Secondary Hypertension

• Severe hypertension

  • Resistant hypertension

  • Target organ damage disproportionate to the degree of hypertension

  • Hypertensive emergency

• Unusual onset of hypertension

  • Abrupt onset

  • Onset at < 30 years of age [10]

  • Onset of diastolic hypertension at > 65 years of age

  • Exacerbation of previously controlled hypertension

  • Drug-induced hypertension

• Unprovoked or significant hypokalemia

Aortic dissection is a (rare) life-threatening cause of secondary hypertension that may manifest with a blood pressure difference between the right and left arm.

• Most common causes in adults include:

  • < 40 years of age: thyroid dysfunction, fibromuscular dysplasia, and renal parenchymal disease

  • 40–64 years of age: hyperaldosteronism, thyroid dysfunction, and obstructive sleep apnea

  • ≥ 65 years of age: renal artery stenosis

• Most common causes in children and adolescents (< 18 years of age) include renal parenchymal disease and coarctation of the aorta.

Young adults (especially women < 40 years of age) with suspected secondary hypertension should be assessed for renal artery stenosis caused by fibromuscular dysplasia.

RECENT: Renal (e.g., renal artery stenosis, glomerulonephritis), Endocrine (e.g., Cushing syndrome, hyperthyroidism, Conn syndrome), Coarctation of the aorta, Estrogen (oral contraceptives), Neurological (raised intracranial pressure, psychostimulants use), and Treatment (e.g., glucocorticoids, NSAIDs) are the causes of secondary hypertension.

• Renal artery stenosis (e.g., due to atherosclerosis, fibromuscular dysplasia, polyarteritis nodosa, aortic arch syndrome)

  • Potential indications for further workup

    • Resistant hypertension

    • Recurrent flash pulmonary edema

    • Abdominal bruit

    • ↑ Serum creatinine (by ≥ 50%) within 1 week of starting an ACEI or ARB [19]

    • Hypokalemia [20][21]

    • Asymmetric kidney size

  • Workup and findings: Duplex ultrasonography or MRA or CTA of the renal arteries

• Renal parenchymal disease (e.g., due to glomerulonephritis, polycystic kidney disease, systemic lupus erythematosus, renal tumors, atrophic kidney)

• Chronic kidney disease

• Coarctation of the aorta distal to the left subclavian artery

  • Potential indications for further workup: Blood pressure difference between the upper and lower limbs

  • Workup and findings

    • Doppler echocardiography

    • X-ray chest

    • CTA or MRA chest and abdomen

• Obstructive sleep apnea

  • Pathophysiology: ↑ catecholamines during apneic phases → secondary hypertension

  • Potential indications for further workup

    • Resistant hypertension

    • Obesity, snoring, and/or daytime sleepiness

    • Nondipping pattern on 24-hour blood pressure monitoring

  • Workup and findings: sleep studies often leads to resolution of hypertension.

  • Continuous positive airway pressure (CPAP)

• Substance-related

  • Potential indications for further workup

    • Recreational drug use: amphetamines, cocaine, phencyclidine

    • Caffeine, nicotine, and/or alcohol use

    • Use of certain medications: sympathomimetic drugs (e.g., decongestants), corticosteroids, NSAIDs, oral contraceptives

  • Workup and findings

    • Urine drug screening

    • Response to withdrawal of suspected culprit