6/3 Mixed

Question 1

Uremic platelet dysfunction

Answer 1

Abnormal bleeding in patients with uremia is due to a qualitative platelet disorder that causes prolonged bleeding time with normal platelet count, PT and APTT.

Accumulation of uremic toxins impair platelet aggregation and adhesion

Question 2

Vitamin E deficiency

Answer 2

Can occur in individuals with fat malabsorption (CF patients)
Deficiency of fat soluble vitamin is associated with increased susceptibility of the neuronal and erythrocyte membranes to oxidative stress
Clinical manifestations include ataxia, impaired proprioception, and vibratory sensation and hemolytic anemia

Question 3

Valsalva maneuver

Answer 3

Increases vagal tone and can be used to abolish paroxysmal supraventricular tachycardia
The RECTUS ABDOMINIS is the most important muscle in achieving the increased intradominal and intrathoracic pressure of the Valsalva maneuver

Question 4

L5 radiculopathy

Answer 4

Occurs due to compression of the L5 nerve root, usually as a result of vertebral disc herniation or spinal foraminal stenosis
Patients typically present with back pain radiation down the leg with sensory loss over the buttocks, lateral thigh and calf, and dorsal foot
There may also be weakness on foot dorsiflexion, inversion, eversion, and toe extension

Question 5

Effects of estrogen on thyroid hormone levels

Answer 5

Increased estrogen (pregnancy, post-menopausal estrogen replacement therapy), increases the levels of thyroxine-binding globulin
This leads to an increase in total thyroid hormone levels but feedback control maintains normal levels of free (biologically active) thyroid hormone)

Question 6

Non-selective B-blockers exacerbate hypoglycemia and mask its adrenergic symptoms mediated by NE and EPI

Answer 6

They should be used with caution in patients with Diabetes Mellitus
If B-blocker administration is necessary, selective B1-antagonists should be used instead

Question 7

Asthma

Answer 7

Intermittent respiratory symptoms in a patient with a normal CXR, occasional sputum eosinophils, and reduced FEV1 suggest a diagnosis of asthma.
Extrinsic allergic asthma provoked by inhaled allergens such as animal dander is the most common type

Question 8

Mycobacterium avium complex (MAC)

Answer 8

A common opportunistic pathogen that causes disseminated disease in HIV+ patients
Patients with CD4+ counts

Question 9

Polyarteritis nodosa (PAN)

Answer 9

Transmural inflammation with fibrinoid necrosis is characteristic of PAN
It may affect almost any system and specific symptoms are due to ischemia of the involved organs
PAN is commonly associated with HEPATITIS B!!!

Question 10

Most sensitive screening test for diagnosing primary hypothyroidism

Answer 10

Serum TSH

Question 11

Rough endoplasmic reticulum (RER)

Answer 11

Involved in the transfer of proteins to the CELL MEMBRANE and extracellular sapce

Smooth ER does lipid synthesis, carb metabolism, and detox of harmful substances

Question 12

SLE manifestations

Answer 12

Pericarditis is the most common cardiovascular manifestation associated with systemic lupus erythematous
Presents with sharp pleuritic chest pain that is relieved by sitting up and leaning forward

Question 13

First and second pharyngeal arch development

Answer 13

The development of derivatives of the first (trigeminal nerve, mandible, maxilla, zygoma, incus, malleus) and second (facial nerve, stapes, styloid process, lesser horn of hyoid) pharyngeal arches can be disrupted in genetic disorders (e.g. Treacher-Collins syndrome) resulting in hypoplasia of the mandibular and zygomatic bones

Question 14

Phencyclidine (PCP) MOA

Answer 14

Primarily an N-methyl-D-asparate receptor antagonist

Question 15

Crohn disease and gallstones

Answer 15

Crohn disease affecting the terminal ileum > prone to developing gallstones
Decreased bile acid reabsorption and wasting promote supersaturation of bile with cholesterol resulting in gallstone formation

Question 16

Primary adrenal insufficiency (Addison’s disease)

Answer 16

Patients with type I diabetes mellitus are prone to developing other autoimmune endocrinopathies including Hashimoto thyroiditis, Grave’s disease, and primary adrenal insufficiency
Electrolyte abnormalities include hyponatremia, hyperkalemia, hyperchloremia, and non-anion gap metabolic acidosis

Question 17

Diabetic mononeuropathy involving cranial nerve III

Answer 17

Caused by predominantly central ischemia, which affects the somatic nerve fibers but spares peripheral parasympathetic fibers
Symptoms include ptosis, a “down and out” gaze, and normal light and accommodation reflexes

Question 18

Aedes aegypti mosquitoes

Answer 18

Can transmit the viruses that cause dengue fever and chikungunya
Classic dengue fever presents as an acute febrile illness with HA, retro-orbital pain, and join and muscle pain, hemorrhage (petechiae, purpura, epistaxis, melena), thrombocytopenia, leukopenia
Chikungunya is a febrile illness with flulike symptoms, prominent polyarthralgias, and diffuse macular rash

Question 19

Postural skeletal muscles

Answer 19

Ex. soleus, paraspinal muscles
Contain predominantly Type I slow twitch red muscle fibers that derive ATP primarily from oxidative (aerobic metabolism)
Myoglobin RICH, glycogen POOR with many MITOCHONDRIA

Question 20

Serotonin syndrome

Answer 20

Characterized by confusion, agitation, tremor, tachycardia, hypertension, clonus, hyperreflexia, hyperthermia, and diaphoresis
Any drugs that increase serotonin levels including combination of SSRIs and MAO inhibitors and high doses of SSRIs can precipitate this syndrome
Tryptophan is a precursor of serotonin

Question 21

Rx: Serotonin syndrome

Answer 21

Cyproheptadine

An antihistamine with anti-serotonergic properties

Question 22

Atherosclerotic plaques

Answer 22

Release of platelet-derived growth factor (PDGF) by locally adherent platelets, endothelial cells, and macrophages promotes the migration of smooth muscle cells from the media into the intima and their subsequent proliferation

Question 23

Unilateral renal artery stenosis

Answer 23

Cause of secondary hypertension in two to fiver percent of hypertensive patients
The kidney affected by the stenosis may become atrophied due to oxygen and nutrient deprivation

Question 24

Abetalipoproteinemia

Answer 24

Inherited inability to synthesize apolipoprotein B, an important component of chylomicrons and very low-density lipoprotein
Lipids absorbed by the small intestine cannot be transported into the blood and accumulate in the intestinal epithelium, resulting in enterocytes with clear or foamy cytoplasm

Question 25

B cell lymphoma

Answer 25

EBV is identified in approximately 50% of systemic B-cell lymphomas and almost all primary CNS lymphomas occurring in the setting of HIV infection
A high mitotic index is typical of Burkitt lymphoma

Large mass surrounding the small intestine, on biopsy shows uniform, round, medium sized tumor cells with basophilic cytoplasm and a proliferation fraction (Ki-67 fraction) of >99%

Question 26

Diphtheria exotoxin

Answer 26

Inhibits host cell protein synthesis by catalyzing the ADP-ribosylation of host cell elongation factor-2

Nonmotile, unencapssulated, gram-positive rods
V- or Y shaped chains
Cytoplasm contains metachromatic (polar) granules that stain with aniline dyes

Question 27

Wallerian degeneration

Answer 27

Process that occurs when an axon is damaged > axonal degeneration and breakdown and myelin sheath distal to the site of injury
Axonal regeneration does not occur in the central nervous system due to the persistence of myelin debris, secretion of neuronal inhibitory factors and development of dense glial scarring

Question 28

Ethosuximide

Answer 28

Rx of absence seizures
Blocks T-type Ca channels that trigger and sustain rhythmical burst discharges in thalamic neurons

Phenytoin, carbamazepine, and valproic acid inhibit neuronal high frequency firing by reducing the ability of Na channels to recover from inactivation

Question 29

Changes that occur during aerobic exercise

Answer 29

Increased skeletal muscle CO2 production increases the PCO2 of mixed venous blood. Homeostatic mechanisms maintain arterial blood gas levels and arterial pH near the resting values

Question 30

Piriformis

Answer 30

Passes through the greater sciatic foramen and is involved with external hip rotation
Muscle injury or hypertrophy can compress the sciatic nerve in the foramen, causing piriformis syndrome

Question 31

Diastolic Heart Failure

Answer 31

Caused by decreased ventricular compliance and is characterized by normal left ventricular (LV) ejection fraction, normal LV end-diastolic volume and elevated LV filling pressures

Question 32

Cause of dimpling of the overlying skin of breast

Answer 32

Invasive breast carcinoma typically presents as an irregularly shaped adherent breast mass, most commonly in the upper outer quadrant
Malignant infiltration of suspensory ligaments of the breast causes dimpling of the overlying skin

Question 33

Diphenoxylate

Answer 33

Opioid antidiarrheal drug that binds mu opiate receptors in the gut to slow motility
Overuse can lead to euphoria and physical dependence
To discourage abuse, diphenoxylate is combined with atropine which induced adverse effects if taken in high doses

Question 34

ACE inhibitors causing acute renal failure

Answer 34

Can cause an acute rise in serum creatinine by blocking angiotensin mediated efferent arteriole vasoconstriction.
This leads to a reduction in renal filtration fraction (decreased GFR).
For those patients dependent on efferent arteriole constriction to maintain renal perfusion (those with renal artery stenosis), ACE inhibitors can be detrimental by precipitating acute renal failure

Question 35

Shigella

Answer 35

Non-motile, non-lactose fermenting organism that does not produce H2S when grown on triple sugar iron agar
Mucosal invasion of the M cells that overlie Peyer’s patches is an essential pathogenic mechanism for Shigella infection
Shigella then escapes the phagosome and spreads laterally to other epithelial cells via actin polymerization

Question 36

Hemolytic uremic syndrome (HUS)

Answer 36

Acute kidney injury, microangiopathic HEMOLYTIC anemia, and thrombocytopenia
Labs: decreased hemoglobin and platelet count and increased bleeding time, lactate dehydrogenase, indirect bilirubin, blood urea nitrogen and creatinine

Question 37

Chronic rejection of a lung transplant

Answer 37

Can occur months to years following transplantation
The immune reaction affects the small airways, causing bronchiolitis obliterans syndrome. Symptoms include dyspnea and wheezing.

Question 38

c-Myc oncogene

Answer 38

chromosome 8

Transcription activator

Question 39

Wilson disease

Answer 39

AR, excessive copper deposition into tissues (liver, basal ganglia, cornea)
Typically presents in young adults with liver disease, neuropsychiatric symptoms (gait disturbance, dysarthria, depression, personality changes), and Kayser Fleischer rings on slit lamp examination

Question 40

Epithelial ovarian cancer

Answer 40

The most common ovarian malignancy and is typically diagnosed in postmenopausal women
Anaplasia of epithelial cells with invasion into the ovarian stroma, along with multiple papillary formation with cellular atypia
CA-125 is produced by epithelial ovarian tumors and can be used as a serum marker for this condition