Cryptococcosis

Cryptococcosis is relatively rare in immunocompetent people. Immunocompromised patients with this infection usually present with subacute or chronic meningitis. The fungus is commonly found in pigeon droppings, but no case clusters associated with this particular exposure have been reported.

CASES/YEAR
5,000 (US); 1,000,000 (Global)
CATEGORY
Sapronoses
AGENT TYPE
Fungi (Pathogenic Yeasts)
OTHER NAMES
Cryptococcus neoformans infection; Cryptococcus gattii (Related Infection);
ACUITY
Subacute/Chronic
INCUBATION
Unknown for C. neoformans; Meningitis follows pulmonary infection by months or years; C. Gattii: 2-13 months; [CCDM, p. 135]
INITIAL SYMPTOMS
Commonly presents with fever and dry cough in immunocompetent and fever, headache, and stiff neck in immunocompromised; [CCDM, p. 134]
PRECAUTIONS
Standard; "Not transmitted from person to person, except rarely via tissue and corneal transplant."" [CDC 2007 Guideline for Isolation Precautions] "No person-to-person or animal-to-person transmission." [CCDM, p. 135]
COMMENTS
FINDINGS:
Immunocompromised patients with this infection usually present with subacute or chronic meningitis. [CCDM, p. 134] Cryptococcosis is an opportunistic infection. Patients usually present with pneumonia, meningitis, or lesions of the skin, bone, or other organs. Immunocompetent patients often have only a self-limited respiratory infection. Fever is usually low-grade or absent in meningitis patients. Symptoms of meningitis are usually nonspecific, e.g., headache, visual impairment, confusion, and agitation. Blindness may result from brain swelling and optic nerve injury. [Merck Manual, p. 1572] In disseminated cryptococcosis, skin lesions are common. Skin lesions are highly variable: papules (may resemble molluscum contagiosum), tumors, purpura, vesicles, and rashes. [Harrison ID, p. 1008] Among HIV-negative patients with cryptococcosis, about 20% are healthy without chronic disease or immunosuppression. In a review of 266 HIV-negative patients, 36% had only pulmonary involvement, and 51% presented with CNS disease. One third of normal hosts with cryptococcosis are asymptomatic and diagnosed because of abnormal chest x-ray findings (single or multiple nodules). Symptoms of CNS disease include headache, fever, lethargy, cranial nerve palsies, coma, and memory loss. Cryptococcemia may be common in some countries with high AIDS prevalence, but it rarely leads to shock. [PPID, p. 3153-6] In patients with pulmonary disease, cavitations are rare. [ID, p. 2207] Cryptococcosis is one of the uncommon causes of nodular lymphangitis; [Am Fam Physician 2001;63:326-32]

EPIDEMIOLOGY:
The fungus is commonly found in pigeon droppings, but no case clusters associated with this particular exposure have been reported. [CCDM, p. 135] Grows in gut of pigeons and in dried pigeon droppings; [Wallach, p. 1163] Cryptococcal infection is common, but cryptococcal disease is relatively rare in immunocompetent people. Some infections produce a state of latency. [Harrison ID, p. 1007] Cryptococcosis is no longer common in AIDS patients in the US and Europe, but occurs in as many as 30% of AIDS patients in Africa. [Cecil, p. 2046] An ongoing outbreak of cryptococcosis (C. gattii) has been reported on Vancouver Island in British Columbia. C. gattii is associated with eucalyptus and a variety of coniferous trees. [PPID, p. 3149] C. gattii is found in Australia and Southeast Asia where it is associated with eucalyptus trees. Also reported in Pacific Northwest and Brazil; [Cecil, p. 1983]
DIAGNOSTIC
Culture is 90-100% sensitive. Histopathology; [Wallach, p. 1164] CSF cryptococcal antigen is highly sens & spec; [ABX Guide]
SCOPE
Global; In a given country, cases tend to follow the AIDS epidemic; [CCDM]
SIGNS & SYMPTOMS
  • >fever
  • G blood in stool
  • G nausea, vomiting
  • H lymphadenopathy
  • N confusion, delirium
  • N headache
  • N lethargy
  • N seizure
  • N stiff neck
  • R chest pain
  • R cough
  • R dyspnea
  • R hemoptysis
  • R sputum production
  • S lymphangitis
  • S nodular lymphangitis
  • S papules or plaques
  • S petechiae and ecchymoses
  • S pustule
  • S rash (exanthem)
  • S skin blister or vesicles
  • S skin or subcutaneous nodule
  • S ulcer of skin
  • X cystic or cavitary lesions
  • X hilar lymphadenopathy
  • X lung infiltrates
  • X pleural effusions
  • *ARDS
  • *arthritis
  • *blindness
  • *brain abscess or lesion
  • *cranial neuropathy
  • *encephalitis
  • *endocarditis
  • *erythema nodosum
  • *hepatitis
  • *mediastinitis
  • *meningitis
  • *myelitis
  • *myocarditis
  • *osteomyelitis
  • *pancreatitis
  • *pericarditis
  • *pneumonia
  • *pneumonitis
  • *shock
  • *stupor, coma
  • *uveitis
  • *weight loss
ANTIMICROBIC

Yes

VACCINE

No

ENTRY
Inhalation
SOURCE
Fecally Contaminated Soil, Soil or Dust (Ingesting or Inhaling)
RESERVOIR
Birds and Poultry
RISK FACTORS
  • AIDS patients
  • Cancer patients
DRUG LINK
Merck Manual: Cryptococcosis
REFERENCES FOR CASES/YEAR
1. (US) Cryptococcal infections per 1000 AIDS patients dropped from 66 to 7 in Atlanta and from 24 to 2 in Houston; [Gorbach, p. 140] Calculate: If use 5 cases per 1000 AIDS patients, assuming 1 million AIDS patients in US, then 5 x 1000 = 5000;
2. (Global) Rare in absence of impaired immunity; Most cases occur in patients with AIDS not on antiretroviral therapy, i.e., in Africa and Asia, and about 1/3 of these patients have cryptococcosis. Estimate is 1 million cases and >600,000 deaths annually. [Harrison ID, p. 1007]