• DEMENTIA

The term rapidly progressive dementia refers to dementia (and excludes delirium) typically developing over weeks or months, including those evolving in less than 1–2 years from onset.1 2 The fact that they are rapidly progressive underlines the need for critical clinical evaluation and detailed investigations. The case report from Zambia in Practical Neurology,3 caused by cryptococcal infection in a non-HIV setting, illustrates that rapidly progressive dementia can occur anywhere in the world and may have a treatable cause. While practising neurologists will be very familiar with the main categories of rapidly progressive dementia, the relative infrequency and diversity of causes of these conditions presents a formidable diagnostic challenge.

The main categories reported worldwide are non-prion neurodegenerative disorders, mostly dementias, autoimmune encephalopathies, prion disease, infective, metabolic, nutritional and malignant disorders.1 2 Of these causes, human prion disease, Creutzfeldt-Jakob disease (CJD) has received most attention globally. CJD is classified into sporadic 85%–90%, genetic 10%–15% and acquired 1%. It is a relatively infrequent and universally fatal disease with an annual incidence of approximately 1–2 per million worldwide but is on the increase.4 Only 23 cases, mostly of sporadic CJD, have been reported from Africa,5–12 …