Comments
INITIAL SYMPTOMS:
Fever, cough; myalgia, and headache; [ID, p. 1871] Tends to be more severe than C. chlamydiae pneumonia with high fever and few or no upper respiratory symptoms; [Cecil, p. 1922]
FINDINGS:
A common pattern is mild respiratory symptoms and extensive pneumonia demonstrated by chest x-ray. Coughing may be absent initially, and then nonproductive or minimally productive. Pulse may be slow relative to temperature elevation. Other symptoms seen in some cases are pleuritic chest pain and splenomegaly. Possible complications include encephalitis, endocarditis, hepatitis, and respiratory failure. [CCDM, p. 491-3] C. psittaci can cause conjunctivitis and keratitis. The rash may resemble the rose spots of typhoid fever. Other associated skin manifestations are erythema multiforme and erythema nodosum. [Guerrant, p. 321, 1004-5]
In an Australian series of cases, about 50% of patients had elevated liver transaminases. Pleural effusions may occur. P. psittaci is one of the rare causes of endocarditis. Some patients with severe disease have acute renal failure. [ID, p. 534-5] The main syndromes are mononucleosis-like, typhoidal, and atypical pneumonia. Symptoms present in a minority of patients include sweating, ataxia, nausea/vomiting, abdominal pain, diarrhea, constipation, sore throat, dyspnea, hemoptysis, epistaxis, arthralgia, rash, confusion, tachycardia, bradycardia, splenomegaly, and adenopathy. Anemia from hemolysis occurs in some cases. Other occasional findings are hepatitis with jaundice, reactive arthritis, cranial nerve palsies, transverse myelitis, confusion, encephalitis, meningitis, seizures, urticaria, glomerulonephritis, and bleeding diathesis. Usually normal WBC count, but 2/3 have left shift. Eosinophilia may be seen during convalescence. [PPID, p. 2171-2]
EPIDEMIOLOGY:
Most often implicated are imported psittacine birds (households, pet shops, aviaries, and pigeon lofts) and then turkeys and ducks (poultry processing and rendering workers). [CCDM, p. 491] Due to quarantine of imported birds and improved veterinary hygiene, fewer than 50 cases per year are reported in the USA. Psittacine birds (parrots and parakeets) are the type of birds most often infected. Organisms spread by direct contact or aerosols to humans from nasal secretions, excreta, tissues, and feathers. [Harrison, p. 683] Case fatality rate up to 10% in untreated pneumonia; "Transmission from person to person has never been demonstrated." [Harrison ID, p. 754]