GENERAL THERAPIES / HYPERTENSION
Hypertensive crisis
Created 03/11/2022, last revision 25/01/2023
Definition
- a hypertensive crisis is a medical emergency characterized by a sudden and severe elevation in blood pressure
- the levels of hypertension are not universally established and are arbitrary (usually > 180/120 mmHg)
- the rate of BP elevation seems more important than its absolute value
- the term crisis gets abandoned in favor of the following two terms
- the presence of a target-organ lesion distinguishes:
- hypertensive urgency – without target-organs damage
- hypertensive emergency – with acute target-organs complications (heart, kidneys, brain, eyes)
- hypertensive emergency has a mortality rate of up to 7% (Katz, 2009)
Etiology
- decompensation of chronic hypertension
- most commonly caused by sudden discontinuation of antihypertensive medication or drug interactions
- perioperative
- acute stroke (which may be a cause or a result of uncontrolled hypertension)
- secondary hypertension
- pheochromocytoma
- preeclampsia/eclampsia
- abuse of sympathomimetic drugs (amphetamine, LSD, cocaine)
Clinical presentation
- cerebrovascular
- hypertensive encephalopathy (confusion, headaches, nausea/vomiting, visual disturbances, seizures)
- symptoms of hypertensive encephalopathy resolve after blood pressure is lowered and autoregulation of cerebral flow is restored
- posterior reversible encephalopathy syndrome (PRES)
- intracerebral hemorrhage (focal symptoms)
- subarachnoid hemorrhage (headache, meningeal syndrome)
- hypertensive encephalopathy (confusion, headaches, nausea/vomiting, visual disturbances, seizures)
- cardiovascular (chest pain, shortness of breath)
- acute left-sided heart failure (dyspnea, pulmonary edema)
- acute MI/unstable AP
- acute aortic dissection (acute and severe chest or back pain)
- renal
- acute renal failure
- eye symptoms
- hemorrhages, exudates, or edema of the papillae (signs of hypertensive retinopathy grade III or IV) are associated with hypertensive encephalopathy
Diagnostic evaluation
- repeated BP measurement or continuous BP monitoring
- start by measuring both arms’ blood pressure (aortic dissection or coarctation, subclavian artery stenosis)
- if aortic dissection is suspected, also measure BP in the lower limbs
- look for organ damage
- blood samples
- CBC + coagulation
- renal and hepatic tests
- NT-proBNP (heart failure)
- cardiac enzymes (in suspected ACS)
- urine chemistry and urine sediment examination
- D-dimers (when aortic dissection is suspected)
- ECG
- brain CT + CTA (in patients with acute neurological complaints/signs or case of head injury)
- chest x-ray (in patients with shortness of breath)
- CTA of the chest and abdomen for suspected aortic dissection
- fundoscopic exam (ophthalmoscopy)
- blood samples
- exclude secondary hypertension
- CT/MR angiography of renal arteries (renovascular hypertension)
- plasma renin activity (PRA) and aldosterone, plasma or urine metanephrines
- arterial blood pressure (BP) monitoring is a mainstay of hemodynamic monitoring in neurocritical care
- both hypotension and hypertension can impair vital organ function and worsen the outcome
- BP monitoring techniques:
- non-invasive BP monitoring (more common)
- intermittent (inflatable cuff) – the proper cuff size is critical
- manual (auscultatory, palpatory)
- automated (oscillometric)
- continuous
- volume clamp method
- arterial applanation tonometry
- intermittent (inflatable cuff) – the proper cuff size is critical
- invasive BP measurement via arterial cannulation (most commonly automated)
- non-invasive BP monitoring (more common)
- choice of BP monitoring must be individualized
- low-risk patients – intermittent oscillometric BP monitoring
- high-risk, hemodynamically unstable patients – continuous BP monitoring (noninvasive or invasive)
- critically ill patients/hypertensive emergencies – continuous invasive BP monitoring via an arterial catheter is preferred
Proper cuff size
- the cuff bladder length should be at least 80% of the upper arm circumference
- arm circumference < 35 cm – cuff 16×30 cm (suitable for most patients)
- arm circumference 35-44 cm – cuff 16×36 cm
- arm circumference > 45 cm – cuff 16×42 cm
- preeclampsia = new onset hypertension >140/90 mmHg + proteinuria > 500 mg/24 h or 300 mg/l occurring after 20 weeks gestation or during the second half of pregnancy
- most commonly occurs during the 3rd trimester of pregnancy and may occur before, during, or after delivery
- eclampsia = elevated BP associated with seizures, multi-organ damage (aspiration pneumonia, cerebral hemorrhage, kidney failure, pulmonary edema, HELLP syndrome), and coagulopathy
Classification
The severity of a hypertensive crisis depends on:
- current BP values
- presence of acute target-organ damage
- rate of BP increase (how long it took for BP to increase from the baseline values to the current values)
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Management of hypertensive emergency
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