Vignette: A 45-year-old woman with a 15-year history of type 2 diabetes presents to the clinic for a routine checkup. She is currently taking metformin and glyburide for her diabetes. On physical examination, her blood pressure is 140/90 mmHg, and she is noted to have decreased sensation in her feet. A urinalysis reveals proteinuria.
Question: What is the most likely underlying pathophysiological process causing this patient's renal and peripheral nerve abnormalities?
A. Hyperfiltration injury
B. Ischemic neuropathy
E. Renal stone formation
This patient's longstanding history of diabetes, hypertension, proteinuria, and peripheral neuropathy is suggestive of diabetic nephropathy and peripheral neuropathy - two complications of chronic diabetes. The underlying pathophysiological process is microangiopathy, which is the thickening and leakage of small blood vessels. In the kidneys, this leads to glomerular basement membrane thickening and eventual glomerulosclerosis (Kimmelstiel-Wilson nodules), resulting in proteinuria and, ultimately, end-stage renal disease. In the peripheral nerves, microangiopathy leads to nerve ischemia and the symptoms of peripheral neuropathy.
Hyperfiltration injury (Choice A) is an early process in diabetic nephropathy but does not explain the peripheral neuropathy. Ischemic neuropathy (Choice B) can occur in diabetes but is usually associated with macrovascular diseases, not microangiopathy. Pyelonephritis (Choice D) and renal stone formation (Choice E) would not explain the peripheral neuropathy.