Introduction
Cryptococcosis is a subacute or chronic infection caused by Cryptococcus neoformans, an encapsulated budding yeast
-Cryptococcal cells are typically present in bird droppings, particularly pigeon droppings
–C. neoformans is a yeast that is characterized by a thick polysaccharide capsule.
-Polysaccharide capsule is the major virulence factor and basis for antigen testing
-it is most common cause of fungal meningitis
-Cryptococcosis is acquired by inhaling aerosols containing the yeast, which disseminate to other organs via blood
Symptoms & Signs
-The most common sites of infection are the lungs, central nervous system and skin
Pulmonary cryptococcosis
it is often asymptomatic or may cause an influenza-like illness with cough, fever, chest pain and dyspnea
Meningoencephalitis
-Meningitis is the most commonly recognized and most serious form of cryptococcal disease
-In immunocompetent patients, it takes a slow, indolent course but in immunocompromised patients, it takes a more rapid course
-Headache, fever, nausea, vomiting, neck stiffness, dizziness, somnolence, irritability, confusion, photophobia, seizures, cranial nerve defects, confusion, mental status changes
Cryptococcal skin disease:
Cryptococcal cellulitis: resembles bacterial cellulitis, red, hot, tender plaques
Cryptococcal dermatitis: resembles molluscum contagiosum, papular, nodular lesions with central umbilication
Immune Reconstitution Syndrome
-A paradoxical clinical worsening which comes with enhanced inflammatory response due to immune reconstitution
-worsening meningitis, increased intracranial pressure, hypercalcemia
Diagnosis
Histopathology and Cytology: globose or oval to lemon-shaped yeast with a polysaccharide capsule after staining with India ink, Gomori methenamine silver (GMS) and periodic acid–Schiff (PAS) stain, Mayer’s mucicarmine stain, and Masson–Fontana melanin stain; On diphenolic substrate, the phenol oxidase of cryptococcus produces melanin in the cell walls producing brownish colored colonies
Antigen detection: detection of Cryptococcal capsular antigen in serum, CSF, pleural fluid
Culture: whitish mucoid colonies with spherical budding yeast cells surrounded by a thick non-staining capsule
CSF: increased opening pressure, increased protein, decreased glucose, presence of cryptococcal capsular antigen
Imaging: Cryptococcal granulomatous calcifications on CXR; cryptococcomas in the brain on MRI, CT scan
Treatment
Pneumonia: Fluconazole, itraconazole, voriconazole, posaconazole
Meningitis: Amphotericin B, Fluconazole