| Summary points: | A 52-year-old male from the Democratic Republic of Congo presents with shortness of breath, general weakness, weight loss, and a sore tongue lasting 14 days. Physical, cardiovascular, and neurological examinations, along with laboratory data, and chest x-ray are described. The authors discuss cobalamin deficiency resulting in pancytopaenia, and emphasise the importance of defining, diagnosing, and treating cobalamin deficiency. |