Psittacosis (Parrot Fever) Clinical Presentation

Updated: Sep 08, 2017
  • Author: Klaus-Dieter Lessnau, MD, FCCP; Chief Editor: Burke A Cunha, MD  more...
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Presentation

History

The incubation period of psittacosis is generally 5-14 days. The longest observed incubation time was 54 days. The predominant presentation is respiratory tract infection with constitutional symptoms. Clinical findings vary.

  • Constitutional
    • Fever (50-90%)
    • Chills
    • Malaise
  • Respiratory
    • Cough (50-90%), usually not productive
    • Pleuritic chest pain (rare)
    • Dyspnea
    • Sore throat and mild pharyngitis (common)
    • Epistaxis (common)
  • Gastrointestinal
    • Nausea and vomiting (uncommon)
    • Abdominal pain (uncommon)
    • Diarrhea (rare)
    • Jaundice (rare)
  • Neurological
    • Severe headache (common)
    • Photophobia (common)
    • Agitation and lethargy
  • Dermatological - Includes facial rash (Horder spots)
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Physical

Psittacosis may range from mild insidious presentations to severe pneumonia that requires mechanical ventilation.

  • Respiratory
    • Nonspecific auscultatory findings that often underestimate clinical and radiographic findings may develop.
    • Patients may develop fatal pulmonary embolism and pulmonary infarction.
    • Pleural effusion is rare.
  • Cardiac
    • Relative bradycardia is common.
    • Physicians may observe pericarditis, culture-negative endocarditis, and myocarditis.
  • Gastrointestinal
    • Splenomegaly occurs in 10-70% of patients, depending on the study.
    • When present, this sign suggests psittacosis in patients with pneumonia.
  • Neurological
    • Patients may develop meningitis, encephalitis, seizures, and Guillain-Barré syndrome, but these are rare.
    • Cerebrospinal fluid (CSF) findings are usually normal.
  • Dermatological
  • Hematological
  • Renal symptoms include acute glomerulonephritis and tubulointerstitial nephritis.
  • Musculoskeletal symptoms include reactive arthritis that is usually polyarticular. Rarely, rhabdomyolysis has been observed. [4]
  • Stages of disease progression
    • Flulike syndromes without radiographic abnormalities
    • Mild-to-moderate pneumonia
    • Severe pneumonia
    • Acute respiratory failure, sepsis, and septic shock
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Causes

Psittacosis is an infectious disease caused by the obligatory intracellular bacterium C psittaci.

C psittaci is associated with psittacine birds and poultry.

Psittacosis is an occupational disease of poultry farmers, pet-shop workers, and veterinarians.

Relapses may occur.

Because psittacosis is a bacterial disease, major protective immunity is unlikely to develop after a single episode of disease. The exact risk of recurrence upon reexposure is unknown. It is reasonable to advise avoidance of infected birds.

Laboratory or laboratory-related infections are possible. These are particularly underreported for several reasons, particularly because of fear for reprisal and stigma associated with such events. In addition, it would be difficult to prove that the infection is indeed laboratory related. [5]

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