There are numerous medical conditions which may produce
an encephalopathic illness which may mimic viral encephalitis,
and some of the most important of these are listed in
table 2. Particularly prominent among these are systemic
infections which can look very much like an encephalitis on
presentation. In patients recently returning from abroad,
particular vigilance must be paid to the possibility of such
non-viral infections as cerebral malaria which may be rapidly
fatal if not treated early. A number of metabolic conditions
including liver and renal failure and diabetic complications
may also cause confusion. The possible role of alcohol and
drug ingestion must always be considered. Table 2 also
indicates the need to sometimes consider some of the rarer
causes of encephalopathy where appropriate pointers exist.