Clinical profile and difficulties in diagnosis of central nervous system infections in adult patients in a tertiary care hospital.

OBJECTIVES: We aimed to describe the pattern of central nervous system (CNS) infections and accuracy of diagnosis in a Sri Lankan tertiary care hospital. METHODS: We prospectively studied all adult patients with suspected CNS infection admitted over a two-year period. Data were collected on demographic and clinical features, laboratory findings, treatment and immediate outcome. Diagnosis of CNS infection was categorized as definite, probable, possible and uncertain. RESULTS: We studied 215 patients [59.1% males; mean age (SD) 44 (20) years]. Blood cultures were done in 65 (30.2%) and only one was positive. Lumbar puncture was done in 146 (67.9%), and cerebrospinal fluid Gram stains, culture and acid-fast bacilli stains were all negative. Diagnosis of CNS infection was considered 'definite' in only one patient, 'probable' in 57.2%, 'possible' in 5.6%, and 'uncertain' in 26%. An alternative diagnosis was found in 23 patients (10.7%). Intravenous antibiotics and aciclovir were given on emperical grounds, largely without microbiological confirmation. CONCLUSIONS: Diagnosis of CNS infections is highly unsatisfactory with available facilities, even in a tertiary care setting.

Influenza virus infections among a sample of hospital attendees in Ragama, Sri Lanka.

OBJECTIVES: This study was carried out to define the types of influenza viruses circulating among humans and to understand the seasonality of influenza virus activity. Such information is essential for deciding on influenza vaccination strategy and on the appropriate time for delivering influenza vaccination, if such a vaccination policy was decided to be a priority. METHOD: During the period July 2003 - August 2004, 300 nasopharyngeal aspirates (NPA) were obtained from a systematic sample of patients reported to Out-patient Department, Colombo North Teaching Hospital, Ragama with < or =4 days history of acute respiratory tract infection (ARTI). The clinical signs and symptoms of the patients were prospectively recorded. Isolation of the influenza virus was carried out by inoculating in Madin Darby Canine Kidney cell line (MDCK). The isolates were identified by immunofluorescence assay and characterised by haemagglutination inhibition test. RT-PCR was carried out on all NPA samples. Genetic sequencing and phylogenetic analysis of the haemagglutinin gene of representative viruses were carried out. RESULTS: Twenty three influenza A and nine influenza B viruses were isolated by cell culture methods. Influenza A H3N2 Panama/2000/99-like viruses were isolated in 8% of patients with ARTI and influenza B/Sichuan/ 379/99-like viruses were isolated in 3%. Twenty eight influenza A virus infections were identified by the RT-PCR method. Phylogenetic analysis was carried out with data from other H3-subtype viruses isolated worldwide. The Sri Lanka viruses are antigenically and genetically similar to those in the northern and southern hemispheres. CONCLUSIONS: Influenza viruses circulate at different times of the year and is the aetiological agent causing 11% of all ARTI. Influenza activity corresponded to a peak in rainfall; however the correlation of influenza virus activity with rainfall is not invariable. The Sri Lankan isolates of 2003-4 were genetically related to the influenza A viruses circulating around the globe.

A clinical guide for early detection of dengue fever and timing of investigations to detect patients likely to develop complications.

We aimed to identify clinical features that would be useful for case detection and the appropriate timing of investigations and hospital admissions in patients with short-duration fever, suspected to be dengue fever (DF). Of 928 adult patients with short-duration fever admitted to Colombo North Teaching Hospital, Sri Lanka during February-June 2004, one in four were randomly selected for assessment of the severity of six clinical features: headache, body aches, vomiting, retro-orbital pain, generalised weakness (scale 0-9) and skin erythema (grade 1-5). There were 148 DF patients (95 males, mean age+/-SD: 28+/-12 years) and 54 non-DF patients as controls (44 males, mean age+/-SD: 25+/-11 years). All symptoms assessed (cut-off >or=5) and skin erythema (>or=grade 2) had a good positive predictive value for DF. However, erythema had the best negative predictive value, helping to differentiate DF from other short-duration fevers. More than 95% of patients with dengue had a platelet count above 50000/microl until the third day of illness. The platelet counts were significantly reduced when erythema, fever, vomiting and generalised weakness were persistent. In conclusion, erythema elicited by hand impression may help in the prediction of DF, and follow-up blood counts are indicated when symptoms persist.