A 21-Year-Old Woman With Persistent Fever and Malaise

Muralikrishna Gopalakrishnamoorthy, MBBS, PGY-1; Archana Bhaskaran, MBBS, PGY-1; Rajeswari Anaparthy, MBBS, PGY-1; Ted T. Lin, MS3; Syed Hasan, MBBS


September 30, 2015


The differential diagnosis in a patient with HIV/AIDS and a 1-month history of nonspecific symptoms of weakness, fatigue, weight loss, and fever is broad. In addition to the usual etiologies in immunocompetent individuals, numerous specific diseases that are more commonly found among immunocompromised patients must be considered, such as disseminated MAI, Pneumocystis jiroveci pneumonia (PJP), tuberculosis, disseminated cryptococcosis, and disseminated histoplasmosis. The presence of markedly elevated LDH levels makes histoplasmosis the most probable diagnosis in this case.[1]

An extremely high LDH level, with few or no other conditions, has a relatively high diagnostic accuracy for histoplasmosis (especially in HIV-positive patients). In addition, the pulmonary infiltrates seen on the plain chest radiograph and CT scan in this case are suggestive of histoplasmosis. However, the alternative diagnoses must also be considered.

The nonspecific symptoms seen in this patient may suggest disseminated MAI infection; however, such markedly high LDH levels are uncharacteristic of MAI. Moreover, patients with HIV/AIDS who are infected with MAI typically present with extrapulmonary symptoms, rather than with the pulmonary manifestations that predominated in this patient.

Although the presence of fever, shortness of breath, cough, and hemoptysis in this patient suggest PJP, the findings of multiorgan involvement make PJP a less likely diagnosis. The duration of symptoms, lack of hypoxia, and characteristic infiltrates on the chest radiograph also make PJP unlikely.

The occurrence of chronic pulmonary symptoms in a patient with HIV/AIDS is certainly suggestive of tuberculosis, but the chest radiograph seen here is not classic for tuberculosis, and the diagnosis would require demonstration of a positive acid-fast bacilli smear from respiratory tract specimens or a positive culture (eg, blood, sputum, or bone marrow culture). Another possibility is disseminated cryptococcosis, which can also cause a similar clinical picture; however, significant central nervous system (CNS) involvement and skin lesions (which may be observed in patients with cryptococcal infection) were absent in this patient.[1]

Histoplasmosis is a fungal infection caused by Histoplasma capsulatum, a thermally dimorphic fungus found in nature. It grows saprophytically and replicates outside the human host in order to evolve into an infectious form. Its natural habitat is warm, humid soil contaminated with bird droppings or bat excrement (such as that found in old barns, caves, and parks).[2] In the soil, the organism exists in a mycelial form with macroconidia and microconidia. It grows in mold form at 77°F, and as yeast at 98.6°F.


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