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Chlamydia psittaci pneumonia presenting as acute generalised peritonism
  1. D Bourne1,
  2. N Beck2,
  3. C B Summerton2
  1. 1Department of Medicine, Manchester Royal Infirmary, Manchester, UK
  2. 2Trafford General Hospital, Manchester, UK
  1. Correspondence to:
 Dr D Bourne, Department of Elderly Medicine, Platt Rehab 2, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL, UK; 


A 63 year old man presented with the signs of acute generalised peritonism in the presence of a clear chest radiograph. At laparotomy no abnormal findings were noted. Further inquiries revealed a history of recent acquisition of budgerigars, over the following days the chest radiograph developed patchy opacification. Subsequently IgG immunofluorescence confirmed the diagnosis of Chlamydia psittaci. The presentation of psittacosis with gastrointestinal features is well recognised. This is believed to be the first account in the literature of a human case of Chl psittaci pneumonia presenting with acute generalised peritonism indicating an exploratory laparotomy. It is suggested that Chl psittaci pneumonia should be considered in the differential diagnosis of an acute abdomen in the presence of a history of exposure to psittacine birds.

  • Chlamydia psittaci
  • ornithosis
  • acute abdomen
  • peritonism

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A 63 year old man was referred to the care of a surgical team with a two day history of severe abdominal pain, vomiting, and headache associated with constipation and weight loss over the preceding six months. There was no history of cough or sputum production. He had previously undergone a right sided hernia repair, left sided orchidectomy, and had been diagnosed with oesophagitis 10 years earlier after a gastroscopy. He was taking omeprazole and an alginic preparation. He denied smoking and drank little alcohol.

On admission his temperature was 38.5°C, respirations 32 settling to 18 within two hours, his chest was clear on auscultation, pulse 80 and blood pressure 120/70 mm Hg. Examination of the abdomen revealed rebound tenderness and guarding, bowel sounds were present. Initial investigations included haemoglobin concentration 15.6 g/dl, white cell count 11 100 mm3, and plasma sodium 128 mmol/l. Other electrolytes, aminotransferase activities, and amylase were within normal limits. The chest radiograph was normal, erect abdominal radiograph showed gaseous distension of the small bowel. He was initially treated with broad spectrum intravenous antibiotics but generalised abdominal guarding persisted and a laparotomy was performed 36 hours after admission. No abnormal intra-abdominal findings were noted and no samples were available for microbiological analysis.

Further inquiries revealed that he was employed as a metalworker; there was no history of foreign travel and no risk factors for immunodeficiency. However, 10 days earlier he had purchased several budgerigars none of which had been noted to be unwell.

On day 5 of his admission he was still complaining of abdominal pain, he had not opened his bowels since the laparotomy; there was no cough or shortness of breath. Respirations were 15, crepitations were noted at the right lung base, and a further chest radiograph demonstrated patchy opacification in the right lower lobe. Ciprofloxacin was added to his treatment.

Over the subsequent three days he became increasingly short of breath and profoundly hypoxic with an arterial blood gas Pao2 of 6.1 kPa on high flow oxygen via a Hudson mask. On day 8 he was transferred to the intensive care unit, and the antibiotics were changed to erythromycin and rifampicin. He was maintained on a ventilator for the following 20 days. He made a full recovery and was discharged 41 days after admission.

Clinical features of Chlamydia psittaci infection localising to the gastrointestinal system

  • Diarhoea 2,3

  • Vomitting 2,3

  • Anorexia 3

  • Abdominal pain 3

  • Nausea 3

  • Constipation 3

  • Hepatitis 3,6

  • Tender hepatomegaly 7

  • Splenomegaly 7

  • Pancreatitis 7

Infection with Chl psittaci was subsequently confirmed by specific IgG immunofluorescence testing, antibody values rising from <1/32 on day 7 to 1/256 on day 30.


Psittacosis is found in psittacine birds including budgerigars and can be transmitted to humans by inhalation or direct contact.1 The presentation of psittacosis is well known to cause diagnostic difficulties relating to the late or sometimes absent onset of respiratory symptoms.2 In the series published by Crosse3 the diagnosis of psittacosis was considered at the time of admission in 20% of cases, late diagnosis being related to a fulminant course and high mortality.4,5 The range of clinical features localising to the gastrointestinal system is summarised in the box. However, this is believed to be the first account in the literature of a human case of Chl psittaci pneumonia presenting with acute generalised peritonism indicating an exploratory laparotomy although there is a report of peritonism associated with chlamydia in a cat.8

In the case reported here the illness was characterised by gastrointestinal tract features. The patient did not complain of cough or sputum production at any time. The initial chest radiograph was normal, a finding reported to occur in 18% of patients.3 Pointers to the correct diagnosis included: hyponatraemia (49% of cases), relative bradycardia (26% of cases), and white cell count less than 11 100/mm3 (71% of cases).3 Contact with birds is reported in between 20%9 and 80% of cases,10 the birds are newly acquired in 15%3 of these. It has been suggested that exposure to psittacine birds is the most valuable diagnostic clue.4

Tetracycline is traditionally the drug of choice in treating Chl psittaci although erythromycin may be equally effective.11 In addition, quinolones have been used successfully to treat Chl pneumoniae.12

In summary, Chl psittaci pneumonia infection should be considered in the differential diagnosis of peritonism in association with a history of exposure to psittacine birds even in the absence of respiratory features.


Dr David Bourne: author and senior SHO on the medical team responsible for the case. Dr C B Summerton, consultant physician and gastroenterologist: medical consultant responsible for the case and comments on manuscript. Dr N Beck, consultant in anaesthetics and intensive medicine: intensive care consultant responsible for the case and comments on the manuscript. Guarantor: Dr David Bourne.


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  • Funding: none.

  • Conflicts of interest: none.