uWorld 6

Question 1

if an incapacitated patient doest to have an advanced directive designating a proxy what should be done (say for intubation for someone when a friend says they wouldn’t want to be put on life support)

Answer 1

attempt to contact patient’s FAMILY MEMBER who can act as the SURROGATE DECISION MAKER
if the patient has NO FAMILY, then a PERSON who CARES ABOUT THEM AND KNOWS the patient’s wishes can act as a substitute

Question 2

what is a Dohle body and when is it seen

Answer 2

light blue (BASOPHILIC) peripheral granules in neutrophils- likely due to ribosomes round with RER
commonly seen in toxic systemic illness but can also occur with burns or myelodysplasia

Question 3

pain in multiple joints , 5yr history of lumbar pain and 2yr bilateral knee pain
blue-black spots on sclerae and diffuse darkening of the auricular helices

Answer 3

Alkaptonuria (AR)
homogentisic acid dioxygenasse deficiency
relatively benign in childhood but marked by severe ARTHRITIS in adult life
urine turns black upon exposure to air (due to oxidization of homogentisic acid

Question 4

what is the structure involved “housemaids knee”

Answer 4

PREPATELLAR BURSA

due to repetitive ANTERIOR knee trauma from kneeling

Question 5

what is anserine bursitis

Answer 5

pain along the medial knee and well-defined tenderness approximately 4cm distal to the anterolateral joint margin of the knee
frequently results from obesity or overuse in athletes

Question 6

what is Popliteal (Baker) cyst

Answer 6

swelling of GASTROCNEMIUS or SEMIMEMBRANOUS BURSA
often due to extrusion of synovial fluid from the knee joint into the bursa in patients with OSTEOARTHRITIS or INFLAMMATORY JOINT DISEASE

Question 7

what is WDHA syndrome

Answer 7

VIPoma aka pancreatic cholera
Watery Diarrhea Hypokalemia Achlorhydria (WDHA) Snydrome

VIP stimulates pancreatic bicarbonate and chloride secretion and its binding to intestinal epithelial cells less to adenylate cyclase activation and increased cAMP production causing sodium, chloride, and water section into the bowel

Question 8

what is the Phalen sign and what is the Tinel sign

Answer 8

Phalen sign- flexion at the wrist reproduces symptoms of carpal tunnel
Tinel sign- tapping over the flexor surface of the wrist reproduces symptoms

Question 9

what is deposited in dialysis-associated amylodisis

Answer 9

beta2-microglobulin (can deposit in the carpal tunnel causing CTS)

Question 10

endoneural inflammatory infiltration with multifocal demyelination i seen in what disease state

Answer 10

Guillain-Barre syndrome

a demyelinating peripheral neuropathy

Question 11

endomysial inflammatory infiltration is found on muscle biopsy of what condition

Answer 11

polymyositis- a myopathy that usually presents with proximal muscle weakness

Question 12

what step of the citric acid cycle produces FADH2

Answer 12

succinate dehydrogenase (succinate to fumarate)
succinate dehydrogenase is COMPLEX II in the electron transport chain

Question 13

what causes bacterial toxin-mediated axonal damage occurs in what

Answer 13

infections secondary to Corynebacterium diptheriae

Question 14

what is opsoclonus-myoclonus syndrome and what is it associated with

Answer 14

non-rhythmic conjugate eye movements associated with myoclonus
neuroblastoma in young children (most common extra cranial childhood cancer)

Question 15

what is the second most common brain tumor in children and it causes gait and ataxia and is located in cerebellum

Answer 15

medulloblastoma

Question 16

Mutation of the TRR gene results in what

Answer 16

misfolding and extracellular tissue deposition of transthyrein protein (pre albumin)
cause familial amyloid polyneuropathy or familial amyloid cardiomyopathy

Question 17

how can one pick out the lunate on x-ray

Answer 17

more medial of two bones that articulate with the radius

Question 18

of the what bone of the wrist articulates with eh first metacarpal

Answer 18

trapezium

“the thumb swings on the trapezium”

Question 19

what is the most commonly injured leg nerve and what injury can do it

Answer 19

common peroneal nerve

trauma to the lateral aspect of the leg, fibular neck fractures, external pressure due to prolonged immobility

Question 20

what is a pure sensory nerve that innervates the psoterolateral leg and lateral foot

Answer 20

sural nerve

Question 21

the rond ligament of the uterus starts and end where and what is in it

Answer 21

originates a uterine fundus, anteroinferior to the fallopian tubes, coursing through the inguinal coal out the labia major
contain artery of Sampson
(clamped in hysterectomy)

Question 22

what is the transverse cervical ligament (aka cardinal ligament)

Answer 22

extends from cervix and lateral fornix of vagina to lateral pelvic walls
uterine artery courses in its superior portion
(division and ligation during hysterectomy)

Question 23

what is used to calculate renal plasma flow (RPF)

Answer 23

para-aminohippuric acid clearance:

(PAH urine * urine flow)/PAH serum

Question 24

what is the generic equation for clearance

Answer 24

Cs= ([urine concentration of S]*[urine flow rate])/(plasma concentration of S)

Question 25

how is filtration fraction calculated

Answer 25

FF= GFR/RPF and is usually equal to 20% in healthy individuals

Question 26

absent CD18

staph aureus on culture but NO PURULENCE

Answer 26

LEUKOCYTE ADHESION DEFICIENCY
PERSISTENT LEUKOCYTOSIS (neutrophils mainly)
absent pus at sites of infection
poor wound healing
recurrent skin and mucosal bacterial infections
periodontitis, often necrotizing
culture with staph a and gram negative bacilli
LATE SEPARATION OF UMBILICAL CORD (more than 21 days)

Question 27

colchicine affect what part of the arachidonic acid/leukotriene/ prostaglandin pathway

Answer 27

stops the inflammation following leukocyte attraction caused by LTB4
MOA is micro tubular polymerization- disrupting CHEMOTAXIS, PHAGOCYTOSIS, DEGRANULATION

Question 28

what is the metyrapone stimulation test

Answer 28

sensitive indicator of the hypothalamic-pituatiary-adrenal axis integrity
blocks synthesis of 11-beta-hydroxylase which converts 11-deoxycortisol to cortisol in the zona fasciculata
no negative feedback on ACTH secretion and thus pituitary ACTH secretion increases ;eating to increase in 11-deoxycortisol which is converted in the liver to 17-HYDROXYCORTICOSTEROIDS that get excreted in urine

failure of 11-deoxycortisol and 17-hydroxycorticosteroids to increase implies primary or secondary adrenal insufficiency (distinguished from each other based on plasma ACTH levels)

Question 29

what diagnostic test result is most SPECIFIC for acute cholescysitsis

Answer 29

failed gallbladder visualization on radio nucleotide biliary scan

ultrasounds is PREFERRED initial imaging test for diagnosis of acute cholecystitis but hepatobiliary scanning can be alternative means when ultrasound is INCONCLUSIVE

Question 30

what is seen in obstructive sleep apnea

Answer 30

HYPERCAPNIA
HYPOXIA
reflexive systemic and pulmonary vasoconstriction
endothelial dysfunction
abnormal venous return and cardiac output
SYMPATHETIC cardiac stimulation
untreated OSA can lead to PULMONARY HTN and right heart failure
most pts get SYSTEMIC HTN due to chromic sympathetic stimulation and elevated plasma NE levels

Question 31

prolonged ACTH stimulation causes what in the adrenals

Answer 31

HYPERPLASIA of fasciulata and reticularis

Question 32

what happens to plasma renin levels in diuretic induced hypovolemia vs drugs that black sympathetic stimulation (beta blocker and clonidine)

Answer 32

diuretics increase renin

drugs that black sympathetic stimulation decrease renin

Question 33

what does the time constant represent

Answer 33

time it takes for a change in membrane potential to achieve 63% of the new value
lower time consents allow quicker changes in membrane potential, thus increasing axonal conduction speed
myelination decreased membrane capacitance, which reduces the time constant
demyelination would increase the time constant and lead to slower impulse conduction

Question 34

the length constant is a measure of what

Answer 34

how far along the axon an electrical impulse can propagate
low length consent reduces distances an impulse can travel
myelination increases length constant and decreases time constant, both of which improve axonal conduction speed

Question 35

a carotid sinus massage leads to what

Answer 35

stimulation of baroreceptors and increases the firing rate form the carotid sinus, leading to INCREASES PARASYMPATHETIC OUTPUT and withdrawn of sympathetic output to the heart and peripheral vasculature
leads to SLOWING of heart RATE and AV CONDUCTION
PROLONGS the AV node REFRACTORY PERIOD with decreased SVR

useful for terminating paroxysmal super ventricular tachycardia (usually do to reentrant impulse traveling circularly b/w the slow and rapidly conducting segments of the AV node)

Question 36

what is the preferred treatment of an elderly person with acer, pruritic rash and history of environmental allergies (typical presentation of utricaia)

Answer 36

antihistamine but MAKE SURE ITS SECOND GENERATION (LORATADINE or CETIRIZINE)
avoid 1st generation because of blockage of cholinergic, serotonergic, and alpha-adrenergic pathways

Question 37

what is seen with chronic rejection in the lungs

Answer 37

bronchiolitis olbiterans syndrome

Question 38

the QT interval reflects what and is determined in part by what currents

Answer 38

cardiac myocyte action potential which is determined in part by POTASSIUM channels

Question 39

what are the two important congenital syndromes that cute QT prolongation

Answer 39

Jervell and Lange-Neilsen syndrome (AR w. neurosensory deafness)
Romano-Ward Syndrome (AD, no deafness)
both may predispose to tornadoes de points at a young age, causing syncopal episodes and possible sudden cardiac death