Block 23

Question 1

Rapidly progressive GN

Answer 1

• deposition of fibrin within bowmnas space —> crescent formation
• the crescent consists of proliferated glomerular cells, monocytes, and macrophages that have migrated into the bowmans space, as well as abundant fibrin between the cellular layers of crescent.

Question 2

Clostridum botolonium toxin

Answer 2

• preformed neurotoxin.
• charactersticly presents as paralysis that first manifests with cranial nerve abnormalities (diplopia , dysphagia and dysphonia)
• nausea and vomiting,
• history of homemade “canned food”
• it enters nerve terminals thorough endocytsosis, where it prevents binding and fusion of Ach containing synaptic vesicles with plasma membrane, effectively “blocking Ach release into NM synapse”

Question 3

ACEI and ARBS are contraindicated in

Answer 3

-bilateral renal artery stenosis

Question 4

Precursors of gluconeogenesis

Answer 4

• lactate
• alanine
• glycerol
• propionyl-coa

Question 5

Infleuenza virus can predispose to what infection

Answer 5

• outbreaks of infleuenza A can affect 50-75% of school aged children, many of who then spread the virus to family members. Individuals infeceted with infleuenza tend to expirience abrupt onset fever, headache ,mylagia , and malaise.
• a subset of patients stricken by infleuenza go on to develop secondary bacterial pneumonia charactrized by recurrent fever, dyspnea, and productive cough.
• the most frequent organisms associated are S.pneumoniae, S.aureus, and H.infleuenzae.

Question 6

K.pneumoniae

Answer 6

Respobsible for nosocomial UTI, nosocomial pneumoniae, and pneumonia in alcoholics and IV drug users.

Question 7

Linkage diseqiulibirum

Answer 7

2 genetic loci are said to be in linkage disequlibrium when their respective alleles are inherited together in the same gamete more or less often that expected by chance alone given their corresponding allele frequencies. (E,g DQ8-DQ2 alleles )

Question 8

Factors that causes left shift and right shift

Answer 8

Right shift: 
1. Increases H+
2. Increase tempreture
3. Increase 2,3 BPG
4. Increase CO2
5. Increase altitude
6. Altitude 
Left shift: 
-all above decreases 
-HbF

Question 9

Phenotypic mixing

Answer 9

• the acqusition of new viral surface protein is often all that is necessary for a virus to infect a new type of host cell.
• its generally occur when a host cell is coinfected with 2 viral strains and progeny virions contains unchanged parental genome from one strain and nucleocapsid proteins form the other strain.
• however because there is no change in underlying viral genome (no genetic exchange), subsequent progeny will revert to having only the primary genoem (not the adjusted) and wont be infectious unless again it gain the nucleocapsid proteins.
• this is unlike reassortment when the genome is changed thus the progeny or daughter cells will have the same effect.

Question 10

Muscle fibers type I and II

Answer 10

Type I fibers are slow twitch and type II are fast twitch .

• type I performs action requiring low level sustained force (e.g postural maintanance), this means they have high myoglobin and mitochondrial concentration. (Paraspinal and postural muscles predominantly composed of type I)
• type II fibers are specialized for generating rapid forceful pulses of movement type IIb derives energy throguh anaerobic glycogenolysis and subsequent glycolysis, while type IIa are intermediated between ttype I and type IIb

Question 11

Pineal gland mass

Answer 11

Classic manifestation :

• obstructive hydrophalus from aquedectal stenosis (papilledema, headache and vomiting )
• dorsal midbrain syndrome (parainaoud syndrome)
• charactrized by limitation of upward gaze with a downward gaze perferance, bilateral eyelid retraction and light near dissociation.
• most common pineal mass is germinoma, midline malignant tumor thought to arise from embryonic germ cells.

Question 12

injuries after Thyroid surgery

Answer 12

Superior laryngeal nerve - may be misaligated during thyroid surgery due to its proximity to the superior thyroid artery
Recurrent laryngeal nerve- may be misligated during thyroid surgery due to its proximity to the inferior thyroid artery. (Unilateral injury can lead to hoarsness while double ay cause inspiratory stridor.and respiratory distress due to complete vocal cord paralysis.

Question 13

Zolpidem

Answer 13

Short acting agent structually similar to BENZO. They both bind to same portion of GABA-A receptor and enhance the inhibitory action of GABA on CNS.

• its used for short term treatment of insomnia. It has a rapid onset of action and is metabolized by liver P450 microsomal oxidases.
• its elimination half life is normally about 3 hours but may be prolonged in patients with liver disease.

Question 14

Surface ectoderm give rise

Answer 14

• rathke pouch
• lens and cornea
• inner ear
• sensory organs
• olfactory epithelium
• nasal and oral epithelial lingings
• epidermis
• salivary and sweat and mammary glands

Question 15

Fidaxomicin

Answer 15

Is macrocyclic antibiotic that inhibits the sigma subunit of RNA polymerase, leading to protien synthesis impairment and cell death (bactericidial activity).
Its useful in patients with recurrent C.difficle colitis and are at increased risk of recurrence.
-Its administred orally and has minimal systemic absorption,resulting in high fecal concentrations.
- it also have rrow spectrum of activity with lesser effect on normal colonic flora than either metranidazole or vancomycin.

Question 16

Poor prognostic indicator for PSGN

Answer 16

• adult onset

- pre existing kidney disease

Question 17

Primary hyperaldosteronism

Answer 17

• secondary HTA
• low renin, hypernatremia, hypokalemia, and muscle weakness
• edema is absent due to aldosterone escape

Question 18

Lactase deficiency

Answer 18

Congenital or acquired , results in incomplete hydrolysis of the disaccharide lactose to glucose and galactose—> osmotic diarrhea.
Normal biopsy

Question 19

Vitilligo

Answer 19

Common, charactrized by partial or complete loss of epidermal melanocytes.
-there is correlation between autoimmune disorders and vitilligo

Question 20

Acute synovitis

Answer 20

• especially if waranted with fever represent true emergency
• potential causes include septic arthritis, crystal arthropathy, hemarthrosis or rhumatic disease.
• delayed diagnosis may lead to loss of the joint and ling term disability which may be fatal.
• signs and symptoms include acute joint pain, swelling ,erythema and restricted range of motion.
• diagnosis is by arthrocentesis and synovial fluid analysis.

Question 21

H.infleuenzae virulant factor

Answer 21

Capsule

• encapsulated strain consists of 6,(a-f).
• type b is the only serotype that contains pentose monosaccharide rather than hexose sugar as the carbohydrate component of the capsule.
• the PRP capsule prevents phagocytosis and intracellular killing by neutrophils, allowing the organism to invade the vasculature, persists in blood stream and spread hematogenously to distant sites.
• vaccine against H.infleunza type B is available

Question 22

ADH acts on kidney on

Answer 22

Medullary collecting duct
ADH increases the numebr of passive urea transporter in the inner medullary collecting duct allowing substantial fraction of the highly concentrated urea to diffuse down its concentration gradient.

Question 23

Which parts of the kidney are in medulla and which parts in cortex

Answer 23

Cortex : glomerulus, bowmans space, PCT, DCT, cortical collecting tubule
Medulla : descending and ascending limb of loop of henele, collecting duct (medullary part)

Question 24

Radiofrequency ablation of AV node is done in which location ?

Answer 24

-the AV node is located on the endocardial surface of the right atrium, near the insertion of the septal leaflet of the tricuspid valve and the orifice of coronary sinus.

Question 25

Medical therapy for BPH

Answer 25

1. Alpha blockers: relaxes smooth muscles in bladder neck, prostate capsule and prostatic urethra, usually first line therapy
2. 5-alpha reductase inhibitors: inhibit conversion of testosterone to DHT, reduce prostate gland size, effectiveness may take 6-12 months, side effects decreased libido, erectile dysfunction
3. anti muscarininc : used to treat over active bladder

Question 26

Clearance equation

Answer 26

• its the volume cleare od frug per unit time and is an index of how well a medication is removed from circulation.
• it determine the dose rate required to maintain a steady state plasma concentration(Cp-ss)
• maintenance dose = Cp-ss X CL/ [bioavailability fraction]
• for medication administred IV , bioavailavility = 1.
• maintance dose is calculated per minute

Question 27

Aminoglycoside resistance

Answer 27

Methylation of aminoglycoside binding protein of the ribosome.

Question 28

Infectious urethritis in young men

Answer 28

• gonocococcal or nongonoccal.
• with gonorrhea, gram negative intracellular diplococci are likely to be seen in urethral exudate, in contrast C trochomatis is an obligae intracellular and doesnt stain well on gram stain
• in case of gonoccocal, single dose of IM ceftriaxone can treat the patient, however if co infection with occur with chlamydia, dose of tertacyclin or macrolides must be given,

Question 29

odynophagia in the setting of GERD indicates

Answer 29

Progression to erosive esophagitis and formation of ulcer.

Question 30

Neonatal complication of diabetes during pregnancy

Answer 30

• premature delivery
• feta macrosomia
• congenital malformation (neural tube defects, cardiovascular anomalies and caudal regression syndrome)
• respiratory distress
• transient hypoglycemia
• polycythemia

Question 31

Ortner syndrome

Answer 31

MS that lead to left atrial enlargement sufficient enough to cause recurrent laryngeal nerve compression —> hoarseness.

Question 32

Xanthochromia

Answer 32

Blood in CSF (usually present in subarachinoid hemorrhage-most sensitive test)
Should be checked if CT doesnt show conclusive results (although CT is positive in 90% of cases)

Question 33

Uric acid stones in kidney

Answer 33

Apperas yellow brown with diamond or rhomboid shaped crystals.

• pure uric acid stones are radiolucent and therefore cant be visualized on plain radiography.
• biochemical risk factors include low urinary PH and low urine volume with high uric acid concentration.
• this may occur in the setting of gout, high cell turnover states , metabolic syndrome and chronic diarrhea.

Question 34

Dehydration effect on making kidney stones

Answer 34

• patients with chronic diarrhea or recurrent dehydration, have reduced bicarbonate reabsorption from the guy, leading to a state of chronic metabolic acidosis.
• the kidneys compensate by increasing the excertion of hydrgen ions and reabsorption of bicarbonate in the collecting ducts.
• this lowers the urinary PH (acidic urine), increasing the conversion of soulable urate salts into insoulble uric acid.
• uric acid stones further promoted by dehydration due to the production of concentrated urine.

Question 35

IFN function

Answer 35

-synthesized in response to viral infections
-they bind to type I IFN receptors found on infected and neighboring cells.
-transcription of antiviral enzymes capable of halting protein synthesis such as RNASE L and protein kinase R (inactivates eIF-2). However these enymes become active only in the presence of DsRNA, which forms in infected cells.
-they inhibit the synthesis of protein n virally infected cells
-

Question 36

Primary hemochromatosis

Answer 36

• Is most commonly caused by mutation affecting the HFE protein.
• he protein interact with the transferrin receptor to form complex that functions as a sensor of iron stores
• mutations that inactivate the HFE protein causes hepatocytes and enterocytes to detect falsely low iron levels.
• this increases iron accumulation in the body through
  1. Incerease iron absorption in enterocytes
  2. Decreasing hepcidin synthesis in hepatocytes —> increased ferroportin expression —> iron overload.

Question 37

Primary hemochromatosis clinical

Answer 37

When body iron exceeds 20g, pts typically develop the classic triad of micronodular cirrhosis, diabetes mellitus and skin pigmentation. These patients are at increased risk for hepatocellular carcinoma, CHF, and testicular atrophy/hypogondasim.

Question 38

Nef and tat genes in HIV

Answer 38

Tat gene plays a role in viral replication 
Nef decreases expression of MHC class I proteins of infected cells.