What are the causes and management of sudden hypertension and bradycardia?

From the Guidelines

Sudden hypertension and bradycardia together often indicate autonomic dysregulation, most commonly seen in the Cushing reflex or autonomic dysreflexia. The Cushing reflex occurs with increased intracranial pressure, while autonomic dysreflexia typically affects individuals with spinal cord injuries above T6. Other causes include baroreflex failure, certain medications (beta-blockers, clonidine), vasovagal reactions, and rarely pheochromocytoma. Management depends on the underlying cause but generally involves immediate assessment of airway, breathing, and circulation. For autonomic dysreflexia, the priority is to sit the patient upright and remove triggering stimuli (like full bladder or bowel, tight clothing). Pharmacological management may include short-acting antihypertensives such as nifedipine 10mg sublingually, nitrates, or hydralazine 10-20mg IV for severe hypertension. For Cushing reflex, addressing the increased intracranial pressure is paramount, potentially requiring neurosurgical intervention. Atropine 0.5-1mg IV may be used for symptomatic bradycardia if hypotension develops, as recommended by the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1. Continuous cardiac and blood pressure monitoring is essential during treatment. The pathophysiology involves disruption of normal autonomic feedback mechanisms, where the body's attempt to lower blood pressure through bradycardia fails to adequately compensate for the hypertension, creating this paradoxical presentation.

Some key points to consider in management:

• Identifying and treating the underlying cause of secondary hypertension can lead to improved blood pressure control and reduced cardiovascular risk, as noted in the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1.
• The 2010 international consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations suggests atropine as the first-line drug for acute symptomatic bradycardia, with alternatives including isoproterenol, epinephrine, dopamine, or transcutaneous pacing 1.
• The British Hypertension Society guidelines for hypertension management 2004 (BHS-IV) recommend considering secondary causes of hypertension in patients with sudden onset or worsening of hypertension, resistant to multidrug regimen, or with target organ damage disproportionate to the duration or severity of the hypertension 1.

Given the complexity and variability of presentations, it is crucial to approach each case individually, considering the most recent and highest quality evidence available, such as the 2018 ACC/AHA/HRS guideline 1, to guide management decisions and optimize patient outcomes in terms of morbidity, mortality, and quality of life.

From the Research

Causes of Sudden Hypertension and Bradycardia

• Sudden hypertension can be caused by various factors, including end-organ damage, which can lead to a hypertensive emergency 2, 3, 4.
• Bradycardia, on the other hand, can be caused by pathology within the sinus node, atrioventricular (AV) nodal tissue, and the specialized His-Purkinje conduction system 5.
• In some cases, sudden hypotension and bradycardia can occur together, and the underlying causes can be complex and multifactorial, requiring detailed interrogation of the patient's medical history and current medications 6.

Management of Sudden Hypertension and Bradycardia

• The primary goal of intervention in a hypertensive crisis is to safely reduce blood pressure, and immediate reduction is required only in patients with acute end-organ damage 2, 3, 4.
• Treatment of hypertensive emergencies typically involves the use of short-acting, easily titratable, intravenous antihypertensive medications, such as clevidipine, labetalol, esmolol, fenoldopam, nicardipine, and sodium nitroprusside 2, 3.
• Management of bradycardia should focus on evaluating and managing the underlying disease state, rather than solely treating the heart rate, and treatment should rarely be prescribed solely on the basis of a heart rate lower than an arbitrary cutoff or a pause above certain duration 5.
• In cases of simultaneous hypotension and bradycardia, treatment should be individualized and based on the underlying causes, and may require hospitalization for detailed evaluation and management 6.