Transient cardiac constriction is an unusual complication of purulent pericarditis. It should be suspected in the presence of clinical and haemodynamic deterioration when signs of activity have abated. Features of cardiac constriction were observed in a 4-year-old boy 2 weeks after surgical drainage. The patient was managed conservatively without surgery and the outcome was good. Follow up 2 years later showed a healthy boy with a normal cardiological examination.