Admission to medical schools in Sri Lanka: predictive validity of selection criteria.

OBJECTIVE: To assess the extent to which current selection criteria predict success in Sri Lanka's medical schools. METHODS: The study sample consisted of all students selected to all six medical schools in two consecutive entry cohorts. The aggregate marks of these students at the General Certificate of Education (GCE) Advanced Level examination, the district of entry, admission category, candidate type (school/private) and gender, were identified as entry point variables. Success in medical school was measured in four ways: the ability to pass the first summative examination and the final examination at the first attempt, and obtaining honours in either examination. Multivariate analysis using logistic regression was used to assess the extent to which these entry point factors predict variability in outcome measures. RESULTS: Aggregate scores among the 1740 students in the study sample ranged from 212 to 356, with a median of 285. The male:female ratio was 1.4:1. Private candidates (taking the examination for the third time) accounted for 22% of students. Being a school candidate, female and having a higher aggregate score, were the only independent predictors of success for all four outcome measures. The aggregate score alone accounted for only 1-7% of the variation in performance in medical school. CONCLUSIONS: Marks obtained at the A Level examination (the only academic criterion currently used for selection of medical students in Sri Lanka) is a poor predictor of success in medical school.

Microbiology of cerebral abscess at the neurosurgical unit of the National Hospital of Sri Lanka.

OBJECTIVES: To determine the microbial pathogens responsible for cerebral abscess, ascertain the most suitable antibiotic for treatment and to determine the predisposing causes of cerebral abscess. DESIGN: Prospective study with microbiological investigation of pus aspirated from cerebral abscesses. SETTING: Neurosurgical Unit, National Hospital of Sri Lanka, Colombo. STUDY GROUP: 41 patients with cerebral abscess. PERIOD OF STUDY: 18 months (May 1997 to December 1998) RESULTS: Of the 41 samples of pus 26 (63.1%) gave a positive microbial culture. The Gram stain of the direct smear was positive in 77% of the 26 positive cultures. The most frequently occurring species were Streptococcus milleri group (35%) followed by Staphylococcus aureus (10%). Anaerobes accounted for 23% of positive cultures. All Streptococcus milleri isolates were penicillin and cefotaxime, and all anaerobic isolates except one were susceptible to sensitive to metronidazole. 75% of Gram negative bacilli isolated were sensitive to cefotaxime. All Staphylococcus aureus isolates were methicillin resistant, but sensitive to vancomycin and chloramphenicol. Common predisposing conditions were congenital heart disease (30%), trauma (25%), middle ear disease (7%), and meningitis (7%). CONCLUSIONS: Organisms of the Streptococcus milleri group were most frequently found in cerebral abscesses. The present empirical therapeutic regime adopted in the unit which consisted of cefotaxime 1 g intravenously three times daily and metronidazole 500 mg intravenously three times daily was found to be satisfactory as a majority of the organisms isolated were sensitive to these antimicrobials. In the case of methicillin resistant Staphylococcus aureus (MRSA), it is recommended that chloramphenicol be added to the current regime in management until the antibiotic sensitivity pattern is available.

Leiomyosarcoma of the inferior vena cava.

A 63-year old with an 8-month history of backache had a leiomyosarcoma of the inferior vena cava. Although inoperable, she benefitted from cobalt therapy. A review of the literature suggests an evolving clinical picture which will facilitate earlier diagnosis, and perhaps allow resection.