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)
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
Patients may develop Horder spots, which are macular rashes that resemble the rose spots observed in typhoid fever but appearing on the face.
Patients may also develop erythema multiforme and erythema nodosum.
-
Hematological
Patients may develop anemia secondary to hemolysis.
Disseminated intravascular coagulation may occur in patients with overwhelming infections.
-
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
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]
Complications
Potential complications of psittacosis include the following:
-
Acute respiratory failure
-
Pericarditis
-
Culture-negative endocarditis
-
Renal failure (rare, only a few case reports)
-
Disseminated intravascular coagulation (rare)
-
Arterial embolism (rare, 2 case reports)
-
Reactive arthritis
-
Transverse myelitis
-
Meningitis or encephalitis
