Wrong answers

Question 1

Familial hypercholestermia (type II A)

Answer 1

the most common inherited dyslipidemia lipid disorder; defect in LDL receptors and ApoB-100; there is elevated LDL; pt will present w/ premature atherosclerosis (men <55; women <65), tendon xanthomas and xanthelasmas (skin xanthomas - deposits of lipid-rich foam cells in the dermis; presents w yellow rubbery nodules and plaques)

Question 2

False negative H. pylori test

Answer 2

can occur in urea breath testing and stool antigen studies in pts using **PPI’s bismuth or antibiotics; they suppress bacterial growth but do not eradicate H. pylori unless used in combination in quadruple therapy

Question 3

diastolic thrill palpable over the cardiac apex and a low-pitched, rumbling, mid-diastolic murmur best heard over the apex when the pt is lying in the left lateral decibitus position

Answer 3

mitral stenosis findings

Question 4

adolescent with bloody stools, PE reveals conjunctival pallor and blood-streaked stool within the rectal vault

Answer 4

Peutz-Jeghers syndrome; AD tumor suppressor gene mut; pigmented macules in lips/palms/soles; **multiple GI hamartomatous polyps - increased cancer risk (GI, breast and GU)

Question 5

Liposarcoma

Answer 5

soft tissue malignancies that contain a numerous lipoblasts (well-demarcated lipid shifts with the cells characteristically causing nuclear indentations and **scalloping of the nuclear membrane; most common in middle aged adults as slow-growing masses

Question 6

Pemphigus Vulgaris (PV)

Answer 6

painful bullae and erosions, oral involvement and extension of lesions w/ direct pressure (Asboe-Hansen sign); antibodies against desmogleins (help form desmosomal junctions - epidermal IgG and C3 deposits will be found between keratinocytes); ** net-like or chicken-wire pattern

Question 7

Alcohol-related cerebellar degeneration

Answer 7

results from long-term heavy alcohol use; loss of purkinje cells that are prominent in the cerebellar vermis; pt experience ataxia the progresses over weeks to months before eventually stabilizing; wide-based gait and truncal instability; a course, rhythmic, postural tremor of the fingers and hands, dysarthria and diplopia

Question 8

A systolic murmur that increases in intensity with maneuvers that decrease LV blood volume is highly suggestive of what pathology?

Answer 8

hypertrophic cardiomyopathy

Question 9

proteins and their functions in prokaryotic DNA replication

Answer 9

Question 10

Lynch syndrome

Answer 10

ovarian mass, ascites and elevated CA-125 has the typical presentation of ovarian cancer FH in 1st degree relatives strongly suggest Lynch syndrome (AD) that increased risk of colorectal, endometrial and ovarian cancers; Lynch is caused by germline mut involving mismatch repair (MMR) in MSH2, MLH1, MSH6 and PMS2

Question 11

MOA of tacrolimus (immunosuppressant)

Answer 11

a calcineurin inhibitor that prevents the gene transcription of IL-2 in T-cells; can cause a rise un BUN and creatinine levels that is thought to be due to afferent and efferent arteriolar constrictions - **Renal arteriolar vasoconstriction; long-term can lead to obliterative vasculopathy

Question 12

Alkaptonuria

Answer 12

AR distordre caused by defectes in homogentisic acid deoxygenate (HGD) leading to impaired tyrosine metabolism; clinical homogentisic aciduria (blackening of the urine); ochronosis (blue-black pigments deposits in eyes, ears and nose); and pigment deposits in spine and large joints; diagnose w/ increased homogentisic acid levels in the urine

Question 13

Clinical homogentisic aciduria (blackening of the urine); ochronosis (blue-black pigments deposits in eyes, ears and nose); and pigment deposits in spine and large joints

Answer 13

Alkaptonuria - AR distordre caused by defectes in homogentisic acid deoxygenate (HGD) leading to impaired tyrosine metabolism; diagnose w/ increased homogentisic acid levels in the urine

Question 14

Fragility fracture

Answer 14

fracture resulting from a low-level trauma (fall from standing height); strongly suggest osteoporosis; the most common cause in a young active women is **hypogonadatrophic hypogonadism which manifests as suppressed GnRH; leading to amenorrhea and bone loss

Question 15

Homocystinuria

Answer 15

an AR disorder results cystathionine-beta synthase (CBS) mut; leads to a buildup of both methionine and homocysteine; pt presents with marfanoid features - tall, thin stature, arachnodactyly (elongated fingers and toes)

** distinguish from Marfan syndrome - intellectual disability, hyper coagulability and ectopic lentis (dislocated lens) - displaced upward in homocystuniura and upward in Marfan

Question 16

CMV retinitis treatment

Answer 16

HIV pt is likely to have cytomegalovirus (CMV) retinitis - CD4 <50/mm3; best treated w/ ganciclovir - inhibits DNA chain elongation by incorporating into viral DNA and viral DNA polymerase

Question 17

Genetic shift

Answer 17

nonpathogenic and pathogenic strains are grown in culture and the nonpathogenic strain presents with enhanced infectivity - cause by **reassortment

Question 18

McArdle disease

Answer 18

glycogen storage disease type V - AR caused by deficiency in muscle glycogen phosphorylase (myophosylase) - enzyme that **cleaves 1,4 - alpha-glycoside bonds; presents w/ muscle weakness shortly after initiating exercise in adolescence or early adulthood

Question 19

Answer 19

Question 20

Atrial fibrillation JVP waveform - ineffective atrial contraction and absence of end-diastolic atrial kick that forces blood into the ventricles

Answer 20

Question 21

Tetralogy of Fallot (TOF) clinical presentation

Answer 21

cyanosis at birth with a harsh systolic ejection murmur; situations that increase right ventricular outflow obstruction (crying, agitation) or decrease SVR (exercise) can trigger **hypercyanotic episodes “tet” spells which present in rapid/deep breathing and cyanosis - during these spells children **squat to relieve cyanosis - increases SVR resistance improving oxygenation

Question 22

A tumor of this structure

Answer 22

pineal gland tumors (pinealomas) - damage the dorsal midbrain causing Parinaud syndrome; presents with **upward gaze palsy, absent pupillary light reflex and impaired convergence

Question 23

During healing if the GI, new intestinal epithelial cells differentiate from *stem cells that reside where?

Answer 23

in the deepest portions of the Crypts of Lieberkuhn

Question 24

Important inherited hyperlipoproteinemias

Answer 24

Question 25

Familial chylomicronemia syndrome (type I)

Answer 25

defect in lipoprotein lipase and ApoC-2; there will be elevated chylomicrons Major manifestations: acute pancreatitis, lipemia retinals and eruptive xanthomas

Question 26

Familial hypercholesterolemia (type IIA)

Answer 26

defect in LDL receptor and ApoB-100; there will be elevated LDL Major manifestations: premature atherosclerosis, tendon xanthomas and xanthelasmas

Question 27

Familial dysbetalipoproteinemia (type III)

Answer 27

defect in ApoE; will have elevated chylomicron and VLDL remnants Major manifestations: premature atherosclerosis, tuboeruptive and palmar xanthomas

Question 28

Familial hypertriglyceridemia (type IV)

Answer 28

polygenic defect; elevated VLDL; associated with coronary disease, pancreatitis and diabetes

Question 29

False negative H. pylori urea breath test

Answer 29

can occur in pts using PPIs, bismuth, or antibiotics; these agents suppress growth but do not eradicate H. pylori unless given in combination as part of quadruple therapy

Question 30

Horner Syndrome

Answer 30

triad of miosis (constricted pupil), ptosis (droopy eyelid), and anhidrosis (loss of hemifacial sweating) Interruption in the pathway: T1/T2 level at spinal cord to *stellate ganglion in paravertebral sympathetic chain to superior cervical ganglion to carotid plexus, transverse to ciliary and oculomotor nerves

Question 31

receiver operating characteristic (ROC) curves

Answer 31

can be produced by plotting sensitivity (true positive rate) against 1-specicity (false positive rate) Accuracy is reflected by the areas under the ROC curve (AUC) line A is the most accurate for diagnoses purposes

Question 32

Medication used to treat a small bowel obstruction that is contraindicated in Parkinson disease

Answer 32

Metoclopramide - dopamine receptor antagonist can lead to an exacerbation of existing parkinsonian symptoms and sometimes de novo in pts w/o parkinson

Question 33

MOA of antiviral medications: acyclovir, valacyclovir, famciclovir and ganciclovir?

Answer 33

inhibits DNA chain elongation by incorporating into viral DNA and inhibiting viral DNA polymerase

Question 34

Parkinson disease pathology?

Answer 34

degeneration of dopaminergic neurons in substantial nigra leading to progressive deficiency of dopamine w/I the basal ganglia characteristic finding of intraneuronal accumulation of **alpha-synuclein and ubiquitin

Question 35

Antibiotics acting on 50S subunit

Answer 35

chloramphenicol, clindamycin, linezolids and some macrolides such as: Azithromycin and Clindamycin which bind the 23S rRNA of the 50S ribosomal subunit

Question 36

Cystic hygroma

Answer 36

a lymphatic malformation caused by dysgenesis of the lymphatic system: 1 hour baby w/ anterior fontanelle open, soft and flat; neck is supple, there is a large, doughy mass covered by skin above the left clavicle and lateral to SCM; the mass transilluminates w a light source most commonly associated w trisomies (particular trisomy 21) and Turner syndrome (45, XO)

Question 37

lactose intolerance pathology

Answer 37

lactase expression is generally high in infancy and early childhood when milk is the primary source of nutrition however *gene expression naturally declines with age resulting in primary lactose intolerant

Question 38

Kluver-Bucy syndrome

Answer 38

neuropsychiatric syndrome that results from b/l damage ti the temporal lobes (amygdala - represented as C) presents w/ socially inappropriate sexual activity and an oral fixation that motivates people to put things in their mouths (hyperphagia), placidity and amnesia commonly associated w HSV-1 encephalitis due to the virus affinity for temporal lobes and limbic system

Question 39

Tardive dyskinesia (TD)

Answer 39

medication-induced movement disorder that results from *prolonged exposure/long-term use of dopamine-blocking agents; this will cause receptor up regulation

Question 40

Dopamine beta-hydroxylate deficiency

Answer 40

impair synthesis of NE and epi; there will be impaired sympathetic adrenergic activity; presents w/ postural (orthostatic) hypotension, exercise intolerance, nasal congestion and ejaculatory difficulties

Question 41

Polio vaccines

Answer 41

oral polio vaccine contains attenuated live virus that can revert to a virulent form and cause vaccine-associated paralytic poliomyelitis. Inactivated polio vaccine contains killed virus and canNOT revert to a virulent form

Question 42

Superior vena cava (SVC) syndrome

Answer 42

SVC obstruction which is caused by tumor (90%); impaired upper body venous drainage results in increased venous pressure and symptoms that include face and neck edema, neck vein engorgement and dyspnea.

Question 43

Rabies

Answer 43

eosinophilic neuronal cytoplasmic inclusions (Negri bodies); causes painful pharyngeal muscle spasms and hydrophobia; most cases arise from an animal bite (I the US bats are the most common vector, outside of the US, unvaccinated dogs)

Question 44

Orlistat

Answer 44

an intestinal lipase inhibitor that reduces dietary fat; it is often recommended as 1st line tx due to favorable safety profile, but has significant GI side effects; anti-obesity drug - produces modest weight loss

Question 45

Membranous nephropathy

Answer 45

nephrotic syndrome; imune-complex deposition in the subepitehlial portion of glomerular capillary walls; often idiopathic but associated w/ solid tumors; will see diffuse thickening of the glomerular BM; sub epithelial immune-complex deposits form "spikes" visible w/ silver stain and electron microscopy

Question 46

Entamoeba histolytica

Answer 46

protozoan transmitted via oral-fecal contact (contaminated water/sexual activity), may present w. abdominal pain, diarrhea, and bloody or mucoid stool. Stool microscopy shows cysts and trophozoites which characteristically possess phagocytoses erythrocytes

Question 47

Urethritis with epididymitis

Answer 47

urethral discharge and enlarged, painful testicles caused by STIs: C trachomatis (nongonococcal urethritis) - neutrophils w/ no organisms on gram stain - tx w/ bacterial protein synthesis inhibitors (azithromycin and doxycycline) N gonorrhoeae - gram (-) stain w/ diplococci - tx w/ both a cephalosporin and azithromycin

Question 48

Answer 48

16% "68/95/99" rule is an important attribute of normal distribution; 68% of values will lie within 1 SD, 95% of values within 2SD and 99.7 of values of 3SD 90 BG is the mean so 85-95 is 68%, values below and above are 16%

Question 49

Primary ovarian insufficiency

Answer 49

the premature depletion of ovarian follicles, presents with amenorrhea and elevated FSH in women age <40. the pathophysiology is accelerated follicular atresia, an apoptotic process clinical features: increased FSH and decreased estrogen

Question 50

Purpose of drug coating in a stent placement

Answer 50

drug-eluting stands contain cytostatic drugs (mTOR inhibitors) that reduce smooth muscle cell proliferation; this helps prevent neointimal hyperplasia and stent restenosis

Question 51

ornithine transcarbamylase deficiency

Answer 51

most common urea cycle disorder; urea cycle disorders typically present with very high ammonia levels, poor feeding, vomiting, lethargy and seizures; ornithine transcarbamylase deficiency is the most common defect; accumulation of carbonyl phosphate which is converted to orotic acid by the pyrimidine biosynthetic pathways and low citrulline levels

Question 52

Somatic symptom disorder

Answer 52

excessive thoughts or behaviors associated with one or more somatic symptoms, resulting in functional impairment.

Question 53

Postmenopausal osteoporosis

Answer 53

following menopause, the loss of ovarian function and decline in estrogen levels lead to increased bone resorption, accelerated bone loss, and an increased risk of osteoporosis; vertebral compression fractures are a common complication of postmenopausal osteoporosis due to loss of trabecular bone and can occur with low-intensity trauma

Question 54

Normal pressure hydrocephalus (NPH)

Answer 54

classic triad of urinary incontinence, gait disturbance, and dementia

Question 55

Korsakoff syndrome

Answer 55

characterized by retrograde and anterograde amnesia with preserved remote memory, confabulation and lack of insight; commonly Pelops in pts w/ alcohol use disorder following an episode of Wernicke's encephalopathy

Question 56

Best next steps for pt on loop diuretics

Answer 56

pts on high doses of loop diuretics are predisposed to hypokalemia and contraction alkalosis; early signs of hypokalemia (muscle weakness, cramps, myalgias, and fatigue); prompt tx is needed to prevent respiratory depression and ventricular arrhythmias next step: check blood electrolyte level

Question 57

MOA of HIV antiretroviral medications

Answer 57

Question 58

NADPH oxidase

Answer 58

catalyzes the first step of the respiratory burst pathway, producing ROS that facilitate intracellular killing of phagocytized organisms; deficiency results in chronic granulomatous disease which presents w/ increased risk of infection w/ catalase (+) organisms

Question 59

Acute aortic dissection

Answer 59

sudden-onset severe chest pain and a widened mediastinum and enlarged aortic knob on chest x-ray; uncontrolled HTN is the strongest risk factor in >60 yrs and CT dieases (Marfan syndrome) is usually the primary risk in younger pts

Question 60

Cardiovascular response to exercise

Answer 60

increased CO and vasodilation in exercising muscles; EDV and HR are increased and ESV and SVR are decreased

Question 61

Cardiovascular response to exercise

Answer 61

increased CO and vasodilation in exercising muscles; EDV and HR are increased and ESV and SVR are decreased

Question 62

brain development

Answer 62

Question 63

Answer 63

Reed-Sternberg "owl's eyes" cell, a large cell with abundant cytoplasm, multiple nuclei or a multilobated nucleus and prominent eosinophilic nucleoli is classic histologic finding in Hodgkin lymphoma

Question 64

antifungal drug targets

Answer 64

Cryptococcus neoformans is typically tx w/ Amphotericin B which is a polyene macrolide anti fungal that binds ergosterols (unique to fungi) creating pores in the cell membrane; nephrotoxicity is major adverse effect

Question 65

Pathological findings in Nephritic Syndrome

Answer 65

Question 66

Klinefelter syndrome (47, XXY)

Answer 66

results from meiotic conjunction and is characterized by small, firm, nonfunctional testes; infertility; gynecomastia and increased long bone growth; serum testosterone is low and LH and estradiol are increased

Question 67

cervical transformation zone

Answer 67

Question 68

Hypersensitivity pneumonitis

Answer 68

mold hay secondary to inhalation of dust and mold spores (hundreds of other causes often grouped by occupational exposure); commonly presents w dyspnea, cough, fatigue, and weight loss; imaging shows interstitial inflammation and fibrosis of the lung

Question 69

S2 heart sound in association with heart dysfunction

Answer 69

poorly controlled HTN pt presents w progressive dyspnea and cxr shows pulmonary edema; long standing HTN leads to LV hypertrophy due to chronic increase in after load leading to a diastolic dysfunction

Question 70

Prevention of STI related infections

Answer 70

discuss proper condom use

Question 71

Prevention of STI related infections

Answer 71

discuss proper condom use

Question 72

Answer 72

Renal cell carcinoma; adenocarcinoma of the tubular epithelial cells; a primarily malignancy that occurs in older male smokers; presents as gross hematuria, flank pain, weight loss or fever; labs may show polycythemia or hypercalcemia as result of paraneoplastic syndrome of EPO and PTHrp; well-circumscribed, centered on the renal cortex and if large may distort kidney contour; brain is frequent site of metastasis (hematogenous)

Question 73

Trichophyton rubrum

Answer 73

dermatophyte that causes superficial fungal infections; common sires of involvement include scalp, trunk, nails, groin and feet microscopic scrapings with KOH show branching septet hyphae; commonly treated w topical azole antifungals that inhibit the conversion of lanosterol to ergosterol in the cell wall by 14-alpha demethylase

Question 74

Candida vulvovaginitis

Answer 74

involves the overgrowth of normal vaginal Candida flora; symptoms of pruritus, erythema and white discharge; tx w intravaginal agents such as clotrimazole, miconazole, or nystatin or oral fluconazole

Question 75

A male newborn has multiple dysmorphic features suggestive of Down syndrome. Chromosomal analysis is ordered. Which of the following choices is most appropriate regarding what the parents should be told?

Answer 75

"The newborn has some features of Down syndrome, and chromosomal analysis has been requested" Physicians should address objective findings by explaining their differential diagnosis and next diagnostic steps in simple language.

Question 76

organs affected in a pt w decreased activity of steroid 5-alpha reductase 2?

Answer 76

steroid 5-alpha reductase 2 is an enzyme that catalyzes the metabolism of testosterone to DHT; individuals w this deficiency exhibit decreased concentrations of DHT and impaired development of the male urogenital tract; affected pts may appears phenotypically female or have ambiguous external genitalia - undescended testes and *prostate hypoplasia

Question 77

Obstructive uropathy

Answer 77

can occur in ureter, bladder or urethra; causes distended bladder b/l hydronephrosis and AKI; leads to defects in urinary acidification resulting in metabolic acidosis

Question 78

Acute hemolytic transfusion reactions (AHTR)

Answer 78

most often occur due to ABO incompatibility which occurs when pt receives inappropriately types blood and crossed transfusion products; pts will present w fever, flank pain, chills, hypotension and dark urine within an hour of the start of the transfusions; d/c the transfusion

Question 79

Myotonic dystrophy

Answer 79

AD condition that is caused by trinucleotide repeat expansion; successive generations typically have an increased number of repeats, resulting in earlier and more severe disease (anticipation); in children cognitive/behavioral issues may be the initial findings before development of muscle weakness and myotonia; can also see nonmuscular involvement such as frontal hair loss, *cataracts and insulin resistance

Question 80

55 yr old w severe vaginal pain and itching during intercourse; here is the vaginal smear.

Answer 80

Candida albicans

Question 81

x moves to which location during exercise?

Answer 81

to H

Question 82

relationship among these three agents

Answer 82

Drug X is more potent than drugs Y or Z

Question 83

red bumps on the skin looks like "goosebumps"

Answer 83

Keratosis pilaris

Question 84

Park At Venture Avenue

Answer 84

cardiac action potential is the slowest in the AV node and fastest in the Purkinje system; note that speed of atrial muscle is higher than the ventricular muscle

Question 85

Paget disease of bone

Answer 85

Paget disease of bone is characterized by excessive and disordered bone formation; commonly involves the skull (ex: HA), spine (ex: radiculopathy, spinal stenosis) or long bones (bone pain); long-term complications of Paget disease include fracture, hearing loss and malignant transformation leading to osteosarcoma

Question 86

Globus sensation

Answer 86

is the feeling of a "lump in the throat" w/o accompanying physical, endoscopic, or radiologic findings of esophageal obstruction

Question 87

Oseltamivir

Answer 87

Oseltamivir is an inhibitor of the neuraminidases of influenza A and influenza B viruses; prevents the release of newly formed viral particles

Question 88

Protein synthesis

Answer 88

many proteins are synthesized as a large precursor polypeptides containing the active protein sequence in addition to signaling sequences and protective sequences; removal of these nonfunctional polypeptide sequence (post translational) is accomplished by specific end-proteases and yields a smaller functional protein

Question 89

bronchial smooth muscle relaxation

Answer 89

activation of the M3 receptors in the lung by Ach leads to bronchial smooth muscle constriction; atropine competitively inhibits muscarinic receptors on bronchial smooth muscle, leading to smooth muscle relaxation

Question 90

Elderly and benzodiazepines

Answer 90

slower benzodiazepine metabolism and elimination in the elderly increase the liklihood of adverse effects such as confusion, anterograde amnesia, ataxia and falls

Question 91

Anticholinergic toxicity

Answer 91

anticholinergic intoxication causes fever, dry skin and mucous membranes, flushing, blurred vision, and altered mental status; Jimson weed is a drug of abuse that can cause anticholinergic toxicity

Question 92

diabetic foot

Answer 92

individuals w DM should inspect their feet daily for signs of trauma or infection

Question 93

Molluscum contagiosum

Answer 93

characterized by umbilicated flesh-colored papules on the skin and mucous membranes; caused by a poxvirus which appears in pathologic specimens as eosinophilic cytoplasmic inclusions (molluscum bodies)

Question 94

Answer 94

characterized by umbilicated flesh-colored papules on the skin and mucous membranes; caused by a poxvirus which appears in pathologic specimens as eosinophilic cytoplasmic inclusions (molluscum bodies)

Question 95

Posterior knee dislocation

Answer 95

the popliteal artery runs just posterior to the knee joint and is rigidly fixed proximally and distally by the adductor magnus and soles muscles, respectively making it highly susceptible to injury during tibiofemoral dislocation; injury is a primary concern in posterior knee dislocation due to the potential for LE ischemia-related complications

Question 96

key defense mechanisms

Answer 96

Question 97

Sublimation

Answer 97

mature defense mechanism in which a person channels unacceptable thoughts and impulses into socially acceptable behavior

Question 98

paralysis of the serrates anterior muscle

Answer 98

injury to the long thoracic nerve along the lateral chest wall my occur due to penetrating trauma or a surgical procedure (ex: axillary lymph node dissection); damage to this nerve causes inability to raise arm above the head and protrusion or winging of the medial border of the scapula when the outstretched arm is pushed forward against resistance

Question 99

Schizophreniform disorder

Answer 99

psychotic disorders share signs and symptoms but differ in duration; brief psychotic disorder lasts <1 month; Schizophreniform disorders lasts >1 month and <6 months; a dx of schizophrenia requires a duration of at least 6 months

Question 100

DSM-5 psychotic disorders

Answer 100

Question 101

False positive rate (FPR)

Answer 101

this is not the same as FP!! FPR = 1- specificity

Question 102

Acute intermittent porphyria

Answer 102

acute intermittent porphyria is caused by deficiency of porphobilinogen deaminase and is characterized by intermittent episodes of abdominal pain w neurological manifestations following exposure to an offending medication; urine from pts during attacks will classically darken when exposed to sunlight; skin photosensitivity is characteristically absent

Question 103

Subacute combine degeneration

Answer 103

Vitamin B12 (cobalamin) deficiency can cause SCD of the spinal cord due to impaired myelination in the dorsal columns (diminished tactile/vibratory sensation) and lateral corticospinal tracts (hyperreflexia, Babinski)

Question 104

Myasthenia gravis

Answer 104

MG is an autoimmune disease that affects the postsynaptic Ach receptors on NMJ and presents w fatiguable MSK weakness (comply the eyes); thymus abnormalities are extremely common in pts w MG; pts often improve w thymectomy

Question 105

Knudson's 2-hit hypothesis

Answer 105

Retinoblastoma is a childhood tumor that results from separate mutagenic events that inactivate both copies of the RB1 tumor suppressor gene; gremlin mut is one the RB1 gene cause "hereditary" retinoblastoma, which is associated w the development of other primary tumors (ex: osteosarcoma)

Question 106

DiGeorge syndrome

Answer 106

results from failed development of the 3rd and 4th pharyngeal pouches; a hypo plastic or absent thymus results in recurrent Candida infections (thrush) due to impaired cell-mediated immunity; flow cytometry show low CD3+ fraction but normal CD20+ fraction

Question 107

Phenoxybenzamine

Answer 107

Surgical resection of a pheochromocytoma can trigger preoperative HTN crisis due to the release of catecholamines; this can be prevented w alpha-adrenergic blockers (phenoxybenzamine); beta blockers are typically added after alpha blockers because unopposed alpha adrenergic stimulation can cause severe vasoconstriction and HTN crisis

Question 108

neonatal intraventricular hemorrhage

Answer 108

premature infants are at high risk of intraventricular hemorrhage due to germinal metric fragility; the germinal matrix is dense, highly cellular, vascularized layer of the brain that starts disappearing at 28 wks gestation and fully involutes by term; hemorrhage and clots may extend into the ventricular system and cause altered mental status

Question 109

Cisplatin

Answer 109

the MOST ototoxic chemo agent; thought to damage hair cells in the cochlear membranous labyrinth

Question 110

Amiodarone-induced interstitial pneumonitis

Answer 110

presents w progressive dyspnea, nonproductive cough, fever and patchy interstitial infiltration; condition is usually reversible;e w a reduction in dose or discontinuation of the drug

Question 111

keratinizing invasive squamous cell carcinoma

Answer 111

cervical lymphadenopathy may be presenting symptoms of the head and neck SCC, which originates from the mucosa of the upper GI tract

Question 112

Allelic heterogeneity

Answer 112

different mutations in the same genetic locus causes similar phenotypes; heterogeneity of disease may be explained by the fact that some mutation cause complete loss of protein while others only cause partial loss

Question 113

cysteinyl-containing leukotrienes

Answer 113

inspiration of high volumes of cold and dry air can trigger an inflammatory response similar to atopic asthma; mast cells and eosinophils release cysteinyl-containing leukotrienes (leukotriene C4, D4, and E4) that trigger bronchospasm, bronchial mucus secretion and bronchial edema

Question 114

bacterial antibiotic efflux pumps

Answer 114

common cause of drug or multi drug resistance; they actively transport antibiotics out of the bacteria into the external environment using ATP, sodium gradients or proton electrochemical gradients for energy

Question 115

Achondroplasia

Answer 115

caused by a GOF point mut of the fibroblast growth factor receptor 3 (FGFR3) gene and presents w proximal limb shortening w resultant short stature, mid face hypoplasia and frontal bossing

Question 116

X-linked agammaglobulinemia

Answer 116

caused by a defect in the BTK gene on the X chromosome which results in defective Bruton tyrosine kinase signaling within CD19+ B cells; impaired B-cell maturation leads to low serum immunoglobulins and recurrent infections

Question 117

allogenic hematopoietic stem cell transplantation resulting in a functioning donor hematopoietic stem cell

Answer 117

when a pt receives a bone marrow transplant, the donor stem cells engraft in the bone marrow and produce all the hematopoietic cells for the recipient; the recipient's peripheral blood cells will be genetically different from the rest of the body's cells; when the sex of the recipient and donor differ, peripheral blood cells will have sex chromosomes that do not match the pts birth sex

Question 118

Insulin synthesis and secretion

Answer 118

proteins destined for the rough ER possess hydrophobic N-terminal peptide signal sequences that identify them as such; removal of these signal sequences would cause inappropriate protein accumulation in the cytosol

Question 119

Sertoli cells

Answer 119

Androgen-binding protein is synthesized by the Sertoli cells of the seminiferous epithelium and secreted into the seminiferous tubule lumen; ABP maintains the high local concentration of testosterone necessary for normal sperm production and maturation

Question 120

round ligament of the uterus

Answer 120

the round ligament of the uterus is a vestige of the gubernaculum; it projects from the uterus, travels through the inguinal canal and attaches to the labia majora

Question 121

arterial blood gas in PE

Answer 121

sudden-onset SOB and chest pain in combination w unilateral leg swelling are strongly suggestive of PE; PE causes hypoxemia due to increased dead-space ventilation w worsening V/Q mismatch; hyperventilation leads to hypocapnia w respiratory alkalosis (increased pH, decreased PaCO2) which is the typical presentation of acute PE