Micro: Aids Associated Infections
Terms
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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
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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?
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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
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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)
fever
headache
meningismus
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
Diagnosis -
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
treatment -
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 -
Toxoplasmosis
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 -
Toxoplasmosis
pathogenesis -
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 -
Toxoplasmosis
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 -
Toxoplasmosis
diagnosis - How is Toxoplasmosis treated?
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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 - toxoplasmosis
- How is toxoplasmosis prvented in AIDS patients?
- TMP/SMX rec when CD4 is below 100 and patient has positive IgG
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Aids patient with CD4 of 15 complains of occasional "floaters"
optho exam reveals retinal infarction with bleeding, described as eggs and ketchup - Cytomegalovirus (CMV)
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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?
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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)
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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:
fatigue
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?
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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