Secondary hypertension
From IDWiki
Epidemiology
- In ALLHAT trial, about 30% of patients had resistant hypertension
- In a hypertension clinic, 6% of patients referred to them had secondary hypertension
Differential Diagnosis
- Medication/lifestyle non-adherence
- Salt intake
- NSAIDs
- Stimulants
- Alcohol
- Withdrawal from medications or recreational drugs
- Pain
- Poor medication choice
- White coat hypertension
- Transient hypertension
- Drugs: glucocorticoids, stimulants (including caffeine, pseudephedrine, cocaine), OCP, NSAIDs
- Renal causes
- Renal artery stenosis
- Fibromuscular dysplasia (FMD)
- Polyarteritis nodosa (PAN)
- Systemic sclerosis
- Intrauterine growth restriction (IUGR)
- Endocrine causes
- Hyperaldosteronism
- Pheochromocytoma
- Thyroid disease
- Hyperparathyroidism
- Other
- Obstructive sleep apnea
- Drugs/alcohol
Approach/Template
- Accurate BP evaluation; that is, do they have high blood pressure?
- Is it primary or secondary? What is the cause?
- Is there end-organ damage?
- Global cardiovascular risk assessment
- Based on the above, what is the optimal BP treatment target?
- Best drugs available for treatment
- Arranging ongoing follow-up
When to Investigate
- All patients should be screened for OSA and intrinsic renal disease with urinalysis
- Symptomatic presentation with urgency or emergency
- Younger than 20 years or older than 50 years
- Unprovoked hypokalemia or hypokalemia on low-dose diuretic
History
- Lifestyle factors
- Substance addiction
- Substance withdrawal
- Medication adherence
- Endocrine causes
- Vascular causes
- Obstructive sleep apnea
Exam
- BMI and waist circumference
- Proper BP including bilateral and orthostatic
- ABPM is best >> AOBP > ROBP > casual office BP
- Ideally includes nocturnal sleeping BP
- Evidence of end-organ damage
- Evidence of endocrine/secondary causes
- Cushingoid?
- Coarctation
- RAS
Investigations
- Urinalysis in all people
- STOP-BANG or sleep study in all people
- Electrolytes, creatinine, CBC
- TSH, calcium/albumin, urinalysis, A1c, lipids
- Consider
- CXR showing rib notching for coarctation (from enlarged intercostal arteries)
- Renin-aldosterone (renin better than aldo, if only one is available)
- If renin suppressed, is essentially diagnostic for primary hyperaldosteronism
- Try to get them off RAS-inhibiting therapies (use alpha-blockers and CCBs instead)
Further Readings
- Hypertension Canada Guidelines 2018
- AHA/ACC Guidelines 2017
