Test 18 Flashcards
sore throat, malaise, lymphadenopathy, myalgias, slenomegaly, fever
infectious mono
This virus infects the pharpyngeal mucosa and tonsillar crypts, gains access to the blood stream, preferentially infects B lymphocytes by binding to CD21.
EBV
How does the IS respond to EBV infected cells?
CD8 T cells (cytotoxic T lymphocytes), clonally expand expand to destroy virus infected cells
Larger cells w/ abundant cytoplasm and eccentrically placed nucleus + cell membrane that conforms to the borders of neighboring cells
Atypical lymphocytes seen in EBV
What cell surface marker is expressed on monocytes and mphages and serves as a receptor for LPS (LPS binding to this receptor activates the mphage)
CD14
What do the cardinal veins give rise to?
SVC and other constituents of the venous circulation
What happens to the umbilical veins, vitelline and cardinal veins during development?
umbilical veins= degenerate
vitelline veins= become the veins of the portal system
cardinal veins= veins of systemic circulationg
What is the main mechanism by which increases in myocardial O2 demand are satisfied?
Hypoxia and adenosine accumulation increase cardiac perfusion
Where does most coronary venous blood drain into?
coronary sinus in the right atrium (the remainder drains into the chambers of the heart
What three features distinguish heart circulation from blood flow to skeletal muscle and viscera?
- Heart is perfused during diastole and consumes 5% of CO
- Myocardial O2 requirement is high (extracts 90%)
- Coronary flow is regulated by local metabolic factors (hypoxia and adenosine accumulation)
What part of the heart is prone to ischemia?
endometrium
Myocardial contraction during systole compresses the coronary arteries and disrupts blood flow (contraction is highest in the endocardium leading to severe coronary vessel compression)
Hypo-hyperpigmeneted skin patches that become more visible after tanning
Malassezia furfur causes PITYRIASIS VESICOLOR (stratum corneum)
*more common in hot humid climates
KOH scraping show spaghetti and meatballs on light microscopy
Malassezia furfur
Two toxins act by ribosylating and inactivating EF2, inhibiting host cell protein synthesis and causing cell death?
Diptheria toxin= C. Diptheriae
Pseudomonal exotoxin A= Exotoxin A
Superantigen that acts locally in the GI tract causing vomiting
Enterotoxin= S. Aureus
Superantigen that stimulates T cells leading to widespread cytokine release and shock (IL-1, TNF alpha)
TSS toxin
Induces actin depolymerization leading to mucosal cell death, necrosis of colonic muscosal surfaces and pseudomembrane formation
Toxin B= C. Diff
Blocks presynaptic release of Ach at NM jxn resulting in flaccid paralysis
Botulinum toxin= c. botulinum
Disinhibits AC via G ADP ribosylation> increased cAMP> increased histamine sensitivity and phagocyte dysfxn
Pertussis toxin= bordatella pertussis
Acitvates AC via G ADP ribosylation> increased cAMP> secretory diarrhea, dehydration, electrolyte imbalances
cholera toxin= v. cholerae
Unconscious manifestations of neurologic sxs w/ no pathophyisiological manifestations often after significant life stress
converseion disorder
most lateral of hte distal carpal bones, thumb “swings on it”
trapezium
What bone lies at the center of hte wrist?
capitate
What bone is located at the proximal medial wrist and with the lunate forms the small articular surface between teh ulna and carpal bones?
triquetrum
What type of fall classically causes lunate dislocation?
fall on oustretched hand
cause of avascular necrosis of proximal scaphoid fx fragment
lunate dislocation that also causes fx of scaphoid
Noninfective glycoprotein component of HVB envelope that forms spheres and tubules 22 nm in diameter
HBsAg (secreted by infected hepatocytes)
Nucleocapsid core protein taht resides in hepatocytes and assembles virion
HBcAg
Nucleocapsid core and precore protein that is a marker of high infectivity. Core component resides in hepatocytes and assembles virion, while precore is secreted in the blood
HBeAg
TRanscriptional transactivaitor of viral gens from X region that is necessary for viral replication
HBx
What type of mutations results ina glutamate residue being substituted by lysine in the beta globin chain?
Missence mutation causing hemoglobin C (HbC in both beta chain)
Hb A> HbS> HbC
1 HbS allele and 1 HbC allele
Asymptomatic pt w/ mild hemolytic anemia and splenomegaly
Hemoglobin SC disease
Mental retardation, facial dysmorphism, cardiac defects
Down Syndrome (usually caused by extra chromosome 21– trisomy)
What are other less common cuases of Down Syndrome?
Robertsonian translocations mosaicism
What is a Robertsonian translocation?
46 chrom, but extra arm of chrom 21 is attached to another chrom (translocation)
How can mosaicism cause Downs?
Pts have 2 cells lines: one w/ a normal genotype and one w/ trisomy 21
(no maternal association, post fertilization mitotic error)
Causes of secondary hyperaldosteronism
renovascular disease
malignant HTN
renin secreting tumors
HyperTN, hypokalemia and muscle weakness can be attributed to…
elevated serum adlosteorne levels
Increased renin and aldosterone
secondary hyperaldosteronism
A pt who is a known HBV carrier presents to your office w/ malaise, weight loss and abdominal fullness. CT reveals a liver mass and increased AFP.
Hepatocellular carcinoma
carcinoma assocaited w/ HBV infeciton
Hepatocellular
What triggers neoplastic changes in HBV?
integration of viral DNA into genome of host hepatocytes
Increased incidence of Burkitt lymphoma and nasopharyngeal carcinoma
EBV infection
see atypical lymphocytes on blood smear CD21
measure of association between exposure and outcome
Odds ratio
Formula for OR?
OR= ad/bc
RR formula
a/ (a+b)/
c/ (c+d)
risk of disease in hte exposed divided by risk of disease in the non exposed
Difference in risk between exposed and unexposed
AR
A/ (a+b) - c/ (c+d)
Bean shaped gram negative cocci that causes meningitis
N. meningitidis
How does N. meningitidis gain access to the CNS?
respiratory droplets> colonizes nasopharynx> bloodstream> choroid plexus> meninges
What is the second MC cause of acute bacterial meningitis in adults in the US?
N. Meningitidis
Which neisseria ferments maltose and glucose?
MeninGococci ferment Maltose and Glucose
meningococcemia
meningitis
WF syndrome
n. meningococci
Pharynx> lymphatics> meninges
H. Influenza meningitis in infants and children
Middler ear> contiguous tissues>
meninges
S. Pneumoniae gains acces to CNS during acute ear infection
Traumatic wound>
leak CSF>
meninges
S. Aureus meiningitis/CNS abscess (fullowing penetrating skull trauma or neurosurgery)
Primary lung focus>
blood >
meninges
Myobacterium TB meningitis or S. pneumoniae meningitis
