uWorld 31 Flashcards
what is used as prophylaxis for mycobacterium avium complex in HIV patients with CD4 less than 50
AZITHROMYCIN in combo with rifabutin or ethambutol
what is used as prophylaxis for histoplasma capsulatum in hIV patients with CD4 less than 150 in endemic areas (ohio and mississippi river valleys)
itraconazole
can be used as chemoprophylaxis for Coccidiodies too
wha are the mitochondrial syndromes that are important
LEBER HEREDITARY OPTIC NEUROPATHY- leads to bilateral vision loss
MYOCLONIC EPILEPSY WITH RAGGED-RED FIBERS- myoclonic seizures and myopathy associated with exercise. skeletal muscle biopsy shows irregularly shaped muscle fibers (ragged red fibers)
MITOCHONDIRAL ENCEPHALOMYOPATHY with LACTIC ACIDOSIS and STROKE-LIKE EPISODES (MEALS)
what are the function of EOSINOPHILS
PARASITIC DEFENSE:
- stimulated by IL-5 (from Th2 and mast cells)
- parasite gets coated in IgG and IgE antibodies that bind the Fc receptors located on eosinophil
- degranulation happens and cytotoxic proteins (MAJOR BASIC PROTEIN) and ROS
- ANTIBODY-DEPENDENT CELL-MEDIATED CYTOTOXICITY (ADCC)
TYPE I HYPERSENSITVITY REACTIONS (and chronic allergic reactions):
-LATE PHASE synthesis of PROSTAGLANDINS, LEUKOTRIENES, and CYTOKINES
how does niacin cause flushing, warmth and itching and what is used to prevent it
PROSTAGLANDIN (PGD2 and PGE2)
use ASPIRIN (30 minutes before niacin) to inhibit prostaglandin synthesis and reduce this
how does topical capsaicin work
causes release of substance P, resulting in burning pain in the area of application
prolongs use causes depletion of substance P, and the pain diminishes with time
if pH is low (7.27) and PaCO2 is normal (40mmHg) and the patient is in diabetic ketoacidosis and has been for two days what the fuck is going on to cause the acid base disorder
patient IS NOT COMPENSATING for acidosis with BREATHING thus they must have RESPIRATORY FAILURE from pulmonary edema or significantly decreased mental function due to DKA
b/c PaCO2 is normal (ABOVE what we want to see for COMPENSATION) this means that there is SUPERIMPOSED RESPIRATORY ACIDOSIS that is interfering with the normal compensatory response
what is the appropriate compensation for metabolic acidosis
PaCO2 = 1.5(serum HCO3-) +8 +/-2
what is the appropriate compensation for metabolic alkalosis
↑ PaCO2 by 0.7 mmHg for ever 1mEg/L rise in serum HCO3
what is the appropriate compensation for acute respiratory acidosis
↑ serum HCO3 by 1mEq/L for ever 10 mmHg rise in arterial PaCO2
what is the appropriate compensation for acute respiratory alkalosis
↓ serum HCO3 by 2 mE1/L for every 10mmHg decrease in arterial PaCO2
what is seen in heroin withdrawal
YAWNING LACRIMATION hyperactive bowel sounds PILOERECTION dilated pupils
what can be used as a surgical landmark during surgery of the appendix
TENIAE COLI (which are a layer of longitudinal muscle that surrounds the rectum just below the serosa, at the recmosigmid junction, this lacer condenses to form 3 DISTINCT LONGITUDINAL BANDS that travel on the outside of the entire colon before CONVERGING at the root of the vermiform APPENDIX)
what are haustra
colonic sacculations causing the colon’s segmented appearance
occur when the teniae coli contract lengthwise
where is cholecystokinin (CCK) secreted and in response to what
hormone responsible for gallbladder contraction, and increase pancreatic enzyme secretion, also decrease gastric emptying
produced by I cells from duodenum and jejunum when a FAT-PROTEIN-rich chyme enters the duodenum
what doe secretin do
promotes bicarb secretion from pancreatic DUCTAL epithelium
what does VIP do
produced in pancreas and stimulates intestinal water secretion, counteracts gastrin in the stomach, and promotes bicarb secretion for the pancreas
complex atypical hyperplasia of the endometrium is associated with what
prolonged exposure to estrogen without opposing progesterone, which may develop form chronic anovulation over many years
most common in obese older women or those who receive estrogen without progesterone during hormone replacement therapy
endometrial atrophy is an expected find in whom, what does it cause
post-menopausal women or women using certain types of hormonal contraception
can cause intermittent spotting
when is anovulation common and what is seen
first several years after menarche and the last few years before menopause
marked menstrual cycle irregularity is seen
when performing a midline episiotomy what is usually cut
vertical incision from the posterior vaginal opening to the PERINEAL BODY
transects the vaginal lining and the submucosal tissue (not the external anal sphincter or the rectal mucosa)
improper repair of a midline episiotomy may result in PELVIC ORGAN PROLAPSE or DYSPAREUNIA
what is the perineal body
essental to the integrity of the pelvic floor
tendinous CENTER POINT of the PERINEUM separates the urogenital and anal triangles
blends anteriorly with the perineal membrane and superiorly with the rectovesical or rectrovesical septum
what structures are anchored to the perineal body
bulbospongiosus muscle
external anal sphincter muscle
superficial and deep transverse perineal muscles
fibers from the external urethral sphincter, levator ani, and muscular coat of the rectum
what is the ischiocavernosus muscle
part of urogenital triangle
arises from the ischial tuberosities and the ischiopubic rami and inserts into the corpus cavernous
when CLITORIS is STIMULATED the ischiocavernosus muscle forces BLOOD into the vlitoris
what is the transverse perineal muscle
art of the superficial perineal space (urogenital triangleO
arises form the ischial rami and tuberosities and inserts into the perineal body
muscle is out during MEDIOLATERAL EPISIOTOMY
what muscle is cut during a mediolateral episiotomy
TRANSVERSE PERINEAL MSUCLE
what is the virulence mechanism of Salmonella osteomyelitis in a Sickle cell patient
CAPSUL called the “Vi antigen” (Vi standing for virulence)
protects it from OPSONIZATION and PHAGOCYTOSIS
what is the main virulence factor of Staph aureus causing OSTEOMYELITIS
adhesion to collagen
when and how to the lip and the palate form
FIFTH-SIXTH WEEK of embryonic development
- first pharyngeal arch splits into he upper maxillary prominence and lower mandibular prominence
- fusion of the 2 medial nasal prominences form the midline INTERMAXILLARY SEGMENT. (intermaxillary segment becomes the PHILTRUM of the upper lip, the 4 medial maxillary teeth, and the PRIMARY PALATE)
- the left and right maxillary prominences then fuse with the midline inter maxillary segment to form the UPPER LIP and PRIMARY PALATE
what happens if one of the maxillary prominences failures to fuse with the inter maxillary segment, what if both
UNILATERAL cleft lip
if both: BILATERAL cleft lip
failure of the medial nasal prominence to fuse an form the inter maxillary seeming is associated with what
severe midline defects (like holoprocencephaly)
what is seen in the Pierre-Robin Seqence
severe MICROGNATHIA results in POSTERIOR displacement of the tongue (GLOSSOPTOSIS) and prevents fusion of the secondary palate (CLET PALATE)
what causes a cleft palate
failure of palatine shelves to fuse with one another (secondary palate) or with the primary palate
catabolism of isoleucine, valine, threonine, methionine, cholesterol, and odd-chain fatty acids leads to the formation of what
PROPIONIC ACID, which is converted to METHYLMALONIC ACID by biotin-dependent carboxylation
isomerization of methylmalonyl CoA forms succinyl CoA, which then enters TCA cycle
what is seen in congenital decificency of PROPIONYL CoA CARBOXYLASE
development of propionic academia, as propionyl CoA accumulates (can’t be converted to methylmalonyl CoA)
POOR FEEDING, VOMITING, LETHARGY, DEHYDRATIOn, anion gap ACIDOSIS
produced as intermediate in catabolism of BRANCHED CHAIN AMINO ACID (Val, Ile, Met, Thr), ODD-NUMBERED fatty acids, CHOLESTEROL SIDE CHAINS
what is special about lysine
essential amino aid that is strictly KETOGENIC
unique metabolism in that it is NOT TRANSAMINATED as the initial step
an increase in what will stop beta oxidation of fatty acids
MALONYL-CoA
it in habits CARNITINE ACYLTRANSFERAE, preventing the transfer of acyl groups into the mitochondria
where does beta-oxidation happen and how does it get there
MITOCNONDRIAL MATRIX
membranes are impermeable to fatty acids dup to their negative charge, so a specialized membrane carrier (CARNITINE) must be used to shuttle them into the matrix
in the WELL-FED STATE, the abundance of ATP in hepatocytes inhibits isocitrate dehydrogenase, leading to high levels of citrate int eh mitochondria. What does this citrate do
is transferred to the cytosol via the citrate shuttle and cleaved by ATP citrate lyase to form acetyl-CoA
high citrate levels (in addition to elevate insulin caused by high carbohydrate intake) causes upregulation of ACETYL-CoA CARBOXYLASE- a cytosolic enzyme that catalyzes the conversion of acetyl-CoA to malonyl-CoA in the rate-limiting step of FATTY ACID SYNTHESIS
what is Burkholderia cepacia
a catalase-positive organism that is common cause of infection in Chronic Granulomatous Disease
so are (Serrate, Aspergillus, Nocardia, Staph A)
how does latanoprost work in treating glaucoma
increased outflow of aqueous humor (via decreasing collagen content int eh uveoscleral outflow pathway)
how do carbonic anhydrase inhibitors (dorzolamide) work in trading glaucoma
decerase formation of bicarbonate in the ciliary body, leading to decreased sodium and fluid transport
who do alpha-adrenergic agonists (brimonidine) that glaucoma
inhibit production of aqueous humor via VASOCONSTRICTION in the CILIARY BODY
how do beta blockers (Timolol) treat glaucoma
decrease aqueous humor production
what is the order of compartments inhaled anesthetics must go through before they can reach the target organ (brain)
inhaled air → lungs → blood → brain
onset of anesthesia is transferred to the brain
what is the arteriovenous concentration gradient of inhaled anesthetics
difference in the concentration of fas anesthetic in arterial blood and venous blood
solubility of the anesthetic in the peripheral tissues is a major factor in determining the size of the AV gradient
the more anesthetic absorbed into the tissue the more that needs to be replaced before it can get to the brain- HIGH AV gradient
what is Marlin’s ulcer
an aggressive, ulcerating squamous cell carcinoma that presents in an area of previously traumatized, chronically inflamed, or scarred skin
malignant transformation often occurs long after initial trauma (like more than 10 years)
if a patient has painful subcutaneous nodules in a location that days or weeks previously had SUTURES and you see a GRANULOMA, what caused it
reaction to FOREIGN BODY (retained sutures)
what happens to QRS interval normally during exercise
REDUCED
what drug for treating arrhythmias would cause an increase in QRS during exercise
TYPE IC anti-arryhtmic (flecainide)
USE-DEPENDENCE: phenomenon in which sodium-blocking effect intensifies as the heart rate increases due to less time between action potentials for the medication to dissociate form the receptor
how do class 4 antiarrythmics work
calcium channel blockers which slow SA and AV nodal conduction
increases coronary blood flow and reduces myocardial oxygen demand, can mask ischemia during stress test
what is a gallstone ileus
mechanical bowel obstruction caused when a large gallstone erodes into the intestinal lumen (through a CHOLECYSTOENTERIC FISTULA)
PNEUMOBILIA (air in the biliary tract) is a common finding
what is seen in an ovarian dysgerminoma
malignant germ cell ovarian tumor that presents as a RAPIDLY GROWING mass or a RUPTURED OVARIAN CYST
common cause of ovarian cancer in PREGNANCY
vesicular cells with clear cytoplasm and large central nuclei due to increased N?C ratio (“fried egg cells”)
what is seen in a endodermal sinus (yolk sac) tumor in a female
malignant germ cell tumor
abdominal pain due to ovarian TORSION without virilization
Schiller-Duval bodies (glomerulus like papillary structures with a central vessel)
the metabolism of ethanol b alcohol dehydrogenase and aldehyde dehydrogenase consumes what and fucks up what ratio
consumes NAD+ causing an INCREASE in NADH to NAD+ RATIO
INHIBITS ALL PATHWAYS that REAUIRE NAD+ (citric acid cycle)
thaimine is necessary for what
pyruvate dehydrogenase
alpha-keotglutarate dehydrogenase (alpha ketoglutarate to succinyl-CoA, produces NADH)
transketolase
what perianal disease might be seen in Crohn’s
fistulas (enterocutanous (skin), enterovesical (bladder), enterovaginal (vag), eneroenteric (more bowel))
skin tags
fissures
what is intergluteal pilonidal disease
acquired skin infection involving upper natal cleft of the buttocks
may present with draining sinus tracts in intergluteal region
no abdominal pain/tenderness or diarrhea
what does actinomyces do
anaerobic bacteria
can form abscission in cervicofacial region or abdominal cavity
abscesses dont form as quick as B. fragilis (and actinomyces is less common of a cause of abscesses than B. fragilis)
