Over time, HIV decreases the number of CD4 cells. As a person’s CD4 count drops, he becomes at increasing risk of developing opportunistic infections and certain malignancies.
Opportunistic infections normally respond to conventional treatment although they may require a longer treatment period or a higher dose than is necessary for HIV negative patients.
Opportunistic infections in HIV/AIDS patients
In this article, we shall look at a few of the common opportunistic infections and their treatment regiments.
Pneumocystis carinii pneumonia (PCP):
When CD4 count falls to between 100–200/mL there is an increased incidence of developing pneumocystis carinii pneumonia.
The principal manifestation of PCP is Pneumonia; dyspnea on exertion; dry cough; fever; chest pain; usually subacute onset and progression.
Bronchoscopy with bronchoalveolar lavage for direct identification of the organism is the principal diagnostic test. You can perform a chest x-ray which will indicate bilateral, interstitial infiltrates. Serum LDH is usually moderately elevated.
Its treatment entails administration of Tabs prednisone 60mg daily and taper off over 3 weeks in addition to cotrimoxazole (TMP/SMX) IV 15mg TMP/ kg/day IV 6 or 8 hourly for 21 days or double strength cotrimoxazole 2 tablets 8 hourly for 21 days in addition to oral dapsone 100mg OD daily for 21 days.
Primaquine and clindamycin or atovaquone or trimetrexate (with leucovorin) can also be used for mild to moderate disease.
Steroids are used as adjunctive therapy for any patient with severe pneumonia.
With the increasing use of cotrimoxazole, occasional hepatotoxicity is being recognized with growing frequency.
Its likelihood is unpredictable, but when it occurs, trimethoprim-sulfamethoxazole hepatotoxicity follows a relatively uniform latency period of several weeks and is often accompanied by eosinophilia, rash, and other features of a hypersensitivity reaction.
Prophylaxis of PCP may be discontinued if antiretrovirals raise CD4 count >200/mL for >6 months
Most pneumonia is due to Streptococcal infections.
To treat a patient who has come with features of pneumonia administer crystalline penicillin (or ampicillin) or a combination of cotrimoxazole and gentamicin in unresponsive cases.
In HIV/AIDS patients who present with diarrhea ensure you correct dehydration. Specific therapy depends on the causative organism.
A combination of cotrimoxazole and metronidazole is often helpful or chloramphenicol may be combined with metronidazole in an alternative treatment.
Another opportunistic infection is cytomegalovirus. In most cases, it affects patients with CD4 counts of less than 50 /µL.
The principal clinical features of cytomegalovirus are
- Retinitis: blurry vision, double vision, or any visual disturbance.
- Colitis evidenced by diarrhea,
- Esophagitis presenting with odynophagia, fever, retrosternal chest pain if endoscopy is performed it will reveal multiple shallow ulcers in the distal esophagus.
- Encephalitis where the patient presents with altered mental status, cranial nerve deficits.
Diagnosis is by funduscopy to look for retinitis and colonoscopy with biopsy for diarrhea or upper GI endoscopy with biopsy of ulcers.
Oral thrush is another common opportunistic condition that is encountered in immunocompromised patients.
Apply 1% gentian violet paint three times a day or nystatin oral drops or cream, OR miconazole oral gel twice a day or tabs ketoconazole 3–6mg/kg/day in 2 doses for 7 days, OR you can give fluconazole 200mg STAT then 100mg OD for 2 weeks.
Cloxacillin 500mg four times a day for 14 days ie quite effective in their treatment OR erythromycin 500mg QID for 14 days OR topic Bactroban.
Cryptococcis or cryptococcal meningitis is one of the severe opportunistic infection that is also challenging to treat considering the side effects of the drugs used and the regimen itself.
Cryptococcosis usually sets in when the patient's CD4 counts is less than 100/µL.
These immunocompromised patients will present with meningitic features; fever, headache, and malaise.
As part of your diagnosis workup, Lumbar puncture with an initial evaluation by India ink and then specific cryptococcal antigen testing. A lower CSF cell count implies worse disease.
Serum cryptococcal antigen testing will help you predict the prognosis. A high antigen titer, high opening pressure, and low CSF cell count all imply a worse prognosis.
Treatment of cryptococcosis entails the use of Amphotericin intravenously for 10−14 days at least (with flucytosine), followed by oral fluconazole 400mg daily for 6–10 weeks then 200mg OD for life for maintenance and suppressive therapy.
Amphotericin B, 0.7–1mg/kg intravenous infusion daily is recommended for these patients. You need to take some precautions when administering this drug for it can cause hypokalemia. You can also administer
Oral fluconazole is not recommended for general use as prophylaxis because the incidence of cryptococcal meningitis is too low to demonstrate a mortality benefit with its use.
Another opportunistic infection that you need to be cautious about is toxoplasmosis.
Toxoplasmosis is most cases sets in when CD4 counts are less than 100/µL.
The clinical manifestations include brain mass lesion: headache, confusion, seizures, and focal neurologic deficits
A CT or MRI scan of the head showing a “ring” (contrast) enhancing lesion with edema and mass effect.
A trial of specific therapy is given for 2 weeks, and the scan is repeated. Shrinkage of the lesions is considered diagnostic.
Brain biopsy is occasionally necessary if there is no shrinkage of the lesions with treatment for toxoplasmosis.
Clindamycin can be substituted for sulfadiazine in the sulfa-allergic patient. Leucovorin is given to prevent bone marrow suppression.
Prophylaxis of toxoplasmosis is effected by TMP/SMZ and Dapsone.
Treatment is by giving Pyrethamine 25–100mg PO OD + folic acid 10–20mg QID + either sulphadiazine 1–1.5mg 8hourly OR clindamycin 600–1,200mg 8 hourly OR azithromycin 1,200–1,500mg every 24 hours
CTX is safe after the second trimester and azithromycin are safe in pregnancy since it is similar to erythromycin.
Why do you need to admit patients with opportunistic infections?
Patient admission is preferred if:
- Further investigations are required when the diagnosis is uncertain and if such investigations are not possible in an outpatient setting.
- There are opportunistic infections that cannot be effectively treated in an outpatient setting for example amphotericin B.
Mycobacterium avium complex
Mycobacterium avium complex is one of the opportunistic infections that set in among the HIV/AIDS patients who have CD4 counts less than 50 /mL.
The classic clinical features of mycobacterium avium complex are fevers, night sweats, bacteremia, wasting, anemia, and diarrhea. Ubiquitous atypical mycobacteria found in the environment.
This infection is transmitted by inhalation or ingestion.
Principle Diagnostic Tests are blood culture and a culture of bone marrow, liver, or other body tissue or fluid
Mycobacterium avium complex treatment is by the use of Clarithromycin and ethambutol ± rifabutin.
Prophylaxis is effected by giving Azithromycin orally once a week or clarithromycin twice a day
If antiretrovirals raise the CD4 count >100/mL for several months then it is recommended to halt the prophylaxis.
In treating Tuberculosis Patients you need to Avoid antiretrovirals ARVs in the intensive phase: D4T + 3TC and EFV (800mg per day).
Remember that protease inhibitors are contraindicated when rifampicin is used.