What are the symptoms of histoplasmosis?

Symptoms of Histoplasmosis

The most common symptoms of histoplasmosis include fever, chills, headache, myalgia, anorexia, cough, and chest pain, which are seen in 85-100% of cases. 1

Acute Pulmonary Histoplasmosis

• Fever is the most common presenting symptom in both adults and children 2
• Chills, headache, myalgia (muscle pain), and anorexia (loss of appetite) are frequently reported 1
• Cough and chest pain occur in most cases, with possible pleuritic pain 1
• Physical examination may reveal rales or pleural friction rubs, though findings are often unremarkable except for fever 1
• Symptoms typically abate within a few weeks in immunocompetent patients with low-level exposure 1

Severe Acute Pulmonary Histoplasmosis

• Diffuse radiographic involvement following intense exposure can cause more severe disease 1
• Hypoxemia may develop, sometimes requiring ventilatory support 1
• Without treatment, recovery is usually slow and can potentially be fatal 1
• Prolonged symptoms (>1 month) may indicate progression to more severe disease 1

Disseminated Histoplasmosis

• Common in immunocompromised patients, particularly those with CD4+ counts <150 cells/μL 1
• Characterized by fever, fatigue, weight loss, hepatosplenomegaly, and lymphadenopathy 1
• Respiratory symptoms (cough, chest pain, dyspnea) occur in approximately 50% of patients 1
• CNS, gastrointestinal, and cutaneous manifestations occur in a smaller percentage of cases 1
• Less than 10% of patients experience shock and multi-organ failure 1
• Hematogenous dissemination from lungs to other tissues occurs in early infection before immunity develops 2

Central Nervous System Involvement

• Patients with CNS histoplasmosis typically experience fever and headache 1
• If brain involvement is present, seizures, focal neurological deficits, and mental status changes may occur 1
• Meningitis presents with lymphocytic pleocytosis, elevated protein, and low glucose in CSF 1

Gastrointestinal Manifestations

• Diarrhea, fever, abdominal pain, and weight loss are common presentations 1
• Hepatosplenomegaly may be present on physical examination 1, 2

Chronic Manifestations

• Chronic pulmonary histoplasmosis presents similarly to reactivation tuberculosis 3
• Inflammatory or fibrotic responses can lead to various complications including:
  • Rheumatologic syndromes and pericarditis (within first year after exposure) 1
  • Chronic mediastinal inflammation or fibrosis 1
  • Broncholithiasis 1
  • Enlarging parenchymal granulomas (histoplasmomas) 1, 4

Important Clinical Considerations

• Severity of illness varies based on exposure intensity and host immunity 1
• Asymptomatic infection or mild disease follows low-intensity exposures in healthy individuals 1
• In immunocompetent patients, most infections are self-limited and resolve without therapy 1
• Patients with CD4+ counts >300 cells/μL often have symptoms limited to the respiratory tract 1
• Radiological findings commonly include diffuse reticulonodular infiltrates and hilar/mediastinal lymphadenopathy 3
• Pulmonary nodules may persist radiologically for months after clinical recovery 5

Diagnostic Pitfalls

• Histoplasmosis can mimic other conditions, leading to unnecessary invasive procedures 5
• Travel history to endemic areas (Ohio and Mississippi River Valleys, Latin America) and exposure to risk factors (caves, bat droppings) should trigger clinical suspicion 1, 5
• Solitary histoplasmomas can be mistaken for lung malignancy 4