COVID-19 in a Patient with Chronic Lymphocytic Leukaemia with Pseudohypoxemia

Infection with SARS-CoV-2 causes critical disease in approximately 5% of affected patients, particularly the elderly, hypertensive, obese and immunocompromised. Patients with haematological cancer, including chronic lymphocytic leukaemia (CLL), are particularly at risk of complications. Very rarely, patients with extreme leukocytosis may develop spurious hypoxemia, or pseudohypoxemia, which confuses the diagnosis of complications and can lead to intervention errors. We report the case of a patient with CLL, severe infection with SARS-CoV-2 and pseudohypoxemia. LEARNING POINTS: Patients with haematological neoplasms are susceptible to viral, bacterial and fungal infections, and are thus at risk of COVID-19. Patients with chronic lymphocytic leukaemia may rarely, due to a high lymphocyte count, present with spurious, or in vitro, hypoxemia. The clinician must identify and properly treat such cases to prevent any unnecessary treatments and their complications.