Block 35

Question 1

SIADH due to carcinoma

Answer 1

• small cell lung carcinoma can lead to SIADH.
• the inappropriate secretion of ADH leads to hyponatremia, decreased plasma osmolality and elevated urine osmolality (which normally should be <100 mosm/kg if hyponatremia is present).
• the profound hyponatremia present in SAIDH can cause headache, weakness, altered mental status and seizures.
• in SIADH increase ADH —> hypervolemia —> suppresses aldosterone-renin axis and stimulate production of naturitic peptides —> excertion of sodium in urine.
• patients with SIADH as a result of this hyponatremia have normal extracellular fluid volume and low plasma osmolality —> “euvolemic hyponatremia”
• features of volume overload such as jugular vein distension, pulmonary crackles and elevated jugular venous pressure are not seen.

Question 2

Enterobiasis

Answer 2

Its the most common helmenthic infection in USA.

• occuring most frequently in children 5-10 years of age.
• the etiology is enterobius vermicularis
• the adult worms live in human intestine, particulary in cecum and appendix. The female worm migrates out through the rectum onto the perianal skin to deposit eggs (commonly at night). Larvae inside eggs mature in 6 hours and can be ingested by the swame individual or spread to other humans.
• this leads to intenste nocturnal itching in perianal area.
• abdominal pain, nausea, and vomiting can also manifest in patients with a heavy worm burden.
• diagnosis is done via scoth tape test and treated with albendazole.

Question 3

Diethylcarbamazine

Answer 3

Is indicated in the treatment of loa loa and wucheria bancrofti

Question 4

Meningococci virulance

Answer 4

Meningococcus are commonly isolated from the oropharynx and nasopharynx of asymptomatic patients.

• colonization rates are variable but highest in close populations.
• transmission of meningococci usually occur thorugh exposure to respiratory droplets or direct contact with respiratory secretion.
• meningococci then attach to and colonize the pharynx via pilus mediated adherence to mucosal epithelial cells. They subsequent invade the epthelium and gain access to vasculature where they spread hematogenously.
• pilli may also play a role in crossing BBB in the brain.

Question 5

Atonic bladder is treated with

Answer 5

Muscarinic agonist

• which have the side effects of flushing, diaphoresis and nausea, bradycardia, decreased BP and miosis.
• bethanecol is used to treat atonic bladder after surgery.

Question 6

Lv cycle

Answer 6

1. Isovolumetric contraction: begins with the closure of MV. During this period the LV contracting and interventricular pressure is increased but no blood is leaving the LV.
2. Ventricular ejection: occurs after the AV opens.
3. Isovolumetric relaxation: this phase begins with closure of AV. The pressure in ventricles decrease during this time but there is no blood entering the ventricles because both the aortic and mitral valves are closed.
4. Ventricular filling: this phase begins with the opening of the mitral valve as ventricular pressure drops below atrial pressure.blood fills the ventricles during this time.

Question 7

Mysthenia gravis pathophysiology

Answer 7

Autoantibodies against postsynaptic nicotinic actylcholine receptors.

• binding of the antibody to these receptors —> damage to the motor endplate due to complement fixation —> decreased number of functional actylycholine receptors at the neuromuscular junction.
• the decrease in the number of available cation channels reduces the end plate potential following Ach release. Because the threshold potential isnt reached the muscle dont depolarize.
• synaptic concentration of Ach are unaffected.

Question 8

Scoplomaine VS pilocarpine

Answer 8

Scopolamine —> cholinergic antagonist

Pilocarpine —> cholinergic agonist

Question 9

hemolytic anemia of the new is due to

Answer 9

Erythrocyte opsonization by maternal antibodies

Question 10

Abnormal hemoglobin polymerization is seen in

Answer 10

Sickle cell anemia

Question 11

Enoxaprin

Answer 11

Is a form of LMWH that like heparin function by binding to antithrombin III —> inhibit factor Xa

Question 12

Vertigo

Answer 12

Its a sensation of motion when no motion is present or an exaggerated sense of motion for a given bodily movement.

• it results from vestibular dysfunction tends to be of a sudden onset, interferes with walking and causes nausea and vomiting.
• typical causes include menierre disease, perilymphatic fistulas, beingin positional vertigo and labyrinthitis and acoustic neuromas.

Question 13

Tadnem walking and romberg test

Answer 13

Positive romberg test indicates sensory ataxia while positive tadnem walking test (inabillity) usually indicates cerbellar dysfunction.

Question 14

Hemiballism

Answer 14

Damage to the subthalamic nucleus can decrease excitation of the globus pallidus internus therby reducing inhibition of the thalamus over the subthalamic nuclei.
-its a movement disorder charactrized by wild, involuntary, large amplitude flinging movements invloving the proximal limbs on one side of the body. The most commonly occurs in setting of lacunar stroke.

Question 15

Low grade fever, anorexia/ nausea, dark urine and RUQ pain is suggestive of

Answer 15

• acute viral hepatitis
• HAV is most likely the cause especially if the pts have travelled.
• HAV is seen as hepatocyte swelling, balloining degeneration.
• hepatocyte apoptosis is characterized be cellular shrinkage and nuclear fragmentation with intense eosinophilia .

Question 16

P.jiroveci infection

Answer 16

Is associated with CD4 <200 cells only.

If pneumonia is present and the cell count is >200 , the most likely agent is s.pneumonia as the rest of population.

Question 17

Allergic bronchopulmonary aspergillosis

Answer 17

Asthma and CF history
Chest imaging : recurrent fleeting infiltrates and bronchoectasis
Diagnosis : esoinophilia, positive skin test for aspergillus , positive aspergillus specific IgG, elevated aspergillus specific and total IgE.
-repeated excacerbation may produce transient pulmonary infiltrates and proximal bronchoectasis.

Question 18

Congenital Absence of serotoli cells

Answer 18

-mullerian ducts develop into internal female reproductive organs (fallopian tube, uterus, cervix, upper vagina).
-therefore the infant would develop male male internal and external reproductive organs due to the presence of lydig cells however hell also have female internal reproductive organs from the lack of sertoli cells.
-

Question 19

serotoli and leydig cells in development

Answer 19

1. Sertoli cells supress female internal reproductive organ development by producing anti mulleria hormone which causes mullerian duct involution.
   - sertoli cells also produce androgen binding protein, which concentrates testosterone in the seminferous tubules to enable spermatogenesis.
2. Leydig cells secrete testosterone which stimulates the wollfian duct to develop into the internal male reproductive organs.
   Testosterone is peripherally converted into DHT which transform the genital tubercle, urogenital folds and labioscrotal swelling into external male reproductive organs.

Question 20

Fluent aphasia

Answer 20

• due to MCA injury
• its a form of repetitive aphasia characterized by speech that is fluent, well articulated and meloding but meaningless (word salad).
• individuals with fluent aphasia is often due to lesion in wernickes area which is located in the auditory association cortex within the posterior portion of superior temporal gyrus in the dominant temporal lobe.
• typically patients arent aware of their cognitive defect

Question 21

OCT side effects and contraindicatios

Answer 21

Side effects of OCT may include: breakthrough menustrual bleeding, breast tendreness and weight gain.
Additionally there is a risk of more serious events such as DVT,PE ischemic stroke and MI.
-the risk of cardiovascular pills is increased in smokers and in pts over 35 y.o.
-patients who smokes more than 15 cigarrete per day have a high risk to develop cardiovascular events.

Question 22

Transketolase enzyme

Answer 22

When ribose - 5 -phosphate is produced in excess, transketolase and transaldolase can produce the glycolytic intermediates glycerolaldehyde 3 phosphate and fructose 6 phosphate for ATP generation.
-when ribose-5-phosphate demand excess the production capabilities of the oxidative pathway, the non oxidative pathway functions in reverse an transketolase and transaldolase catalyze the conversion of fructose 6 phosphate into ribose 5 phosphate.

Question 23

Vwf disease

Answer 23

Deficiency impairs platelet function. Decreased platelet adhesion and aggregation causes easy bruising and mucocutaneous bleeding (gingival bleeding and heavy menses).

• lab workup reveals a normal platelet count,
• the restocetin aggregation test measure in vitro vWF dependent platelet aggregation. Ristocetin activates GP Ib receptors on platelets and makes them available for vWF binding.
• when the vWF level is decreased there is poor platelet aggregation in presence of ristoctin (unlike factor IIb/IIIa deficiency- glanzmann thrombosthenia which shows normal aggregation in presence of ristoctin).
• prolonged PTT, normal PC, normal PT, and increased BT.
• combined oral contraceptives are the first line therapy for menorrhagia due to vWF disease, and desmopressin can be used.

Question 24

Atrovastatin and gemifbrozil combination

Answer 24

The primary side effects of statins include myopathy and hepatitis.
Statin associated myopathy is usually charactrized by mild muscular pain and resolves with discontinuation of medication. However some patients develops severe myopathy with striking elevation in creatine kinase levels and occasional rhambdomyelesis.
The risk of severe myopathy is increased when statins are given concurrently with fibrates particularly which impair the hepatic cleaeance of statins and leads to excessive blood levels.
- an increased risk of statin myopathy is also likely with concurrent use of niacin or ezetimibe, but lesser extent.

Question 25

Propofol

Answer 25

Is a highly lipophilic anesthetic drug used both for induction and maintenance of general anesthesia as well as procedural sedation. When administred as an iv bolus its onset of action is apprixmately 30 seconds with duration of action typicaly lasting <10 minutes. Administration causes rapid decrease in the level of consiousness as well as global amnestic effect.
-obertime propofol is redistributed to organs recieving less blood flow. Because of the site of action for propofol is the brain, redistribution accounts for the rapid termination of drug action.

Question 26

Atropine antidote

Answer 26

Physostiogmine

Question 27

The gonadal arteries

Answer 27

Arises from the abdominal aorta slightly below the renal arteries.

• each gonadal artery coursed obliquely downward and laterally within the retroperitoneal space near the psaos major muscle. The right gonadal artery coursed behind the left colic and sigmoid arteries and iliac colon. After crossing anteriorly over the ureter, the gonadal arteries run parallel to the external iliac vessels and eventually traverse the inguinal canal to supply testis via spermatic cord.
• blockage of the spermatic cord leads to testicular torsion. Which is blockage of blood flow from the gonadal arteries

Question 28

HIV associated dementia

Answer 28

• history of HIV with medical noncompliance and progressive decline likely has HIV associated dementia.
• the condition usually presents in patients with CD4 counts <200 cell/MM3, but its incidence has significantly declined since the introduction ART.
• patients typically have features of subcortical dementia as HIV affects primarily the subcortical/ deep gray matter sturctures.
• the pathogenesis of HIV associated dementia involves inflammatory activation of microglial cells. HIV infected monocytes initially cross the BBB to become perivascular macrophages.
• activated macrophages and microglial cells form groups (microglial nodules), around small areas of necrosis and may fuse to form multi-nucleated giant cells. Neuronal damage is believed to occur from inflammatory cytokines release by macrophages/microglial cells and the direct toxic effects of HIV derived proteins.

Question 29

Chrons disease typically

Answer 29

• prolonged diarrhea and abdominal pain
• constitutional symptoms (low grade fever , fatigue), malabsorption, and weight loss are also common
• entercutaneous fistula is common with perianal fistula and abscesses are also often.

Question 30

Eosinophils cells morphology

Answer 30

Biloped nuclei

Question 31

Goodpasture syndrome

Answer 31

Autoantibodies against the alpha 3 chain of type IV collagen found in glomelular basment membrane and pulmonary capillary membrane.

• anti GBM antibodies formation may be triggered by an antecedent viral respiratory infection, although most cases are idiopathic these antibodies promotes inflammatory injury of the glomerular and alveolar basement membranes resulting in rapidly progressive glomerulonephritis and alveolar hemorrhage respectively.
• alveolar hemorrhage manifests with shortness of breath and hemoptysis with infiltrates on chest X-ray. Hb in alveoli leads to increased alveolar oxygen absorption and high CO diffusing capacity.

Question 32

Complete atrioventricular canal defect

Answer 32

• the most common type of cardiac defect in patients with down syndrome(autsomal trisomy)
• failure of endocardial cushions fusion results in an ostium primum ASD, a VSD and single atrioventricular valve.
• significant left to right shunting and AV valve regurgitation leads to excessive pulmonary blood flow and symptoms of heart failure.
• auscultatory findings of AV valve regurgitation (holosystolic beast heard at apex) and increased pulmonary venous return (mid diastolic rumble) are characterestic.

Question 33

Left heart failure signs

Answer 33

-the most prominent extracardiac effects of left sided HF occurs in the lungs.
-the increased LV filling pressure required to maintain an adequate SV are reflected back to the left atrium and pulmonary veins.
Pulmonary venous hypertension produces pulmonary interstitial edema in interlobular septa, edematous widening of alveolar septa and finally intra-alveolar accumulation of fluid.
-orthopnea is a specific sign of LV HF.
-orthopnea in the absence of LV dysfunction is seen in MS —> pulmonary edema -> orthopnea.

Question 34

Non-caseting granulomas

Answer 34

Aggregates of epitheloid macrophages and multinucleated giant cells

Question 35

Churg straus syndrome

Answer 35

Eosinophilic granulomatosis with polyangitis
Chronic rhinosinusitis, asthma and peripheral eosinphilia.
The granuloma seen with churg straus typically have eosinphilic infiltration and prominent areas of necrosis.