UWorld Test Review 3 Flashcards
name the 4 classes of anti-fungal drugs and their MOA
- polyenes (amphotericin B, nystatin): bind ergosterol in fungal cell membranes and create pores
- triazoles (ketoconazole, fluconazole, itraconazole, voriconazole): inhibit ergosterol synthesis
- echinocandins (caspofungin, micafungin): inhibit glucan synthesis (component of cell wall)
- pyrimidines (flucytosine): converted to 5-fluorouracil and interferes with fungal RNA/protein synthesis
which of the following cytokines is an important mediator of sepsis?
a. IL-3
b. IL-4
c. IL-10
d. LTB4
e. TGF-beta
f. TNF-alpha
f. TNF-alpha (tumor necrosis factor-alpha): stimulates systemic inflammation via leukocyte recruitment
others important for systemic inflammation are IL-1 and IL-6
Pt w/ PMH of Staph. aureus due to IV drug use now has aortic regurgitation. Which of the following changes is most responsible for maintaining cardiac output in the setting of this valvular abnormality?
a. concentric LV hypertrophy
b. decrease in LV preload
c. increase in aortic elasticity
d. increase in LV afterload
e. increase in LV stroke volume
f. sustained increase in HR
e. increase in LV stroke volume
regurgitation causes LV dilation (eccentric hypertrophy) —> increase in SV
oocytes are arrested in which state of meiosis immediately prior to fertilization?
metaphase of meiosis II
[frozen in prophase of meiosis I until ovulation]
where would type I vs II vs III vs IV collagen be found?
type I = bones, tendons, ligaments, cornea, blood vessels, scar tissue (mutation = osteogenesis imperfecta)
type II = cartilage, vitreous humor, nucleus pulposus (mutation = skeletal dysplasias)
type III = lungs, intestines, blood vessels, bone marrow, lymphatics, granulation tissue (mutation = Ehlers-Danlos)
type IV = basement membranes (mutation = Alport syndrome)
Pt arrives comatose to ED after car accident. CT of head within an hour shows no abnormalities. Pt dies several hours later, and autopsy is performed. Brain histopathology shows widespread axonal swelling, predominantly at the gray-white junction. Immunohistochemical staining of these axons shows an accumulation of alpha-synuclein and amyloid precursor. What is the most likely cause of these findings?
a. Diffuse cerebral hypoperfusion.
b. Glutamate mediated neuronal injury.
c. Interruption of white matter tracts
d. Secondary microvascular spasm.
c. Interruption of white matter tracts
diffuse axonal injury is type of TBI occurring form direct blunt force injury or abrupt changes in acceleration-deceleration —> shearing of white matter tracts —> normal axonal transport is inhibited, leading to accumulation of transported proteins (amyloid precursor, alpha-synuclein)
which 3 mutation sites have been associated with early-onset familial Alzheimer’s?
- amyloid precursor protein (APP) gene on chromosome 21
- presenilin 1 gene on chromosome 14
- presenilin 2 gene on chromosome 1
homozygous for apolipoprotein E-4 allele confers risk of:
a. familial hypercholesterolemia.
b. Hypertrophic cardiomyopathy.
c. diabetes mellitus type 2
d. Polycystic kidney disease.
e. Alzheimer’s disease.
e. Alzheimer’s disease.
7mo M presents with irritability and white patches in mouth. PMH notable for 3 episodes of otitis media and 2 episodes of bronchiolitis. Also has history of chronic loose stools. Child is small and ill-appearing. PE is notable for wheezing but cardiac exam is normal. Serum protein electrophoresis shows a very low gamma globulin level. Chest x-ray reveals an absent thymic shadow. What is the dx?
severe combined immunodeficiency (SCID): presents with severe viral/bacterial infections, mucocutaneous candidiasis, persistent diarrhea, failure to thrive
labs show absent CD3+ T cells and hypogammaglobulinemia + thymic hypoplasia due to severe T cell deficiency
[NOT DiGeorge because this would present with craniofacial abnormalities, cardiac abnormalities, and hypocalcemia due to parathyroid hypoplasia]
what are the distinctive features of the following primary immunodeficiencies:
a. Chediak-Higashi
b. chronic granulomatous
c. DiGeorge
d. SCID
e. Wiskott-Aldrich
a. Chediak-Higashi: albinism, pyogenic infections, progressive neuro dysfunction
b. chronic granulomatous: bacterial + fungal infections, granulomas
c. DiGeorge: heart disease, dysmorphic facies, hypocalcemia (parathyroid hypoplasia)
d. SCID: bacterial + viral infections (infancy), chronic diarrhea, mucocutaneous candidiasis
e. Wiskott-Aldrich: recurrent infections that worsen with age, easy bleeding, eczema
which of the following pathways mediates EPO signaling?
a. adenylate cyclase/ cAMP
b. arachidonic acid/phospholipase A2
c. Janus kinase 2/ STAT
d. phosphatidylinositol/ inositol triphosphate
e. Ras/mitogen-activated protein kinase
c. Janus kinase 2 (JAK2/STAT)
[STAT = signal transducer and activator of transcription]
which of the following pathways mediates glucagon signaling?
a. adenylate cyclase/ cAMP
b. arachidonic acid/phospholipase A2
c. Janus kinase 2/ STAT
d. phosphatidylinositol/ inositol triphosphate
e. Ras/mitogen-activated protein kinase
a. adenylate cyclase/ cAMP
this pathway also mediates effects of ADH (V2 receptor) and corticotropin
which of the following pathways mediates ADH signaling at V1 vs V2 receptors?
a. adenylate cyclase/ cAMP
b. arachidonic acid/phospholipase A2
c. Janus kinase 2/ STAT
d. phosphatidylinositol/ inositol triphosphate
e. Ras/mitogen-activated protein kinase
a. adenylate cyclase/ cAMP = ADH at V2 receptor
d. phosphatidylinositol/ inositol triphosphate = ADH at V1 receptor
which of the following pathways mediates GnRH and oxytocin signaling?
a. adenylate cyclase/ cAMP
b. arachidonic acid/phospholipase A2
c. Janus kinase 2/ STAT
d. phosphatidylinositol/ inositol triphosphate
e. Ras/mitogen-activated protein kinase
d. phosphatidylinositol/ inositol triphosphate
as well as ADH at V1 receptors
which of the following pathways mediates growth factor signaling?
a. adenylate cyclase/ cAMP
b. arachidonic acid/phospholipase A2
c. Janus kinase 2/ STAT
d. phosphatidylinositol/ inositol triphosphate
e. Ras/mitogen-activated protein kinase
e. Ras/mitogen-activated protein kinase
therefore, uncontrolled activation = malignancy
4yo M presents with 3 days of fever, irritability, and oral lesions. PE shows painful ulcers on tongue and gingiva, as well as swollen gums and cervical lymphadenopathy. What is the most likely dx? What would histology show?
HSV-1 gingivostomatitis - peak age for primary infection is 6mo-5yrs, causes painful vesicles covering lips and gingiva (may include palate, tongue, oropharynx)
histology shows multinucleated giant cells on Tzanck smear
mothers with which blood type are most at risk for causing fetal hemolysis? why?
maternal antibodies (anti-A/B) are of IgM type, but mothers with blood type O also produce IgG which can cross placenta
78yo F presents with acute vision loss in L eye that developed over an hour. It is not painful, but the patient has had L-sided headaches for the past 3 weeks and aching in the shoulders that has slowly worsened over the last month. PE shows decreased pupillary light reflex in the L eye with impaired acuity. What is the dx and the tx?
dx: giant cell (temporal) arteritis - presents with fever/fatigue/weight loss + headache + jaw claudication + visual disturbances (ischemic optic neuropathy) + polymyalgia rheumatica
labs show elevated erythrocyte sedimentation rate and C-reactive protein
temporal artery biopsy shows intimal thickening, elastic lamina fragmentation, and multinucleated giant cells
tx: glucocorticoids
what is the cause of visual disturbances in giant cell (temporal) arteritis? what is the treatment?
presents with fever/fatigue/weight loss + headache + jaw claudication + visual disturbances (ischemic optic neuropathy) + polymyalgia rheumatica
labs show elevated erythrocyte sedimentation rate and C-reactive protein
temporal artery biopsy shows intimal thickening, elastic lamina fragmentation, and multinucleated giant cells
tx: glucocorticoids
what do labs and histology show in giant cell (temporal) arteritis?
labs show elevated erythrocyte sedimentation rate and C-reactive protein
temporal artery biopsy shows intimal thickening, elastic lamina fragmentation, and multinucleated giant cells
which of the following would best treat visual disturbances caused by giant cell arteritis?
a. acetazolamide
b. clopidogrel
c. methylprednisolone
d. sumatriptan
c. methylprednisolone (tx w/ glucocorticoids)
a. acetazolamide = carbonic anhydrase inhibitor/ diuretic, tx idiopathic intracranial HTN and angle-closure glaucoma
b. clopidogrel = anti-platelet
d. sumatriptan = migraine treatment
how do levels of the following change as fetal lungs mature?
a. lamellar bodies
b. sphingomyelin
c. phosphatidylglycerol
d. lecithin
lecithin (aka phosphatidylcholine) / sphingomyelin (L/S) ratio increases (>2) - lecithin increases while sphingomyelin remains low
lamellar bodies increase - organelles within type 2 pneumocytes that store/secrete surfactant
phosphatidylglycerol increases - component of surfactant
as fetal lungs mature, the ratio of _____ to ______ increases
lecithin (aka phosphatidylcholine) / sphingomyelin (L/S)
ratio increases (>2) because lecithin increases while sphingomyelin remains low
what is used to treat the following?
a. gonorrhea with neg. chlamydia NAAT
b. chlamydia with neg. gonorrhea NAAT
c. gonorrhea with pos. or uncertain chlamydia status
a. gonorrhea with neg. chlamydia NAAT = ceftriaxone
b. chlamydia with neg. gonorrhea NAAT = azithromycin or doxycycline monotherapy
c. gonorrhea with pos. or uncertain chlamydia status = ceftriaxone + doxycycline
Fracture of the greater trochanter will impair the function of which of the following muscles? what is the action of the muscle?
a. adductor Magnus.
b. Gluteus medius
c. Iliopsoas.
d. Rectus femoris.
e. Sartorius.
b. Gluteus medius - originates from ilium, inserts on greater trochanter; action = hip abduction
a. adductor Magnus - inserts on medial condyle of distal femur
c. Iliopsoas - inserts onto lesser trochanter (primary flexor)
d. Rectus femoris - attaches to lower leg via patellar tendon
e. Sartorius - inserts on pes anserinus
the pes anserinus is the common tendon for which 3 muscles?
- Sartorius.
- Gracilis.
- Semitendinosous.
pes anserinus is on superior medial surface of tibia
Crystalline-induced kidney injury most commonly occurs from which two types of drugs?
- acyclovir
- sulfonamide
what is the meaning of the following urinary cast findings?
a. Hyaline
b. Waxy.
c. Granular/muddy brown.
a. Hyaline (Tamm-Horsfall protein) = nonspecific, concentrated urine, prerenal azotemia
b. Waxy (degenerated hyaline cast) = chronic kidney disease.
c. Granular/muddy brown (sloughed tubular cells) = acute tubular necrosis
what kind of drugs are anastrozole, letrozole, and exemestane?
aromatase inhibitors - block conversion of testosterone to estradiol
used to treat ER-positive tumors
which of the following would cause an increase in both renin and aldosterone?
a. adrenal cortical tumor
b. adrenal medullary tumor
c. juxtaglomerular cell tumor
d. pituitary tumor
e. primary HTN
c. juxtaglomerular cell tumor - secretes renin
high renin + high aldosterone = secondary hyperaldosteronism (renovascular HTN, malignant HTN, renin-secreting tumor, diuretic use)
low renin + high aldosterone = primary hyperaldosteronism (aldosterone-producing tumor, bilateral adrenal hyperplasia)
low renin + low aldosterone = non-aldosterone causes (congenital adrenal hyperplasia, Cushing syndrome, exogenous mineralocorticoids)
what is the histological finding of the following opportunistic causes of diarrhea in HIV patients?
a. cytomegalovirus
b. cryptosporidium
c. microsporidium
d. mycobacterium avium complex
a. cytomegalovirus: multiple ulcers + mucosal erosions, large cells w/ basophilic inclusions
b. cryptosporidium: non-ulcerative inflammation, basophilic clusters on surface of mucosal cells
c. microsporidium: distortion of villus without inflammation, small spores with diagonal/equatorial belt-like structure
d. mycobacterium avium complex: granulomas, acid-fast staining bacilli
______ must be ligated during an oophorectomy to prevent heavy ovarian bleeding
suspensory ligament of the ovary (aka infundibulopelvic ligament) - contains the ovarian artery
Where are the SA node and AV node found in the heart?
SA node - right atrium near the opening of the superior vena cava
AV node - right atrium near the septal cusp of tricuspid valve
[a-fib often originates in the area around the pulmonary veins in the left atrium)
pt is started on ramipril for HTN and their serum creatinine increases - why?
“-pril” = ACE inhibitor
ACEi cause efferent arteriole dilation, which lowers intraglomerular pressure and prevents kidneys from maintaining GFR in setting of decreased renal perfusion
many pts see increase in serum creatinine within 2-5 days of starting ACEi
which of the following explains the hemoglobinuria seen in acute hemolytic transfusion reaction?
a. CD8+ mediated cytotoxicity
b. complement mediated cell lysis
c. endotoxin-induced TNFalpha surge
d. IgE-mediated reaction to serum proteins
b. complement mediated cell lysis
anti-ABO Abs (mainly IgM) bind antigens and activate complement –> C3a + C5a cause vasodilation/ shock symptoms while C5b-C9 form MAC
which of the following is first to be released during an allergic reaction?
a. histamine
b. leukotriene D4
c. major basic protein
d. platelet-activating factor
e. prostaglandin D2
a. histamine - from preformed granules
b. leukotriene D4 - synthesized via 5-lipoxygenase
c. major basic protein - released from eosinophils in late stage of Type I hypersensitivity, causes local tissue damage
d. platelet-activating factor - secondary inflammatory mediator, must be synthesized from phospholipid prior to release
e. prostaglandin D2 - synthesized via cyclooxygenase
the type of hepatitis virus that has a high mortality rate in pregnant women also:
a. is an unenveloped RNA virus
b. is transmitted parenterally
c. is associated with chronic hepatitis
d. infects only HBsAg+ individuals
e. has oncogenic properties
Hep E: unenveloped RNA virus (a), fecal-oral route in Asia/Africa/Mexico, incubation 6 weeks
b. is transmitted parenterally = Hep B, C, D
c. is associated with chronic hepatitis = Hep C
d. infects only HBsAg+ individuals = Hep D
e. has oncogenic properties = Hep B, C
weakness with hip flexion and knee extension = injury to which muscle?
rectus femoris
what transporter facilitates intracellular Ca2+ efflux from cardiomyocytes during myocyte relaxation?
- Na+/Ca2+ exchange pump (NCX)
- Ca2+-ATPase pump (SERCA)
22yo F presents w/ 5d history of nausea, constipation, and abdominal pain. She also reports trouble concentrating and tingling in her limbs. She has had similar episodes in the past. She does not take medication, but has been restricting her diet to lose weight. Pt receives an IV infusion of heme and the symptoms rapidly improve. What is the dx? What enzyme is being downregulated by the treatment?
dx: acute intermittent porphyria (AIP) - AD deficiency of porphobilinogen (PBG) deaminase
presents w/ abdominal pain, neuro manifestations, port-wine urine, PBG + ALA in urine [NO photosensitivity]
tx: glucose or hemin –> inhibit hepatic aminolevulinate synthase (ALAS) (rate-limiting enzyme in heme synthesis)
what brings on an attack of acute intermittent porphyria (include some examples), and how does it present?
acute intermittent porphyria (AIP) = AD deficiency of porphobilinogen (PBG) deaminase
attack also requires induction of aminolevulinate synthase (ALAS) (rate-limiting step) via medications (phenobarbital, phenytoin), alcohol, smoking, progesterone (puberty), or low-calorie diet
presents w/ abdominal pain, neuro manifestations, port-wine urine, PBG + ALA in urine [NO photosensitivity]
what are 2 clinical scenarios in which a patient could have a deficiency in ferrochelatase? how would this present?
- lead poisoning
- erythropoietic protoporphyria - cutaneous photosensitivity beginning in early childhood
ferrochelatase converts protoporphyrin into heme
24yo F has fevers/chills for past 24 hours. She underwent GI surgery 3 weeks ago without complication and now has a central venous catheter for parenteral nutrition. She has fever, hypotension, and elevated pulse. Blood cultures are positive for yeast. Why is it probably Candida, and why ISN’T it any of the following:
a. blastomyces
b. coccidioides
c. cryptococcus
d. mucormycosis (Mucorales, Rhizopus)
parenteral nutrition via catheter is a high risk for candidemia - can colonize catheter, and parenteral nutrition solution promotes growth
a. blastomyces - causes pulmonary infection w/ occasional dissemination, but unlikely in setting of catheter
b. coccidioides - endemic to southwest, inhaled (pulm infection), immunocompromised patients
c. cryptococcus - causes meningitis, immunocompromised patients
d. mucormycosis - invasive disease in immunocompromised, do not grow in blood cultures, not associated with catheters
a patient with refractory N/V due to chemo drugs may benefit from therapy that blocks which receptor?
a. endogenous opioid
b. motilin
c. neurokinin 1
d. neuropeptide Y
e. nicotinic ACh
c. neurokinin 1 (NK1) inhibitors prevent substance P release –> blocked signaling to area postrema
other anti-emetic drugs include:
1. anti-muscarinic (scopolamine)
2. antihistamines
3. dopamine antagonists
4. 5-HT3 antagonists
name 3 antihistamines that can treat motion sickness
- diphenhydramine
- meclizine
- promethazine - also treats hyperemesis gravidarum
name 2 5-HT3 receptor antagonists that can treat chemotherapy-induced emesis
- ondanestron
- granisetron
block signaling to area postrema in 4th ventricle
what is the mechanism behind the pathology of Fragile X syndrome? BE SPECIFIC
mutation of FMR1 on X chromosome –> trinucleotide expansion of CGG –> FMR1 hypermethylation in promoter region –> inhibited transcription
causes neurobehavioral features (ADHD, autism, lack of social skills) and developmental delay
rate the following in order of increasing cost of monthly premiums: preferred provider organization (PPO), health maintenance organization (HMO), and point of service plan (POS)
HMO = $
POS = $$
PPO = $$$
lateral epicondyle = [tennis/golf] elbow = pain with wrist [flexion/extension]
medial epicondyle = [tennis/golf] elbow = pain with wrist [flexion/extension]
lateral epicondyle = tennis elbow = pain with wrist extension
medial epicondyle = golf elbow = pain with wrist flexion
in addition to beta-adrenergic receptor blocking, how does propranolol benefit a patient with hyperthyroidism?
also reduces peripheral conversion of T4 to T3 by inhibiting 5’-monodeiodinase ! (idk why just go with it)
peripheral conversion is also decreased by glucocorticoids and propylthiouracil
when you have to wear crutches for awhile you might injure the ____ nerve
radial nerve !!!
aka “crutch palsy,” or if sleeping on a chair, “Saturday night palsy” –> weak extensor muscles (wrist drop, absent triceps reflex)
which of the following is a possible affect of tamoxifen?
a. decrease in bone mass
b. endometrial hyperplasia
c. fibroadenoma of the breast
d. increase in LDL levels
b. endometrial hyperplasia
tamoxifen (SERM): anti-estrogen in breast tissue (ER+ breast cancer), estrogen promoting in endometrial tissue (can increase endometrial cancer risk)
zero-order vs first-order drug metabolism
zero-order = fixed amount eliminated per unit of time (straight line with negative slope)
first-order = fixed proportion eliminated per unit of time (exponential decay curve)
which of the following happens after ligation of a PDA and why?
a. decreased RV output
b. decreased RV preload
c. increased LV afterload
d. increased LV output
e. increased RV afterload
c. increased LV afterload - this is because the diastolic pressure in the aorta increases
which immune cells control tuberculosis infections?
CD4+ T lymphocytes + macrophages –> granuloma formation
why would a woman with primary hypothyroidism present with galactorrhea?
increase in TRH (thyrotropin-releasing hormone) –> increase in TSH secretion from pituitary
lactotrophs also express TRH receptors, so increase in TRH can induce increase in prolactin release
celecoxib
selective COX-2 inhibitor that can be used to treat gout in patients with history of GI disease like peptic ulcers (because COX-1 is important for gastric mucosal production)
COX-2 = inducible enzyme upregulated during inflammation
which infectious agent is associated with the following malignancies?
a. cervical carcinoma
b. hepatocellular carcinoma
c. Kaposi sarcoma
d. mucosa-associated lymphoid tissue tumor
e. nasopharyngeal carcinoma
a. cervical carcinoma - HPV (16, 18, 31, 33)
b. hepatocellular carcinoma - chronic Hep B or C
c. Kaposi sarcoma - HIV, HHV type 8
d. mucosa-associated lymphoid tissue tumor - Helicobacter pylori
e. nasopharyngeal carcinoma - Epstein-Barr (EBV)
intracellular, round-oval protozoa with rod-shaped kinetoplasts =
leishmaniasis: endemic to Middle East and Central/South America, transmitted via infected sand fly
what type of diuretic can help prevent calcium kidney stones? name an example
thiazide diuretics: inhibit apical Na+/Cl- cotransporter in DCT (prevents Na+ reabsorption into cell), which activates basolateral Na+/Ca2+ antiporter (allowing Na+ into cell, and preventing Ca2+ excretion)
ex: hydrochlorothiazide
exudative vs transudative pleural effusion
exudative: inflammatory increase in membrane permeability (infection, malignancy, rheumatologic disease)… pleural protein/serum protein >0.5 OR pleural LDH/serum LDH >0.6 OR pleural LDH greater than 2/3 upper limit of normal serum LDH
transudative: change in hydrostatic or oncotic pressure (heart failure, cirrhosis, nephrotic syndrome)
which of the following are increased by dobutamine:
a. cardiac diastolic filling time
b. myocardial O2 consumption
c. peripheral vascular resistance
d. pulmonary capillary wedge pressure
e. RV end diastolic pressure
b. myocardial O2 consumption
dobutamine = beta1 agonist, used to treat cardiogenic shock
–> positive inotropy and chronotropy, which increases CO and myocardial O2 consumption (can trigger myocardial ischemia, not for routine use in patients with decompensated HF)
how do the following affect PaO2, SaO2, and oxygen content?
a. CO poisoning
b. cyanide poisoning
c. anemia/ chronic blood loss
d. polycythemia
e. high altitude
a. CO poisoning = normal PaO2, detected normal SaO2, low O2 content
b. cyanide poisoning (inhibits oxidative phosphorylation) = normal PaO2, normal SaO2, normal O2 content
c. anemia/ chronic blood loss = normal PaO2, normal SaO2, low O2 content
d. polycythemia = normal PaO2, normal SaO2, high O2 content
e. high altitude = low errything
pt w/ recurrent nosebleeds and pink spider-like lesions on oral and nasal mucosa, face, and arms =
Osler-Weber-Rendu syndrome, aka hereditary hemorrhagic telangiectasia: AD inheritance of congenital telangiectasias, which may rupture and cause epistaxis, GI bleeding, hematuria
fetal ultrasound shows severe unilateral hydronephrosis without ureteral dilation - where is the most likely site of obstruction?
ureteropelvic junction: where pelvis of kidneys meets ureter; obstruction likely due to failure of canalization
(if it were further down at vesicoureteral junction, there would be dilation of ureters)
2 most important factors for osteoclast differentiation
- macrophage colony-stimulating factor (M-CSF)
- receptor for activated nuclear factor kappa-B ligand (RANK-L)
elderly man with R tibial pain and progressive hearing impairment. PE notable for lumpy protuberance over R tibia. pathology shows multinucleated cells containing over 100 nuclei. dx?
Paget disease: excessive osteoclast resorption followed by osteoblast bone formation –> disorganized bone with high turnover
osteoclasts in Paget disease are super large and have 100+ nuclei (normal osteoclasts have 2-5)
73yo M presents w/ hematuria. PMH includes HTN, chronic bronchitis, and smoking. Urine cytology shows malignant cells. Which type of cancer is most likely, and which of the following features is most suggestive of poor prognosis?
a. high-grade intraepithelial lesion
b. involvement of muscular propria layer
c. location at anterior bladder wall
d. papillary morphology
e. tumor size >2cm
dx: urothelial (transitional cell) carcinoma: smoking is major risk factor
b. involvement of muscular propria layer - tumor stage (invasion/metastasis) is most important for determining prognosis
[tumor grade = degree of cellular abnormality, not as important as staging, as high-grade cells could have favorable prognosis if they have not yet invaded]
immunosuppressant that inhibits conversion of inosine monophosphate to guanosine monophosphate in activated lymphocytes
mycophenolate
de novo purine synthesis:
1. ribose 5-phosphate –> PRPP (phosphoribosyl pyrophosphate)
2. PRPP –> –> –> inosine monophosphate, via PRPP aminotransferase (inhibited by azathioprine/6-MP)
3. inosine monophosphate –> GMP via IMP dehydrogenase (inhibited by mycophenolate)
fill in the blanks regarding de novo purine synthesis:
1. ______ –> PRPP
2. PRPP –> –> –> _____ via PRPP aminotransferase (inhibited by _______ drug)
3. ______ –> GMP via _______ (inhibited by ____ drug)
de novo purine synthesis:
1. ribose 5-phosphate –> PRPP (phosphoribosyl pyrophosphate)
2. PRPP –> –> –> inosine monophosphate, via PRPP aminotransferase (inhibited by azathioprine/6-MP)
3. inosine monophosphate –> GMP via IMP dehydrogenase (inhibited by mycophenolate)
which of the following increase during exercise:
a. arterial blood mean CO2 content
b. arterial blood mean O2 content
c. pH of arterial blood
d. venous blood mean CO2 content
d. venous blood mean CO2 content - due to increase in skeletal muscle production of CO2
mean values of arterial O2 and CO2 remain stable during exercise due to tight regulation
pH during exercise decreases due to lactic acid production
45yo M w/ groin pain/swelling. -1mo had painless ulcer on penis that healed spontaneously within 1 week. Several days ago, had painful inguinal swelling and formation of several draining ulcers. Cell scrapings show cytoplasmic inclusion bodies. Which is most likely? Rule out the other options.
a. Chlamydia trachomatis
b. Haemophilus ducreyi
c. Herpes simplex virus
d. Klebsiella granulomatis
e. Treponema pallidum
a. Chlamydia trachomatis: serotypes L1-L3 cause lymphogranuloma venereum (LGV), characterized by initial painless ulcers followed by painful buboes (inguinal nodes), tx = doxycycline
b. Haemophilus ducreyi: painful papules (you “do cry” with H. ducreyi)
c. Herpes simplex virus (type 1/2): painful vesicles that develop into ulcers , histology shows multinucleated giant cells and pink-purple intranuclear inclusions
d. Klebsiella granulomatis: painless genital papule, but intracytoplasmic Donovan bodies are diagnostic
e. Treponema pallidum (Syphilis): painless chancre that does not develop into buboes, no inclusion bodies (Gram - spirochete)
which HIV ART medication can cause hyperglycemia?
protease inhibitors (PI) - adverse effects include lipodystrophy (buffalo hump, central obesity), hyperglycemia (insulin resistance), inhibition of P450
ex: atazanavir, darunavir, indinavir, ritonavir, lopinavir
how are the following used to treat patients with HIV?
a. acyclovir
b. lopinavir
c. azithromycin
d. foscarnet
e. TMP-SMX
f. zidovudine
a. acyclovir = antiviral against HSV1/2 and VZV
b. lopinavir = protease inhibitor (“-navir”)
c. azithromycin = macrolide, treats/prophylaxis of Mycobacterium avium
d. foscarnet = treats CMV
e. TMP-SMX = prevents/treats pneumonia by Pneumocystis jirovecii
f. zidovudine = nucleoside RT inhibitor (NRTI)
Kussmaul sign
in constrictive pericarditis, right pericardium prevents R side of heart from accommodating increased venous return, leading to paradoxical rise in JVP during inspiration
what does a sustained left parasternal lift indicate?
sign of RV hypertrophy (pulmonary HTN, pulmonic stenosis, tricuspid regurgitation)
fill in the blank:
1. glucose –> sorbitol via ______ and requiring cofactor _____ (fast)
2. sorbitol –> _____ via _______ and requiring NAD+ (slow)
- glucose –> sorbitol via aldose reductase and requiring cofactor NADPH (fast)
- sorbitol –> fructose via sorbitol dehydrogenase and requiring NAD+ (slow)
when is methimazole vs propylthiouracil (PTU) prescribed for hyperthyroidism?
PTU is hepatotoxic, but methimazole is teratogenic
therefore, methimazole is preferred usually, except during first trimester of pregnancy when PTU is used (after first trimester, switch back to methimazole)
which of the following hormones binds to a receptor containing a zinc finger? what does this mean?
a. ACTH
b. ADH
c. epinephrine
d. insulin
e. thyroid hormone
e. thyroid hormone
zinc fingers are DNA binding domains - therefore, found in intracellular receptors
therefore, lipid soluble hormones could bind this - ex. include thyroid hormone, steroids, fat-soluble vitamins
most common site of thrombus formation in atrial fibrillation
left atrial appendage
which 2 cytokines are important in the pathology of psoriasis, and what do they do?
IL-12 –> Th1 activation
IL-23 –> Th17 activation
6yo unvaccinated M presents w/ persistent cough, which began as mild URI -2 weeks. Dry cough has progressed, and spells are now often followed by vomiting. Child recently returned from summer camp. On PE, pt is afebrile and clear to auscultation. Respiratory secretions show gram-neg. coccobacilli. What is the most likely pathogen? What is the tx?
Bordetella pertussis: spreads via airborne droplets, causes mild cough/rhinorrhea followed by several weeks of severe paroxysmal cough with inspiratory whoop and vomiting after coughing spells
attaches to respiratory epithelium and releases pertussis/AB toxin (releases adenylate cyclase) + tracheal cytotoxin (damages ciliated cells)
rx: macrolides (azithromycin)
accumulation of ultra large von Willebrand factor multimers is due to…
what do labs show?
thrombotic thrombocytopenic purpura (TTP): reduced activity of ADAMTS13, which cleaves vWF multimers
labs show low platelets, but NORMAL PT/PTT (coagulation cascade unaffected) + normal fibrinogen
what are the 3 functions of thyroid peroxidase (TPO)?
- oxidation of iodide
- iodinating of thyroglobulin
- coupling reaction between 2 iodized tyrosine residues
2 week old presents with runny nose, low-grade fever, skin rash for 2 days. Mother had poor prenatal care. PE shows nasal drainage and peeling on face, hands, and feet. Hepatosplenomegaly and lymphadenopathy are present. Which of the following is most likely? Rule out the other options:
a. erythema multiforme
b. Kawasaki disease
c. measles
d. Scarlet fever
e. syphilis
e. congenital syphilis: early signs include snuffles + maculopapular rash (desquamation involving palms/soles) + skeletal anomalies (long bones)
a. erythema multiforme - rash involving palms/soles, but with target lesions (dusky center)
b. Kawasaki disease - super rare in neonates, desquamating rash involving hands/feet, but also includes conjunctivitis and mucositis, will not see hepatosplenomegaly/lymphadenopathy
c. measles - rash spreads cephalocaudally, spares palms/soles
d. Scarlet fever - diffuse sandpaper rash sparing palms/soles
what type of antibodies are important in preventing reinfection with influenza virus?
anti-hemagglutinin Abs - block binding to host cell
[anti-neuraminidase Abs decrease extent of viral invasion/shedding, but are not main source of protection against reinfection]
pt w/ resistant HTN is given a medication that causes selective direct relaxation of smooth muscle of arterioles but not veins - which of the following adverse effects is expected?
a. angioedema
b. bradycardia
c. cold extremities
d. decreased CO
e. sodium and fluid retention
f. transient hypertension
e. sodium and fluid retention
selective arteriolar vasodilators (hydralazine, minoxidil) reduce SVR, but this stimulates baroreceptors —> SNS activation causes increased HR, CO + RAAS activation —> sodium/ fluid retention
which of the following is an effect of a sodium-glucose cotransporter 2 Inhibitor?
a. Decreased blood pressure.
b. Increased fluid retention.
c. Increased postprandial satiety
d. Increased risk for fasting hypoglycemia.
a. Decreased blood pressure.
SGLT-2 inhibitors include Canagliflozin and dapagliflozin - decrease renal reabsorption of glucose in sodium, lowering blood glucose and causing osmotic diuresis
Decreases mortality in heart failure, and slows progression of diabetic neuropathy
Positive blood on urine dipstick in absence of red blood cells on microscopic urinalysis suggests…
myoglobinuria (rhabdomyolysis)
subgaleal hemorrhage
neonatal bleed that occurs during delivery (typically vacuum delivery) when emissary veins between dural sinuses and scalp are sheared
blood accumulates between periosteum and galea aponeurosis —> diffuse, progressive scalp and neck swelling
what is ganciclovir vs acyclovir used to treat? (specifically)
ganciclovir - treats CMV
acyclovir - treats HSV and VZV
how does renal involvement of SLE manifest, and what does histology show?
diffuse proliferative glomerulonephritis - light microscopy shows thickening of glomerular capillary walls + “wire loop” structures due to sub-endothelial immune complex deposition
Pt has UTI. Urinalysis shows pH of 5, positive for leukocyte esterase, positive for nitrites, negative for blood. Which of the following is most likely:
a. Candida albicans
b. Enterococcus faecalis
c. Escherichia coli
d. Herpes simplex virus
e. Proteus mirabilis
f. Staphylococcus saprophyticus
c. Escherichia coli - positive for nitrites and pH will be acidic
[leukocyte esterase is released by lysed WBC, marker of inflammation]
Proteus mirabilis also produce nitrites, but pH would be >8 (produces urease)
3 day old M w/ vomiting, poor feeding, and lethargy. Parents report sweet smelling urine. PE shows dry mucous membranes and hypertonia. Which of the following should be restricted from diet?
a. galactose
b. leucine
c. methionine
d. phenylalanine
e. tyrosine
dx: maple syrup urine disease - AR inborn error of metabolism due to branched-chain alpha-keto acid dehydrogenase complex deficiency
branched chain amino acids = leucine, isoleucine, valine —> accumulation is neurotoxic
dietary restriction of methionine is required for treatment of…
how does this present?
homocystinuria: AR defect in cystathionine beta-synthase —> elevated homocysteine and methionine
presents w/ marfanoid appearance, lens dislocation, developmental delay, risk of thromboembolism
what disease requires dietary restriction of phenylalanine, and how does it present?
phenylketonuria: AR deficiency of phenylalanine hydroxylase
presents w/ intellectual disability, seizures, decreased hair/skin pigmentation, musty odor
which primary immunodeficiency presents with a deficiency of platelets which are abnormally shaped?
Wiskott-Aldrich syndrome: X-linked (males), eczema + thrombocytopenia (petechiae, purpura, epistaxis) + recurrent infections
which of the following medications has the greatest positive impact on fetal survival in a preterm birth?
a. dexamethasone
b. insulin
c. magnesium
d. nifedipine
e. terbutaline
a. dexamethasone - corticosteroids increase surfactant production by accelerating maturation of type II pneumocytes
c. magnesium sulfate - given in pregnancies at risk for preterm, decreases risk of cerebral palsy
d. nifedipine (Ca2+ channel blocker) & e. terbutaline (beta-sympathomimetic) - inhibit preterm labor
what is the cause of head louse?
Pediculus humanus capitis
what is the species that causes bedbugs?
Cimex lectularius
patient with transient febrile illness and rash while traveling in Puerto Rico now presents with severe, persistent polyarthritis - what is the dx?
Chikungunya virus: alphavirus transmitted via Aedes mosquitoes, outbreaks common in tropical/subtropical regions
the MOA of sildenafil is most similar to the intracellular signaling of which of the following?
a. 1,25-dihydroxycholecalciferol
b. BNP
c. gamma-aminobutyric acid
d. insulin
e. IL-2
f. platelet-derived growth factor
sildenafil = phosphodiesterase inhibitor, decreases degradation of cGMP —> relaxation of vascular smooth muscle and vasodilation
b. BNP (and ANP) - increase cGMP to cause vasodilation
a. 1,25-dihydroxycholecalciferol - binds nuclear receptor
c. gamma-aminobutyric acid - inhibitory NT, hyperpolarizes membrane
d. insulin - binds membrane receptor (alpha subunits extracellular, beta subunits intracellular)
e. IL-2 - activates JAK-STAT, MAPK, and phosphoinositide 3-kinase
f. platelet-derived growth factor - activates tyrosine kinase receptor
genetic cause of alpha vs beta thalassemia
alpha thalassemia = complete gene deletion
beta thalassemia = point mutation
synovial fluid crystals which are blue when aligned parallel and yellow when aligned perpendicular to the slow ray of the compensator =
pseudogout due to calcium pyrophosphate deposition disease (CPPD)
