Pelger-Huet anomaly mimicking 'shift to the left'

A case report is presented of an 83-year-old male patient with respiratory distress, body temperature of 38.5°C, bilateral white infiltrates on chest X-ray and ECG showing acute myocardial infarction. Clinical evaluation led to the suspicion of severe infection accompanying lung congestion due to the infarction, mostly because his white blood cell differential count showed a persistent severe 'shift to the left'. Re-examination of his blood smear showed that the 'shift to the left' did not consist of band forms but of a 'Pelger-Huet' anomaly of the granulocytes. Recognition of this anomaly in the light of rapid clinical and radiological improvement precluded the administration of antibiotics for the diagnosis of severe infection with pulmonary involvement, which responded to diuretic therapy alone.