A 3 year old boy was admitted to the hospital for high fever and difficulty in breathing. He had been well until 4 days before admission, when he developed sneezing and a runny and stuffy nose followed by a non-productive cough on next day. This was followed by appearance of characteristic rash on face, trunk, extremities and back along with fever. O/E, Shotty anterior cervical and supraclavicular lymph nodes. Hyperaemic conjunctiva Ceain spots on buccal mucosa The white blood cell count was 3,100/ml, with a differential of 70 % polymorphonuclear leukocytes. All of the following are complications of the above disease EXCEPT?