Hypotension Flashcards
What does hypotension typically refer to?
BP <90/60
When is hypotension considered pathologic?
If symptomatic (may be physiologic ie athletes)
What is the pathophysiology of hypotension?
- Reduced blood flow
- Decreased oxygen delivery to organs and tissues
- cellular damage and dysfunction
When oxygen delivery is insufficient to support metabolic requirements, a patient is said to be in what?
circulatory shock
What is arterial pressure determined by?
- Cardiac output
- Venous pressure
- Systemic vascular resistance
A decrease in any of these can lead to hypotension
What are hypovolemia causes of hypotension?
- hemorrhage
- dehydration
- dialysis
what are endocrine causes of hypotension?
- adrenal insufficiency
- diabetes (orthostatic mainly due to ANS dysfunction)
- hypothyroidism
What are vascular causes of hypotension?
- Aortic dissection or rupture
- peripheral vascular disease
- pulmonary embolism
what are drug-induced causes of hypotension?
- alcohol
- antidepressants
- antihypertensives
- antipsychotics
- anxiolytics
- general anesthesia
- narcotics
what are neurogenic causes of hypotension?
- age-related
- medullary stroke
- parkinsonism
- postprandial
- peripheral neuropathy
- syphilis
- vasomotor: emotional or micturition
What is important historical information to gather about hypotension?
- Acute change in BP?
- Precipitating events/symptoms?
- Medications, including any recent changes?
- Pre-existing medical conditions?
- Are they symptomatic?
what are symptoms of hypotension?
- lightheadedness, dizziness
- syncope
- nausea
- confusion
- fatigue
what are signs of hypotension?
- bradycardia or tachycardia
- skin: pallor, diaphoresis, cool, clammy, prolonged capillary refill
- altered LOC
what clinical presentation can be present in both hypertension or hypotension?
- dizziness
- blurred vision
- nausea
What diagnostic testing can be helpful for hypotension?
- EKG
- CBC, CMP, UA
- Echocardiogram
- Urine drug screen
- CT head
The majority of patients with hypotension can be resuscitated with what?
IV bolus of normal saline
If a patient is hypovolemic, what is the treatment?
Fluid resuscitation
Who do we need to avoid giving fluids to?
heart failure
drop in blood pressure upon standing, leading to symptoms of hypotension
orthostatic hypotension
what can cause orthostatic hypotension?
- impairment of autonomic reflexes
- volume depletion
who is more commonly impacted by orthostatic hypotension?
- elderly
what is classified as orthostatic hypotension?
- drop of either 20 mmHg in SBP
- or 10 mmHg in DBP
usually within 2-5 minutes
what is normal response to standing?
- rapid decrease in venous return and CO
- detected by baroreceptors in carotid
- SNS increases HR and peripheral vascular resistance –> increased CO and limited drop in SBP
what are causes of orthostatic hypotension?
- prolonged lying or sitting
- volume depletion
- autonomic failure
- neurodegenerative disease, such as Parkinson’s
- Neuropathies, as a result of DM, B12 deficiency, amyloidosis, sarcoidosis, lyme disease
- SE of medications of peripheral vasodilation, autonomic dysfunction, and volume depletion
what are medications that cause orthostatic hypotension?
- alpha-1 antagonists (terazosin, prazosin, doxazosin)
- ACEI, BB, clonidine
- diuretics (HCTZ, loops)
- PDE-5 (sildenafil, vardenafil)
- Antidepressants (TCAs, trazodone, MAOIs)
- Opioids (morphine, oxycodone, tramadol)
What are additional causes of orthostatic hypotension?
- aging
- adrenal insufficiency
- cardiogenic: CHF, AS, arrhythmias
why can aging cause orthostatic hypotension?
- decrease in baroreceptor sensitivity
what are symptoms of orthostatic hypotension?
- generalized weakness
- dizziness or lightheadedness
- blurry vision or darkening of visual fields
- syncope
what are atypical presentations of orthostatic hypotension?
- fatigue
- cognitive slowing
- nausea
how can orthostatic hypotension be evaluated?
- bedside tilt test/orthostatic BP measurement (take BP on standing, at 2 mins, at 5 mins)
- Formal tilt table test
What happens during a tilt table test?
- Patient lies down on table
- IV
- ECG, BP cuff, and straps on chest/legs
- Pt lies flat then is raised to almost standing angle
- Stays upright for 45 mins to determine symptoms
- If no reaction, medication (NTG) is given to increase HR while flat
- Pt tilted upright and symptoms measured
- Pt lowered to flat and allowed to rest. HR/BP measured
How is orthostatic hypotension worked up in addition to tilt table testing and orthostatic hypotension measurement?
- CBC, BMP
- EKG
- EMG
Over 1/3 of patients will have no identifiable cause discovered, even after extensive work-up :(
How is orthostatic hypotension treated?
- Acute orthostasis due to volume depletion- IV fluids
- Chronic- initially nonpharm, pharm added with severe symptoms or refractory
what is nonpharm management of orthostatic hypotension?
- Removal of causative medication
- Get up slowly
- Straining, coughing, and exertion in hot weather can exacerbate
- Maintain hydration
- Elastic compression stockings
- Increase salt and water intake
- physical maneuvers
how much salt and water should a patient with orthostatic hypotension consume per day?
6-10 g of sodium per day
at least 3 liters of water a day
What are physical maneuvers for orthostatic hypotension?
- tensing leg muscles while standing; crossing legs tightly while standing
- isometric handgrip when standing
what is pharmacological management of orthostatic hypotension?
- fludrocortisone
- midodrine
what should be kept in mind when giving pharmacoligic treatment for orthostatic hypotension?
- close patient monitoring
- should monitor BP at home several times a day
- supine hypertension can occur
- elevate head of bed 10-20 degrees to protect brain while sleeping
what is the drug class of fludrocortisone?
- potent mineralcorticoid with high glucocorticoid activity
what is the mechanism of action of fludrocortisone?
- promotes increased sodium reabsorption and potassium excretion from renal distal tubules
What are considerations when using fludrocortisone for orthostatic hypotension?
- patients must be monitored for edema, sitting/supine hypertension
- BMP in a week to monitor for hypokalemia
- Discontinuation is common due to side effects, predominantly HTN and edema
what is the drug class of midodrine?
- alpha-1 selective adrenergic agonist
what is the moa of midodrine?
- increased peripheral vascular resistance, which increases arteriolar and venous tone, resulting in increased SBP and DBP
- does not cross BBB
what are considerations when using midodrine?
- supine hypertension is most common cause of discontinuation
what are side effects of midodrine?
- paresthesias
- piloerection
- pruritis
- GI upset
- urinary retention or urgency
what is the hallmark response to standing with POTS?
exaggerated increase in HR
What are cardiogenic causes of hypotension?
- Acute coronary syndrome
- Arrhythmias
- Cardiomyopathy
- Congestive heart failure
- Valvulopathy
- Pulmonary embolism
- Pulmonary hypertension
- Cardiac tamponade
- Tension pneumothorax
What are general causes of hypotension?
- Cardiogenic
- Hypovolemia
- Orthostatic
- Sepsis
- Endocrinologic
- Vascular
- Drug-induced
- Neurogenic
Who most commonly gets POTS?
- young patients (14-45)
- more common in females than males
What are possible causes of POTS?
- Distal denervation
- Hypovolemia
- Venous dysfunction
- Cardiovascular deconditioning
- Baroreflex abnormalities
- Increased sympathetic activity
- Genetic abnormalities
- Can be triggered by infectious illness or post-surgical
What are the most common symptoms of POTS?
- Dizziness/lightheadedness
- Syncope
- Weakness and fatigue
- Blurry vision
What are possible symptoms of POTS?
- Nausea
- Abdominal cramping
- Diarrhea or constipation
What can worsen symptoms of POTS?
- Dehydration
- Menstruation
- Prolonged standing
What is the diagnostic criteria for POTS?
- History of symptoms of orthostatic intolerance with or without systemic symptoms
- Correlation of symptoms with increase in upright heart rate by at least 30 bpm (40 under 20 yo) within 10 minutes of standing, or head-up tilt, without orthostatic hypotension
- Autonomic testing to correlate symptoms with hr changes, confirm the diagnosis, and assess degree of objective signs of orthostatic intolerance
- Exclusion of alternative diagnoses or confounding concomitant conditions
What is the gold standard diagnostic evaluation of POTS?
- Formal tilt table test
- Increase in HR of greater than 30 bpm or increase to 120 bpm or higher in first 10 mins of test
- No drop in BP
How would you initially evaluate a patient with POTS?
- CBC
- CMP
- EKG
- Thyroid function tests
How is POTS treated?
Nonpharmacologic treatment and pharmacologic treatment
What is nonpharmacological treatment for POTS?
- Avoid any exacerbating factors
- Increase water intake (2 L per day)
- Increase salt intake (3 to 5 g per day)
- Aerobic exercise of the lower extremities/compression stockings
What is pharmacological treatment for POTS?
- Fludricortisone
- Midodrine
- Beta blockers, such as propranolol (not well tolerated but blunts response)
- SSRI/SNRI- rarely used but have been shown to be beneficial in some
What is the prognosis of POTS?
Most patients have improved symptoms after 1-2 years
What is the underlying cause of cardiogenic shock?
- Failure of the heart in its function as a pump, resulting in inadequate cardiac output
What is the prognosis of cardiogenic shock?
50% do not survive, extremely morbid
What is the MC cause of cardiogenic shock?
- Extensive myocardial damage from an acute MI
- Mechanical complications of an acute MI: valve lesions, arrhythmias, and cardiomyopathies
What are possible causes of cardiogenic shock?
- Acute MI complications
- End-stage, severe cardiomyopathies (secondary to valvular disease, chronic ischemic disease, restrictive/infiltrative, idiopathic)
- Acute myocarditis
- Stress cardiomyopathy
- Endocrine disease (hypothyroidism, pheochromocytoma)
- Medications
- Posttraumatic
What is the principle feature of shock?
Hypotension with end-organ hypoperfusion
What is the presentation of the classic patient with cardiogenic shock?
Evidence of peripheral vasoconstriction (cool, moist skin) and tachycardia
What is the vicious cycle of cardiac injury?
Myocardial cell death –> decreased cardiac output –> hypotension –> decreased coronary perfusion –> ischemia and/or occlusion of coronary artery –> myocardial cell death
What are lab findings of cardiogenic shock?
- Recent MIs: Elevations in cardiac-specific enzymes (CK-MB, troponin)
- Renal and hepatic hypoperfusion: elevations in serum creatinine and in AST, ALT
- Hepatic congestion or hepatic hypoperfusion: coagulation abnormalities, anion gap acidosis may be present, serum lactate level may be elevated
What are diagnostic studies for cardiogenic shock?
- Electrocardiogram
- Chest radiography
- Laboratory tests
- Echocardiography
- Pulmonary artery catheterization
- Cardiac catheterization
What is treatment for cardiogenic shock?
- Oxygen supplementation; intubation; ventilation
- Vasopressors/inotropes; consider careful IV fluids, arterial line and pulmonary artery catheter insertion; correct underlying causes of acidemia
- Intra-aortic balloon pump, if needed
- For suspected acute MI: aspirin, heparin, urgent cardiac catheterization, revascularization; fibrinolysis?
