Cryptococcosis

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Case history #1

A 54-year-old HIV-positive man with a CD4 count of 50 cells/mm³ presents with a 1-week history of feeling unwell with fever, malaise, headache, and increasingly bizarre behaviour. His chest x-ray is unremarkable. The bronchoalveolar lavage is positive for yeast, and serum cryptococcal polysaccharide antigen (CrAg) is positive. A mass lesion is detected on computed tomography and magnetic resonance imaging of the head, and central nervous system involvement is confirmed by a positive lumbar puncture for the organism on India ink staining. The opening pressure on lumbar puncture is 25 cm H₂O.

Case history #2

An asymptomatic 33-year-old male lifelong non-smoker undergoes a chest x-ray following minor chest trauma. The x-ray reveals a pleurally based right lower lobe lesion. Fine-needle aspiration biopsy of the lesion grows Cryptococcus neoformans var. grubii. The serum CrAg is negative.

Other presentations

Central nervous system and respiratory tract involvement are most common.[1][2] In immunocompetent hosts, cryptococcosis is usually asymptomatic with an abnormal chest x-ray only and may resolve spontaneously. However, more severe disease may occur.[3] Immunocompromised patients can present with meningitis or meningoencephalitis. Clinical features of these include fever, headache, mental-status changes, signs of meningeal irritation, cranial palsies, and coma. The presentation of pulmonary cryptococcosis ranges from asymptomatic infection to severe pneumonia and acute respiratory distress syndrome. Acute pulmonary cryptococcosis presents with dyspnoea, cough, fever, and pleuritic chest pain.[2][4] In immunosuppressed patients, disseminated infection can occur in multiple organs, including the skin, prostate, eyes, bone, urinary tract, and blood. Cutaneous infections can manifest as a molluscum contagiosum-like lesion (especially in HIV-positive patients), granulomas, plaques, and cellulitis. Cryptococcosis of the prostate is usually asymptomatic and can represent a relapse reservoir. Eye infections commonly manifest with retinal and peripapillary haemorrhages. Bone and joint infections present with osteolytic lesions or arthritis. Peritonitis, cryptococcuria, and cryptococcaemia causing endocarditis have also been reported.[1]

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