A report of respiratory diphtheria in a southwest Nigeria tertiary health institution

Abstract

Dear Editor, INTRODUCTION Corynebacterium diphtheriae is the main cause of diphtheria, a toxin-mediated infection. This infectious disease is typified by infections of the skin and mucous membranes and sometimes develops into localized infections following bacteremia.[1] Over the past five decades, the incidence of diphtheria has reduced dramatically worldwide due to immunization with diphtheria toxoid-containing vaccine. In Nigeria, the number of diphtheria cases has declined from about 100,000 in 1980 to less than 10,000 in 2021.[2] There were 13,416 suspected cases in 2022, with 8,576 confirmed cases across 116 Local Government Areas in 19 States and the Federal Capital Territory, as of 2023 it was more prevalent in states like Kano, Yobe, Katsina, Bauchi, Borno, and Kaduna, accounting for 95·8% of cases, with 73·6% affecting children aged between 1 and 14 years. In 2023, diphtheria accounted for over 600 deaths, primarily in children.[3] These numbers remain higher in certain global regions, particularly Southeast Asia and Africa.[1] The outbreak worsened because of factors such as population growth and climate-related declines in hygiene due to water shortages, and inadequate diphtheria vaccination coverage.[3] CASE PRESENTATION This is a case of a nine-year-old boy admitted in a Teaching Hospital Southwest Nigeria. Biodata of the patient were obtained from hospital records. Relevant literatures were searched on important search engines, such as PubMed, Google Scholar, and Research Gate, using the search words ‘diphtheria’ or ‘respiratory diphtheria’. The nine-year-old male patient presented with three days history of fever, sore throat, and progressive neck swelling. The fever was high grade with chills and rigor. The sore throat was associated with hoarseness which progressively worsened till he could no longer speak. There was no nasal discharge or cough. Neck swelling was gradual, progressive, worse laterally with associated worsening of dysphagia, difficulty breathing, and snoring. General physical examination showed a toxic-looking child, drooling saliva, in severe respiratory distress, and diffuse neck swelling (bull’s neck). Throat examination revealed the presence of greyish pseudo-membrane in the pharynx. A presumptive diagnosis of diphtheria was made prompting the initiation of universal precautions and isolation of the child for management. Initial samples were taken for full blood count, blood culture, throat swab and child was immediately commenced on intravenous IV amoxicillin–clavulanic acid 1.2 g 12 hourly and IV Dexamethasone 0.15 mg/kg 6 hourly for 24 hours. Intravenous fluid, 4.3% dextrose saline, was commenced at 500 ml 8 hourly. Consults were sent to ENT surgeons and Community Medicine Physicians for review. The full blood count results (packed cell volume (PCV) 36% white blood cell count (WBC) 32,300/mm3, neutrophil 78%, lymphocyte 22%) showed neutrophilic leucocytosis and hypochromic anaemia reported from the blood film. Culture yielded growth of Corynebacterium diphtheriae, which showed sensitivity to amoxicillin–clavulanic acid, erythromycin, and azithromycin. The child significantly improved on admission and has been discharged to the clinic after full recovery. The recurrent outbreaks in the country have been attributed to lack of immunization or under-immunization and low socioeconomic class[1-3] as observed in this case. Vaccine hesitancy by parents is a known and identified risk factor for the disease.[4] This case was immediately reported to the Nigeria Center for Disease Control and Prevention (NCDC). A representation was sent, and specimens were obtained for confirmation. Contact tracing was done in this index case starting with family members and friends. And it was observed that two other younger siblings had also came down with similar symptoms. The youngest had earlier died few days before the index case admission, while the second was later admitted and co-managed with index case. Antibiotics prophylaxis was also administered to household contacts, and they were monitored per the protocol of the NCDC.[2] The symptoms of respiratory diphtheria include fever, nasal discharge, cough, and throat pain as observed in previous reports.[1,3,5-7] The index case also had those symptoms, in addition to neck swelling, hoarseness, and snoring. The presence of an adherent pseudo-membrane on the pharynx, tonsil, larynx, and/or nose is a pre-requisite for the case definition of diphtheria.[1,7] This pseudo-membrane is considered a marker of disease severity.[1] This pseudo-membrane was visualized in the index case and the other surviving sibling. It has been identified as one of the most common signs seen at presentation.[1,2] Other common signs, like cervical lymphadenopathy and neck swelling,[2,3] have been reported from similar reports. Confirmation of a case of diphtheria requires a positive culture of Corynebacterium diphtheriae and demonstration of its toxin.[1,7] The throat swab of this patient yielded Corynebacterium diphtheriae, and a confirmation was also gotten from the Nigeria Center for Disease Control and Prevention (NCDC) laboratory. The patient’s laboratory findings, like white blood cell count, neutrophils, and lymphocytes, have been shown to be associated with hospitalization outcomes in similar reports.[3] This index case was also given a diphtheria antitoxin DAT, which contributed to the full recovery observed. One of the major complications from respiratory diphtheria is airway blockage[5,8] though not manifested in this case due to prompt management and no oxygen therapy given. As opposed a report[6] with a high incidence of acute kidney injury AKI among children with diphtheria and increased odds of death. Other reported complications include polyneuropathy, myocarditis, and kidney failure.[8] CONCLUSION Despite being more common in tropical areas, the disease is a global issue. Patients with potentially fatal pneumonia should be suspected of diphtheria, particularly if they have a history of travel or lack of vaccination. In many developing nations, diphtheria remains an avoidable public health issue. Incidence and death may be decreased with increased vaccine coverage, including booster doses, early detection, and efficient treatment. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.