Cryptococcus
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Cryptococcosis is an opportunistic fungal infection caused by Cryptococcus species with cryptococcus neoformans and cryptococcus gattii being the primary species responsible for human infection. Infection is typically seen in immunosuppressed populations and is relatively uncommon in those with healthy immune systems. HIV infection is associated with greater than 80% of cryptococcosis cases worldwide. Patients who are immunosuppressed from other causes e.g. organ transplant, receiving cytotoxic therapy, long term steroid use or those with haematological malignancies such as lymphoma are also at increased risk.
Cryptococcus fungi are commonly found in environments contaminated with bird droppings, particularly pigeons so pigeon fanciers are at increased risk of infection.
Clinical features
Cryptococcal infections can manifest in various forms, with the lungs and central nervous system (CNS) being the most commonly affected sites.
Management
Treatment of cryptococcosis depends on the severity of the disease and the patient's immune status.
Cryptococcus fungi are commonly found in environments contaminated with bird droppings, particularly pigeons so pigeon fanciers are at increased risk of infection.
Cryptococcus and lymphoma:
Individuals with lymphoma are at heightened risk for cryptococcal infections due to their compromised immune systems, whether from the disease itself or as a result of immunosuppressive treatments like chemotherapy. In such patients, cryptococcosis can present with non-specific symptoms and may mimic other conditions, including disease relapse, leading to potential misdiagnosis and delayed treatment.Transmission
- Inhalation of spores
Clinical features
Cryptococcal infections can manifest in various forms, with the lungs and central nervous system (CNS) being the most commonly affected sites.
- Pulmonary Cryptococcosis: Often asymptomatic or presenting with non-specific respiratory symptoms such as cough, dyspnea, and chest pain. In immunocompromised individuals, it may progress to severe pneumonia.
- CNS Cryptococcosis (cryptococcal meningitis): Characterised by headache, fever, neck stiffness, photophobia, altered mental status, and, in severe cases, coma. This form is life-threatening in immunosuppressed patients. Cryptococcal meningitis usually presents as a subacute meningoencephalitis with time from symptom onset to presentation ranging from 1-12 weeks.
Diagnosis
- Cryptococcal polysaccharide antigen (CrAg) can be detected in serum, CSF or pleural aspirate samples using rapid antigen tests.
- Culture and microscopy are alternate diagnostic tests
Management
Treatment of cryptococcosis depends on the severity of the disease and the patient's immune status.
- Mild to moderate non-CNS infections: Oral fluconazole is typically the first-line therapy.
- Severe or CNS Infections: Induction therapy with amphotericin B combined with flucytosine is recommended, followed by consolidation therapy with fluconazole.