How is Histoplasmosis treated?

For asymptomatic people or people with acute localized infection who  are otherwise healthy, antifungal treatment is  usually not recommended as these people have or will resolve the  infection in about three weeks. If symptoms persist a month or more, itraconazole (Sporanox), ketoconazole (Nizoral) or amphotericin B (Fungizone, Amphocin) may be effective. If CNS involvement occurs, or  if the person  is compromised by other diseases or  is immunocompromised  and has severe histoplasmosis (progressive disseminated histoplasmosis), either itraconazole  or amphotericin B  is recommended.  The lengths of time, dosing amounts,  and dosing routes are usually individualized for  the patient; consultations with both infectious disease  and pulmonary specialists are recommended. Other new azole compound drugs  may be effective in some difficult  or unresponsive cases;  the consultants could help select the appropriate new drug treatment. 

Surgery has been used to treat some complications seen in some cases of histoplasmosis. Examples of surgical procedures include pericardiocentesis or a pericardial window procedure (both designed  to remove fluid that compresses  the heart) in  the few patients that develop pericarditis; resection of cavitary lung lesions; excision of lymph nodes that compress pulmonary, vascular, or other structures;  and replacement  of damaged heart valves  or other structures. 

What are the complications seen with histoplasmosis? 

The majority (about 90%) of people that  are infected with H. capsulatum recover completely with no complications. A few cases may show small areas of lung scarring on chest X-rays. With progressive severity of the disease (chronic  to disseminated), the complications become more numerous  and disabling. Pleural effusions and pericarditis can develop in about 5% of acute symptomatic patients. Another 5%  may develop rheumatologic problems like arthritis, erythema nodosum, or erythema multiforme. About 90%  of patients with chronic pulmonary histoplasmosis develop cavitary lung lesions, and some  may develop pulmonary fibrosis  and dyspnea (shortness  of breath), and some  may get adrenal gland infections which may  be rarely associated with Cushing's syndrome (elevated cortisol levels, causing upper body obesity  and a rounded face). Others may develop ocular histoplasmosis syndrome in which H. capsulatum spreads from  the lungs  to the retinal blood vessels (choroid) which become inflamed (uveitis) and then develop fragile abnormal blood vessels. This area  can form scar tissue  and thus replace the retina's macular tissue, which results in partial blindness. Patients with acute progressive disseminated histoplasmosis may develop CNS problems that result in encephalopathy or seizures; adrenal insufficiency; or cardiac problems like valve failure, angina, and poor cardiac output. Acute progressive disseminated histoplasmosis, if not  treated quickly and appropriately, can lead to death  in a few weeks. Even with lifelong antifungal treatment, about 10%-20% of cases will relapse. 

How is histoplasmosis prevented? 

People living in endemic areas like  the Ohio River Valley are likely to be exposed to histoplasmosis no matter what they do, since  the fungus is likely in  the dust in the air. However, if they are healthy,  most people that get exposed or infected with H. capsulatum will  be asymptomatic. Immunosuppressed (those with HIV  or cancer or who  are receiving chemotherapy  for cancer) might reduce their chances  of exposure if they live in endemic areas by avoiding high dust areas like construction sites. Soil can be decontaminated  with 3% formalin under special circumstances. If people need  to work in  potential high exposure areas like caves, bridges, construction sites, chicken coops, or other areas where bird  and bat droppings could be concentrated, the National Institute for Occupational Safety and Health (NIOSH) recommends using a Part 84 particulate respirator certified by NIOSH. Some investigators suggest that simply watering down soil will help prevent dust formation and reduce the chance of exposure. 

There is no vaccine for histoplasmosis. In some cases, H. capsulatum becomes dormant  and may reactivate if the person becomes stressed or immunodepressed. Although people develop an immune response  to histoplasmosis and recover with no complications,  the response is not completely protective and the person can become reinfected with H. capsulatum. 

What  is the prognosis (outlook) for people with histoplasmosis? 

About 90%  of patients who acquire acute pulmonary histoplasmosis are asymptomatic,  and about another 5%-7% who develop symptoms recover completely. Few may get acute pericarditis and pleural effusions. As the severity of the disease increases, the chance that lifelong problems may occur also increases. Patients with chronic pulmonary histoplasmosis usually develop (90%) cavities in the lungs that may reduce lung capacity and result in respiratory problems  and increase the chances for a secondary lung infection. Progressive disseminated histoplasmosis has a grim prognosis (death  in a few weeks to months) if appropriate treatment is not received. Even with appropriate treatment, some patients will experience relapses and may require antifungal medication for the rest of their life.