Histoplasmosis (actually was sporothrix!)

Fascinating case today -- patient who works in construction who presented to hospital initially with hilar adenopathy, erythema nodosum and ankle arthritis who was initially diagnosed with sarcoidosis, but who went on to develop disseminated histoplasmosis with steroid therapy.

Histoplasmosis mimicing sarcoidosis with EN and arthritis has been described here and has been dubbed 'pseudosarcoidosis'. It has also been described here and here.

Several good reviews of histoplasmosis are available (here, and here- mainly pulmonary).

Manifestations include (but are not limited to):

• Asymptomatic -- majority!
• Acute pulmonary histoplasmosis
  
  • Usually self-limited febrile illness with respiratory symptoms. Mediastinal lymphadenopathy common. Can have erythema nodosum and be mistaken for sarcoidosis.
  • Mild forms do not require treatment.
• Chronic cavitary pulmonary histoplasmosis
• Granulomatous mediastinitis
  
  • large necrotic mediastinal nodes cause compressive symptoms
• Fibrosing mediastinitis
• Pericarditis
• Disseminated (Systemic) Disease
  
  • Ususally immunosuppressed patients: AIDS (CD4 below 150), hematologic malignancies, transplant patients, steroids, TNF alpha inhibitors, congenital immunodeficiencies
  • May occur during initial infection or as reactivation event years later
  • Every organ system may be involved. Commonly, fever, arthralgias, anorexia, malaise. Pancytopenia, hepatosplenomegaly. GI involvement with diarrhea common.
• Endocardtitis/endovascular
• CNS disease

The IDSA guidelines for diagnosis and management are available here.
UPDATE OCT 2011:  This article discusses the diagnosis and the need to recognize that the antigen assay is not 100% sensitive.


Addendum:

• Even more interesting -- the case turns out to be sporothrix schenckii instead of histoplasma!
• See description of sporothrix mimicking sarcoid here, and IDSA guidelines for sporothrix here. There are no published cases like ours to date -- expect that to change.
• According to this article -- Amphotericin B and itraconazole are the most active. Voriconazole is not active, nor is fluconazole.