23rd May 2025

A 21-year-old male with a history of deafness and well-controlled type 1 diabetes mellitus presented to the Eye Clinic due to a decline in his vision.

A 21-year-old male with a history of deafness and well-controlled type 1 diabetes mellitus presented to the Eye Clinic due to a decline in his vision. He was also noted to have polyuria and polydipsia but blood glucose was within range on testing. He was found to have bilateral optic atrophy. He was referred for further investigations. Ultrasound of the urinary tract showed mild bilateral hydronephrosis and enlarged kidneys.

Which investigation would most likely diagnose the most likely endocrine pathology the patient has, in addition to his diabetes mellitus?

Select the SINGLE most appropriate option from the list below. Select ONE option only.