Some opportunistic infections are incurable, whereas others respond well to medicinal therapy and may be prevented with prophylactic medicines. There is at present no adequate and simple treatment for cryptosporidiasis. Treatments are sometimes complex such as for infections with Mycobacterium avium.

Several treatment schemes are possible.

• 1st choice: Intravenous or oral trimethoprim/sulphamethoxazole (= cotrimoxazole, Bactrim®, Eusaprim®) 4 x 3 ampoules IV per day or 6-8 Bactrim forte® tablets per day. If there is no pronounced dyspnoea, the treatment can be given all orally. Side-effects of the medicaments occur frequently (allergic reactions with cutaneous abnormalities).
• 2nd choice: Oral dapsone/trimethoprim (Dapson® 100 mg/day + Wellcoprim® 20 mg/kg/day divided over 4 doses). With less serious PCP 100 mg dapsone is administered together with TMP (trimethoprim) 3 x 300 mg/day.
• 3rd choice: Pentamidine (Pentacarinat®) IV. The guide dose is 4 mg/kg in one administration over 8 hours in a 5% glucose infusion.
• 4th choice: Pentacarinat® in 300 mg aerosol in 6 ml sterile water. It is advised to give salbutamol puffs beforehand.
• Alternatives: other medicaments are clindamycin + primaquine, atovaquone and trimetrexate (Neutrexin®). The duration of the treatment is 21 days.

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In case of severe hypoxia intravenous steroids (methylprednisolone) should be given. The patient may exhibit a hypersensitivity reaction due to the release of large quantities of antigenic material from the organisms. At later stages, corticosteroids are no longer effective.

A relapse frequently occurs after discontinuing a "curative" treatment. Prophylaxis is therefore given after the initial treatment. The same medicaments but in lower dose (Bactrim forte® 1 per day; or dapsone 100 mg/day) PO or 300 mg pentamidine-aerosol once a month can be used. Fansidar® 1 tablet per week can also be given. Cotrimoxazole acts simultaneously as a prophylactic agent for toxoplasmosis. Dapsone can be tried when cotrimoxazole is not tolerated.

This parasite is sensitive to clindamycin (Dalacin C, 4 x 600 mg per day) and to pyrimethamine (Daraprim®, 100 mg day 1, thereafter 50 mg per day) + sulphadiazine (4-6 g per day). It is best with this latter combination to add 15-30 mg folinic acid (Ledervorin®) per day to reduce bone marrow toxicity. Do not confuse folinic acid and folic acid: folic acid counteracts the therapeutic action of pyrimethamine. Pyrimethamine 50 mg together with dapsone 100 mg can also be used for toxoplasmosis. Atovaquone is moderately active against this organism. Corticosteroids are indicated when there are signs of intracranial hypertension. Phenytoin (Diphantoine®) can be used in epilepsy. Prevention of relapse with cotrimoxazole, pyrimethamine + sulphadiazine or dapsone is indicated after the attack therapy.

This is a unicellular organism that causes diarrhoea. Transmission is faeco-oral. It is sometimes quite difficult to detect in the stools. It is sensitive to trimethoprim/sulphamethoxazole (Bactrim®, Eusaprim®). If this cannot be used, pyrimethamine (Daraprim®) can be used. The combination ornidazole-albendazole can be used as third choice.

Candida albicans in the mouth, throat and oesophagus causes difficulty in swallowing. This fungal infection can be treated with gentian violet or nystatin tablets, ketoconazole (Nizoral®), topical miconazole (Daktarin®), systemic itraconazole (Sporanox®) or fluconazole (Diflucan®). Gentian violet (1.5 ml 0.5 % aqueous solution, 2 x per day) is cheap, but stains the mouth purple. Gentian violet does not help in oesophageal candidiasis. Itraconazole and fluconazole are very expensive. Buccal tablets containing miconazole in a prolonged release formulation can be placed under the upper lip for local (topical) treatment of oropharyngeal candidiasis. Voriconazole, a new triazole, is very promising but at the moment there is very little data on it. It is also active against Candida kruseii, a yeast that is inherently resistant to fluconazole. It penetrates the blood-brain barrier and can be used in cases resistant to amphotericin B. Caspofungin (Cancidas®) belongs to the new class of echinocandins, and is active against divers Candida species (C. albicans and several C. non-albicans, including C. krusei). The normal dose is 70 mg as a single start-dose, followed by 50 mg/day IV. For patients heavier than 80 kg, a daily dose of 70 mg/day is advised. In case of medium liver failure (Child-Pughscore 7-9) 35 mg/day as maintenance dose is advised. There is no need for dose-adjustment in case of renal failure.

Cryptococcus neoformans is a yeast sensitive to amphotericin B (Fungizone®) and flucytosine (Ancotil®). Fluconazole (Diflucan®) can also be used and has the great advantage that it can be given orally. This makes prophylaxis possible, though this medication is very expensive. The cost of the medicament brings into questions whether it is worthwhile detecting cryptococcal infection in developing countries. The patient and/or his family can be ruined financially. The combination of antifungal drugs and gamma-interferon is being studied.

Blastomyces dermatitidis causes blastomycosis (USA and Middle East). The disease often resembles tuberculosis or a carcinoma. It can be treated with itraconazole (200-400 mg/day for a minimum of 6 months). Amphotericin B is used when the infection is resistant to itraconazole or when the brain is affected. There is still insufficient experience with echinocandine.

Herpes simplex can cause skin lesions and can also affect the gastrointestinal system. An oral antiviral treatment for 5 days can be considered in cases of a first episode of herpes genitalis. The antiviral agents aciclovir (Zovirax®), famciclovir (Famvir®) and valaciclovir (Zelitrex®) are all equally effective. However, the risk of recurrences is not diminished by these. Treatment must be started as soon as possible. Topical antiviral agents are not very effective. IV administration is no better than oral treatment. Local analgesics help to diminish the pain of miction or defaecation.

Episodic antiviral treatment or a prolonged prophylactic treatment can be considered in addition to the symptomatic treatment.

• Episodic antiviral therapy must be started upon appearance of the first symptoms. The duration of the symptoms is diminished by only 1 to 2 days.
• Prophylactic therapy lasting 6 months to one year is indicated for patients who have more than 6 to 8 relapses per year. A formal diagnosis (culture, PCR) is advisable before starting it. The patient's physical and mental well being can be considerably improved with prophylactic therapy.
• In patients in an advanced stage of immunodepression, herpes infections are often very serious. The possibility of the existence of these should be clinically considered when persistent, painful antibiotic-resistant genital or perianal ulcers are present. In Belgium the prevalence of strains resistant to aciclovir is 5 to 10%. In this case foscarnet can be used as an alternative.

The purpose of the treatment is both to alleviate the symptoms of the mother and to diminish the risk of neonatal herpes. Approximately 85% of neonatal herpes cases are attributable to perinatal transmission of the virus during vaginal childbirth. The risk is particularly high when the woman develops a primo-infection during the third trimester of pregnancy. If herpetic lesions first appear during the first trimester of pregnancy treatment with aciclovir can be considered. However, aciclovir is not registered for use during pregnancy, though the available data show no increase in the number of deformities in the children. A Caesarean section is recommended when there are active lesions at the time of childbirth. In cases where a first episode of herpes genitalis appears during the third trimester the birth must likewise be carried out by Caesarean section. Treatment with aciclovir, orally for the mother and intravenously for the child, should be started if the birth has to take place via the vaginal route.

Herpes zoster lesions occur in the region of a skin nerve (dermatoma). After healing a white band-shaped zone (depigmentation) or hyperpigmentation often remains. When the ophthalmic nerve is affected the eye can be damaged and blindness may occur. Many patients will develop herpes zoster, sometimes with several episodes and sometimes covering more than 1 dermatoma at the same time. If it is localised on the face, the eyes can be affected and blindness can occur. If the tip of the nose shows a lesion, the nasociliary branch of the ophthalmic nerve is involved. This makes corneal lesions very likely. Aciclovir (800 mg, 5 times per day), valaciclovir 1000 mg, 3 times per day or famciclovir (the prodrug of penciclovir) 500 mg, 3 times per day are used in the treatment. Post-herpetic neuralgia is difficult to treat. When customary analgesics or topical lidocaine have insufficient effect, the antidepressants nortriptyline, amitriptyline (Redomex®) or desipramine (Pertofran®) can be tried. Anticonvulsants such as carbamazepine or gabapentine can sometimes alleviate the pain. Opioids such as oxycodone can bring relief in some patients. A peripheral nerve blockade is an emergency solution. When analgesics bring no improvement, methylprednisolone may be administered intrathecally (the neuralgia has an inflammatory component).

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Brivudin, an antiviral agent used in treating herpes zoster, is significantly more efficacious than standard aciclovir. Data also showed that brivudin is as effective as famciclovir in alleviating acute signs and symptoms of herpes zoster. Furthermore, brivudin, which is given orally at a dose of 125 mg once daily for seven days, improves patient compliance.

There is a close connection between HIV infection and tuberculosis. Many tuberculosis patients in Africa are HIV patients and approximately 50% of the HIV patients develop tuberculosis. This makes the struggle against tuberculosis much more difficult. The diminished resistance of the patient often results in a reactivation of tuberculosis bacteria. New infections of course also occur. Clinical symptoms of tuberculosis can appear quite early, even before the CD4-lymphocyte count has substantially decreased. Infections with atypical mycobacteria (for example MAI = Mycobacterium avium intracellulare) are more frequent in the West and seldom occur in developing countries. The discovery of acid-fast bacilli in a patient in Africa is therefore usually synonymous with tuberculosis. Most atypical mycobacterioses in fact occur only when the immunosuppression has advanced much further. However, many patients will have died before this stage is reached.

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The Mantoux-test is unreliable in AIDS (frequently negative due to anergy). Tuberculosis proceeds more aggressively and quickly in HIV patients. Extrapulmonary tuberculosis occurs more in seropositive persons. Fortunately, treatment gives good results. Any new case of tuberculosis that has never been treated before should be given: isoniazid + rifampin + pyrazinamide + ethambutol for 2 months, followed by isoniazid + rifampin for 4 months. It is better not to give streptomycin injections due to the risk of HIV transmission in cases of poor sterilization of needles. AIDS patients often have severe cutaneous side-effects (including Stevens-Johnson syndrome) upon use of thiosemicarbazone, and hence this product is best avoided. The increase in resistant tuberculosis and the lack of cheap alternative therapies may in the near future give rise to extra problems, not only for the patients themselves but also for the non-seropositive population. Compliance with therapy is of utmost importance for the patients themselves and for preventing development of resistance and for counteracting further transmission (also to non-HIV infected persons). Respiratory precautions, till negativity of the sputum (Ziehl-Neelsen), should be implemented.

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Active tuberculosis should be excluded before TB prophylaxis is started in a patient. INH (1 year) combined with pyridoxine (vitamin B6), the latter for prevention of neuritis, is used as prophylaxis. Rifampicin can be given with pyrazinamide for two months as an equally effective alternative.

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Mycobacterium avium is not very sensitive to the conventional tuberculostatic drugs. Treatment of Mycobacterium avium relies on administration of rifabutin [Mycobutin®] + ethambutol [Myambutol®]+ clarithromycin [Maclar®, Biclar®, Heliclar®].

Certain cancers, including Kaposi's sarcoma and certain non-Hodgkin’s lymphomas, occur more frequently due to the immunosuppression. Seropositive women run an increased (5-fold) risk of invasive cervix carcinoma and of vulva carcinoma. This is probably connected with the sexually transmitted papilloma virus. Chemotherapy (vincristine + bleomycin, taxol), alpha-interferon (Intron®, Roferon-A®) and radiotherapy can reduce Kaposi lesions, but do not prolong life. These treatments are very expensive and often not available in developing countries. Kaposi lesions do often improve with HAART.

Schemes with killed vaccines such as those proposed by the WHO may be used, even in seropositive children and in children whose HIV status is not known. The live oral polio vaccine (Sabin) is better replaced by the inactivated Salk vaccine in known HIV+ children. BCG is best avoided in known HIV+ children. For safety’s sake yellow fever vaccination should be avoided, although the risks are probably minimal. More recent data indicate that vaccination is safe when the CD4-count is higher than 200. When the CD4-cells are more than 400, the immunogenicity of the vaccine is reliable.

The following vaccines are advised : Pneumovax, Tetanus, Hepatitis A and B, Influenza.