What is the initial workup for an adult patient with no significant past medical history presenting with hypotension in primary care?

Hypotension Workup in Primary Care

For an adult with no significant past medical history presenting with hypotension in primary care, immediately assess volume status and orthostatic vital signs, obtain basic laboratory tests (CBC, electrolytes, renal function, glucose), perform an ECG, and identify reversible causes (medications, dehydration, bleeding) before considering referral for advanced evaluation.

Initial Clinical Assessment

Vital Signs and Physical Examination

• Measure orthostatic blood pressure changes by obtaining blood pressure and heart rate after 5 minutes supine, then at 1 and 3 minutes after standing 1, 2
• Orthostatic hypotension is defined as a decrease of ≥20 mmHg systolic or ≥10 mmHg diastolic within 3 minutes of standing 2
• Assess volume status including skin turgor, mucous membranes, jugular venous pressure, and presence of peripheral edema 1
• Measure weight and height and calculate body mass index 1
• Document heart rate and rhythm, as irregular pulse requires manual blood pressure measurement rather than automated devices 1

Critical Historical Elements

• Medication review: Focus on antihypertensives, diuretics, tricyclic antidepressants, MAO inhibitors, and any recently started or adjusted medications 1, 3, 4
• Timing and triggers: Determine if hypotension occurs after meals (postprandial), upon standing (orthostatic), or is persistent 4, 2
• Associated symptoms: Assess for chest pain, dyspnea, lightheadedness, visual disturbances, shoulder/neck pain (coat hanger syndrome), or syncope 2
• Fluid losses: Inquire about vomiting, diarrhea, decreased oral intake, or bleeding 5
• Substance use: Document alcohol, illicit drugs, and alternative therapies 1

Initial Laboratory Evaluation

Obtain the following tests immediately 1:

• Complete blood count (to assess for anemia or infection)
• Serum electrolytes including calcium and magnesium
• Blood urea nitrogen and serum creatinine (to evaluate renal function and volume status)
• Fasting blood glucose or glycohemoglobin
• Urinalysis
• Liver function tests
• Thyroid-stimulating hormone

Diagnostic Testing

• Perform a 12-lead electrocardiogram to identify arrhythmias, ischemia, or conduction abnormalities 1
• Obtain chest radiograph (PA and lateral) if cardiac or pulmonary pathology is suspected 1

Classification and Etiology Determination

Neurogenic vs. Nonneurogenic

• Neurogenic orthostatic hypotension shows minimal heart rate increase (<15 bpm) with standing, suggesting autonomic dysfunction 4, 2
• Nonneurogenic causes typically show appropriate compensatory tachycardia (>15 bpm increase) and include volume depletion, medications, or cardiac dysfunction 4, 2

Common Reversible Causes in Primary Care

• Medication-induced: Antihypertensives, diuretics, vasodilators, alpha-blockers, tricyclic antidepressants 3, 4
• Volume depletion: Dehydration, bleeding, inadequate oral intake 5
• Endocrine disorders: Hypothyroidism, adrenal insufficiency (identified through TSH and electrolyte abnormalities) 1
• Cardiac causes: Arrhythmias, heart failure, valvular disease 1

When to Refer or Escalate Care

Immediate referral to emergency department if 5:

• Persistent hypotension despite initial interventions
• Evidence of end-organ hypoperfusion (altered mental status, oliguria, chest pain)
• Suspected acute bleeding, myocardial infarction, or pulmonary embolism
• Severe symptomatic hypotension with syncope

Cardiology referral if 1:

• Suspected structural heart disease or heart failure
• Need for echocardiography to assess left ventricular function, wall thickness, and valve function
• Angina or evidence of myocardial ischemia on ECG

Neurology or autonomic specialist referral if 4, 2:

• Neurogenic orthostatic hypotension confirmed
• Symptoms of autonomic dysfunction (bladder/bowel dysfunction, anhidrosis)
• Refractory symptoms despite initial management

Initial Management Approach

Non-Pharmacologic Interventions

• Review and discontinue or adjust causative medications when possible 4, 2
• Increase fluid intake to 2-3 liters daily and sodium intake to 6-10 grams daily (if no contraindications) 2
• Recommend compression garments (waist-high stockings with 30-40 mmHg pressure) 2
• Teach physical countermaneuvers: leg crossing, squatting, or muscle tensing before standing 2
• Advise slow positional changes and avoiding prolonged standing 2

When Pharmacologic Treatment is Needed

• First-line agents: Midodrine or droxidopa for persistent symptomatic orthostatic hypotension after non-pharmacologic measures fail 2
• Caution with fludrocortisone: While it improves symptoms, it has concerning long-term effects including supine hypertension 2

Critical Pitfalls to Avoid

• Do not assume white coat effect: A single elevated reading in primary care warrants repeat measurements, but persistent hypotension requires investigation 1
• Do not overlook medication interactions: MAO inhibitors require dopamine doses reduced to 1/10 of usual if vasopressor support becomes necessary 3
• Do not miss postprandial hypotension: This occurs 30-120 minutes after meals and requires specific evaluation 4
• Do not ignore supine hypertension: Up to 50% of patients with neurogenic orthostatic hypotension have supine hypertension, complicating management 4, 6
• Recognize that intensive blood pressure treatment does not cause orthostatic hypotension in most patients with essential hypertension, but certain antihypertensive classes may unmask underlying autonomic impairment 6