What is the best course of management for a patient with left hydronephrosis, a smaller left kidney, hypertension, fatigue, nausea, and lightheadedness, who has shown some improvement with prednisone and metformin?

Management of Left Hydronephrosis with Systemic Symptoms

The immediate priority is urgent urological evaluation to determine the cause and severity of the left hydronephrosis, as obstructive uropathy can cause hypertension, renal dysfunction, and systemic symptoms that may explain this patient's presentation. 1, 2

Urgent Diagnostic and Therapeutic Steps

Address the Hydronephrosis First

• Obtain urgent urology consultation for the left hydronephrosis, as relief of obstruction can rapidly resolve hypertension and improve renal function within days to weeks 1, 2
• The smaller left kidney with hydronephrosis suggests chronic obstruction with potential parenchymal damage, making timely intervention critical to preserve remaining renal function 3
• Hydronephrosis-associated hypertension operates through the renin-angiotensin-aldosterone system, and surgical relief of obstruction cures hypertension in 62% of cases and improves it in another 19% 2
• The constellation of hypertension, nausea, lightheadedness, and fatigue may all be manifestations of the obstructive uropathy rather than separate conditions 1, 4

Blood Pressure Management During Evaluation

• Initiate or uptitrate an ACE inhibitor or ARB as first-line therapy for hypertension, targeting systolic BP <120-130 mmHg 5
• ACE inhibitors/ARBs should be used at maximally tolerated doses for both blood pressure control and renal protection 5
• Critical caveat: Counsel the patient to hold RAS inhibitors and diuretics if volume depletion occurs (intercurrent illness, vomiting) 5
• Monitor renal function closely after initiating RAS blockade, as bilateral renal artery stenosis or severe unilateral disease could cause acute kidney injury 5

Determine the Underlying Cause

The response to prednisone suggests a possible inflammatory or autoimmune etiology that requires investigation:

• Consider retroperitoneal fibrosis, IgG4-related disease, or other inflammatory conditions that can cause hydronephrosis and respond to corticosteroids 3
• The nasal polyp resolution with steroids and antibiotics, combined with systemic symptoms, raises concern for granulomatosis with polyangiitis or other systemic vasculitis
• Obtain urinalysis with microscopy, urine protein-creatinine ratio, serum creatinine, and inflammatory markers (ESR, CRP) 5
• Consider ANCA testing, complement levels, and immunoglobulin panel if systemic inflammatory disease is suspected 5

Management Algorithm Based on Findings

If Obstruction Requires Intervention

1. Proceed with nephrostomy tube placement or ureteral stenting to relieve obstruction urgently 1, 3
2. Monitor blood pressure response within 24-48 hours after decompression, as hypertension may resolve rapidly 1
3. Reassess symptoms (fatigue, nausea, lightheadedness) after relief of obstruction, as these may improve with restoration of renal function 1, 4

If Inflammatory/Autoimmune Disease is Confirmed

• Initiate disease-specific immunosuppression based on the underlying diagnosis, following KDIGO guidelines for glomerular diseases 5
• Prednisone dosing should be optimized for the specific condition rather than empiric low-dose therapy 5
• Screen for latent infections (tuberculosis, hepatitis B/C, HIV) before intensifying immunosuppression 5
• Provide prophylaxis with trimethoprim-sulfamethoxazole if high-dose prednisone or other immunosuppressive agents are used 5

Ongoing Hypertension Management

• Add potassium-wasting diuretics if hyperkalemia limits RAS inhibitor uptitration 5
• Consider adding a second mechanistically different diuretic if volume overload persists despite initial therapy 5
• Avoid NSAIDs entirely, as they can worsen renal function, cause sodium retention, and exacerbate hypertension 6, 7

Critical Pitfalls to Avoid

• Do not attribute all symptoms to separate conditions when hydronephrosis can cause hypertension, nausea, fatigue, and lightheadedness through renal dysfunction and renin-mediated mechanisms 1, 2, 4
• Do not delay urological intervention while pursuing medical management, as chronic obstruction causes irreversible nephron loss 3, 2
• Do not continue empiric prednisone without establishing a specific diagnosis, as prolonged immunosuppression carries significant risks including infection and malignancy 5
• Do not assume the smaller left kidney is congenital without excluding chronic obstruction, renal artery stenosis, or prior inflammatory injury 3, 2
• Monitor for volume depletion carefully, as patients on RAS inhibitors and diuretics are at risk for acute kidney injury during intercurrent illness 5

Metformin Considerations

• Continue metformin if renal function is stable (eGFR >30 mL/min/1.73m²), but hold during acute illness or if contrast studies are planned 7
• The modest symptom improvement with metformin may reflect better glycemic control rather than a direct effect on the underlying process 7