Tags: Pentamidine

Leishmania

The genera Leishmania and Trypanosoma are members of the family Trypanosomatidae. These protozoans cause diseases with widely varied clinical presentations as well as geographic distributions, including leishmaniasis, American trypanosomiasis (Chagas’ disease), and African trypanosomiasis (sleeping sickness).

Pathogenic Amebas

There are numerous distinct species of ameba within the genus Entamoeba, and the majority of these do not cause disease in humans. E histolytica is a pathogenic species that is capable of causing disease, such as colitis or liver abscess, in humans. E dispar is prevalent and is indistinguishable from E histolytica by conventional laboratory methods. E dispar exists in humans in only an asymptomatic carrier state and does not cause colitis.

Pneumocystis Carinii

In 1983, P carinii pneumonia (PCP) was described as the AIDS-defining illness in = 60% of the first 1000 patients diagnosed with AIDS in the United States. Subsequently, the advent of prophylactic measures has reduced the incidence of PCP presenting as the initial diagnosis for AIDS to < 50% of cases. In addition, the hospitalization rate is also declining for patients with AIDS who also have PCP. This decline has presumably been caused by successful use of prophylaxis against the organism.

Extrapulmonary P Carinii Infections

Extrapulmonary P carinii infections occur in < 3% of patients and must be diagnosed with histopathologic samples. Primary prophylaxis for PCP with pentamidine may confer a higher risk for extrapulmonary infection. Symptoms of extrapulmonary involvement are nonspecific, usually consisting of fevers, chills, and sweats.

Babesiosis

Several other drugs have been evaluated, including tetracycline, primaquine, sulfadiazine (Microsulfon) and pyrimethamine (Fansidar). Results have varied. Pentamidine (Pentam) has proved to be moderately effective in diminishing symptoms and decreasing parasitemia. Others: High-level parasitemia is more common in asplenic patients.

Parasitic Infections

Most infectious agents fulfill the definition of a parasite: an organism that grows, feeds, and shelters on or in a different organism and contributes nothing to the host. However, medical science has created the classification “parasite” to include a complex group of nonfungal eukaryotic human pathogens. Unlike fungi, parasites have no cell wall and are often motile.

HIV / AIDS

P. carinii pneumonia is the most common life-threatening opportunistic infection in patients with AIDS. The taxonomy of the organism is unclear, having been classified as both protozoan and fungal.

Antimicrobial Regimen Selection

A generally accepted systematic approach to the selection and evaluation of an antimicrobial regimen is shown in Table Systematic Approach for Selection of Antimicrobials. An «empiric» antimicrobial regimen is begun before the offending organism is identified, while a «definitive» regimen is instituted when the causative organism is known. The use of combinations to prevent the emergence of resistance is widely applied but not often realized. The only circumstance where this has been clearly effective is in the treatment of tuberculosis.

Dapsone (Aczone)

The most frequent adverse effects of dapsone are dose-related hemolytic anemia and methemoglobinemia. Hemolysis occurs in most patients receiving 200 mg or more of dapsone daily; however, symptomatic anemia occurs only occasionally. The manufacturer states that the hemoglobin level is generally decreased by 1-2 g/dL, the reticulocyte count is increased 2-12%, erythrocyte life span is shortened, and methemoglobinemia occurs in most patients receiving dapsone. Heinz body formation also occurs frequently.

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