block 20

Question 1

post streptococcal GN

Answer 1

clinical deatures :

if symptomatic

• gross hematuria
• edema (periorbital, generalized)
• hypertension

LAB:

• urinalysis+protein +blood +/- RBC casts
• decreased C3 and possible decrease in C4
• increased serum creatinine,anti DNase B and increase AHase
• increased ASO & increased NAD

Question 2

L/S ratio

Answer 2

lecithin is a component of pulmonary surfactant and sphignomyelin is common membrane phospholipid. its common test to asses lung maturity in utero.

-commonly lecithin is elevated in the thrid trimister and sphingomylin levels begins to decrease

Question 3

psaos abscess

Answer 3

it can occur due to direct spread of infection from an adjacent structure or from hematogenous or lymphatic seeding from a distant and possible unknown site.

• risk factors include D.M , IV drug use, HIV infection and other forms of immunusupression.
• signs and symptoms include fever, back or flank pain, inguinal mass, and difficulty walking.
• pain is excacerbated by movement that causes psaos muscle to be streched or extended, such as extension of the hip (psaos sign).

Question 4

decreased perfusion of peripheral tissue induces ?

Answer 4

number of neuroendocrine compensetory mechanisms, such as:

1. Renin-angiotensin-aldosterone mechanism: decreased renal perfusion leads to diminshed strech of glomelular afferent arterioles and increased synthesis of renin. increasd AG II –> increase arterial resistance and afterload
2. increased sympathetic output is stimulated by baroreceptors that sense decreased perfusion, epinephrine and NE increases HR and contractility. but these neurotransmitters also increase peropheral arterial resistance therby increasing afterload.

Question 5

PCR is used to

Answer 5

amplify small fragments of DNA by repeated replication.

-several elements are required for PCR.

the first is a source DNA template, as well as flanking sequences adjacent to the target region.

-a thermostable DNA polymerase is then used to replicate DNA template from a pool of supplied deoxybucleotide triphosphate using 3 steps (denaturing, annealing and elongation)

Question 6

structre of MHC I vs MHC II

Answer 6

MHC1=

• heavy chain and beta 2 microglobulin.
• all nucleated cells
• presents antigen to CD8+ cytotoxic T-cells
• types of antigens: viruses, tumor proteins, antigens are processed in the cytoplasm.
• Antigen presentation results in apoptosis of the presenting cells

MHCII=

• alpha and beta polypeptide chains
• found exclusively in APC
• present antigen to CD4+ T-helper lymphocytes
• bacterial, antigen are phagocytosed and digested by lysosomes within which Ags binds to MHC II
• activation of TH cells, which stimulates the humoral and cell mediated immune response

Question 7

treponoma pallidum diagnosis

Answer 7

spiral shaped gram negative spirochete.

• classically dark-field microscopy of material scraped from the surface of the cutaneous syphlitic lesion is the fastest and most direct method for diagnosis.
• most commonly the diagnosis is confirmed indirectly with serologic testing :
  1. nontreponopmal test (VDRL), rapdi plasma ragin (RPR) evaluate for the presence of antibody against cardiolipin.
  2. treponomal tests: (fluorescent treponomal antibody absorption FTA-ABS, detects antibodies specific treponomal antigens and are not affected by antitreponemal therapy.

Question 8

45,x ,46,xx turner is which type of mutation

Answer 8

-somatic mosaicism

Question 9

differnce between germline mosaicsim and somatic

Answer 9

• somatic: affects the cells forming the body, causing disease manifestations to develop on affected individuals. e.g 45,x,46xx
• germline: affects cells that give rise to gametes, allowing the affected genes to pass to the offspring. but the affected parent doesnt develop clinical manifestations.

Question 10

HPV affect on the respiratory system

Answer 10

• it can cause papilloma in the true vocal cord (not the flase)
• HPV have a predilection for stratified squamous epithelium, which is found in the anal canal, vagina, and cervix. in the resperatory epithelium the true vocal cord are the only ones that are covered with stratified squamous epithelium.

Question 11

infants HPV

Answer 11

-infants can acquire respiratory papillomatosis via a passage through the birth canal of mothers infected with the virus, warty growth on the true vocal cords can lead to weak cry, hoarsness and stridor.

Question 12

peripheral neuropathy in DM

Answer 12

the most importnat mechanism for development of diabetc neuropathy :

1. non-enzymatic glycosylation of protein leads to increased thickness, hylainization and narrowing of the walls of the arteries. –> diabetic microangiopathy of endoneural arterioles, ischemic nerve damage follows.

2/. intracellular hyperglycemia occurs in peripheral nerves. accumulating glucose is converted into sorbitol and fructose by aldose reductase, –> sorbitol increases cell osmolarity and facilitates water influx into the cell.–> damage to axons and schwann cells.

Question 13

types of diabeic neuropathy:(3)

Answer 13

1. distal symmetric polyneuropathy : sensory (paresthesias, intense burning pain, loss of pain/tempreture/ vibration/ position sensation.

motor: weakness, atrophy and decreased DTR. (both are symmetric and bilateral invloving feet and hands in a stocking and glove distribution.

2. autonomic polyneuropathy: GI: gastroparesis, consipation.

cardiovascular: orthostatic hypotension
urinary: overflow incontinence, neurogenic bladder.
sexual: erectule, and ejaculatory abnormalities.

3. mononeuropathy : cranial : CN III, CN VII, and optic.

somatic : median ulnar and common fibular nerves

Question 14

valproic acid teratogenic effect

Answer 14

• spina bifida, meningiomyocele and more
• neural tube defects.

Question 15

common teratogens

Answer 15

1. phenytoin : neuroal tube defects,orofacial clefts, microcephaly, nail or digit hypoplasia
2. lithium: ebstein anomaly, nephrogenic DI,
3. isoteretonin: microcephaly, thmic dysplasia, small ears and hydrocephalus
4. methotrexate: limb and craniofacial abnormalities, neural tube defects and abortion.

5.ACEi: RENAL DYSGNESIS, OLIGOHYDROAMNIOS

6.Warfarin: nasal hypoplasia, and stippled epiphysis.

Question 16

clearance of a given substance (equation)

Answer 16

(e.g substance S )Cs= ([urine concentration of S] X [urine flow rate]) / (plasma concentration of S)

for creatinine this can result in estimation of GFR and for PAH this can result in estimation of RPF

-normal filtration fraction for normal individual equals 20%

Question 17

cannulation of femoral vein instruction

Answer 17

-should occur 1 CM below inguinal ligament, and 0.5-1 cm medial to the femoral artery pulsation.

Question 18

PICA occlusion leads to

Answer 18

wellenberg syndrome.

its a branch of vertebral artery.

• characterestics include vertigo/nystagmus due to damage of vestibular nucleus, ipsilateral cerberal signs (ataxia with tendency to fall), loss of pain and tempreature sensation in the ipsilateral face and controlateral body (spinal trigiminal nucleus and spinothalamic tract), and bulbar weakness (dysphagia, dysphonia) due to injury of nucleus ambigious.
• pts may develop also ipsilateral horner syndrome.

Question 19

hypertensive vasculopathy

Answer 19

invloving the small penetrating branches of the major cerberal arteries is the most common cause of spontaneous deep intracerberal hemorrhage.

• chronic HTA leads to formation of charcot bouchard aneurysms, which may ultimately rupture and bleed within deep brain structures.
• the most frequently affected locations include the basal ganglia (putamen) , cerbellar nuclei, thalmus, and pons.
• the basal ganglia are supplied by lenticulostriate arteries which are small vessels branches of the MCA

Question 20

MCA branches strokes

Answer 20

superior and infereior division of MCA are more commonly affected in ischemic stroke while that of hemorrhagic stroke commonly affects the lenticulostriate arteries

Question 21

cold agglutinins –>

Answer 21

causes agglutination or clumping of RBC when a sample of RBC is chilled.

• cold agglutinins are antibodies are directed against antigens in the cell membrane of M. pneumoniae that happen to be homologus to antigens that are present on the surface of human erythrocytes.
• these cold aglutinins are responsible for the transient anemia seen in pts with M.pneumoniae infection.

cold agglutinins are also associated with EBV infection and hematologic malignancies.

Question 22

lysl oxidase is found in which organelle

Answer 22

RER

Question 23

secretory IgA in mucosal immunity

Answer 23

upon intestinal exposure to nevel antigen –> B cells activated –> migrate to lamina propria underlting the intestinal mucosa –> fully differentiated plasma cells that begins to synthesize IgA dimers –> linked by J-chain –> these IgA dimer is release into the intestinal lumen, a portion of pIgR remains attached to the antibody, forming a complete secretory IgA molecule.

• stimulation of local secretory IgA production is best promoted when the corresponding mucosal surfaces are directly stimulated by the antigen.
• live attenuated vaccines generally produces stronger immune responses than killed baccines by actiung as persistent stimulus that better activated helper and cytotoxic T-cells.as a result the live attenuated oral vaccine generates more robus oropharyngeal and iintestinal mucosal IgA response that inactivated killed vaccine.

Question 24

TTP

Answer 24

pathophysiology : decreased levels of ADAMTS13 levels –> uncleaved vWF multimers –> platelet trapping and activation

clinical: 1. hemolytic anemia (increasd LDH and decreased hepatoglobin) with shistocytes
2. thrombocytopenia (bleeding time increased and normal PT/PTT)
3. renal failure
4. neurological manifestation
5. fever.

managment:

1/. plasma exchange

2. steroids
3. rituximab

Question 25

stomach ulcers vs erosions

Answer 25

erosions are defined as mucosal defects that dont fully extend through the muscularis mucosa (limitid to the mucosal layer). gastric ulcewrs on the other hand penetrate through the mucosal later and extend into the submucosal layers. - erosions usually occur in the setting of acute erosive gastropathy, a condition that results from short term severe ,ucosal injury leading to inflammation and superfacial mucosal destruction. - the use of NSAID, surgical stress, head trauma, burns, curling ulcers, smoking , alcohol are the most common causes.

Question 26

VSD murmur

Answer 26

holosystolic murmur best heard over the lower left sternal border. this murmur may be absent in larger VSD due to decreased resistance across the VSD and lower tans-septal pressure gradient.

Question 27

risk factors for osteoporotic fractures

Answer 27

**A. nonmoifiable:** 1. advancing age 2. female 3. white, hispanic or asian 4. personal or family history of fractures **B.modifiable:** 1. decreased physical activity 2. low body weight 3. poor calcium 4. excessive alcohol or tobacoo 5. premature menopause 6. glucocorticoids.

Question 28

acyclovir mechanism of action

Answer 28

nucleoside analogue, once activated competes with deoxguanosine triphophate for viral DNA polymerase, when it becomes incorporated into the replication viral DNA chain. viral DNA synthesis is terminated.

Question 29

6- merecaptopurine

Answer 29

azathioprine is byproduct of it. it inhibits lymphocytes proliferation by blocking nucleotide synthesis. - its used in RA,chrons, and others - they are activated by HGPRT and inactivated by xanthine oxidase and thiopurine methyltransferase in the liver. - allupurinol inhibits xanthine oxidase thus, increases the toxicity of 6-MP.

Question 30

inheritence of down syndrome

Answer 30

1. 95% meiotic nondisjunction 2. unblanced translocation (robertsonian) 3. mosaicsm (some cells have extra copy of chromosme 21, non disjunction occured early in embryonic life)

Question 31

side effects of isotretinoin therapy

Answer 31

1. teratogenic 2. hyperlipedemia 3. chelitis 4. mylagia 5. pseudotumor cereberi

Question 32

bostentan

Answer 32

endothillin receptor antagonist that blocks the effect of endothillin --\> vasodilation and inhibits endothelial proliferation. - bosentan therapy decreases pulmonary arterial pressure and lessens the progression of vascular and RVH hypertrophy - its mainly used in pulmonary hypertenstion especially in idiopathic PAH

Question 33

CMV in transplant patients

Answer 33

CMV is common in patietns with lung transplant . CMV is an enveloped dsDNA virus belonging to thge herpesviridae family. - in pts with HIV, VMC typically causes esophagitis, colitis and retinitis. - histopathology of a lung biopsy from patietns with CMV pneumonitis may show enlarged cells with intranuclear and intracytoplasmic inclusion. - there is often halo surrounding (owl's eye)

Question 34

norovirus

Answer 34

- SS-RNA genome, most common cause of viral gastroenteritis in developed countries - clinical: -acute onset, resolves in 2-3 days, vomiting and dirrhea non bloody

Question 35

what tissue cant use ketones for energy

Answer 35

erythrocytes because they lack mitochondria

Question 36

lambert eaton mysthenic syndrome

Answer 36

disorder of neuromuscular junbction woth proximal muscle weakness in the form of gain alteration , difficulty in arising from chair or difficulty climbing stairs. - cranial nerve involvment especially oculubulbar is present in majority of patients (\>60%) and can be found in form of diplopia,ptosis, dysarthria and or dysphagia. - LEMS also can present as dry mouth or impotence. - aproximately half of the patients with LEMS have associated malignancy classically Small lung carcinoma. -

Question 37

B19 virus

Answer 37

pathology : SS-DNA virus resperatory, congeintal or hematogenous transmission clinical features: 1. normal child :fifth disease 2. normal adult: acute symmetric arthropathy 3. chronic hemolytic anemia, transient aplastic crisis.

Question 38

enlarged cells with intranuclear inclusion in biopsy means

Answer 38

CMV infection especially in esopagus can cause linaer ulcers

Question 39

cutaneous small vessel vasculitis

Answer 39

**cutaneous small vessel vasculitis(leukocytoclastic vasculitis)** is vasculitis that affects the skin and typically arises due to drug or pathogen exposure (hep B and C). drug known to cause the condition include penicillin, cephalosporins. sulfonamides, phenytoin and allupurinol. - on skin nonblanching palpable purpura is usually present and often invlives the lower extrimiteies. - histology shows markedly inflamed small blood vessels with fibrinoid nbecrosis.