How common is chronic pulmonary histoplasmosis?
April 27 2020
First described in in 1948 and acknowledged as a separate clinical entity in 1953, many patients with chronic pulmonary histoplasmosis (CPH) languished in US tuberculosis sanatoriums, until picked out in the 1950’s. In one sanatorium in Missouri, 7.2% of ‘TB patients’ actually had CPH. In a review just published in Open Forum Infectious Diseases, Jacob Baker et al, the current knowledge about CPH is summarized as follows:
- Older reports emphasized chronic cavitary pulmonary histoplasmosis, whereas in the last 2 decades Histoplasma nodules dominate diagnosed cases in the USA.
- Emphysema is the main risk factor for the cavitary form of CPH.
- Diagnosis relies on a high index of suspicion, use of fungal culture of respiratory samples, antibody testing and a compatible radiological appearance.
- Morbidity from CPH results from slow progression of cavities and gradual loss of lung function.
- This disease has barely been described outside the USA, but is likely to have a global distribution, with some features similar to chronic pulmonary aspergillosis.
- Access and performance of Histoplasma antibody testing needs addressing.
- Itraconazole is the treatment of choice and recommended for 12 months or longer, in the absence of prospective studies.