Systemic Mycoses

These are systemic fungal infections - either endemic or opportunistic, generally only infecting those who are immunocompromised.^1,2

Histoplasmosis

This is linked to exposure to bird and bat droppings especially along the Ohio and Mississippi river valleys in the USA.
It usually as an atypical pneumonia, in the acute form appearing in epidemics with prostration, fever, and respiratory symptoms.

• Progressive disseminated histoplasmosis - fever, dyspnoea, cough, loss of weight and prostration with hepatosplenomegaly. Usually fatal within 6 weeks.
• Chronic progressive pulmonary histoplasmosis is usually seen in older patients with COPD.
• Disseminated disease when seen in the immunocompromised is usually due to reactivation of prior infection often seen in HIV infection.

Management: itraconazole, amphotericin B in severe cases or those who fail on itraconazole.

Coccidioidomycosis

The organism is a mould that grows in the soil in South Western USA, Mexico, Central and South America. <1% of immunocompetent affected people suffer dissemination, but in these cases mortality is high. 40% of primary infections are symptomatic, usually presenting with respiratory tract symptoms plus fever, with pleuritic pain. There may be arthralgia with swelling (often knees and ankles).
Management: IV amphotericin B, in mild cases oral fluconazole³ or itraconazole continued for 6 months or longer. May need surgery to drain cavities or abscesses.

Pneumocystosis

See Pneumocystosis. It is very rarely symptomatic in immunocompetent patients,⁴ but in immunocompromised patients (especially HIV^5,6,7), abrupt onset of fever, tachypnoea, shortness of breath and non-productive cough. If untreated, there is rapid deterioration to death.^8,9
Start treatment on clinical suspicion but confirm before continuing. Cotrimoxazole, nebulised pentamidine. Also adjuvant steroids.¹⁰ Cotrimoxazole is given prophylactically when CD4 count falls.

• Aspergillosis¹¹ - This is usually caused by Aspergillus fumigatus, occasionally may see chronic sinusitis and colonisation of existing pulmonary cavities to form aspergilloma in immunocompetent patients - patients with very advanced HIV are particularly at risk, mostly with pulmonary disease leading to severe necrotising pneumonia.
  
  
• Mucormycosis - This includes zygomycosis and phycomycosis found in patients with pre-disposing conditions such as diabetic ketoacidosis, chronic renal failure and immunosuppressant drugs.
• Mycetoma¹² - This includes maduromycosis and actinomycetoma which is a slowly progressive locally destructive infection beginning in subcutaneous tissues often after trauma and spreads to contiguous structures (see Madura Foot)^13,14. A maduromycosis is a mycetoma caused by true fungi. May start as a papule, nodule or abscess and progresses over months or years to form multiple abscesses and sinus tracts reaching deep into the tissue.
• Blastomycosis - This usually occurs in men working outdoors in certain areas of South, Central and Mid-Western USA and Canada, usually affects the lung but can disseminate to the skin, bones and urogenital tract. Symptoms include cough, fever, dyspnoea and chest pain. May resolve or progress with bloody, purulent sputum, pleurisy, fever, chills, loss of weight and prostration. In disseminated form, raised verrucous skin lesions with abrupt, downward sloping border often seen.
• Paracoccidioidomycosis - South American blastomycosis only found in patients who have lived in South or Central Africa or Mexico initially affecting the upper respiratory tract. Usually appears with ulceration of upper respiratory tract. Ulcers can coalesce to destroy epiglottis, vocal cords and uvula. Eating and drinking very painful. May be skin lesions on face.
• Sporotrichosis - This occurs when organism is inoculated into the skin during gardening. Usually causes a skin infection - hard, non-tender subcutaneous nodule which later ulcerates. Similar nodules then appear along the lymphatics draining the area.
• Chromoblastomycosis - This is mainly tropical skin infection usually affecting agricultural workers causing skin infections. Begins as a papule or ulcer usually on lower extremity and enlarges over months or years to become vegetation, papillomatous, verrucous nodule.
• Cryptococcus neoformans - see separate article Cryptococcosis. This is a yeast found in soil and dried pigeon droppings. Infection usually transmitted by inhalation. Immunodeficient patients develop progressive lung disease and dissemination. Can involve any organ but mainly CNS. Often presents with meningitis. May progress to confusion, cranial nerve abnormalities, nausea and vomiting. Treat with oral fluconazole, IV amphotericin B.
• Candida yeast infection¹⁵ - this is normally associated with predisposing factors, e.g. neutropenia, antibiotic use, indwelling lines and abdominal surgery. Can cause candidaemia and disseminated candidosis. Also deep focal candidosis in which it infects the peritoneum or meninges often implanted following dialysis or surgery. Also, candida endocarditis and urinary tract candidosis. Treat with amphotericin B, fluconazole, consider adding flucytosine in severe cases.