Box 18: Case report
Poor communication with blinding results
A diabetic clinic in a teaching hospital diagnosed TB in a diabetic patient with a history of weight loss. He was admitted to hospital and, on discharge, was prescribed three months’ supply of ethambutol, rifampicin, pyrazinamide, isoniazid and pyridoxine.
A month later, he was seen in the diabetic clinic but there was no discussion of his TB treatment. He failed to attend his next appointment.
Three months after starting TB treatment, the patient began to complain of deteriorating vision and his GP made an urgent referral to the eye clinic. The GP had not yet received a discharge letter about the patient’s last hospital admission for the treatment of TB, nor had the diabetic clinic informed him of the diagnosis, so his referral letter to the eye clinic made no mention of the fact that the patient was taking ethambutol.
The patient attended the eye clinic several times over a month, but no history of TB or treatment for TB was obtained – his visual loss being attributed to diabetes. However, his vision continued to deteriorate and by the end of this period he was only capable of counting fingers. A week later, the patient attended the diabetic clinic. Only then was the diagnosis of ethambutol eye toxicity raised.
The patient was seen immediately in the eye clinic where the diagnosis was confirmed and the ethambutol stopped, but by then he had sustained a permanent loss of 90% of his vision.