Hypertensive Emergency

Definition of Hypertensive Emergency

• A hypertensive emergency is characterized by high blood pressure (BP) causing or worsening acute end-organ dysfunction.
• To differentiate it from less urgent cases, consider if the dysfunction is related to the elevated BP and if modifying the BP is necessary for improving the dysfunction.

Two Categories of Hypertensive Emergencies

1. Microvascular disorders(characterized by small vessel dysregulation, endothelial damage, and inflammation):
   • encephalopathy
   • pre-eclampsia/eclampsia
2. Macrovascular disorders:
   • CHF
   • aortic dissection
   • stroke
   • subarachnoid hemorrhage.

Symptoms in severe hypertension (>180/110):

1. Cardiovascular System:
   • Chest pain, indicating potential acute coronary syndrome.
   • Shortness of breath, fatigue, or weakness due to heart failure or pulmonary edema.
   • Abnormal heart sounds or rhythms upon auscultation.
2. Central Nervous System:
   • Severe headache, often described as the worst headache ever experienced.
   • Altered mental status, ranging from confusion to stupor or coma.
   • Focal neurological deficits (like weakness, numbness, or speech disturbances), suggesting a stroke.
   • Nausea or vomiting, which can be a sign of increased intracranial pressure.
   • Seizures.
3. Renal:
   • Oliguria (low urine output) or anuria (no urine output), indicating renal impairment.
   • Signs of fluid overload, such as peripheral edema, due to kidney dysfunction.
4. Respiratory System:
   • Pulmonary edema, evident by crackles on lung auscultation and severe shortness of breath.
5. Gastrointestinal System:
   • Epigastric pain or discomfort, possibly indicative of renal or cardiac involvement.
   • Nausea and vomiting without other gastrointestinal causes.

• Diagnosis is confirmed by a normal CT and improvement in cerebral function after BP reduction.
• Treatment aims for a diastolic BP between 100-105 within 2-6 hours, avoiding more than a 20% BP reduction in the first hour.

Clinical Signs

• Fundoscopy Exam Findings : hypertensive retinopathy, which includes
  • Retinal Hemorrhages: Dot or flame-shaped hemorrhages in the retina.
  • Hard Exudates: These appear as yellowish-white spots on the retina.
  • Cotton Wool Spots: Soft exudates that indicate nerve fiber layer infarction.
  • Arteriolar Narrowing: Generalized or focal narrowing of retinal arterioles.
  • Arteriovenous Nicking: Arterioles crossing over veins leading to vein compression.
  • Papilledema: Swelling of the optic disc due to increased intracranial pressure, more common in severe or malignant hypertension.
• Neurological Exam Findings
  • altered Mental Status: Confusion, disorientation, or decreased alertness.
  • Focal Neurological Deficits: Weakness or numbness in limbs, facial droop, aphasia, or other specific neurological impairments indicating a possible stroke.
  • Seizures: In severe cases, especially in hypertensive encephalopathy
  • Visual Disturbances: Including blurred vision or transient loss of vision.
• Cardiovascular Exam Findings
  • signs of CCF: Jugular venous distension, pulmonary rales, peripheral edema.
• Gastrointestinal Exam Findings
  • Decreased Bowel Sounds: In severe cases, particularly if there is associated visceral organ ischemia.

Bloods – to check End-organ dysfunction in the context of a hypertensive crisis

• Creatinine and Blood Urea Nitrogen (BUN): Elevated levels indicate impaired kidney function.
• Urinalysis: Proteinuria, hematuria, or casts in urine can indicate glomerular damage
• Troponin I or T: Elevated levels are indicative of myocardial injury or infarction.
• BNP (Brain Natriuretic Peptide) or NT-proBNP: Elevated in acute heart failure.
• Liver Enzymes (AST, ALT): Elevation can indicate hepatic injury.
• Lactic Acid: Elevated levels can indicate tissue hypoxia or shock.
• Serum Electrolytes: Disturbances can be indicative of metabolic derangements secondary to end-organ damage.

Principles for Lowering BP in the ED

• Avoid rapid BP lowering, except in aortic dissection cases.
• Target to lower BP by no more than 25%, to prevent ischemia.
• Effective therapies often correct the underlying cause.
• Monitor symptoms to determine if BP lowering is sufficient.

IV Drug Choices for Hypertensive Emergencies

1. B-blockers: Labetolol (20mg slow IV push, doubling dose every 10 minutes up to 300mg) is effective, but caution is advised in asthma/COPD and hepatic failure. Esmolol has a quicker onset and offset.
2. Vasodilators: Nitroglycerin for ACS and pulmonary edema; Nitroprusside for both artery and vein dilation but watch for cyanide risk; Hydralazine for artery dilation; Phentolamine for catecholamine-induced hypertension.
3. Calcium channel blockers: Dihydropyridine CCBs for vasodilation (amlodipine, nifedipine, nicardipine); phenylalkylamine CCBs (diltiazem, verapamil) mainly affect heart rate and strength.

Defining features and management of severe hypertension (Table 3.6) [NB1]

	Severely elevated BP without symptoms	Hypertensive urgency	Hypertensive emergency
Typical blood pressure (mmHg)	180/110 or higher	180/110 or higher	usually 220/140 or higher [NB2]
Symptoms [NB3]	not present	present	present
End-organ damage or dysfunction [NB4]	not present	acute end-organ damage or dysfunction is not presentmoderate nonacute damage or dysfunction may be present	significant acute end-organ damage or dysfunction is present
Immediate threat to life	no [NB5]	no [NB5]	yes
Timeframe to achieve initial BP reduction	1 to 2 days [NB5]	hours [NB5]	within minutes
Initial management goals	reduce BP to a safe level, usually below 180 mmHg systolic	relieve symptoms and reduce BP to a safe level, usually below 180 mmHg systolic	reduce BP quickly but without causing a precipitous fall in BP, which is difficult to correctavoid lowering BP by more than 25% in the first 2 hours
Drug delivery route	oral	oral	intravenous
Management setting	primary care, with follow-up within days [NB5]	hospital (ED), with possible admission for ongoing management	hospital (ED, ICU or CCU), with admission for ongoing management

Subarachnoid Hemorrhage & Intracranial Hemorrhage BP Management

• Slow BP reduction is essential, with corrections for other metabolic issues (hyperglycemia, acidosis, fever).
• INTERACT 2 trial suggests a safe reduction to systolic BP of 140, but no benefit for re-bleeding was observed.
• AHA guidelines recommend a target systolic BP of 160.
• Labetolol or nifedipine is preferred, avoiding nitroprusside due to peripheral shunt effects.

Impact of Antihypertensive Drug Choice on Mortality and Morbidity

• A Cochrane review of 15 RCTs (869 patients) found no class of IV antihypertensive drugs significantly reduced mortality/morbidity.
• The CLUE trial highlighted advantages of nicardipine over labetolol for acute hypertension with end-organ damage.

Drug of Choice in Specific Conditions

• Hypertensive encephalopathy, aortic dissection, eclampsia: Labetolol is generally recommended.
• Renal impairment with high BP: Requires close follow-up or hospital admission for workup; use a cautious and individualized approach.
• CHF: High doses of nitroglycerine for arterial dilatation, supplemented with NIPPV ventilation.

Management of Aortic Dissection

• BP should be monitored via an arterial line in the right radial artery.
• Target HR of 60 and systolic BP of <120 mmHg.
• Diltiazem can be used if B-blockers are contraindicated.
• If the aortic root is involved, avoid B-blockers due to risk of tamponade.

Blood Pressure Management in Eclampsia & Pre-eclampsia

• Defined by BP >160/110 with proteinuria/low platelets/elevated LFT or Cr, or symptoms in a patient >20 weeks pregnant. Eclampsia includes seizures.
• Labetolol with Mg+ for seizure prophylaxis; hydralazine as a second line.
• Goal is a 25% BP reduction; OB consultation is vital as delivery is definitive treatment.

General Principles for Rapid BP Reduction in ED

1. Rapid lowering is rarely recommended.
2. Limit BP reduction to 25% to prevent ischemia.
3. Treatments addressing the cause are most effective.
4. Focus on symptom resolution rather than specific BP numbers.

Comparing IV Antihypertensives

• No IV antihypertensive has been shown superior in reducing mortality/morbidity.

Managing High BP with Poor Renal Function

• Assess for proteinuria, active sediment, and retinal changes.
• Close follow-up or hospital admission is advised.

INTERACT 2 Trial and ICH Management

• Slow BP reduction recommended, with other metabolic disturbances managed.
• INTERACT 2 suggests a safe systolic BP of 140, but no re-bleeding benefit.
• AHA guidelines suggest a target systolic BP of 160