REEVALUATION OF PNEUMONIA REQUIRING ADMISSION TO AN INTENSIVE-CARE UNIT - A PROSPECTIVE-STUDY

Background - Appropriate treatment of severe community and hospital ac quired pneumonias requiring admission to a medical intensive care unit depends on knowledge of the likely aetiological agents in any communi ty. Little is known about the pattern and outcome of patients with suc h pneumonias in Saudi Arabia. Methods - In a prospective study 113 pat ients with pneumonia were investigated in the medical intensive care u nit at King Khalid University Hospital, Riyadh, Saudi Arabia between S eptember 1991 and December 1992. The diagnosis was established by micr oscopy and culture of sputum, blood culture, or serological examinatio n. A standard proforma was used to collect demographic, clinical, and laboratory data. Results - A microbiological diagnosis was made in 80% of the cases with a single pathogen accounting for 69% of the isolate s and multiple pathogens for 11%. Pseudomonas aeruginosa was the most common infecting agent (16%), followed by Streptococcus pneumoniae (12 %), Staphylococcus aureus (9%), and Mycobacterium tuberculosis (8%). P neumonia due to Legionella pneumophilia was diagnosed in three patient s and infection due to Mycoplasma pneumoniae in two. These five cases were identified by serological examination. Gram negative rods were th e predominant pathogens in both community and hospital acquired pneumo nia. The aetiology of pneumonia was not identified in 20% of cases. Th e overall mortality was 37%. Patients with hospital acquired pneumonia had a higher mortality than those with a community acquired pneumonia . Similarly, a high mortality was found in patients who had a serious underlying disease, abnormal mental state, diastolic blood pressure < 60 mm Hg, blood urea > 7mmol/1, abnormal liver function tests, serum a lbumin < 30g/1, those who required mechanical ventilatory support, and those with APACHE II scores > 20. Conclusions - This study highlights two major findings which differ from previous reports on the aetiolog y of pneumonia. Firstly, Gram negative rods were the predominant patho gens in community acquired pneumonia and secondly, M tuberculosis was an important cause of pneumonia in these patients, indicating that tub erculous pneumonia should be considered in the differential diagnosis of pneumonia in Saudi Arabia.