UWorld Practice Questions #2 Flashcards
What is omaluzimab and what is it used to treat?
It is anti-IgE antibody therapy that is approved for use in moderate to severe persistent asthma.
What do the shigella, campylobacter, giardia, entamoeba histolytica have in common?
The have very low ID50s.
Which two cells/tissues can’t use ketones for energy and why?
Erythrocytes can’t because they lack mitochondria which are required to convert ketones in acetyl CoA which is the process that generates energy.
Liver can’t utilize ketones for energy b/c they lack the enzyme thiophorase which is required to convert acetoacetate to acetyl CoA as part of the energy generation process.
What is glycopyrrolate and what is it used to treat?
It is a selective muscaranic antagonist and can be used to treat the side effects of the cholinesterase inhibitors used to treat myasthenia gravis.
What is the second line preventative therapy for gout and in what population is it contraindicated?
Uricosuric agents like probenecid are 2nd line preventive therapy and they work by increasing the excretion of uric acid in the kidneys. As such, they are contraindicated in pts w/ PMH of renal stones.
What is the cell to cell connection (if any) of osteocytes?
They are connected via gap junctions. Important for sharing signals, waste products and nutrients.
What is a cholesteatoma?
It is a collection of squamous cell debris that forms a round, pearly mass behind the tympanic membrane in the middle ear.
Why does M. leprae tend to infect skin and outer surface body areas whereas TB causes visceral disease?
Because M. leprae grows best at temperatures below core body temperature.
What is it meant by saying that two genetic loci are in linkage disequalibrium?
This means that the two alleles are inherited together more or less commonly than chance alone given their individual allele frequencies.
Which drug inhibits host DNA synthesis more, acyclovir or gancyclovir?
Gancyclovir. This is why one of its side effects is neutropenia, which can be exacerbated when combined w/ other drugs that can cause bone marrow suppression like TMP-SMX.
What sort of drugs are pramipexole and ropinirole? What can they be used to treat?
They are dopamine agonists and as such can be used to treat Parkinson’s disease.
What sort of drugs are entacapone and tocapone? WHat do they treat?
They are catechol-O-methyltransferase (COMT) inhibitors and as such prevent the degradation of levodopa in the periphery. They treat Parkinson’s disease.
What is the mechanism w/ which amantadine treats parkinson’s disease?
It increases dopamine release and decreases dopamine reuptake.
What is one way to distinguish btwn prospective cohort study and cross-sectional study?
In a cross-sectional study you are looking at exposures and outcomes at the same time. Whereas in a prospective cohort study you look at exposures in the present and then way down the line you look at who develops your outcome.
What is AngII’s effect at the kidney?
Causes efferent arteriolar vasoconstriction.
The afferent limb of the pupillary reflex involves what?
The retina, optic nerve, optic chiasm, optic tract and the pretectal nucleus in the midbrain. Damage to these can produce a Marcus-Gunn pupil.
Embryologically, what happens that results in hypospadias?
There is failure of fusion of the urethral folds.
What sort of toxin causes staph scalded skin syndrome?
The exfoliatin exotoxin. Works by cleaving desmoglein in desmosomes.
Being oxidase positive means you possess what enzyme?
Cytochrome oxidase
Insulin lispro, aspart and glulisine are all what types of insulin?
Short acting insulins that are best for post-prandial glycemic control.
What sort of insulin is NPH?
An intermediate acting insulin that has onset about 2 hours after admin, peaks in 4-12 hours and lasts about 18 hours.
Is it bipolar I or II where the pt has hypomanic episodes and major depression episodes?
Bipolar II. Note that in hypomania it is less severe than mania and there is no psychosis (which can accompany manic periods in bipolar I).
Repeated blocks of glycine-X-Y, with X and Y being proline, hydroxyproline, or hydroxylysine is characteristic of what protein?
Collagen
What is dyschezia? What location of endometriosis does it suggest?
Pain with defecation. Suggests endometriosis in the rectouterine pouch (aka pouch of douglas aka posterior cul-de-sac).
What are the four muscles of mastication? Which one lowers the jaw while the other 3 close the jaw?
Muscles = masseter, medial pterygoid, lateral pterygoid and temporalis.
Lateral pterygoid is unique in that it lowers the jaw while the others close the jaw.
The most commonly torn ligament w/ ankle inversion sprains is the?
anterior talofibular ligament
The nodes of Ranvier are sites of _____ capacitance and ______ resistance?
High capacitance (thus rapid AP propagation) and low resistance.
What artery runs in the radial groove along with the radial nerve?
The radial collateral artery.
______ emphysema occurs in pts w/ alpha1-antitrypsin deficiency whereas _______ emphysema tends to be what is seen in chronic smokers?
alpha 1 –> panacinar emphysema
smokers –> centriacinar emphysema
In the presence of MIF, what do the paramesonephric ducts become?
The appendix testes (a vestigial remnant) and the prostatic utricle.
On physical exam how can you distinguish btwn bullous pemphigoid and pemphigus vulgaris?
In bullous pemphigoid the bullae do NOT rupture easily to touch (negative Nikolsky sign) whereas in pemphigus vulgaris they do.
Endomysial inflammation showing infiltrate of macrophages and CD8+ lymphs is characteristic of?
Polymyositis
Perimysial inflammation of CD4+ cells and atrophy of the muscle is characteristic of?
Dermatomyositis
What is the triad of scleroderma?
Autoimmunity, non-inflammatory vasculopathy, and collagen deposition w/ fibrosis.
*This is the disease that can present w/ taut skin or CREST syndrome.
What is the treatment of sclerodermal renal crisis
Short acting ACEIs like catopril.
What is the only tx that can be given in Measles infection?
Vitamin A. It can reduce morbidity and mortality.
What is a cherry hemangioma?
It is a benign capillary hemangioma that occurs in the elderly usually and can bleed a lot when ruptured. Basically looks like a red to purple to black lagoon of blood.
What is the characteristic triad of ataxia telangiectasia? What gene is mutated?
Triad = cerebellar ataxia, telangiectasias (superficial blanching nests of distended capillaries) and recurrent sinopulmonary infections.
ATM gene is mutated and it is responsible for DNA repair.
What are the common adverse effects of lithium?
Hypothyroidism, Ebstein anomaly, DI and tremor.
The transmembrane receptors for ANP and BNP are linked to what enzyme?
Guanylyl cyclase. Causes cGMP levels to rise and leads to vasodilation.
How is carotid sinus massage able to treat paroxysmal supraventricular tachycardia?
Massage increases barorecptor firing which is transmitted to the vagal nucleus (via CN9). This causes an increase in vagal parasympathetic tone which will slow conduction thru the AV node and prolong the AV refractory period.
What are two txs for nephrogenic DI
HCTZ and indomethacin
What makes up the splicesome that does mRNA processing?
snRNPs which are made up of snRNA and other proteins, as well as additional proteins.
what are anti-Smith (highly specific for SLE) antibodies targeting?
snRNPs for the splicesome (removes introns).
What is the RNA polymerase whose function is restricted to the nucleolus?
RNA pol I. It works to make most of the rRNA.
Which RNA polymerase makes the tRNA?
RNA pol III
True or false, insulin directly suppresses glucagon secretion by acting on alpha cells in the pancreas?
True!
Distinguish between agoraphobia and social anxiety disorder.
In agoraphobia pts fear public places, enclosed spaces, being in lines or crowds or leaving home. Conversely, in social anxiety disorder pts fear embarrassment or scrutiny from others and experience anticipation anxiety and social avoidance when it comes to things like parties.
Describe the pathogenesis of polyol pathway overactivity that occurs in uncontrolled hyperglycemia.
In uncontrolled hyperglycemia, aldose reductase converts glucose to sorbitol, which is later converted into fructose. However, this second conversion can get overwhelmed by the hyperglycemia and sorbitol can accumulate. This creates osmotic pressure in tissues and can lead to damage (cataracts, retinopathy, etc.). Additionally, aldose reductase consumes NADPH and so that deficiency can exacerbate damage as oxidate damage occurs (oxidative stress from the depletion of NADPH).
Absence of CD18 suggests what disorder?
Leukocyte adhesion deficiency.
Infants with hydrocephalus develop what if untreated?
Muscle hypertonicity, hyper-reflexia, macrocephaly and poor feeding. Can get developmental delay too.
How should you manage somatic symptom disorder?
Schedule regular visits with the patients primary care provider and avoid un-necessary dx testing and referrals to specialists.
What distinguishes schizoaffective disorder from major depressive disorder w/ psychotic features?
In MDD w/ psychotic features the psychotic features only occur during the depressed mood whereas schizoaffective disorder requires the presence of psychotic features in the absence of depression for at least 2 weeks.
What are Leptin’s actions in the arcuate nucleus of the hypothalamus?
Decreases production of NPY which is a potent appetite stimulant, and increases production of POMC which will in turn reduce food intake.
Hyperplasia of the glomerular layer of the adrenal cortex is associated w/ what disease?
Conn syndrome
What is the flora the is generally causing UTIs?
It is generally flora that originate from fecal flora and includes gram negative rods and enterococcus. It is NOT generally the urethral flora (lactobacilli, non-pathogenic staph and strep) as these do not multiply readily in the urine and generally do NOT cause infection.
Name 5 common triggers for candida vaginitis
Antibiotic use, high levels of estrogen (i.e. pregnancy), systemic corticosteroid therapy, uncontrolled DM, and immunosuppression.
What is the most common neurologic complication of VZV infection (i.e. shingles)?
Post-herpetic neuralgia –> pain in the dermatomal area where the skin rash occurred. It persists after rash resolves.
What causes the dynamic left ventricular outflow tract obstruction (LVOT) to worsen in patients with HOCM?
Decreased L ventricular preload (or afterload) worsens LVOT obstruction.
What sorts of meds should be avoided in HOCM? Why?
Those that decrease L ventricular preload like systemic vasodilators (dihydropyridine CCBs, nitroglycerin and ACEIs) as well as diuretics. This is because they will worsen LVOT obstruction.
What sorts of meds help reduce LVOT obstruction in HOCM?
Negative inotropic agents like B blockers, non-dihydropyrimidine CCBs like verapamil, and disopyramide.
Which amino acid is a precursor for serotonin?
Tryptophan
What is cyproheptadine used to treat?
Serotonin syndrome (as the med has serotonin antagonist properties).
Which patients are most at risk for “first dose hypotension” when starting an ACEI?
Those w/ high renin activity like pts w/ HF or those taking a diuretic.
Where is acid phosphatase found and what does it do?
Found in the lysosome of most cells and it hydrolyzes organic phosphates.
What are caspases?
A family of proteases that are essential for apoptosis.
What is the most common location of blunt aortic trauma (traumatic aorta rupture caused by sudden deceleration that results in extreme stretching and torsional forces affecting the heart and aorta)?
The aortic isthmus as it is tethered by the ligamentum arteriosum so it is relatively immobile relative to the adjacent ascending and descending aorta.
What are 3 effects of DHT in a male?
Male pattern hair growth, external genitalia, growth of the prostate.
How does HBV infection initially present?
Like a serum sickness illness w/ fever, rash, arthralgias, etc as well as hepatomegaly and elevated transaminases.
What are the short acting benzos? Half live less than 6 hours
Triazolam, oxazepam, and midazolam.
What are the intermediate acting benzos? (half-life 6-24 hours)
lorazepam, alprazolam, and temazepam
What are the long acting benzos (half-life > 24 hours)
diazepam, chlordiazepoxide, and flurazepam.
Which group of benzos have a higher addictive potential?
Those with a shorter half-life.
Only the polyprotein of the _____ gene in HIV is glycosylated
env gene. These products become gp160 and are then cleaved to become gp41 and gp120.
How long can patients still have viable sperm after vasectomy?
Up to 3 months and for at least 20 ejaculations after the procedure.
Having the ApoE4 allele places someone at risk for what?
Alzheimer’s disease
What three genes have been found to be associated w/ early onset familial Alzheimer’s disease?
Amyloid precursor protein (chromosome 21), presenilin 1 (chromosome 14), and presenilin 2 (chromosome 1)
Why is propofol’s onset of action and termination of anesthesia rapid?
Because it is highly lipophilic so it initially distributes to organs receiving a ton of blood flow (i.e. brain where it has its effect) but then is redistributed to less vascular tissue like bone and adipose and this redistribution is what causes its effect to terminate.
Name 8 CYP450 inducers
Carbamazepine, barbiturates, phenytoin, rifampin, griseofulvin, St. John’s wort, modafinil, cyclophosphamide
Name 8 CYP450 inhibitors
Amiodarone, cimetidine, fluroquinalones, clarithromycin, azole antifungals, grapefruit juice, isoniazid, ritonavir
What sort of drug is ramelteon?
A melatonin agonist.
What drug is ideal for tx of insomnia in the elderly?
Ramelteon. This is b/c it doesn’t have the bad side effects of other options like benzos (delirium and fall risk) or diphenhydramine (anticholinergic effects)
The vascular type of Ether-Danlos (associated w/ increased risk for aortic aneurysm) is due to a defect in what?
Defect in type III collagen. These pts also often demonstrate thin/translucent skin and increased varicosity.
The branchial arches are composed of what two types of embryologic tissue?
Neural crest cells and mesoderm.
How does mercury poisoning present?
Intention tremor, nephrotoxicity, and change in personality
How does iron toxicity present?
Vomiting, diarrhea, gastrointestinal bleeding, cyanosis, and metabolic acidosis.
How does Pompe disease present? What enzyme deficiency causes it?
By the sixth month of life, children with Pompe disease experience developmental delays, feeding problems, and eventual heart failure. Skeletal muscle and the liver are also affected. ECG shows short PR intervals with large QRS complexes signaling biventricular hypertrophy. Cardiomegaly is also evident on x-ray of the chest.
It is due to enzyme deficiency of α1,4-glucosidase (aka acid alpha glucosidase) which is necessary for hydrolysis of the outer branches of glycogen.
What does alpha galactosidase A deficiency cause? How does it present?
This causes Fabry’s disease. Ceramide trihexoside accumulates, resulting in peripheral neuropathies of the hands and feet, angiokeratomas, and cardiovascular and renal disease.
What does beta-glucocerebrosidase deficiency cause and how does it present?
Causes Gaucher’s disease. Presents w/ hepatosplenomegaly, aseptic necrosis of the femur, bone crises, and Gaucher cells
What does glucose-6-phosphatase deficiency cause? How does it present?
Causes type I glycogen storage disease (aka Von Gierke disease). Patients have severe fasting hypoglycemia with large stores of glycogen in the liver, hepatomegaly, and increased blood lactate levels.
What does skeletal muscle glycogen phosphorylase deficiency cause? How does it present?
Causes type V glycogen storage disease (aka McArdle’s disease). Pts have cramping and myoglobinuria with strenuous exercise. This can lead to hypotonia.
What dictates the severity of disease in tetralogy of fallot?
The degree of pulmonic stenosis as this will dictate the degree of R –> L shunting and hypoxia.
What is a pneumonic to remember the causes of renal papillary necrosis? It manifests as gross hematuria and proteinuria.
Consider the mnemonic POSTCARDS for causes of papillary necrosis: Pyelonephritis, Obstruction of urinary tract, Sickle cell, TB, Cirrhosis/Chronic alcoholism, Analgesic abuse, Renal transplant rejection/Radiation, Diabetes, Systemic vasculitis
How does the drug ribavirin work?
It is a nucleoside antimetabolite that interferes with duplication of viral genetic material.
What happens to C-peptide of insulin?
It is cleaved from proinsulin by endopeptidases while in the actual secretory granules. As such, C peptide is released along w/ insulin.
Describe DRESS syndrome
DRESS = drug reaction w/ eosinophilia and systemic symptoms. It occurs 2-8 weeks after drug exposure and signs and sxs include fever, general lymphadenopathy, a morbiliform race and facial edema. Labs show eosinophilia, elevated transaminases, and atypical lymphocytosis.
Name some drugs that are common offenders in DRESS syndrome
Anticonvulsants (carbamazepine, phenytoin), allopurinol, sulfonamides and antibiotics.
What gene is mutated in spinal muscular atrophy? What are the consequences of said mutation?
The SMN1 gene which codes for a protein involved in the assemby of snRNPs. As such, the slicesome is dysfunctional and there is degeneration of anterior horn cells in the spinal cord.
What happens when the ribosome encounters a stop codon (UAA, UAG or UGA)?
A releasing factor binds to the ribosome stimulating release of the formed polypeptide and dissolution of the ribosome mRNA complex.
Narcolepsy is most commonly due to deficiency of what?
Hypocretin-1 (orexin-A) and hypocretin-2 (orexin-B). Low levels of hypocretin-1 in the CSF is suggestive of this disease.
