Assessment for a Person Reporting Low Blood Pressure
Initial assessment of a person reporting hypotension should include measurement of orthostatic blood pressure, evaluation of symptoms, and laboratory tests to identify underlying causes and assess end-organ perfusion.
Blood Pressure Measurement Technique
- Measure blood pressure after 5 minutes of rest in the sitting or lying position, followed by measurements at 1 minute and 3 minutes after standing 1
- Use a validated blood pressure device with appropriate cuff size, with the patient in a quiet environment and the BP cuff at heart level 1
- Orthostatic hypotension is defined as a decrease in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg within 3 minutes of standing 1, 2
- Measure BP in both arms at the first visit to detect inter-arm differences; if systolic BP differs by >10 mmHg, use the arm with higher values for subsequent measurements 1
Clinical Assessment
- Evaluate for symptoms associated with hypotension: dizziness, lightheadedness, blurred vision, weakness, fatigue, nausea, palpitations, headache, syncope 3
- Assess the patient's ability to perform routine and desired activities of daily living 2
- Determine if hypotension is symptomatic or asymptomatic, as this affects management decisions 4, 2
- Calculate body mass index (BMI) as part of the initial examination 2
- Evaluate for signs of inadequate organ perfusion: altered mental status, cool extremities, decreased urine output 5
Laboratory Evaluation
- Complete blood count to assess for anemia 2
- Serum electrolytes including calcium and magnesium 2
- Blood urea nitrogen and serum creatinine with eGFR to evaluate kidney function 2
- Fasting blood glucose (or glycohemoglobin) to screen for diabetes 2
- Thyroid-stimulating hormone to rule out thyroid dysfunction 2
- Urinalysis to screen for kidney disease 2
- 12-lead electrocardiogram to assess for cardiac abnormalities 2
Evaluation for Specific Causes
Medication-Related Causes
- Review current medications, particularly antihypertensives, diuretics, antidepressants, and antipsychotics 3
- Assess timing of medication administration in relation to symptoms 2
Endocrine Causes
- Screen for adrenal insufficiency, especially if accompanied by hyponatremia and hyperkalemia 5
- Consider pheochromocytoma in patients with episodic symptoms 5
- Evaluate for diabetic autonomic neuropathy in patients with diabetes 5, 6
Cardiovascular Causes
- Consider echocardiography to assess cardiac function, especially in patients with history of heart disease 2
- Evaluate for heart failure, which may present with low blood pressure 2
Neurogenic Causes
- Assess for symptoms of autonomic dysfunction (e.g., bowel/bladder dysfunction, anhidrosis) 6
- Consider autonomic testing in patients with suspected neurogenic orthostatic hypotension 3
Special Considerations
Elderly Patients
- More cautious approach needed for patients ≥85 years or with moderate-to-severe frailty 2
- Consider starting with lower doses of medications if pharmacologic treatment is needed 2
- Assess for frailty and risk of falls 2
Trauma Patients
- In elderly trauma patients with hypotension, identify the cause of hypoperfusion before choosing vasopressors 2
- Monitor tissue perfusion by base excess level, arterial lactates, urine output, and neurologic assessment 2
Management Considerations
- For symptomatic orthostatic hypotension, consider nonpharmacologic measures first (increased salt and fluid intake, compression stockings, avoiding precipitating factors) 6
- For persistent symptomatic orthostatic hypotension, medications such as fludrocortisone or midodrine may be considered 7, 6
- Midodrine can increase standing systolic blood pressure by 15-30 mmHg at 1 hour after a 10 mg dose 7
- Treatment goals should focus on relieving symptoms and preventing falls rather than achieving specific BP targets 6