LAUSR

In contrast to many cases today that have a rare genetic cause, this case highlights the continuing value of recognizing salient historical and clinical features in making a diagnosis of a treatable acquired cause. The differential diagnosis for subacute confusion and abnormal movements is lengthy but instead of jumping ahead with extensive testing, his physicians noted a history of recent diarrhea, observed skin changes, and delving further into the history learned that this man had been subsisting on only corn and rice, leading to the diagnosis of pellagra. The follow-up video, after replacement, shows marked improvement, demonstrating the value in starting a differential diagnosis with potentially treatable disorders. The term pellagra comes from the Italian “pelle” (skin) and “agra” for rough, emphasizing one of the four classical Ds of pellagra: dermatitis. The others include dementia, diarrhea and if untreated, death. Inadequate dietary niacin leads to a deficiency of nicotinic acid and nicotinamide, precursors of NAD and NAD-phosphate, parts of the mitochondrial chain. It is important to remember that pellagra may also occur in other settings such as inflammatory bowel disease, malabsorption, anorexia nervosa, alcoholism with malnutrition, and long-term use of isoniazid and other drugs. Although dementia is the most recognized neurological sign of pellagra, there is a wide range of neurological manifestations of pellagra including sensory-motor neuropathy, spastic paraparesis, delirium, delusions and hallucinations, psychomotor slowing, and irritability. Although rare, movement disorders due to pellagra include tremor, parkinsonism, chorea/athetosis and gait ataxia. A challenge in the diagnosis of pellagra is that a “full suit” of symptoms and signs may not be present initially leading to a delay in the diagnosis. This case is an important reminder to consider pellagra and be aware of its myriad manifestations and causes. In this era of high-tech medicine, it also demonstrates the importance of a careful history and looking beyond the neurological examination for diagnostic clues. Author Roles