What is the best way to treat acute hypertension associated with Wilms tumor?

Management of Acute Hypertension in Wilms Tumor

The best approach to treat acute hypertension associated with Wilms tumor is to use intravenous labetalol or nicardipine as first-line agents, followed by oral antihypertensive therapy with calcium channel blockers and/or ACE inhibitors until tumor resection. 1, 2

Pathophysiology and Presentation

• Hypertension is a frequent complication of Wilms tumor, occurring in approximately 55% of patients at diagnosis 2
• The hypertension is primarily renin-mediated, with elevated plasma renin levels found in 81% of hypertensive Wilms tumor patients 2
• Hypertension is often severe but asymptomatic in children with Wilms tumor, with blood pressure typically elevated to 99th percentile + 30 mmHg 1
• Wilms tumor-associated hypertension typically affects young children under 2.5 years of age 1

Initial Management of Acute Hypertension

First-line Treatment

• For severe hypertension (≥180/110 mmHg with risk of acute organ damage), immediate intravenous antihypertensive therapy is indicated 3
• Intravenous labetalol or nicardipine are the preferred first-line agents for initial management 1
• Labetalol is particularly effective due to its combined alpha and beta-blocking properties, which helps control both peripheral resistance and heart rate 4

Cautions with IV Therapy

• Blood pressure reduction should be controlled and gradual, with a target of no more than 25% reduction in the first hour to avoid organ hypoperfusion 3, 5
• Careful monitoring is essential as rapid decreases in blood pressure can lead to cerebral, cardiac, or renal hypoperfusion 4
• Central venous and arterial pressure monitoring may be beneficial during the perioperative period 6

Transition to Oral Therapy

• After initial stabilization with IV agents, transition to oral antihypertensive medications is recommended 1
• Calcium channel blockers (such as nifedipine or amlodipine) are effective and commonly used as first-line oral agents 1
• ACE inhibitors (such as captopril) are particularly effective due to the renin-mediated nature of hypertension in Wilms tumor 2
• In resistant cases, combination therapy may be necessary, with dual therapy required in approximately 23% of cases 1
• For particularly resistant cases, a combination of ACE inhibitor and angiotensin receptor blocker (e.g., captopril and losartan) has been reported to be effective 7

Definitive Treatment

• The primary treatment for Wilms tumor-associated hypertension is surgical resection of the tumor 6
• Preoperative chemotherapy may be indicated based on tumor stage and may help reduce blood pressure before surgery 1
• Blood pressure typically normalizes after tumor resection, with most patients returning to normal blood pressure within one month of surgery 6
• The median duration of antihypertensive therapy is approximately 40 days (range: 9 to 195 days) 1

Long-term Considerations

• Long-term follow-up is important as Wilms tumor survivors have an increased risk of developing hypertension later in life 8
• Contributing factors to long-term hypertension risk include decreased nephron mass after nephrectomy, exposure to abdominal radiation, and nephrotoxic therapies 8
• Ambulatory blood pressure monitoring (ABPM) may be beneficial for detecting masked hypertension in Wilms tumor survivors 8

Treatment Algorithm

1. Acute phase (BP ≥180/110 mmHg):

   • Start IV labetalol or nicardipine 1
   • Target gradual BP reduction (no more than 25% in first hour) 3
   • Monitor for signs of organ hypoperfusion 4

2. Stabilization phase:

   • Transition to oral therapy with calcium channel blockers and/or ACE inhibitors 1, 2
   • Consider combination therapy if single agent is insufficient 1
   • For resistant cases, consider adding angiotensin receptor blockers 7

3. Definitive treatment:

   • Preoperative chemotherapy if indicated 1
   • Surgical resection of tumor 6
   • Continue antihypertensive medications until BP normalizes 1

4. Follow-up phase:

   • Monitor BP regularly after tumor resection 8
   • Consider ABPM for long-term surveillance 8
   • Evaluate for other cardiovascular risk factors 8

This approach effectively manages the acute hypertensive crisis while addressing the underlying cause, leading to resolution of hypertension in most patients following tumor resection.