Histoplasmosis

Histoplasmosis - deep mycosis caused by dimorphic yeast fungus Histoplasma capsulatum, which affects tissue macrophages lungs, liver, spleen, lymph nodes, skin and mucous membranes. Among the various forms of the disease is dominated by acute pulmonary histoplasmosis, characterized by fever, chest pain, cough, weakness, lymphadenopathy, radiographic changes. In the diagnosis of histoplasmosis used culture, microscopic, histological examinations; serological tests, allergy tests buy doxycycline online.

Histoplasmosis (Darling's disease, reticuloendothelial tsitoplazmoz) - a fungal disease that causes loss of mononuclear phagocyte system and proceeding with limited or generalized manifestations. Histoplasmosis is an infection endemic to the western and southern states of the USA, Central and South America, Africa; less common in Europe and Asia. There are single episodes of disease histoplasmosis in Russia, however, are not excluded imported cases of athlete's foot. Men suffer histoplasmosis in 2 times more often than women, children are twice as likely than adults.

According to the clinical course of isolated pulmonary histoplasmosis, extrapulmonary histoplasmosis (skin, mucous membranes, CNS and others. Bodies) and disseminated histoplasmosis. The course of pulmonary histoplasmosis may be asymptomatic, acute (symptomatic) or chronic. An important factor in determining the severity and prognosis of histoplasmosis, a state of cellular immunity. Severe disseminated form of the disease usually occurs in the Darling children, the elderly, HIV-infected patients with leukemia and lymphoma.

Dimorphic fungus Histoplasma capsulatum, which is the causative agent of histoplasmosis, may exist in 2 forms: tissue (yeast) and mycelium (the culture). In the human body tissue occurs the form of a microorganism that invades the cells of the reticuloendothelial system organs (liver, spleen, lymph nodes, etc.). The culture of the fungus develops shape outside the body at a temperature below 30 ° C and grows well on nutrient media. Histoplasma capsulatums long remain in the water and in moist soil; quickly perish under the influence of disinfectants.

The natural reservoir of the fungus is soil contaminated with feces and feces of infected birds and animals (bats, dogs, cats, chickens, doves, and others.). Favorable environment for the development of fungi are abandoned buildings and wells, caves, caves, hollows of old trees, air conditioners and so on. Infection of human histoplasmosis occurs by inhalation of dust by inhalation of fungus cells with particles of dust, often during construction and excavation work. At risk of disease histoplasmosis are villagers, farmers, poultry workers, miners, geologists, tourists, cavers and others. Histoplasmosis transmission from animals to humans or from person to person is excluded.

In most cases gateway infections are respiratory tract. Once in the bronchi and alveoli, Histoplasma capsulatums disputes turn into a fabric form and cause the development of the primary tumor in the lung and regional lymph nodes. In lung tissue developed granulomatous process with the outcome of necrosis, ulceration, or calcification, at least - abstsedirovanie. Acute pulmonary histoplasmosis in its pathogenesis is similar to the primary pulmonary tuberculosis. Getting into the systemic circulation Histoplasma capsulatums cause sensitization and production of specific antibodies. Sometimes the disease process that is limited, which corresponds to a subclinical form of histoplasmosis. In other cases, hematogenous spread of fungal infection leads to development of disseminated histoplasmosis.

In connection with the airborne infection by pulmonary form prevails in clinic histoplasmosis. Primary extrapulmonary Darling's disease are rare; usually loss of skin, mucous membranes, the intestines are manifestations of disseminated histoplasmosis. The incubation period lasts on average 7-14 days, sometimes less or more (from 4 to 30 days).

In 80% of infected acute pulmonary histoplasmosis is asymptomatic, showing up on the positive results of intradermal tests with histoplasmin, serological, radiological changes in the lungs. In less severe histoplasmosis health of patients almost does not suffer; rarely bothers short-term fever, catarrh of the upper respiratory tract, cough, which cropped during the week. For severe pulmonary histoplasmosis typically sudden onset, high fever (up to 40-41 ° C) with significant diurnal temperature changes; change chills diffuse sweating; severe headache, and myalgia ossalgia. There is pain in the chest, cough with purulent sputum, coughing up blood; nausea, diarrhea, abdominal pain. Febrile period lasts from 2 to 6 weeks, followed by a prolonged phase of recovery, which flows from the low-grade fever, asthenia, decrease disability.

Chronic pulmonary histoplasmosis is a long progressive course. It is characterized by mild fever, cough with sputum, radiographic changes (cavities, fibrosis, multiple calcifications in the lung tissue). Histoplasmosis is often combined with sarcoidosis, tuberculosis, leukemia, retikulezah.

With the development of acute disseminated histoplasmosis against the backdrop of severe fever and general intoxication there are multiple foci of secondary fungal infection in various organs. The defeat of the skin and mucous membranes may appear different rashes (maculopapular, hemorrhagic, furunkulopodobnoy rash, erythema), ulcerative stomatitis and pharyngitis, subcutaneous tissue abscesses, ulcers of the vulva, anus fissures. Among other organ manifestations of disseminated histoplasmosis may occur lymphadenopathy, meningoencephalitis, retinitis, choroiditis, pericarditis, infective endocarditis, ulcerative colitis, hepatosplenomegaly, mesadenitis, peritonitis. The course of chronic disseminated histoplasmosis more blurred and sluggish, but inevitably leads to multiple organ lesions.

Its characteristics for histoplasmosis is in young children and HIV-infected people - in these cases, the disease develops as a disseminated process. The children observed a pronounced Banti's syndrome, generalized lymphadenopathy, lung damage, skin and intestines. HIV-infected persons get sick histoplasmosis approximately 0.5% of the cases, ie. E. Less than candidiasis or aspergillosis. Clinical and radiological picture is characterized by lymphadenopathy, high fever, significant hepatosplenomegaly, cough and pulmonary infiltrates. Mortality from histoplasmosis in these patients is 80%.

Acute pulmonary histoplasmosis often occurs in asymptomatic and usually ends favorably for the patient. Long-term consequences of chronic histoplasmosis may include pulmonary fibrosis, arthritis, erythema nodosum, uveitis, encephalopathy, convulsions, cardiac failure. Disseminated forms are the greatest threat to children, the elderly, patients with HIV infection. Nonspecific prevention of histoplasmosis should include soil decontamination, reduction of air dust, respirators during excavation.