymoma
-> likely some autoimmune failure to generate T cells which activate B cells properly
-> recurrent sinopulmonary infections with a mediastinal mass in adults
What is tertiary adrenal insufficiency and what precipitates it?
Chronic exogenous glucocorticoids -> atrophy of HYPOTHALAMUS (CRH), pituitary (ACTH), and adrenal glands (cortisol)
Can be precipitated with abrupt withdrawal (low CRH levels) = low ACTH levels = low cortisol, or relative deficiency (due to need for supplementation in stress situations, i.e. surgery) -> presents as acute adrenal insufficiency w/ vascular collapse #609.
Tertiary = treatment
What is the mechanism of euvolemia in SIADH?
Increased ECF volume -> decreased aldosterone levels with activation of the ANP / BNP system -> excretion of Na+ with normalization of ECF volume. Leads to profound hyponatremia to preserve euvolemia.
What happens to the cerebellum of alcoholics in the longterm?
Degradation of the Purkinje cells, most prominently in the cerebellar vermis -> truncal ataxia #6810
What are the DNA binding protein motifs of significance?
- Helix-loop-helix
- Zinc fingers
- Leucine zipper -> leucines every 7 amino acids which interact in dimerization + a basic DNA binding domain (contains arginine / lysine)
Where do carbamoyl phosphate synthetase 1 vs 2 act?
CPS 1 - mitochondria, to start off the urea cycle
CPS 2 - cytosol, where nucleotide synthesis is taking place
Is alcoholic cardiomyopathy reversible?
Yes - but recovery is slow. Dilated cardiomyopathy will not recovery once it has progressed to fibrosis.
What gene defect commonly causes non-insulin dependent diabetes with mild hyperglycemia in young, lean adults?
Glucokinase deficiency - maturity onset diabetes of the young #6759
What are the three types of edema?
- Vasogenic edema - i.e. due to mass or tumor breaking the BBB -> “white matter edema”
- Cytotoxic edema - i.e. due to ischemia, sodium influx due to loss of Na/K ATPase activity -> “gray matter edema”
- Interstitial edema - CSF leakage surrounding the ventricles due to increased pressure -> secondary to subarachnoid inflammation or obstructive hydrocephalus
What are the risk factors for cervical cancer?
- Smoking! Important one (along with pancreatic being a counterintuitive one that smoking causes)
- Immunodeficiency -> squamous cell carcinoma of anus or cervix is actually an AIDS-defining illness (CD4 < 500)
Immunodeficiency increases your risk for persistent HPV infection
In what way are Rabies (virus) and Tetanus (bacteria) similar?
Both Rabies virus and tetanospasmin (the toxin) travel up the nervous system via retrograde axonal transport
