What is the appropriate workup and treatment for a 33-year-old patient with an incidentally discovered atrophic left kidney, indicating possible Impaired renal function?

From the Guidelines

For a 33-year-old with an incidentally discovered atrophic left kidney, I recommend a comprehensive evaluation starting with a complete history and physical examination, focusing on symptoms of urinary tract infections, flank pain, hematuria, or hypertension. Laboratory tests should include a complete blood count, comprehensive metabolic panel, urinalysis, urine culture, and assessment of kidney function with serum creatinine and estimated glomerular filtration rate (eGFR) 1. Imaging studies should include a renal ultrasound to confirm atrophy and assess the right kidney, followed by a CT or MRI urogram to evaluate for obstruction, stones, or masses 2. A nuclear medicine renal scan (DMSA or MAG3) should be performed to assess differential renal function. If hypertension is present, start with an ACE inhibitor like lisinopril 10mg daily or an ARB such as losartan 50mg daily, which provide renoprotection 3. Regular monitoring should include blood pressure checks every 3 months, annual kidney function tests, and ultrasound follow-up every 1-2 years. The atrophic kidney likely resulted from congenital hypoplasia, reflux nephropathy, chronic obstruction, or vascular insufficiency. The primary concern is preserving function in the remaining kidney and preventing hypertension, which commonly develops due to activation of the renin-angiotensin-aldosterone system in response to reduced renal mass 4.

Some key points to consider in the evaluation and management of this patient include:

• The importance of a thorough history and physical examination to identify potential causes of the atrophic kidney
• The use of laboratory tests and imaging studies to assess kidney function and structure
• The role of ACE inhibitors or ARBs in providing renoprotection and managing hypertension
• The need for regular monitoring to prevent progression of kidney disease and development of hypertension
• The potential for the atrophic kidney to be a result of various underlying conditions, such as congenital hypoplasia or reflux nephropathy.

Overall, the goal of the evaluation and management plan is to preserve kidney function, prevent progression of disease, and reduce the risk of complications such as hypertension.

From the Research

Diagnostic Approach

• The patient's incidentally discovered atrophic left kidney requires a thorough diagnostic workup to determine the underlying cause of the atrophy 5.
• Imaging studies such as magnetic resonance imaging (MRI) can provide valuable information on the kidney's anatomy and function 6, 7.
• MRI can help identify potential causes of renal atrophy, such as obstructive disorders, inflammation, or vascular diseases 6.

Imaging Modalities

• Computed tomography (CT) reconstruction can also be used to diagnose renal artery stenosis, a potential cause of renal atrophy 8.
• Multiparametric MRI can assess histopathological changes associated with renal atrophy and fibrosis, including tubular atrophy and fibrosis 9.
• The choice of imaging modality depends on the clinical situation and the need to minimize radiation exposure and potential adverse events 7.

Potential Causes

• Left renal atrophy may be caused by aortic pressure-induced flow disorders in the left renal vein, structural anomalies of the left renal vein, or higher arterial pressure in the left kidney 5.
• Other potential causes of renal atrophy include obstructive disorders, inflammation, or vascular diseases, which can be identified through imaging studies 6, 8.
• The patient's medical history and physical examination can also provide clues to the underlying cause of the renal atrophy 5.

Treatment Approach

• The treatment approach will depend on the underlying cause of the renal atrophy, which can be determined through diagnostic imaging and other tests 8.
• Percutaneous transluminal angioplasty may be a treatment option for patients with renal artery stenosis, a potential cause of renal atrophy 8.
• Medical management may also be necessary to control blood pressure and slow the progression of renal disease 8.