Malignant hypertension with acute kidney injury — case discussion

Presentation

Practice case (not a real patient). A 47-year-old man with known hypertension stopped his tablets 2 months ago. He presents with 3 days of headache and blurred vision. BP is 228/136 mm Hg in both arms. He is alert with no focal neurological deficit. Fundoscopy shows flame haemorrhages, cotton wool spots and papilloedema. Creatinine has risen acutely from a normal value, and acute kidney injury is diagnosed. He is not pregnant, has no chest or back pain, and CT shows no stroke and no acute aortic syndrome.^[1][9][2]

Step 1 — Is this a hypertensive emergency?

Discussion:

• Yes. ESC 2024 defines hypertensive emergency as BP of 180/110 mmHg or more associated with acute hypertension-mediated organ damage, often in the presence of symptoms, and AHA/ACC 2025 defines it as BP above 180/120 mm Hg with evidence of acute target organ damage.^[1][2]
• His picture fits the ESC 2024 description of malignant hypertension: extreme BP elevations and acute microvascular damage, typically characterised clinically by retinopathy (flame haemorrhages, cotton wool spots and/or papilloedema), with acute deterioration in renal function among its other manifestations.^[1]
• A 2024 review names nonadherence to the antihypertensive regimen as the most common cause of malignant hypertension.^[9]

Step 2 — Where and how is he managed?

Discussion:

• In nonpregnant, nonstroke adults with a hypertensive emergency (BP above 180 and/or above 120 mm Hg and evidence of acute target organ damage), AHA/ACC 2025 recommends ICU admission for continuous monitoring of BP and target organ damage and for consideration of parenteral administration of appropriate therapy (COR 1, LOE B-NR).^[2]
• ESC 2024 frames treatment around three considerations: the affected target organ(s) and any specific interventions they need besides BP lowering; any precipitating cause or concomitant condition that might affect the plan; and the recommended timing and magnitude of safe BP lowering.^[1]
• ESC 2024 says i.v. treatment with a short half-life drug is typically ideal to allow careful titration, and that this requires a higher dependency clinical area with facilities for continuous or near-continuous haemodynamic monitoring.^[1]

Step 3 — How fast should BP come down?

Discussion:

• AHA/ACC 2025 gives acute aortic syndrome or acute aortic dissection as examples of a compelling condition; neither is present, and in this scenario the team judges that he has no compelling condition, so the row without a compelling condition applies.^[2]
• For nonpregnant, nonstroke adults with a hypertensive emergency but without a compelling condition, AHA/ACC 2025 states that SBP should be reduced with oral or parenteral therapy by no more than 25% within the first hour; then, if stable, to below 160/100 mm Hg within the next 2 to 6 hours; and then cautiously to 130 to 140 mm Hg during the next 24 to 48 hours to limit target organ injury (COR 1, LOE C-LD).^[2]
• From an SBP of 228 mm Hg, 25% is 57 mm Hg, so the first-hour SBP should not fall below 171 mm Hg.^[2]
• The 2024 malignant hypertension review states that BP must be lowered within hours to mitigate risk.^[9]
• ESC 2024 text states that rapid and uncontrolled or excessive BP lowering is not recommended, as this can lead to further complications.^[1]

Step 4 — Which drug?

Discussion:

• AHA/ACC 2025 Table 27 lists clevidipine, fenoldopam and nicardipine as preferred IV drugs in acute kidney injury, in alphabetical order rather than order of preference.^[2]
• Nicardipine (AHA/ACC 2025 Table 26): initial 5 mg/h, increasing every 5 min by 2.5 mg/h to a maximum of 15 mg/h; contraindicated in advanced aortic stenosis.^[2]
• Nitroprusside is not among the Table 27 preferred drugs for acute kidney injury, and AHA/ACC 2025 Table 26 notes that thiocyanate toxicity (increased risk in kidney dysfunction, sCr above 3) may occur at infusion rates of 3 mcg/kg/min or more and/or durations of 3 days or more.^[2]

Step 5 — Follow-up

Discussion:

• ESC 2024 states that patients who have had a hypertensive emergency remain at high risk and should be screened for secondary hypertension.^[1]
• The 2024 malignant hypertension review states that prognosis has improved with effective treatment, but patients remain at high risk of adverse cardiovascular and kidney outcomes.^[9]