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Micro: Aids Associated Infections


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opportunistic infection that occurs when CD4 counts are below 200 cell/ ml

organism is a ubiquitous fungus

symptoms are progressive and subacute; include nonproductive cough with fevers
Pneumocystis jiroveci Pneumonia (PCP)
general characteristics
patiens P/W fever, tachypnea, and hypoxia; rest of exam may be normal

Chest radiograph shows bilateral infiltrates in a bat-wing or butterfly pattern

Labroratory data include elevated LDH, increased A-a gradient and decreased PaO
Pneumocystis jiroveci Pneumonia (PCP): clinical presentation
diagnoses is made by history

definitive dx made by bronchial alveolar lavage showing organisms on silver stain
Pneumocystis jiroveci Pneumonia (PCP): how is diagnoses made?
treatment for this infection includes trimethoprim/sulfamethoxazole 15-20mg/kg/day over 3-4 doses

other treatments include pentamadine, atovaquine, combo of clindamycin and primaquine or atovaquone; steroids in some cases
Pneumocystis jiroveci Pneumonia (PCP): treatment
PCP prophylaxis
given to patients with CD4 count < 200 or previous history of PCP

common agents inc TMP/SMX, atovaquone, dapsone, or inhaled pentamadine
usually occurs when CD4 is less than 100

acquired by inhalation of org which is ubiquitous

airway is colonized and the organism doesnt cause infection unless there is a problem with cellular immunity

org invades blood str
Cryptococcal Meningitis
general characteristics
presents with ( in order of incidence)

visual changes
mental status changes
skin findings
Cryptococcal Meningitis
clinical presentation
dx made by lumbar puncture with isolation of org (gold standard)

india ink is negeative in 20% of cases

antigen is 97-100% sensitive

Typical CSF findings include
- pleocytosis w/ predominance of lymphocytes
- el
Cryptococcal Meningitis
treated with amphotericin B with addition of flucytosine

* if sypmtoms do not imporve or worsen then therapeutic LP to remove CSF may be beneficial
Cryptococcal Meningitis
Toxoplasma gondii is intracellular protozoan

acquired by the ingestion of undercooked pork or lamb, inhalation of the org, or transplacental transmission

10-40% of gen population infected
General characteristics
After acquisition, the tachyzoites are released into blood stream and infect cells

immune system contains org which may reactivate when cellular immunity wanes

an HIV infected pt has reactivation of the org when CD4 counts fall belo
symptoms inlcude headache, confusionand fever in 50% of patients with intra-cerebral infection

60% have focal findings

30% have siezures

meningeal signs are rare

usually insiduous onset
clinical presentation
Dx is usually presumptive, based on Neuro imaging for intra cerebral lesions

Serology - IgG,not conclusive

SPECT or PET scans- should show no increased uptake
How is Toxoplasmosis treated?
pyrimethadine and sulfadiazine

steroids can be helpful to relieve intracranial pressure

treat for 4-6 weeks

therapy continued until HAART inc CD4 above 200
AIDS patient presents with fever, headache, seizure and CD4 count of 10

Exam reveals temp of 101, he has diffuculty staying awake and he has left sided weaknesses

CT scan shows multiple ring enhancing structures
How is toxoplasmosis prvented in AIDS patients?
TMP/SMX rec when CD4 is below 100 and patient has positive IgG
Aids patient with CD4 of 15 complains of occasional "floaters"

optho exam reveals retinal infarction with bleeding, described as eggs and ketchup
Cytomegalovirus (CMV)
this is a virus of herpesviridae fam

humans are only resevior

transmitted via body fluids

persistant infection occurs after primary infection

org is shed intermittently

over 75% of adults have this o
Cytomegalovirus (CMV)
general characteristics
occurs in AIDS pts when CD4 count is below 50

presents with retinitis, GI symptoms, Neuro of Pulm Symptoms
Cytomegalovirus (CMV)
Clinical features in AIDS patients
What are the clinical manifestations of CMV retinitis?
symptoms include painless blurring, loss of central vision, flaoters or flashing lights

* overall incidence has decreased since the advent of HAART
Aids patient p/w fatigue, diarrhea, weight loss, fever, and severe night sweats

he has fever of 104.2 but has normal vital signs

CD4 is below 20

inguinal (groin)lymphadenopathy and mild abdominal distension
Mycobacterium avium Complex (MAC)
these organisms are ubiquitous, commonly found in water and soil

one usually develops significant disease with this organism when CD4 is below 75

typically org is digested and dissimenated to rest of body
Mycobacterium avium Complex (MAC)
general characteristics
signs and symptoms include:

weight loss
high fevers
severe night sweats
watery non bloody diarrhea

pts develop significant lymphandenopathy but usually feel well
Mycobacterium avium Complex (MAC)
clinical manifestations
labs demonstrate dec WBCs

Dx made by blood or bone marrow culture
Mycobacterium avium Complex (MAC)
lab and Dx
How is Mycobacterium avium Complex (MAC)treated?
combo of clarithomycin and ethambutol +/- rifabutin

Tx should continue until CD4 is above 100 and pt has received 6-12 mo of therapy

primary prophylaxis is rec for all pts with CD4 below 50

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