UWorld 1 & 2 Flashcards
What affect does estrogen have on HMG-CoA reductase?
Upregulates
Why do pregnant women present more with gallstones?
Estrogen upregulates HMG-CoA reductase, reusling in bile to become supersaturated with cholesterol
What effect does progesterone have on bile acid secretion and gallbladder emptying?
Progesterone reduces bile acid secretion and slows gallbladder emptying
What is used to treat patients with recurrent calcium-based nephrolithiasis?
Thiazide diuretics - increase Ca reabsorption
What drug can be used to treat narcolepsy?
Modafinil
How do you calculate maintenance dose?
(Steady state plasma concentration x clearance) / bioavailability fraction
What is the MOA of ribavirin?
Interfering with the duplication of viral genetic material - it is a nucleoside antimetabolite
Adrenal crisis requires what for immediate treatment?
Fluid resuscitation and glucocorticoid supplementation (hydrocortisone or dexamethasone)
What is a patients greatest risk from dying following complications for acute rheumatic fever?
Pancarditis
DRESS syndrome is seen in what drugs? What timeframe does it present at?
Presents 2-8 weeks after exposure; egs: phenytoin, carbamazepine, allopurinol, sulfonamides, antibiotics (minocycline, vanco)
How does DRESS present
2-8 wks after exposure - fever generalized lymphadenopathy, facial edema, diffuse morbilliform skin rash; labs show eosinophilia
Drug induced antineutrophil cytoplasmic antibodies associated vasculitis presents with what drugs?
Commonly medications for hyperthyroidism (PTU, methimazole) and hydralazine
How does drug induced antineutrophil cytoplasmic antibodies associated vasculitis present?
Constitutional symptoms, arthralgias/arthritis, cutaneous vasculitis
What is mixed cryoglobulinemia?
Small to medium vessel vasculitis caused by circulating immunoglobulin-complement complexes that precipitate on refigeration
What is mixed cryoglobulinemia associated with?
Chronic inflammatory states - SLE, HCV
How does mixed cryoglobulinemia present?
Systemic findings and palpable purpura in the lower extremities due to cutaneous vasculitis
What are the sertoli cells responsible for and where are they found?
Found in the testes; responsible for producing anti-mullerian hormone which causes mullerian duct involution; they also produced androgen-binding protein which concentrates testosterone in the seminiferous tubules to enable spermatogenesis
What do the Leydig cells do and what are they responsible for?
Secrete testosterone and stimulate the Wolffian duct to develop into internal male reproductive organs (epididymides, vas deferens, ejaculatory ducts, seminal vesicles)
What forms the external male reproductive organs? What hormone is responsible?
Genital tuberlce, urogenital folds and labioscrotal swelling; dihydrotestosterone
What is septic abortion?
Abortion resulting in retained products of conception
How does septic abortion present?
Fever, chills, lower abd pain and blood or purulent discharge; boggy, tender uterus with dilated cervix. Pelvic US: retained products of conception, increased vascularity, echogenic material in cavity, thick endometrial stripe
What microorganisms are responsible for septic abortion?
S aureus is very common; others: gram neg bacilli (E coli) and GBS
What is Asherman syndrome?
Long term complication from septic abortion - adhesions in uterine cavity that can lead to secondary amenorrhea and infertility
What organisms are resistant to cephalosporins?
L monocytogenes, MRSA, enterococci, atypicals (mycoplasma and chlamydia)
What type of immunity is required to clear Listeria infection?
Cell mediated immunity; humor responses do not play a role
Why is listeria resistant to cephalosporins?
Altered penicillin binding proteins
What is listeria treated with?
Ampicillin - ampicillin is generally added to empiric treatment for meningitis in young infants or immunocompromised
What cephalosporin covers Listeria, MRSA, enterococcus faecalis?
5th gen - ceftaroline
Down syndrome presenting with 46,XX t(14;21) karyotype is an example of what?
Unbalance robertsonian translocation
Unbalanced translocations resulting in Down Syndrome is most commonly between what two chromosomes?
14 and 21
What causes dry beriberi? What are the symptoms?
B1 def. symmetrical peripheral neuropathy of the distal extremities with resulting sensory and motor impairments
What is Wet beriberi?
Includes symptoms of dry berberi (peripheral neuropathy) with the addition of cardiac involvement (cardiomyopathy, high output CHF)
B1 def resulting in Wernick-Korsakoff damages what regions of the CNS?
Medial dorsal nucleus of the thalamus, mammillary bodies
What enzymes are affected by B1 def?
Pyruvate dehydrogenase, alpha-ketogluturate dehydrogenase, transketolase, and branched-chain ketoacid dehydrogenase
An anion gap metabolic acidosis results in what process in the kidneys?
Renal ammoniagenesis - renal epithelial cells metabolize glutamine, generation ammonium and bicarb; ammonium ions are transported into the tubular fluid and excreted, bicarb functions to buffer acids in the blood
What is renal ammoniagenesis? When do you see it?
Acidosis; results in renal tubular epithelial cells to metabolize glutamine, generating ammonium and bicarb. Bicarb is absorbed into the blood.
What are the clinical features of Fabry disease?
Neuropathic pain (burning sensation in palms and soles), angiokeratomas, telangiectasias, glomerular disease, TIA, stroke, cardiac disease
What is the inheritance pattern of Fabry disease?
Xlinked recessive
What enzyme is deficient in fabry disease?
Alpha galactosidase A - results in accumulation of globotriaosylceramide
Deficiency in alpha galactosidase A results in accumulation of what? What disease is this?
Accumulation of ceramide trihexoside (globotriaosylceramide); fabry disease
What type of murmur is consistent with hypertrophic cardiomyopathy?
Systolic murmur that becomes pronounced with standing from supine position
Hypertrophic cardiomyopathy results in what cardiac flow issue?
Anterior mitral leaflet shfits toward aortic valve, thickened septum further obstructs LV outflow = LVOT obstruction
LVOT obstruction is seen in what disease? What makes it worse?
Seen in HCM; worse with decreased LV volume (also caused by decreased preload or reduced systemic vascular resistance)
What medications should be avoided in patients with HCM?
Vasodilators and diuretics
What is verapamil?
Nondihydropyridine calcium channel blocker
What is disopyramide?
Call IA antiarrhythmic
Subserosal leiomyomas cause what?
Irregular uterine enlargement - causing pelvic pressure
The nucleolus is the primary site for what?
Ribosomal RNA transcription
RNA polymerase I is responsible for what?
Ribosomal RNA
RNA polymerase II is responsible for what RNA production?
Messenger RNA, snRNA, microRNA
RNA polymerase III is responsible for production of what RNA?
Transfer RNA, 5s ribosomal RNA
Where does RNA polymerase I function?
Nucleolus
What lab values are consistent with primary hyperaldosteronism?
Increased aldosterone, low renin
What lab values are associated with secondary hyperaldosteronism?
Increased renin and aldosterone
Inactivated (killed or component) viral vaccines predominantly generate what type of immune response?
Humoral
Live attenuated viral vaccines generate what type of immune response?
Cell mediated in addition to providing humoral immunity
Wilson’s disease can cause cystic degeneration to what?
Putamen, as well as damage to other basal ganglia structures
Where is the putamen located?
Medial to the insula and lateral to the globus pallidus on a coronal section
Interventricular foramina of Monro is located where?
Between lateral and third ventricle
Cerebral aqueduct is located where?
Between third and fourth ventricle
How does CSF enter the subarachnoid space?
Via one of 3 foramina: 2 lateral foramina of Luschka and a single midline foramen of Magendie
Obstruction at the level of the cerebral aqueduct causes increased pressures where?
Third and lateral ventricles
What are the key features of schizotypal PD?
Eccentric; odd thoughts, perceptions and behavior
Schizoid PD is characterized by what?
Prefers to be a loner, detached, unemotional
When the head of the humerous is displace anteriorly, what might you see on PE? What nerve is at risk?
Flattening of the deltoid prominence, protrusion of acromion; axillary n.
How do you calculate sensitivity?
TP/TP+FN
How do you calculate specificity?
TN/(TN + FP)
People who have suffered an AE are more likely to recall previous risk factors than are people who have not experience a poor outcome. This is an example of what?
Recall bias
What is recall bias?
Inaccurate recall of past exposure by people; applies to most retrospective studies such as case control studies
What organism is likely to cause infective endocarditis after a GU procedure?
Enterococci
Patient recently underwent genitourinary procedure comes in with a UTI that results in gram positive cocci. Likely organism?
Enterococci
Are enteroocci aerobic or anaerobic?
Aerobic
Explain the morphology and gram staining and any other important characteristics of enterococcus spp.
Gram + cocci in pairs and chains, gamma hemolysis, PYR +, grow in bile and in 6.5% sodium chloride; they are unable to convert nitrates to nitrites
How does RSV present?
Usually < 2 years old; antecedent nasal congestion/discharge, cough, followed by wheezing/crackles and potentially resp distress
How does thrombotic thrombocytopenic purpura present?
Pentad of symptoms: neurologic and renal symptoms, fever, thrombocytopenia, and MAHA
Bicuspid aortic valves commonly result in what?
Aortic stenosis around 50 years old (10 years prior to the average onset of senile calcific aortic stenosis)
Koilocyte is a sign of infection with what?
Human papillomavirus
What does a koilocyte look like?
Immature squamous cell with dense, irregularly staining cytoplasm and perinuclear clearing, resulting in a halo; nucleus has raisinoid appearance
What affect do thiazide diuretics have on calcium absorption?
Increase calcium absorptions, resulting in decreased calcium excretion
The etiology of narcolepsy is believed to be due to low levels of what?
Orexin (hypocretin)
A neurologic disorder characterized by episodes of irresistible, refreshing sleep during the daytime and usually one or more REM sleep-related phenomena describes what?
Narcolepsy
What is train of four stimulation?
Used during anesthesia to assess the degree of paralysis induced by NMJ-blacking agents; peripheral nerve is stimulated 4 times in a quick succession the the muscular response is recordded
How is maintenance dose calculated?
(Steady state plasma concentration x clearance) / [bioavailability fraction]
What is the MOA of ribavirin? What is it used for?
Nucleoside antimetabolite that is phosphorylated intracellularly and interferes with duplication of viral genetic material; used in HCV and RSV
Ribavirin has multifactorial actions/affects, what are they?
Induces hypermutation, inhibits RNA pol and inosine monophosphate dehydrogenase (resulting in defect 5’-cap formation) and modulating more effective Th1 immune response
How does acute adrenal insufficiency present?
Hypotension, shock, n/v, abdominal pain, weakness, fever
How is acute adrenal insufficiency treated?
Fluid resuscitation and immediate glucocorticoid supplementation
Patient with acute endocarditis is most likely to die from what complication?
Pancarditis
What is the difference in genetic mutation between duchenne and beckers muscular dystrophy?
Duchenne is due to a frameshift mutation and Beckers is due to a non-frameshift mutation (somewhat functional protein)
Dystrophin gene is on what chromosome?
X chromosome
What is the function of dystrophin?
Structural component of skeletal muscle fibers that provide mechanical stability to the sarcolemma; it links component of the cytoskeleton to transmembrane proteins
Polymyositis is associated with inflammation of what?
Endomysial inflammatory infiltration
Dermatomyositis is associated with inflammation of what?
Perifascicular inflammation
What are the results of nitroblue tetrazolium test in a patient with chronic granulomatous disease?
The neutrophils fail to turn blue
What serologic tests can be used to follow disease progression of syphillis?
VDRL and RPR - evaluate for the presence of antibody against cadiolipin (byproduct of treponemal infection)
Wht serologic tests remain positive for life after a syphillis infection?
FTA-ABS and microhemagglutination assay for T pallidum (MHA-TP)
How is visualization of T pllidum done?
Dark field micrscopy - reveals helical motile spirochetes
What is the NPV?
Probability of not having a disease given a negative test result
Punch biopsy with normal appearing epidermis reveals stellar cells with characteristic intracytoplasmic granules having the shape of a tennis racquet describes what type of cells?
Langerhans cells
What is a Birbeck granule?
Characteristic racquet-shaped intracytoplasmic granule seen in Langerhans cells
What cell line are Langerhans cells derived from?
Myeloid
The immune complexes seen in PSGN are composed of what?
IgG, IgM, and C3
What is the function of pyruvate carboxylase?
Converts pyruvate to oxaloacetate
How does acetyl-CoA stimulate gluconeogenesis?
Increases the activity of pyruvate carboxylase when acetyl-CoA is abundant
The cytosol has enzymes necessary for what biochemical pathways?
Glycolysis, fatty acid synthesis, pentose phosphate pathway
Mitochondria are the site for what biochemical pathways?
Beta-oxidation of fatty acids, citric acid cycle, and carboxylation of pyruvate
HMG-CoA is important for what biochemical pathway?
Ketogenesis; found in the mitochondria
What is the function of ornithine transcarbamylase? Where is it found?
Combines ornithine and carbamoyl phosphate to form citrulline; reaction occurs within the mitochondria
What is a comon measure of fetal lung maturity?
Lecithin/sphingomyelin ratio
Lecithin approximately equals sphingomyelin until what time of the pregnancy?
Middle of the 3rd trimester
What is the treatment for gonorrhea?
Ceftriaxone and azithromycin (for resistance and potential chlamydia co-infection)
Gram negative intracellular diplococcus describes what organism? What other important characteristics?
N gonorrhea; pili and non-motile
What happens after decreasing PaCO2 in a mechanically ventilated patient?
Low PaCO2 results in vasoconstriction, which increases resistance and therefore decreases cerebral blood flow. The decreased cerebral blood flow decreases ICP
What influences cerebral circulation?
Systemic blood pressure and arterial blood gas levels; systemic pressures of 60-140mmHg have little effect on cerebral blood volume
What blood pressure values causes increased cerebral vascular volume?
BP >150 mmHg increases vascular volume and blood flow
Blood pressures below what threshold cause cerebral hypoperfusion?
< 50 mmHg
What is the most important regulator of cerebral blood flow?
Arterial blood gases, especially PaCO2
What effect does carbon dioxide have on vasculature?
Vasodilator
What are the important landmarks for pudendal nerve block?
Ischial spines and sacrospinous ligament
Pudendal nerve serves sensory of what?
Perineum
Pudendal provides motor innervation to what?
Urethral and anal sphincters
Pudendal nerve is derived from what nerve roots?
S2-S4
The sacrospinal ligament connects what?
Attached to the ischial spine and sacrum
What runs medial to the pudendal nerve?
Internal pudendal artery and inferior gluteal artery
Injury during closure of a pfannenstiel skin incision can result in damage to what nerve?
This is a c section; injury to iliohypogastric nerve
The obturator provides motor and sensory innervation to what?
Medial thigh
During what procedure can the obturator nerve be injured?
Retroperitoneal pelvic lymph node dissection
How is a pudendal nerve block performed?
Injecting anesthetic intravaginally, medial to ischial spine through sacrospinous ligament
What is the function of hepcidin? Where is it secreted from?
Acts as a central regulator of iron homeostasis-binds ferroportin and causes degradation; released by liver
How is iron absorbed?
From the proximal small intestine facilitated by the divalent metal transporter-1 (DMT-1)
What increases the synthesis of hepcidin?
High iron levels and inflammatory conditions
What lowers hepcidin levels?
Hypoxia and increased erythropoiesis
What is the cause of an imperofrate hymen?
Incomplete degeneration of the central portion of the fibrous tissue band connecting the walls of the vagina
16 yo F presents with abdominal pain that seems to occur at the beginning of each month for a few days, then reside. She has never menstruated, is not sexually active, and has normal secondary sex characteristics. Exam reveals a palpable mass anterior to the rectum; B-hCG is negative. What is the most likely diagnosis?
Imperforate hymen
What is Kallmann syndrome?
Impaired synthesis of GnRH by hypothalamus; presents with primary amenorrhea, absent secondary sex characteristics, and an olfactory sensory defect
What is androgen insensitivity syndrome?
Genetically male, but have female phenotype due to resistance to testosterone
How does androgen insensitivity syndrome present?
In adolescence, breast development results from peripheral conversion of testosterone to estrogen, but axillary and pubic hair are absent; primary amenorrhea occurs due to complete absence of mullerian structures
If endometrial implants occur in the pouch of Douglas, what symptoms will result?
Painful defecation, dyspareunia
Ankle sprain presenting with ecchymosis at the anterolateral aspect of the ankle may have injured what ligament?
Anterior talofibular ligament
How do beta-blockers contribue to the therapy of thyrotoxicosis?
Reduce HR and anxiety; also decreases peripheral conversion of T4 to T3 by inhibiting iodothyronine deiodinase
What are the indications for clozapine treatment?
Treatment resistant schizophrenia; schizophrenia associated with suicidality
What are the AEs of clozapine?
Agranulocytosis, seizures, myocarditis, metabolic syndrome
What is a significant AE of ganciclovir? What can increase the incidence of this AE?
Neutropenia; increased with co-administration of zidovudine or TMP-SMX
What is the genome of parvovirus?
SsDNA virus
What are the autopsy results of fetal hydrops?
Pleural effusion with secondary pulmonary hypoplasia and ascites
What are the effects of an in utero infection of parvovirus?
Profound anemia and CHF; resulting in hydrops fetalis
What is the genome of rubella?
Enveloped ssRNA virus
How is coronary dominance determined?
By the coronary artery supplying the posterior descending artery (which also supplies blood to the AV node)
The posterior descending artery originates from what?
Right coronary artery (70%), both right coronary and left circumflex artery (20%), and the left circumflex artery (10%)
What is the cause of Graves disease?
Type II HSR - IgG stimulating TSH receptors
On jugular venous pressure tracings, what is the first peak?
The a wave - generated by atrial contraction
The a wave on a jugular venous pressure tracing is absent when?
Atrial fibrillation
The y descent on jugular venous tracings does what in constrictive pericarditis?
Becomes more prominent - steeper and deeper during inspiration
What happens to the a wave on a jugular venous tracing in hypertrophic cardiomyopathy?
Prominent a wave
What are common features on CT in constrictive pericarditis?
Calcification and thickening
That are the effects of tetrodotoxin?
Binds Na channels, inhibiting influx and preventing action potential conduction; results in paresthesias, weakness, dizziness, nausea
What determines the ventricular contraction rate in conditions where the atria undergo rapid depolarization?
The AV node refractory period
How is cyclosporine metabolized?
By the liver and GI tract CYP450 enzymes (CYP3A specifically)
What is the most signifiant SE of cyclosporine?
Nephrotoxicity
What compromises the dorsal columns of the spinal cord?
Gracile and cuneate fasciculus
Gracile fasciculus and cuneate fasciculus are important for what?
Position and vibration senses
What are the lateral corticospinal tracts important for? Damage results in what?
Upper motor neuron pathways;spastic paresis, hyperreflexia, pathologic reflexes
Poliomyelitis primarily affects what part of the spinal cord?
Anterior horns
What genes are associated with Lynch syndrome?
MSH2, MLH1, MSH6, PMS2
What genes are associated with familial adenomatous polyposis?
APC
What cancers are associated with lynch syndrome?
CRC, endometrial cancer, ovarian cancer
In HNPCC, what is the genetic defect?
Mutation in gene responsible for DNA mismatch repair
How do nitrates decrease LV wall stress?
Reduced preload (decreased LVEDV); decreases myocardial oxygen demand
Bisphosphontes have a chemical structure similar to what?
Pyrophosphate - attache to hydroxyapatite binding sites
What is the MOA of bisphosphonates?
Bind to hydroxyapatite binding site, osteoclasts take up the bisphosphonate and are unable to continue resorption, so the osteoclasts undergo apoptosis
What is the MOA of bosentan? When is it used?
Endothelin-receptor antagonist; used in pulmonary arterial hypertension
What is the gene mutation seen in familial pulmonary artery hypertension?
BMPR2
What direction does DNA synthesis occur in?
5’ to 3’ direction
What enzyme has 5’ to 3’ exonuclease activity?
DNA poly I in prokaryotes
What type of necrosis is seen after irreversible ischemic injury in most tissues?
Coagulative necrosis
When is fat necrosis seen?
Acute pancreatitis
