Amebiasis and "nonpathogenic" intestinal protozoa

Infection with single or multiple species of intestinal protozoa is common in humans and can result in either asymptomatic colonization or symptoms of intestinal disease. Entamoeba histolytica serves as a paradigm for invasive colonic protozoal infection. The key to diagnosis and treatment of amebiasis is knowledge of the epidemiologic risk factors and clinical manifestations, a rational approach to diagnosis, and an understanding of the sites of action and uses of anti-amebic drugs. This knowledge of treatment provides a context for consideration of intestinal infection with less common protozoan pathogens such as Dientamoeba fragilis and Balantidium coli and 'nonpathogenic' protozoa such as Blastocystis hominis and Entamoeba coli.

Leishmaniasis

Leishmanial infections include three major clinical syndromes: visceral, cutaneous, and mucosal leishmaniasis. Visceral leishmaniasis, usually due to Leishmania donovani, has received increasing attention in the United States because of the growing number of cases seen in AIDS patients and the occurrence of viscerotropic L. tropica disease among Persian Gulf war participants. Cutaneous leishmaniasis is a relatively benign disease caused by L. Mexicana and L. (Viannia) species in the New World, and L. major, L. tropica, and L. aethiopica in the Old World. Many of these cutaneous lesions are self-healing, and treatment recommendations vary and continue to undergo evolution and study. Mucosal disease, caused by Leishmania (V.) braziliensis, is difficult to diagnose as well as to treat. A practical approach to the clinical presentation, diagnostic measures, and some treatment options of these syndromes is presented in relation to specific case studies.

Identification of the microsporidian parasite, Enterocytozoon bieneusi in faecal samples and intestinal biopsies from an AIDS patient

The microsporidian parasite, Enterocytozoon bieneusi, is currently recognized as a potentially important cause of chronic diarrhoea in patients infected with the human immunodeficiency virus (HIV). Faecal concentrates from a 38-year-old, HIV-seropositive patient examined by light and electron microscopy revealed the presence of numerous microsporidian spores. The structural characteristics of the spores were consistent with those previously described for Enterocytozoon bieneusi. Each spore contained a single nucleus, a posterior vacuole and a polar filament with 6-7 overlapping coils which appeared in cross-section as a series of 3 doublets. Mature spores were surrounded by an inner unit membrane, an electron-lucent endospore and a thin, electron-dense exospore. The identity of the parasite was confirmed by the detection of unique endogenous developmental stages in duodenal biopsies. Both proliferative and sporogonial plasmodia (meronts and sporonts) were observed and all stages were monokaryotic (single nucleus) and apansporoblastic (sporophorous vesicle absent). Proliferative and sporogonial plasmodia divided by plasmotomy and spore organelles (polar filament, attachment disc and polaroplast) were well developed prior to fission of the sporogonial plasmodium.

Parasitic infections in AIDS patients. Cryptosporidiosis, isosporiasis, microsporidiosis, cyclosporiasis

AIDS is characteristically associated with several intracellular enteric protozoan infections that often cause chronic and sometimes fatal intractable large-volume diarrhea. Until the AIDS epidemic, several of these parasitic infections were almost unknown as causes of human disease. This article reviews the diseases produced by cryptosporidia, isospora, cyclospora, and microsporidia in humans.

Issues in toxoplasmosis

Toxoplasma has become a well-recognized cause of disease in the last decade, primarily due to the prominence of AIDS. Diagnosis of toxoplasmic encephalitis is discussed, with emphasis on serologic tests, their pitfalls, and empiric therapeutic trials. Randomized trials for treatment of toxoplasmic encephalitis are few, but the combinations of pyrimethamine and sulfadiazine and of pyrimethamine and clindamycin appear comparable. Needs and methods for specific prophylaxis of toxoplasmic encephalitis are not well defined. It is now feasible to diagnose Toxoplasma infection in utero with a high degree of sensitivity and specificity, but whether such diagnosis is effective in the usual practice situation in the United States remains to be proved. Toxoplasmosis in transplant recipients is reviewed briefly.

Clinical manifestations of infection with the human immunodeficiency virus in women in Louisiana

To better understand the clinical manifestations of human immunodeficiency virus (HIV) infection in women in Louisiana, we conducted a retrospective review of the records of HIV-infected women who presented to the largest HIV outpatient clinic in Louisiana as well as to a tertiary care university hospital in New Orleans between January 1987 and December 1991. A total of 224 women were evaluated. Gynecologic examinations revealed that 17.5% had cervical intraepithelial neoplasia and that 35% had evidence of candidal vulvovaginitis or colonization. The following conditions were diagnosed among indicated percentages of patients: syphilis, 22.2%; Neisseria gonorrhoeae infection, 7.2%; Chlamydia trachomatis infection, 12.3%; pelvic inflammatory disease, 5.3%; trichomonal vulvovaginitis, 26.9%; genital ulcers due to herpes simplex virus, 16.5%; and clinically evident genital human papillomavirus infections, 16.5%. Both trichomonal vulvovaginitis and syphilis were more common among intravenous drug users. A total of 82 opportunistic processes were observed in 55 women. Pneumocystis carinii pneumonia was the most frequent complication of AIDS, followed by candidal esophagitis and wasting syndrome. Over 85% of women had received a diagnosis of AIDS before death. Gynecologic diseases occurred often in this population; the frequency of AIDS-defining events was similar to that reported previously in the literature.

The Mycobacterium avium complex

Mycobacterium avium complex (MAC) disease emerged early in the epidemic of AIDS as one of the common opportunistic infections afflicting human immunodeficiency virus-infected patients. However, only over the past few years has a consensus developed about its significance to the morbidity and mortality of AIDS. M. avium was well known to mycobacteriologists decades before AIDS, and the MAC was known to cause disease, albeit uncommon, in humans and animals. The early interest in the MAC provided a basis for an explosion of studies over the past 10 years largely in response to the role of the MAC in AIDS opportunistic infection. Molecular techniques have been applied to the epidemiology of MAC disease as well as to a better understanding of the genetics of antimicrobial resistance. The interaction of the MAC with the immune system is complex, and putative MAC virulence factors appear to have a direct effect on the components of cellular immunity, including the regulation of cytokine expression and function. There now is compelling evidence that disseminated MAC disease in humans contributes to both a decrease in the quality of life and survival. Disseminated disease most commonly develops late in the course of AIDS as the CD4 cells are depleted below a critical threshold, but new therapies for prophylaxis and treatment offer considerable promise. These new therapeutic modalities are likely to be useful in the treatment of other forms of MAC disease in patients without AIDS. The laboratory diagnosis of MAC disease has focused on the detection of mycobacteria in the blood and tissues, and although the existing methods are largely adequate, there is need for improvement. Indeed, the successful treatment of MAC disease clearly will require an early and rapid detection of the MAC in clinical specimens long before the establishment of the characteristic overwhelming infection of bone marrow, liver, spleen, and other tissue. Also, a standard method of susceptibility testing is of increasing interest and importance as new effective antimicrobial agents are identified and evaluated. Antimicrobial resistance has already emerged as an important problem, and methods for circumventing resistance that use combination therapies are now being studied.

Oral infections due to cytomegalovirus in immunocompromised patients

Herpes group virus infections in the immunocompromised host are associated with significant morbidity and mortality. Herpes simplex virus (HSV) and to a lesser extent varicella zoster virus (VZV) have long been recognized as causes of oral and peri-oral lesions in subjects undergoing bone marrow transplantation and in individuals infected with the Human Immunodeficiency Virus (HIV). A role for Cytomegalovirus (CMV) in such lesions is less clear and not well documented. This report describes two bone marrow transplant recipients and one individual infected with HIV in whom CMV was implicated as the cause of oral lesions. Diagnostic and management issues as well as clinical implications are discussed.

Unrecognized coccidioidomycosis complicating Pneumocystis carinii pneumonia in patients infected with the human immunodeficiency virus and treated with corticosteroids. A report of two cases

Coccidioidomycosis is becoming increasingly recognized as an opportunistic infection among patients infected with the human immunodeficiency virus. We treated two cases of concomitant coccidioidomycosis and Pneumocystis carinii pneumonia. In each case, the diagnosis of coccidioidomycosis was delayed despite appropriate examination of bronchoalveolar lavage fluid. Both patients were treated with antimicrobial therapy directed against P carinii and given adjuvant corticosteroid therapy. In both cases, this led to clinical worsening and was associated with the development of a reticulonodular pulmonary infiltrate on chest roentgenograms. When coccidioidomycosis and Pneumocystis pneumonia occur concomitantly in patients with human immunodeficiency virus infection, the diagnosis of coccidioidomycosis may be delayed or missed. In such cases, corticosteroids may lead to overwhelming coccidioidomycosis. Development of a reticulonodular pulmonary pattern on chest roentgenograms is suggestive of this complication.

A population-based assessment of invasive disease due to group B Streptococcus in nonpregnant adults

BACKGROUND

Group B streptococci (Streptococcus agalactiae) are a major cause of meningitis and septicemia in neonates and pregnant women, but the importance of group B streptococcal disease in nonpregnant adults has not been clearly defined.

METHODS

We conducted a prospective surveillance of the pathogens responsible for meningitis for a period of 24 months in 35 hospitals and a referral laboratory in metropolitan Atlanta. We reviewed the clinical and laboratory records of all the nonpregnant adults identified as having invasive group B streptococcal disease during this period.

RESULTS

During 1989 and 1990 there were 424 patients with invasive group B streptococcal disease (annual incidence, 9.2 cases per 100,000 population). Of these patients, 46 percent were 1 month of age or younger, 6 percent were older than 1 month but younger than 18 years of age, and 48 percent were 18 or older. Men and nonpregnant women accounted for 68 percent (n = 140) of all cases among adults (annual incidence, 4.4 per 100,000). Clinical and laboratory records were available for 137. In the nonpregnant adult patients (age, 18 to 99 years), the most common clinical diagnoses were skin, soft-tissue, or bone infection (in 36 percent); bacteremia with no identified source (30 percent); urosepsis (14 percent); pneumonia (9 percent); and peritonitis (7 percent). Risk factors included older age (> or = 60 years), the presence of diabetes mellitus, the presence of malignant neoplasms, and infection with the human immunodeficiency virus. The mortality rate in nonpregnant adults was 21 percent, accounting for 67 percent of all deaths related to group B streptococcal infection during the surveillance period.

CONCLUSIONS

Invasive group B streptococcal infection is a major problem not only in pregnant women and neonates but also in nonpregnant adults, especially those who are elderly and those who have chronic diseases.

Cutaneous disease and drug reactions in HIV infection

BACKGROUND

Skin diseases, including adverse reactions to drugs, are thought to be more common among patients with human immunodeficiency virus (HIV) infection and the acquired immunodeficiency syndrome (AIDS) than among other persons. These skin conditions can be disabling or disfiguring and may require discontinuation of essential drugs.

METHODS

We identified 684 HIV-infected members of a 265,000-member health maintenance organization and reviewed their medical records to determine the frequency of dermatologic diagnoses from April 1, 1988, through January 15, 1991. We compared the rates of visits per year for skin conditions by HIV-infected men, 20 to 49 years of age, with those by non-HIV-infected men. We used an automated prescription data base to quantify exposures to drugs.

RESULTS

Of the 684 HIV-infected patients, 540 (79 percent) were given one or more dermatologic diagnoses, for a total of 2281 diagnoses, including 188 cutaneous reactions to drugs. There were 43 hospitalizations for cellulitis (n = 15), cutaneous drug reactions (n = 13), or other skin problems. As compared with non-HIV-infected men, the men with AIDS had visit rates that were at least 5 times higher for 18 of the 20 most common infectious and inflammatory skin conditions and at least 15 times higher for 9 conditions. Drugs with the highest rate of cutaneous reactions (per 1000 courses) included trimethoprim-sulfamethoxazole (149), sulfadiazine (200), trimethoprim-dapsone (156), and aminopenicillins (93). The number of diagnoses of skin conditions increased according to the stage of disease: it was lowest in patients immediately before the documentation of HIV infection and highest in patients with a diagnosis of AIDS.

CONCLUSIONS

Cutaneous diseases, including drug reactions, are extremely common in patients with HIV infection, and their incidence increases as immune function deteriorates.

Pneumocystis carinii pneumonia in pregnancy. A case report

The association of human immunodeficiency virus (HIV) infection and pregnancy has become more common. This virus has become a factor in the social affairs of even small, rural communities. We present a case in which the diagnosis of HIV was made during admission for Pneumocystis carinii pneumonia (PCP). The patient's condition worsened rapidly, necessitating delivery at 31 weeks' gestation by cesarean section followed by the patient's death from PCP. The infant survived and was healthy at 1 year of age.

[A case of cryptococcal retinochoroiditis associated with acquired immunodeficiency syndrome]

A case of cryptococcal retinochoroiditis associated with acquired immunodeficiency syndrome (AIDS) is reported. The patient was a 22-year-old man with hemophilia A. He was found seropositive for human immunodeficiency virus three years ago. He was admitted with complaints of fever and cough. CD4/CD8 ratio was 0.01 and CD4 lymphocyte count was 10/mm3. Two weeks later, ophthalmological examination revealed some yellowish white focal lesions at the posterior fundus. More detailed examinations were impossible because of his poor general condition. He died one month later. The autopsy showed disseminated cryptococcosis. Ocular histopathological examination revealed cryptococcal retinochoroiditis without any inflammatory reaction. This is the first report in Japan of this disease associated with AIDS and of a histopathological study of it.

Pediatric infection with the human immunodeficiency virus (HIV): head, neck, and oral manifestations

The increasing incidence of HIV infection in the pediatric population is of concern for the practicing dentist. Long incubation periods of the virus, combined with difficulty in detection, results in many undiagnosed cases of prenatal and natal infections with HIV. As a result, many dentists will unknowingly treat HIV-positive children. This article presents most common features of pediatric HIV infection, placing special emphasis on manifestations which affect the head, neck, and oral tissues.