Uworld: 5-22

Front 1

Where are nicotinic receptors found?

What drugs block these receptors?

Back 1

Neuromuscular jn (skeletal muscle)
And postganglionic neurons of symp/psymp

Curare drugs--ex: tubocurarine

Front 2

52 year-old woman
Episodic loss of urine
Can't make it to the bathroom before urinating on self
Detrusor instability

Diagnosis
Treatment

Back 2

Urge incontinence (overactive bladder) due to uninhibited bladder contractions (detrusor instability)

Treat with antimuscarinic drug targeting M3 receptors. Ex: oxybutynin

Be careful bc these drugs may cause confusion in the elderly (antimusc AEs)

Front 3

20 year-old woman
Small, underdeveloped ovaries
Ovaries consist of connective tissue with no follicles present

Back 3

Streak ovaries (Turner's)

Front 4

HLA Class I vs II Serotypes (examples)

Back 4

HLA Class I: HLA B27
HLA Class II: DR, DP, DQ

Front 5

What disorders comprise the seronegative spondylopathies?

Which HLA class predisposes patients to developing them?

Back 5

Seronegative spondylopathies include:
Reactive Arthritis (Reiter syndrome)
Ankylosing spondylitis
Psoriatic arthritis
Arthritis associated with bowel disease

Individuals expressing HLA B28 are at inc'd risk of seronegative spondyloarthropathies.

Front 6

S-100 Tumors

Back 6

Schwannomas
Melanomas
(both melanocytes and Schwann cells are derived from NCC)

Front 7

Which cranial nerves can develop Schwannomas?

Which can't? Why not?

Back 7

All cranial nerves except CN II can develop schwannomas because they are covered by Schwann cells (and thus are considered PNS).

CN II is covered by oligodendrocytes and cannot develop a schwannoma.

Note: the most common site of intracranial schwannomas is the cerebellopontine angle at CN VIII (acoustic neuromas).

Front 8

43 year-old male
Advanced HIV
Develops impaired vision

Diagnosis

Back 8

CMV-induced retinitis

Front 9

This anti-viral is associated with nephropathy and neurotoxicity (delirium/tremor).

Back 9

Acyclivor

Front 10

This anti-viral is associated with severe neturopenia.

Back 10

Ganciclovir

Front 11

This anti-viral is associated with renal wasting leading to low Mg2+ and decreased release of PTH leading to low Ca2+.

Back 11

Foscarnet

Front 12

This anti-viral causes fat redistribution, hyperglycemia, and hypertriglyceridemia.

Back 12

Protease inhibitors

Front 13

Define myocardial stunning.

Back 13

Brief ischemic episodes (<30 mins) followed by reperfusion allows for full recovery--usually over hours to days.

Front 14

Define myocardial hibernation.

Back 14

Repetitive ischemia of cardiac myocytes or persistent hypoperfusion results in chronic but reversible loss of contractile function, referred to as hibernation.

Reversed by resvascularization with CABG or balloon angioplasty. Time course of function recovery is variable, occurring within hours to months.

Front 15

Define ventricular remodeling.

Back 15

Chronic changes in mass, volume, shape, myocyte composition of heart, to compensate for INCREASED hemodynamic load.

Front 16

32 year-old female
Persistent diarrhea
Tea-colored, odorless stool
No response to dietary modification, even despite 2 day fast
Total lack of gastric acid secretion in stomach

Diagnosis
Pathophys
Treatment

Back 16

VIPoma: pancreatic islet cell tumor that causes excess VIP secretion resulting in WDHA (Watery Diarrhea, Hypokalemia, Achlorhydria) syndrome.

Does this because VIP inhibits H+ secretion and stimulates pancreatic HCO3 and Cl- secretion.

Tx: Octreotide to decrease production of all GI hormones (VIP included)

Front 17

46 year-old female
Right-sided flank plain
s/p surgery for cervical cancer
Palpable mass deep in RUQ

Diagnosis
Pathophys

Back 17

Hydronephrosis--ureters are at risk of injury during pelvic surgeries

Hysterectomies especially risky bc ureters course posterior to uterine arteries, which are ligated in this procedure.

Ligating the ureters would allow the kidneys to continue developing urine, but urine would get backed up (causing hydronephrosis).

Front 18

65 year-old smoker
Dyspnea, cough
CXR demonstrates mass in RUL
Elevated serum calcium
Bone Scan negative

Diagnosis
Pathophys

Back 18

Squamous cell carcinoma producing PTHrP (PTH related protein)--acts similarly to PTH although degree of hypercalcemia is higher with PTHrP produciton than in primary hypereparathyroidism.

This phenomenon is known as humoral hypercalcemia of malignancy.

Front 19

Where does the majority of free water reabsoprtion in the nephron occur REGARDLESS OF HYDRATION STATUS?

Back 19

Proximal tubule (absorbs more than 60% of fluid filtered!)

Front 20

22 year-old male
Episodic burning neuropathy in extremities
Non-blanching macules between umbilicus and knees

Diagnosis
Pathophys
Disease sequelae

Back 20

Fabry disease due to inherited deficiency of ALPHA-GALACTOSIDASE A

In patients with this deficiency there is an accumulaiton of CERAMIDE TRIHEXOSIDE in tissues.

Without enzyme replacement tx, progressive renal insufficiency will lead to RENAL FAILURE and death.

Note: presentation--
-acroparesthesia (episodic, debilitating, burning neuropathic pain in extremities)
-angiokeratomas: punctuate, dark red, non-blanching macules and papules that occur between umbilicus and knees

Front 21

PaO2 Normal
SaO2 Decreased
Oxygen content Low

Diagnosis

Back 21

CO poisoning (CO competes with O2 and thus decreases perent saturation of Hgb)

O2 content - both dissolved and O2 attached to Hgb so much be decreased if PO2 is normal

Front 22

PaO2 Normal
SaO2 Normal
O2 Content Decreased

Diagnosis

Back 22

Anemia (low Hgb)--can be due to chronic blood loss

Front 23

PaO2 Normal
SaO2 Normal
O2 Content Increased

Diagnosis

Back 23

Polycythemia (high Hgb)

Front 24

Equation for resistance.

Back 24

R = nL/(r^4)

Where n = viscosity of blood
L = length of vessel
r = radius of vessel

Front 25

Protein in signal transduction contains several alpha-helical regions consisting of valine, alanine, isoleucine.

Function of protein?

Back 25

Non-polar, hydrophobic amino acids such as valine, alanine, isoleucine, methionine, and phenylalanine are generally located interiorly on globular proteins, where they're shielded from direct contact with water.

Thus these proteins act to form the portion of a receptor that spans the phospholipid bilayer ('transmembrane domain')

Front 26

S. pneumoniae:
Virulence factor

Back 26

Capsular polysaccharide that inhibits phagocytosis by macrophages and polymorphonuclear leukocytes

Front 27

What are the 5 general characteristics of DNA viruses?

Exceptions?

Back 27

All DNA viruses:
1. Are HHAPPPPy viruses: Hepadna, Herpes, Adeno, Pox, Parvo, Papilloma, Polyoma

2. Are double stranded EXCEPT parvo (single-stranded)

3. are linear--EXCEPT paiplloma, polyoma (circular, supercoiled); EXCEPT hepadna (circular, incomplete)

4. Are icosahedral (EXCEPT pox--complex)

5. Replicate in nucleus--EXCEPT pos (carries own DNA-dependent RNA polymerase)

Front 28

Where do DNA viruses replicated?

Back 28

All replicate in nucleus (except poxvirus)

Front 29

What are the characteristics of RNA viruses?
Exceptions?

Back 29

All RNA viruses are ssRNA, except Reovirus and Rotavirus (dsRNA)

Positive-stranded:
I went to a RETRO (retrovirus) TOGA (togavirus) party, where I drank FLAVored (flavivirus) CORONA (coronavirus) and ate HIPPY (hepevirus) CALIFORNIA (calicivirus) PICKLES (picornavirus)

Front 30

Where do RNA viruses replicate?

Back 30

All replicate in cytoplasm (except influenza and retrovirus)

Front 31

Which viruses are naked (nonenveloped)?

Back 31

Naked CPRR and a PAPP smear
Calicivirus
Picornavirus
Reovirus
Rhinovirus
Parvovirus
Adenovirus
Papilloma
Polyoma

Front 32

Where do enveloped viruses acquire their envelopes?

Back 32

From plasma membrane, except herpesvirus (nuclear membrane)

Front 33

Which DNA viruses are enveloped?

Back 33

Herpesviruses (HSV, VZV, CMV, EBV)
HBV
Smallpox

Front 34

Which DNA viruses are nucleocapsid viruses?

Back 34

Adenovirus
Papillomavirus
Parvovirus

Front 35

Which RNA viruses are enveloped?

Back 35

Influenza
Parainfluenza
RSV
Measles, Mumps, Rubella
Rabies
HIV

Front 36

Which RNA viruses are nucleocapsid viruses?

Back 36

Enteroviruses (polio, coxsackie, echo, HAV)
Rhinovirus
Reovirus (rotavirus)

Front 37

What characteristics must a naked RNA virus have to act directly as mRNA using the host's intracellular machinery for translation?

Back 37

Must be single-stranded and positive sense.

CANNOT BE double-stranded or negative sense.

Front 38

5 year-old male
Recurrent diarrhea that does not respond to short-term antibiotics
Stool sample below

Diagnosis
Pathophys

Back 38

Giardia lamblia causes injury to duodenal and jejunal mucosa by adhering to intestinal brush border and releasing molecules that induce a mucosal inflammatory response.

Secretory IgA, which impairs adherence, is a major component of adaptive immunity against G. lamblia infection.

Patients deficiency in IgA antibodies against Giardia antigens are prone to chronic giardiasis.

Front 39

57 year-old died in car on way to ER 30 minutes after onset of chest pain
ho HTN, DM, HLD
Cross-section of LAD shown

Diagnosis
Pathophys

Back 39

Sudden Cardiac Death:
Ruptured plaque with superimposed thrombus. Resulted in cardiac arrest within 1 hr of precipitating event. Ischemia produces electrical instability in heart and generates LETHAL ARRHYTHMIA (V FIB)

Note: extensive MI may result in ventricular dysfunction, however, death due to heart failure caused by MI does not occur suddenly. Ventricular failures is most common cause of death due to MI during in-hospital phase.

Front 40

50 year-old female
h/o radical mastectomy
Persistent right arm swelling

Increased risk of developing _________.

Back 40

Persistent lymphedema (with chronic dilation of lymphatic channels) predisposes patients to develop LYMPHANGIOSARCOMA (rare malignant neoplasm of endothelial lining of lymphatic channels)

Typical scenario would be appearance of lymphangiosarcoma approximately 10 years following radical mastectomy for breast cancer

Front 41

31 year-old male
Farm worker
Itchy rash on chest
Annular and scaling plaque
KOH prep shows branching septate hyphae

Diagnosis
Treatment
Treatment MOA

Back 41

Patient presenting with symptoms of tinea corporis (annular scaling plaque w/well-demarcated, raised erythematous borders/central clearing)

Terbinafine used for tx of dermatophytosis.

MOA: Inhibits synthesis of ergosterol by INHIBITING SQUALENE EXPOSIDASE

Front 42

This anti-fungal binds to ergosterol.

Back 42

Amphotericin B
Nystatin

Front 43

IV anesthetic agent used in patient undergoing minor surgical repair.
30 minutes after administration, patient is alert and responsive.

How did he recover so quickly?

Back 43

Accumulation of thiopental and other related lipid soluble barbiturates in brain followed by rapid redistribution into skeletal muscles and adipose tissue (within 5-10 min).

Awakening occurs because plasma level rapidly declines due to REDISTRIBUTION of drug to OTHER TISSUES throughout body (lean tissue).

This rapid brain clearance leads to recovery from anesthesia.

Front 44

35 year-old male
RIght knee pain and swelling
Cultures of joint aspirate reveal no bacteria
Diarrheal illness 2 weeks ago

Diagnosis

Back 44

Reactive arthritis

Front 45

A reaction in which A is converted to B has a standard free energy change Gº = +430 cal/mol. This reaction is catalyzed by enzyme X.

A solution containing 1 mol/L of A and 1 mol/L of B is allowed to sit with enzyme B.

What will happen?

Back 45

Since deltaGº is positive, products are of higher energy state than substrates.

So if add an enzyme, will form more of substrates.

Front 46

Which anticholinesterase can penetrate the CNS?

Back 46

Physostigmine

(others, i.e., neostigmine and edrophonium, can't!)

Front 47

67 year-old male
Alcoholism
Leg edema, rash
Cognitive changes
Multiple vitamin deficiencies

Diagnosis
Pathophys

Back 47

Pellagra due to niacin deficiency: dermatitis, diarrhea, dementia

Dermatitis usually b/l and symmetric on sun-exposed areas of body, consisting of roughened, thickened, scaly skin

Diarrhea due to columnar epithelium atrophy of GI tract

Dementatia due to neuronal degeneration of brain/SC

Front 48

Niacin:
Sources in diet
Physiologic role

Back 48

Can either be ingested as vitamin or synthesized from tryptophan

Niacin is an essential component of NAD and NADP (accepts electrons and donates hydrogen ions!)

Note: populations that consume corn (where niacin is bound and unabsorbable) often have pellagra

Front 49

Tissue plasminogen activator vs Streptokinae:
MOA (similarities and differences)
Uses
Contraindications

Back 49

Both are thrombolytics and increase clot lysis by increasing formation of plasmin from plasminogen

tPA is fibrin specific
streptokinase is non-firbin specific

(in theory, fibrin-specific fibrinolytics assocd w/less systemic activation)

Use: Acute MI

Contraindicated in hemorrhagic stroke, ischemic stroke within one year, active internal bleeding, BP >180/110, suspected dissecting aneurysm

Front 50

28 year-old woman
RLQ pain, vaginal bleeding
Menstrual period 7 weeks ago
h/o pelvic inflammatory disease
BP 80/40, pulse 130
Pale, clammy

Diagnosis
Histologic findings

Back 50

Patient likely presenting with ruptured ectopic pregnancy secondary to PID.

Endometrial biopsy would reveal DECIDUAL (GESTATIONAL) changes in endometrium but no chorionic villi.

Front 51

Colon cancer:
Right vs Left Sided Presentation

Back 51

Right-sided cancer (ascending colon) tends to present with syx of iron deficiency anemia and systemic syx

Patients with left-sided colon cancer manifest as partial intestinal obstruction.

Front 52

Classic appearance of PSGN on microscopy.

Back 52

LUMPY BUMPY HUMPS
LUMPY BUMPY HUMPS
LUMPY BUMPY HUMPS

Front 53

Lumpy bumpy appearance of mesnaium:
Contents

Back 53

Granular deposits of IgG, IgM, C3 (immune complexes)

Front 54

What drugs cause fat distribution from extremities to the trunk?

Back 54

Glucocorticoids
HAART therapy (highly active antiretroviral tx) due to HIV-1 protease inhibitors

Fat also depsoits to thorax, posterior neck (BUFFALO HUMP), and supraclavicular region

Front 55

How exactly dow TZDs decrease insulin resistance?

Back 55

Bind PPAR-gamma to increase transcription of ADIPONECTIN (adiponectin levels are low in DM II) which affects glucose/lipid metabolism.

Front 56

7 year-old boy
Colicky abdominal pain with bloody stools
Urine appeared red
Palpable skin lesions on buttocks

Diagnosis
Pathophys
Other symptoms

Back 56

Henoch-Schönlein Purpura!!
Small vessel vasculitis in children
Usually occurs few weeks after illness

Antigen from infection likely produces IgA ab's and IgA-containing immune complexes deposit on vessel walls, inducing inflammatory reaction.

Syx:
GI: vasculitis within GI tract-->GI bleeds

Kidney: identical to Berger disease-->IgA nephropathy; CRESCENT formation

Skin: palpable purpura

Joints: ARTHRALGIAS, esp. ankle and knee joints

Front 57

10 year-old male
Exertional dyspnea, fatigability
Toe cyanosis, clubbing
No finger abnormalities

Diagnosis

Back 57

Differential cyanosis--cyanosis of lower extremities but not of upper body; it's the result of reduced arterial oxygen saturation in distal aorta

Most likely cause of R to L shunting of blood flow would be PATENT DUCTUS ARTERIOSUS (not VSD!!!)

PDAs act similarly to VSDs; initially begin as LtoR and aren't a problem, until later in life when they're RtoL.

Note: if this presentation were in an ADULT, it would likely be AORTIC COARCTATION

Front 58

What physiologic conditions would minimize the infective dose of V. cholerae?

Back 58

Anything decreasing acidity of stomach (cholera likes alkaline media): Achlorhydria, food ingestion, antacid ingetion

Front 59

Back 59

Curve 1 is phosphatidylcholine, aka LECITHIN (know both of these!!!)

Curve 2 is sphingomyelin (derp)

Front 60

How do the following organs response to minimal change disease?

Kidneys
Liver

Back 60

Due to loss of protein, there's a dorp in colloid osmotic pressure in the blood; as a result fluid moves into the interstitial tissue and edema occurs.

Kidneys detect drop in fluid levels and release renin; this causes sodium and fluid retention, thus exacerbating the edema.

Liver cannot compensate for amount of albumin loss so begins synthesizing as many proteins (doesn't matter what kind) as it can--VLDL, TG, cholesterol, lipoproteins, etc.

Front 61

Diagnosis
Pathophys
Risk factors

Back 61

"Double barrel aorta"--this apparent second cavity is really an intramural hematoma.

Aortic dissections give rise to hematomas as more nad more blood creeps behind medial wall. Intimal tear thought to be primary event.

Single most important risk factor for dev't of intimal tears leading to aortic dissections is HYPERTENSION.

Front 62

What vascular risks does smoking pose?

Back 62

ATHEROSCLEROSIS-->aneursym

Not dissection!