Pleural malpositioning of a haemodialysis catheter causing haemothorax despite the use of ultrasound guided placement and chest radiograph confirmation.

We report an unusual case of haemodialysis catheter malposition into the pleural space causing haemothorax, despite ultrasound-guided insertion and X-ray confirmation. A patient with chronic kidney disease presented in respiratory failure due to pulmonary oedema and was scheduled for urgent haemodialysis. A haemodialysis catheter was inserted under ultrasound guidance, with apparent blood backflow, and postinsertion chest radiograph suggested proper placement. However, dialysis was interrupted multiple times due to persistently inadequate extracorporeal blood flow and visibly diluted blood in the circuit. Blood samples from the catheter revealed a significant drop in haemoglobin levels compared with baseline. Further imaging revealed catheter misplacement into the pleural cavity with haemothorax. This case underscores that even with standard placement verification techniques, rare malposition can occur. Clinicians should maintain a high index of suspicion and pursue further evaluation when unexplained flow or clinical abnormalities arise during dialysis.