Diphtheria is a serious bacterial infection caused by Corynebacterium diphtheriae, an aerobic organism that primarily affects the upper respiratory tract. In communities across Nigeria, transmission occurs mainly through direct person-to-person contact via respiratory droplets expelled when an infected individual coughs or sneezes. Less frequently, the bacteria can spread through contact with infected skin lesions, leading to cutaneous diphtheria. The incubation period typically ranges from two to five days. Once inside the respiratory tract, the organism colonizes the mucosal lining of the pharynx, larynx, or nasal passages, where it begins producing its dangerous toxin.
The true danger of diphtheria lies not in the bacteria multiplying locally, but in the potent exotoxin it secretes. This toxin inhibits cellular protein synthesis, causing localized tissue destruction. As the epithelial cells die, they form a thick, leathery, gray-white coating called a pseudomembrane over the tonsils, pharynx, or larynx. Attempting to forcefully remove this membrane typically causes vigorous bleeding because it adheres tightly to the underlying mucosa. Furthermore, the toxin enters the bloodstream, damaging vital organs such as the heart muscle, leading to myocarditis, and the nervous system, causing cranial and peripheral neuropathies.
The clinical presentation of respiratory diphtheria often begins with a low-grade fever, sore throat, and malaise, mimicking a common throat infection. However, a hallmark feature is the development of significant cervical lymphadenopathy and soft tissue edema, creating a characteristic bull neck appearance. As the pseudomembrane enlarges, it can mechanically obstruct the airway, leading to stridor, hoarseness, and respiratory distress. In cutaneous forms, patients present with non-healing skin ulcers covered by a gray membrane.
Managing a suspected case of diphtheria is a medical emergency requiring immediate isolation and prompt intervention. Treatment focuses on neutralizing unbound toxin and eliminating the bacteria.
Prevention remains the most effective strategy against diphtheria outbreaks. Routine childhood immunization using pentavalent or Diphtheria-Tetanus-Pertussis (DTP) vaccines provides strong active immunity. In Nigeria, this vaccine schedule is delivered through routine primary health care immunization clinics. Midwives play a crucial role in community mobilization, ensuring high vaccine coverage rates, and educating parents on completing all booster doses. Additionally, when a case is confirmed, close contacts must receive prophylactic antibiotics and a booster dose of the vaccine to halt community transmission.