Infections involving the central nervous system (CNS) are important causes of mortality and morbidity in many African countries ¹ and thus arouse tremendous anxiety in both physicians and patients. World-wide, the scenario of CNS infections is changing mainly due to the increase in immuno-compromised patients (due to AIDS, prolonged survival of patient with malignancies and organ transplantation), increase in international travels allowing rapid transmission of infectious agents and widespread use of antibiotics creating the emergence of resistant organisms. The pattern of these infections in Rivers State, Nigeria, is not known. This study was undertaken to determine the types, frequency and mortality associated with these infections. It involved a retrospective review of patients admitted into the medical wards of the University of Port Harcourt Teaching Hospital (UPTH), Port Harcourt, Rivers State, Nigeria² over a ten-year period between April 1993 and March 2003 diagnosed with neurologic infections. The UPTH is a 484-bed tertiary hospital and the main referral center in Rivers State and other neighboring states in Nigeria, and has an annual admission rate of 10,000 .

Methods

The case notes of all admissions into the medical wards of UPTH, Port Harcourt between April 1993 and March 2003 were collected from the medical wards and the medical records department of the hospital. Admission into the medical wards is from age of 14 years, so patients below this were not included. Figures of hospital admissions and deaths during the same period were also collected from the medical records department. Cases admitted with CNS infections were extracted for the study. The following data were extracted from case notes – age, sex, date of admission, diagnosis, date of discharge and outcome (whether discharged, died, discharged against medical advice (DAMA) or absconded, or transferred to other tertiary centers or departments). Sixty seven case notes with defective data were excluded. All diagnoses were made by a consultant physician. These data were then analyzed.

Tetanus: This was the second most common neurologic infection requiring admission in this study. It was responsible for 28.9% of cases admitted with neurologic infections. Case fatality rate (47%) was high consistent with findings of other studies in developing countries. ^7,8 The high mortality rate was due to respiratory failure occasioned by hypoxia and airway obstruction, aspiration hypoventilation, pneumonia and respiratory arrest. Intensive care was rarely utilized because of limited facilities. Other contributing factors were low immunization rates of the population and late presentation of cases.

Pott’s disease with cord compression: All patients were treated with anti-tuberculous drugs only without any surgical intervention because of lack of neurosurgical facilities locally and the unaffordable cost of referral. This may account for the high mortality recorded. Decompressive surgery plus anti-TB chemotherapy remains the best mode of therapy for Pott’s disease.The major causes of death in the UPTH, PH cases were complicating septicemia from infected decubitus ulcers or urinary tract infections and pulmonary embolism from prolonged immobilization. A low mortality of 2% was reported in a Turkish study ⁹. In that study, it was concluded that the neurological involvement due to Pott’s disease is relatively benign if urgent decompression is performed at the onset of the disease.

Viral meningoencephalitis: The mean duration of hospitalization was 9.7 days. Concomitant infection with the HIV virus, secondary bacterial infection and late presentation were factors contributing to the high mortality rate.

Tuberculous meningitis: Nineteen cases (19) cases of TBM, representing 1.4%, 0.5% and 0.02% of neurologic, medical and hospital admissions respectively were identified. TBM had the highest case fatality rate of all neurologic infections with 13 (68.4%) deaths, comparable to that reported by Karstaedt et al ¹⁰ in South Africa.This mortality represented 2.6%, 0.7% and 0.1% of neurologic, medical and hospital deaths respectively. Mortality was related to the patient’s level of consciousness on admission, as over half of those admitted with altered level of consciousness, died. Concomitant HIV infection was also another factor producing a dismal prognosis in these patients.

The less frequent neurologic infections encountered in this study included rabies (1.3%), cerebral malaria (0.6%), cavernous sinus thrombosis (0.6%) and cerebral abscess (0.3%). All the cases of rabies were from dog bites; three of who died and one was discharged against medical advice. Cerebral malaria is mostly observed in children because of their low immunity to the parasite, hence the low frequency in the study population. The cases of cavernous sinus thromboses and cerebral abscess were the result of complications arising from paranasal infections and chronic otitis media respectively.

50% of the cases with HIV infection died during the period of admission. The low rate of screening for HIV in suspected cases was mainly attributable to refusal to give consent and cost of screening. None of the positive cases received anti-retroviral treatment.

Neurologic infections are an important cause of morbidity and mortality in neurologic practice in this environment. The high mortality rates were largely due to late presentation to specialized care. Therefore, cases presenting with suspicious neurologic infections to lessexperienced health workers should be referred immediately to centers where specialized care can be instituted early.The use of penicillin and chloramphenicol for the treatment of bacterial meningitis needs review in light of increasing resistance of the organisms to these antibiotics.

To the Almighty God for His mercies and Guidance; to the Matron and nurses of the Dept of Medicine and the staff of the Medical Records Dept of UPTH, Port Harcourt for tassistance in the collection of the data; to my family for ensuring a conducive study environment.