Differential Diagnosis for Persistent High Blood Pressure and Asymmetry in Kidney Sizes

• Single most likely diagnosis
  • Renal artery stenosis: This condition is a common cause of secondary hypertension, especially in elderly patients, and can lead to asymmetry in kidney sizes due to decreased blood flow to one kidney, resulting in atrophy. The patient's age and the presence of multiple anti-hypertensive medications without adequate blood pressure control increase the likelihood of this diagnosis.
• Other Likely diagnoses
  • Adult Polycystic Kidney Disease (PCK): Although less likely to cause significant asymmetry in kidney sizes compared to renal artery stenosis, adult PCKD can lead to variable kidney sizes and is associated with hypertension. However, the presence of multiple cysts in both kidneys would typically be seen on ultrasound.
  • Pheochromocytoma induced HTN: While pheochromocytoma can cause resistant hypertension, it is less commonly associated with asymmetry in kidney sizes. This condition would more likely present with episodic hypertension, palpitations, sweating, and other symptoms related to catecholamine excess.
• Do Not Miss diagnoses
  • Renal cell carcinoma or other renal tumors: Although less common, a tumor in one kidney could cause asymmetry in size and potentially lead to hypertension through various mechanisms, including renin secretion or compression of the renal artery. Missing this diagnosis could have severe consequences.
  • Renal vascular malformations or other vascular abnormalities: These could also lead to hypertension and kidney size asymmetry. Given the potential for severe outcomes if left untreated, these diagnoses should not be overlooked.
• Rare diagnoses
  • Fibromuscular dysplasia: A rare cause of renal artery stenosis, more commonly seen in younger females, but could be considered in the differential diagnosis of an elderly patient with resistant hypertension and kidney size asymmetry.
  • Other rare genetic or congenital conditions affecting the kidneys or renal vasculature: These might include conditions such as tuberous sclerosis complex or neurofibromatosis type 1, which can affect kidney size and function and lead to hypertension.