Hypotension

Orthostatic hypotension

PATHO

  • Symptomatic falls in blood pressure after standing or eating

  • Impaired autonomic reflexes, older age, depleted volume, medications ➔ ↓ BP upon standing

    • Normally, standing ➔ ~ 1L of blood pooling in lower extremities and splanchnic circulation causes ↓ venous return ➔ ventricular filling ➔ ↓ CO and BP

      • Compensatory reflex ➔ ↑ sympathetic and ↓ parasympathetic stimulation

        • Sympathetic stimulation ➔ ↑ peripheral vascular resistance ↑ venous return ↑ cardiac output

          • Limits fall in systolic BP to 5-10 mmHg, ↑ diastolic BP 5-10mmHg, ↑ HR 10-25 bpm

    • If HR ↑ by 30 bpm ➔ Postural Orthostatic Tachy Syndrome (POTS)

SSX

  • Sx after standing, meals, exertion, prolonged standing

  • ↓ cerebral perfusion ➔ weakness/dizziness, blurred/darkening vision, syncope

  • Pt may report neck pain with headache (suboccipital, posterior cervical, shoulder region ➔ coat hanger headache)

DX

  • 5 minutes of supine rest, then stand

    • Either > 20mmHg ↓ (systolic) or > 10mmHg ↓ (diastolic) within 2-5 mins

  • R/o everything else with EKG, BG, CBC, CMP, BNP

  • Tilt table if pt can't stand for BP measurement or to monitor tx

TX

  • Tx volume depletion, remove offending meds, educate to stand up slowly and tighten legs while standing,

  • ↑ salt & H2O intake

  • Refractory ➔ fludrocortisone (↑s volume)

    • Second line - sympathomimetic agonists

      • Midodrine ⍺1 agonist (selective for periphery)

      • Droxidopa (NE precursor)

Vasovagal hypotension ➔ reflex syncope

PATHO

  • Baroreceptors atria, great veins, LV sense ↑ pressure or volume change ➔ brady & vasodilation

  • Carotid sinus baroreceptors ➔ ↑ vagal activation when mechanical pressure applied

  • Vasovagal syncope "fainting" - MCC of syncope

    • Exposure to stressor/pain ➔ neural reflex ➔ brady & vasodilation

SSX

  • Light headedness, warm/cold feeling, sweating, blurred vision/ ↓ hearing, pallor

DX

  • Nausea, pallor, diaphoresis hints at ↑ vagal tone being the cause of syncope...

    • But r/o other causes using clinical judgement and CYA