Diphtheria, an acute infectious condition caused by Corynebacterium diphtheriae, 
was once a major killer of children. Although the mortality rates dropped 
dramatically in the mid-twentieth century, due to a combination of improved 
standards of living and immunization programs, outbreaks are still occurring. 
Two children, aged four and five years respectively, are reported to demonstrate 
characteristic features of lethal cases. Death in case 1 was due to an extensive 
upper airway pseudomembrane causing acute respiratory failure. The diagnosis of 
diphtheria was only made at postmortem. Death in case 2 was due to acute cardiac 
failure with heart block complicating diphtheria. Other mechanisms in fatal 
cases involve disseminated intravascular coagulation, renal and endocrine 
failure. Declining levels of immunity among adults has resulted in a change in 
the epidemiological pattern of the disease with an older age of victims in 
recent outbreaks. As a result of population shifts and failure to immunize 
children it is likely that forensic pathologists may see more cases of 
diphtheria in the future. Due to the rarity of cases in Western communities and 
atypical presentations, the diagnosis may only be established at autopsy.