Discussion
Rubella, commonly known as German measles, is a common childhood rash disease that usually occurs in children aged between 4 and 15 years. Even though this viral infection is known to be mild and self-limiting and resolves without sequelae, several complicated cases have been previously reported, particularly in adults. These complications can involve neurologic impairment and severe thrombocytopenia. During the last few years, many countries have reported outbreaks of rubella infection. However, to our knowledge, available data in the literature dealing with rubella encephalitis are scarce and are limited to several case reports. Tunisian public health care authorities reported in 2011 an important increase of patients admitted to hospitals because of eruptive fever. In fact, 1600 children underwent serologic tests for rubella and measles: only 6 cases of measles were confirmed whereas 1075 had confirmed rubella infection. In Tunisia, preventive measures have been conducted since 2005 to prevent congenital rubella by vaccinating all young girls aged between 13 and 18 years and nonimmunized women during the post-partum period. Thus, the female population with rubella infection has decreased from 55% in 2003 to 40% in 2011, and children aged between 6 and 11 years represent the population of most concern for this viral infection. Moreover, this explosive rubella outbreak was particularly associated with frequent severe neurologic complication. In fact, available data in the literature suggest that the incidence of rubella encephalitis varies from 1 in 6000 to 1 in 24 000, whereas the reported incidence in our country was 50 cases for fewer than 2000 confirmed rubella infection. The pathophysiology of rubella encephalitis is still debated with 2 possible mechanisms: direct viral invasion and an immune-mediated response. Rubella virus has been known to be pantropic to nerve cells and has the ability to spread through the nervous system. Autopsy studies in patients with rubella encephalitis have revealed diffuse nonspecific neural degeneration, edema, and perivascular lymphocyte infiltrates without demyelination and pronounced inflammatory damage. In our study, we found that maculopapular eruptions were present on admission in 81% of cases. Moreover, hemodynamic impairment was unusual. Respiratory distress was also exceptional despite deep impairments of neurologic status. Main neurologic disturbances were unconsciousness (median Glasgow Coma Scale score was 7; lower and upper quartiles, 7-8) and seizures (95.2%), with frequent episodes of status epilepticus (76.2%).