Definition
Histoplasmosis is an infectious disease caused by fungi of the genus Histoplasma (generally, Histoplasma capsulatum ). The infection is acquired by humans through the inhalation of spores or hyphae of the fungus present in the soil, especially in the presence of bird and bat droppings.
The initial infection is localized at the level of the lungs and normally persists there (pulmonary histoplasmosis). However, if it is not effectively controlled by the host's normal immune defenses, it can spread hematogenously to other organs.
Most common symptoms and signs *
- Oral aphthosis
- Anemia
- Asthenia
- Dyspnoea
- Chest pain
- Muscle pains
- Temperature
- Hypoxia
- Hypotension
- Leukopenia
- lymphadenitis
- Swollen lymph nodes
- Headache
- Mediastinitis
- Meningitis
- Multiple pulmonary nodules
- Nodule
- Solitary pulmonary nodule
- Weight loss
- Rhabdomyolysis
- splenomegaly
- Confusional state
- Sweating
- tachypnoea
- Cough
- Skin Ulcers
- Pericardial effusion
Further indications
The disease presents 3 possible events: acute, chronic and progressive disseminated histoplasmosis.
Most acute Histoplasma capsulatum lung infections are asymptomatic. In some cases, acute pneumonia develops (evident on physical examination and chest X-ray), with fever, cough, headache, myalgia, chest pain, weight loss and general malaise. Primary acute histoplasmosis is almost always self-limiting and does not require any antifungal treatment (unless there are no signs of improvement after 1 month).
Chronic infection (chronic pulmonary histoplasmosis ) is characterized by cavitary pulmonary lesions (multiple nodules), worsening of cough and dyspnea; can cause death from severe respiratory failure.
Progressive disseminated histoplasmosis occurs predominantly in immunosuppressed patients; in particular, it is one of the opportunistic infections that define AIDS. This form of histoplasmosis involves a generalized involvement of the reticulo-endothelial system, with fever, hepatosplenomegaly, lymphadenopathy and bone marrow involvement. Therefore, states of anemia and leukopenia are possible. Moreover, progressive disseminated histoplasmosis can lead to the appearance of symptoms such as oropharyngeal ulcers, hypotension, altered mental status, coagulopathy, rhabdomyolysis and meningitis. If left untreated, it is almost always lethal.
The diagnosis of histoplasmosis is formulated on the basis of chest radiographs, serological analysis, tissue biopsy (histological examination) and identification of the organism on urine cultures, blood and sputum or bronchovascular samples.
The therapy is performed with amphotericin B (in case of very severe pneumonia) and azole antifungal drugs, such as ketoconazole and itraconazole.
