ABSTRACT
The presence of erythrocytosis along with the diagnosis of chronic obstructive pulmonary disease (COPD) may veer a primary care clinician in a busy clinic towards attributing the erythrocytosis to hypoxia secondary to COPD; however, this is not always the case. This case highlights the importance of investigation and the significance not excluding a primary cause in COPD patients with erythrocytosis. A 57-year-old male, presenting with chronic cough, was subsequently diagnosed with COPD clinically and confirmed by spirometry. Erythrocytosis was also incidentally noted. The patient did not have any symptoms of polycythemia or hepatosplenomegaly. Therefore, the erythrocytosis was initially thought to be caused by hypoxia secondary to COPD. However, the JAK2 V617F gene mutation was detected and hence the diagnosis of polycythemia vera was made. Although the erythrocytosis was initially attributed secondary to the underlying pulmonary disease, investigations proved it to be primary in origin. This case report highlights the importance of investigating the underlying cause and to confirm the diagnosis of erythrocytosis as primary and secondary polycythemia differ in their management approach. This will avoid inappropriate diagnosis, treatment, and undesirable outcomes.