23- Systemic infections Flashcards
triad of symptoms for infectious mononucleosis
fever
tonsillar pharyngitis
lymphadenopathy (symmetric and generalised)
- extra: white/gray/green/necrotic tonsils; palatal petechiae
who is the major reservoir for EBV
humans
T/F approx 90-95% of adults are EBV positive
T
T/F EBV acquired during childhood is often subclinical
T
peak incidence of EBV
15-24
is infectious mono more common in children or adults
Children
how does EBV shed
salivary secretions for 6 months after the onset of the illness
T/F EBV is a very contagious disease
F
incubation period for EBV lasts
4-8 Weeks
rare complications of mono
peritonsillar abscess or airway occlucsion (1%), due to edema of soft palate and tonsils
is splenomegaly common in mono
yes, 50-60%. recedes after 3rd week of illness
is mono related to a rash
yes, generalised maculo-papular rash, often post ampicillin, amoxicillin
T/F absence of cervical lymphadenopathy and fatigue make mono unlikely
T
DX of mono
atypical lymphocytes and lymphocytosis
- heterophile antibodies (produced by abnormal B cells- called monospot test) react to unrelated antigens (paul bunnell - latex agglutination using horse RBC)
- ELISA
- IgM VCA; acute infection
- IgG VCA: persistant infection
tx for mono
supportive care
T/F CMV in a competent host is asymptomatic or presents as mono
T
CMV transmission route
- sexual exposure
- close contact: urine, upper resp
- blood or tissue
- perinatal exposure
can CMV have a rash
yes, maculopapular with 1/3 of ppl exposed to ampicillin
dx of CMV
antibodies, PCR
Tx of CMV
most cases are asymptomatic, and if they have symptoms its self limited with a recovery in days to weeks
toxoplasmosis is due to
intracellular protozoan parasite
infection with T gondii sx
asymptomatic
in immunocompromised theres acute systemic infection or posterior uveitis
toxoplasmosis reactivation results in
multiple CNS abscess like, round processes with ring enchancement
how can people become infected with T gondii
- eating undercooked meat of animals harboring tissue cysts
- consuming food or water contaminated with cat feces
- blood transfusion or organ transplantation
- mother to fetus
congenital toxoplasmosis appears as
- look normal on prenatal US
Intracranial calcifications, ventricular dilatation, hepatic enlargement, ascites, increased placental thickness - later symptoms are potential vision loss, mental disability, seizures
if a person has a new infection which antibody is present first
IgM
tx for toxoplasmosis
is usually self limited,
- treat those with severe or longer symptoms
- treat pregnant women with pyrimetamine and sulfadiazine
leptospirosis is due to
spirochete bacteria
transmission of leptospira
by contact of urine of infected animals to mucous membranes; conjunctiva, skin cuts, abrasions of humans
Bacteria can survive for weeks to months in urine contaminated water and soil
There are outbreaks after heavy rainfall
which disease can be biphasis
leptospirosis
First phase: acute febrile bacteremic phase for 2-9 days
Second phase: immune phase with renewed fever (here the bacteria is absent from the blood but present in the urine)
Can occur with jaundice and renal failure (Weils disease). pulmonary hemorrhage, ARDS, uveitis, myocarditis
sx of leptospira
MOST INFECTIONS ARE ASYMPTOMATIC
- fever, rigors, myalgias, headache
- conjunctival suffusion and redness, and subconjunctival hemorrhages
tx of leptospira
for mild sx: doxycycline
or azithromycin, ampicillin, amoxicillin
severe dx: IV penicillin and ceftriaxone
The majority of reactive lymphocytes in pts with infectious mononucleosis are
CD8 cytotoxic t cells
What is an IgG avidity assay in CMV
To measure the binding strength between IgG antibodies and virus
It helps distinguish primary CMV infection from past infection
- Following a primary infection IgG have low binding strenght (low avidity) and 2-4 months after they have high avidity
a serious complication of leptospirosis is
severe pulmonary disease with pulmonary hemorrhage
