Severe Asymptomatic Hypertension

Editor’s Note: Over the next 5 days the theme of the posts will be on different aspects of hypertension. Two topics have already been covered, namely resistant hypertension and hypertension in dialysis patients.

Case Presentation  A young Indian-American man, age 27 years, with IgA nephropathy was seen in the renal clinic for routine follow-up. He felt well. Past medical history was notable for a 6-year history of IgA nephropathy that had originally presented with gross hematuria -- a renal biopsy at the time had shown Haas classification stage 3 IgA nephropathy. His medications were: fish-oil 12 grams/day, aliskiren 150 mg/ day and metoprolol succinate (Toprol XL) 100 mg/day. Allergies were significant for a rash with losartan and a dry cough with lisinopril therapy. One examination: he looked well and was in no distress. His vitals showed a blood pressure of 178/104 mmHg in the right and 175/104 mmHg in the left arm, heart rate was 57 beats per minute. The rest of the examination was normal, including the absence of edema. Laboratory data showed a urinalysis that was essentially unchanged from before: specific gravity 1015, pH 6.0, 2+ blood, 2+ albumin, otherwise negative. Urine sediment showed 5 to 10 red blood cells but no casts. His BUN was 36 mg/dL, serum creatinine is 1.7 mg/dL (both at his baseline). The rest of his electrolytes were unremarkable, except for a plasma potassium of 5.4 mEq/L. An electrocardiogram shows a mild sinus bradycardia but otherwise is read as normal. 

What hypertension syndrome does this patient have, and how would you manage his blood pressure? 

Discussion

This patient has severe asymptomatic hypertension. This syndrome has been extensively discussed in the literature, both generally and with respect to practical management. I would also recommend a well written review on hypertensive emergencies and urgencies published in the Medical Clinics of North America (MCNA). One of the more practical articles was published in the American Family Physician in February 2010.

1. Definitions

Hypertensive emergencies are potentially life-threatening and usually associated with blood pressures ≥180/120 mmHg. A hypertensive urgency is defined as severely elevated blood pressure (ie, systolic >220 mm Hg or diastolic >120 mm Hg) with no evidence of target organ damage. In contrast, severe asymptomatic hypertension is defined as severely elevated blood pressure without signs or symptoms of end-organ damage. Our patient has severe asymptomatic hypertension.

Severe asymptomatic hypertension can be further classified as hypertensive urgency or severe uncontrolled hypertension, based on the patient's medical history and global cardiovascular risk. Hypertensive urgency is defined as the presence of risk factors for progressive end-organ damage (e.g., history of congestive heart failure, unstable angina, or preexisting renal insufficiency), whereas severe uncontrolled hypertension is defined as the absence of these risk factors.

2. Treatment

a.) Most patients who are asymptomatic but have poorly controlled hypertension do not require immediate workup or treatment (i.e., within 24 hours). However, it is important to confirm blood pressure readings, by obtaining at least 2 measurements.

b.) Risk stratify the patient. Indicators of high risk are shown below:

• Systolic blood pressure of greater than 160 mm Hg, with diastolic blood pressure of less than 70 mm Hg 
• Diabetes mellitus and/or the metabolic syndrome 
• At least three cardiovascular risk factors (e.g., age older than 55 years for men or 65 years for women, smoking, dyslipidemia, impaired fasting glucose, obesity) 
• One or more of the following findings associated with subclinical organ damage:
• Left ventricular hypertrophy on electrocardiography (particularly with strain) or echocardiography (particularly concentric). 
• Elevated serum creatinine or reduced estimated glomerular filtration rate (eGFR) Microalbuminuria
• Evidence of underlying cardiovascular or kidney disease 

c.) Sending the patient with asymptomatic but poorly controlled hypertension to the emergency department is usually unnecessary.  This is because rapidly lowering blood pressure can be harmful (1). As well, there are no controlled studies demonstrating long-term improved outcomes with acute treatment of severe asymptomatic hypertension. Aggressive dosing with intravenous medications or fast-acting oral agents, such as hydralazine can lead to hypotension. Reducing severely elevated blood pressure below the autoregulatory zone too quickly can result in markedly decreased perfusion to the brain and eventually ischemia or infarction. 

d.) Treatment of severe asymptomatic hypertension can be initiated or continued with oral agents. In our patient, while he did not have a blood pressure of ≥180/120 mmHg, he did have underlying kidney disease. Therefore, a diuretic agent (furosemide 20 mg BID) was started by the patient on the next day. Why a diuretic? Patients with chronic kidney disease generally have an excess of total body salt, the furosemide will help waste some potassium (the patient is mildly hyperkalemic), and renin-angiotensin blockade seems to work better in the setting of diuretic therapy. The aliskiren dose was not increased because of his mild hyperkalemia. He was also asked to measure his blood pressure twice daily. After 3 days, his blood pressure had fallen to 162/98 mmHg. However, because it was still elevated, amlodipine 5 mg/day was initiated. After 1 week, his blood pressure had fallen to 145-155/90-95 mmHg and the dose of amlodipine was increased further to 10 mg/day.

References 

1. Decker WW, Godwin SA, Hess EP, Lenamond CC, Jagoda AS, for the American College of Emergency Physicians Clinical Policies Subcommittee (Writing Committee) on Asymptomatic Hypertension in the ED. Clinical policy: critical issues in the evaluation and management of adult patients with asymptomatic hypertension in the emergency department. Ann Emerg Med. 2006;47(3):237–249.