Diphtheria mortality at Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria: a review of 98 consecutive cases
Diphtheria is an acute, vaccine-preventable bacterial infection caused by toxigenic Corynebacterium diphtheriae. Despite available immunization, outbreaks continue to occur in resource-limited settings and are often associated with high mortality from toxin-mediated complications such as myocarditis, airway obstruction, and renal failure. To describe the clinical patterns, treatment, and outcomes of suspected diphtheria cases managed at the Usmanu Danfodiyo University Teaching Hospital (UDUTH), Sokoto, Nigeria. This was a retrospective review of children aged 0–15 years treated for suspected diphtheria between January 2017 and October 2024. Data extracted from case notes included sociodemographic profile, clinical features [fever, sore throat, odynophagia, dysphagia, dyspnea, neck swelling, dirty grey oropharyngeal membrane], vaccination history, antitoxin administration, microbiologic confirmation, and complications. Complications were defined as premortem clinical events documented in patient records during hospital admission and management. Data were analysed using IBM SPSS version 25.0. Quantitative variables were expressed as mean ± standard deviation, while categorical variables were summarised as frequencies, percentages, and charts. Associations were tested using Fisher’s Exact Test, with statistical significance set at p < 0.05. Of 98 suspected cases reviewed, 48 [49.0%] were culture-positive for C. diphtheriae. The mean age was 7.0 ± 3.3 years, range 2–14 years, with 49.0% in the 1–5-year group. Females accounted for 61.2% [male: female 1:1.6]. Most patients, 83.0%, were unimmunized. The overall case fatality rate was 75.5% [74/98], with 23.5% discharged and 1.0% discharged against medical advice. Mortality was highest in children aged 1–5 years [51.4%] and among females [60.8%], though neither age nor sex was significantly associated with outcome, p > 0.05. Antitoxin administration, culture-positive status for C. diphtheriae, and presence of documented premortem complications were significantly associated with mortality, p < 0.05. Case fatality was 86.5% among unimmunized patients and 58.1% among those who did not receive antitoxin. All fatalities had documented premortem complications, with cardiorenal complications being the most frequently recorded outcome among deaths at 43.2%, followed by cardiac complications at 37.8%. Mortality from suspected diphtheria at UDUTH was high and was associated with lack of immunization, non-receipt of antitoxin, and the presence of complications, particularly cardiorenal involvement. Although age and sex were not statistically significant, children aged 1–5 years accounted for the greatest proportion of deaths. These findings highlight the need to strengthen routine immunization coverage, improve prompt availability of diphtheria antitoxin, and enhance management of complications to potentially reduce mortality during outbreaks. Not applicable.