CARDIOVASCULAR JOURNAL OF AFRICA • Volume 34, No 2, May/June 2023 120 AFRICA Apart from supportive management and timeous administration of antitoxin, there are no specific treatment measures for diphtheritic myocarditis. Another Vietnamese study assessed the role of temporary pacing in the setting of high degrees of heart block, and found that of the 27 patients who underwent pacemaker insertion, 20 died as a consequence of progressive cardiac failure and refractory hypotension.9 The remaining seven patients survived, and although four went on to develop the late complication of diphtheritic neuropathy, all made a full recovery. Cardiac pacing therefore appears to be most beneficial when conduction abnormalities occur in the absence of significant myocardial dysfunction. In survivors, myocardial function typically returns to normal.5 Until the recent outbreaks, diphtheria had been practically eliminated in South Africa, with only three sporadic cases reported between 2008 and 2015.2 Decreasing vaccination coverage in children has the potential for the occurrence of diphtheria outbreaks of greater magnitudes. In March to July 2015, 15 cases were reported in KwaZulu-Natal, South Africa, with four fatalities.2 While the majority of infections did involve young children, many of whom had incomplete immunisation histories, three adults were affected. In 2017, four cases occurred in the Western Cape and a single case in the Eastern Cape.2 In 2018, a further three cases were reported in KwaZulu-Natal, with two deaths occurring in children who had been incompletely immunised.9 The resurgence of diphtheria in KwaZulu-Natal may be attributed to the combined effect of inadequate childhood immunisation coverage, as well as waning antibody protection in previously vaccinated individuals.2 The South African childhood immunisation programme includes diphtheria toxoid administered as a combined vaccine at age six, 10 and 14 weeks and 18 months, with boosters given at six and 12 years. Our patient did not receive a booster dose of the vaccine at six years. Another major challenge in treating diphtheria infection in South Africa is the limited availability of antitoxin, due to a global decline in its production. South Africa relied upon a donation of antitoxin from the Japanese government during the 2015 outbreak.2 The immunity conveyed by the diphtheria vaccine declines over five to 10 years; in fact serological studies in the United Kingdom confirm that 20 to 50% of the adult population are susceptible to diphtheria.2 The presence of a pool of unvaccinated children who in turn transmit infection to susceptible adults serves as a breeding ground for a potential epidemic. This explains the shift in the susceptible population observed in other developing countries where diphtheria is no longer confined to young children; it now extends to adolescents and adults.10,11 Key points • Myocardial involvement is the commonest cause of death from diphtheria. • Bull neck, airway compromise and extensive pseudomembrane formation predict myocardial involvement. • Immediate treatment (antitoxin and antibiotics) based on clinical suspicion is imperative to limit the development of systemic complications, including myocarditis and death. Conclusion The resurgence of diphtheria in our population highlights the grave consequences of individual failures in childhood immunisation. Our case shows that partial immunisation does not protect against severe forms of disease and reinforces the importance of booster immunisation in late childhood to maintain protective serum titres of antitoxin. Treatment delay remains a serious concern. A high index of suspicion is required, particularly in primary healthcare providers, to allow for early detection and timeous treatment, prior to the onset of systemic complications. Patients presenting with severe neck and facial swelling and extensive pseudomembrane are at risk for myocardial involvement and death, and must receive immediate antitoxin and antibiotics, nursing in a highcare setting and frequent monitoring for cardiac conduction abnormalities and arrhythmias. References 1. National Institute for Communicable Diseases. Communicable Diseases Communiqué 2015; 14(3). http://www.nicd.ac.za/assets/files/NICD-NHLS. 2. Annamalai M. Diphtheria and the respiratory system: lessons from the 2015 outbreak. S Afr Respir J 2016; 22(2): 38–42. 3. Jayashree M, Shruthi N, Singhi S. Predictors of outcome in patients with diphtheria receiving intensive care. Indian Pediatr 2006; 43: 155–159. 4. Du Plessis M, Wolter N, Mushal Allam M, et al. Molecular characterization of Corynebacterium diphtheriae outbreak isolates, South Africa, March–June 2015. Emerg Infect Dis 2017; 23(8): 1308–1315. 5. National Institute for Communicable Diseases. Diphtheria: NICD recommendations for the diagnosis, management and public health response. 22 March 2016. http://www.nicd.ac.za/assets/files/Guidelines_diphtheria_20160322_v2_3(1).pdf (accessed 16/6/2018). 6. Varghese MJ, Ramakrishnan S, Kothari SS, Parashar A, Juneja R, Saxena A. Complete heart block due to diphtheritic myocarditis in the present era. Ann Pediatr Cardiol 2013; 6(1): 34–38. 7. Kole AK, Roy, Karr SS. Cardiac involvement in diphtheria: Study from a tertiary referral infectious disease hospital. Ann Trop Med Public Health 2012; 5: 302–306. 8. Kneen R, Dung NM, Solomon T, et al. Clinical features and predictors of diphtheritic cardiomyopathy in Vietnamese children. Clin Infect Dis 2004; 39: 1591–1598. 9. Dung MN, Kneen R, Kiem N, et al. Treatment of severe diphtheritic myocarditis by temporary insertion of a cardiac pacemaker. Clin Infect Dis 2002; 35: 1425–1429. 10. Pan American Health Organization/World Health Organization. Epidemiological Update: Diphtheria. 22 September 2020, Washington, DC: PAHO/WHO; 2020. 11. Pan American Health Organization/World Health Organization. Epidemiological Update: Diphtheria. 2 March 2021, Washington, DC: PAHO/WHO; 2021.
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