Looking for vacuolated lymphocytes in a blood film may provide a pointer to a diagnosis of metabolic disease. At Great Ormond Street Children’s Hospital, London (

) over a period of 15 years 2550 blood films were examined for lymphocyte vacuolation and 156 (6%) gave a positive result. The reasons for requesting the examination included neurological problems (developmental delay or regression, seizures, ataxia, dystonia), cardiomyopathy, hepatosplenomegaly, and ophthalmic disorders. The last of these gave the highest positivity rate (40%). The most common diagnoses associated with vacuolated lymphocytes were Juvenile Batten’s disease (49 cases), Pompe’s disease (24), and GM1 gangliosidosis (14). Other diagnoses included adult acid maltase deficiency (12 of the 232 films from adults), galactosialidosis (7), mucopolysaccharidosis (7), and I cell disease (6). The number, size, or staining properties of the vacuoles may point to specific diagnoses such as juvenile Batten’s disease or acid maltase deficiency. With good technique there should be no false positives but false negatives may occur and repeated examinations may be necessary.

The pleasure associated with food, alcohol, and recreational drugs may, at least in part, be a result of the release of endocannabinoids that activate the cannabinoid-1 (CB₁) receptor, ultimately causing “pleasure molecules” such a dopamine and serotonin to be released in the brain. Rimonabant …