Cardiogenic Shock (see Cardiogenic Shock)

Arrhythmia/Conduction Disturbance

Cardiomyopathy (see Congestive Heart Failure)

Increased Afterload

Increased Intrathoracic Pressure (with Impaired Right-Sided Venous Return)

  • Herniation of Abdominal Viscera Into Thorax
  • Positive-Pressure Ventilation with High Airway Pressures (see Acute Respiratory Distress Syndrome, [[Acute Respiratory Distress Syndrome]])
  • Tension Pneumothorax (see Pneumothorax, [[Pneumothorax]])

Intracardiac Shunt (see Intracardiac and Extracardiac Shunt, [[Intracardiac and Extracardiac Shunt]])

Valvular Disease/Mechanical Disturbance

Distributive Shock (Vasodilatory Shock)

Anaphylaxis/Anaphylactic Shock

  • Anaphylaxis (see Anaphylaxis, [[Anaphylaxis]])
    • Physiology: peripheral vasodilation (due to histamine and other vasoactive substances)


  • Anaplasmosis Sepsis-Like or Toxic Shock-Like Syndrome (see Anaplasmosis, [[Anaplasmosis]])
  • Ehrlichiosis Sepsis-Like or Toxic Shock-Like Syndrome (see Ehrlichiosis, [[Ehrlichiosis]])
  • Sepsis/Septic Shock (see Sepsis, [[Sepsis]])
    • Epidemiology: sepsis is the most common type of distributive shock
    • Physiology: third-spacing of fluids (with decreased intravascular volume) and peripheral vasodilation
  • Toxic Shock Syndrome (TSS)

Systemic Inflammatory Response Syndrome (SIRS) (see Sepsis)

Endocrine/Metabolic/Nutritional Deficiency-Associated Hypotension

  • Acidemia
  • Adrenal Insufficiency (see Adrenal Insufficiency, [[Adrenal Insufficiency]])
    • Physiology: peripheral vasodilation
  • Hyperthyroidism (see Hyperthyroidism, [[Hyperthyroidism]])
    • Physiology:
  • Hypothyroidism/Myxedema (see Hypothyroidism, [[Hypothyroidism]])
    • Physiology: peripheral vasodilation
  • Pheochromocytoma (see Pheochromocytoma, [[Pheochromocytoma]])
    • Epidemiology: occurs in some cases
    • Clinical Patterns
      • Episodic Hypotension: in rare cases where the tumor secretes only epinephrine
      • Pattern of Rapid Cyclic Fluctuation Between Hypertension and Hypotension (Cycling Every 7-15 min): unclear mechanism
      • Orthostatic Hypotension: due predominantly to decreased plasma volume
  • Thiamine Deficiency (Beriberi) (see Thiamine, [[Thiamine]])
    • Physiology: peripheral vasodilation

Hematologic Disease-Associated Hypotension

Neurogenic Shock (see Neurogenic Shock)

  • Acute Spinal Cord Injury (SCI) (see Acute Spinal Cord Injury)
    • Physiology
      • Interruption of Autonomic Pathways, Resulting in Decreased Systemic Vascular Resistance and Altered Vagal Tone: probably the predominant mechanism
      • Myocardial Depression: may also play a role
      • Acute Blood Loss: may also play a role in some cases
  • Brain Herniation (Due to Foramen Magnum Herniation) (see Increased Intracranial Pressure)
    • Physiology: compression of brainstem and/or upper cervical spinal cord
  • Chronic Spinal Cord Injury (SCI) (see Acute Spinal Cord Injury)
  • Guillain-Barre Syndrome (GBS) (see Guillain-Barre Syndrome)
    • Epidemiology
      • Autonomic Dysfunction is Common in GBS (Occurs in Approximately 66% of Cases)
    • Clinical
      • Arrhythmias
      • Blood Pressure Fluctuations
      • Bradycardia/Tachycardia
      • Gastrointestinal Dysfunction
  • Multiple Sclerosis (see Multiple Sclerosis)
    • Epidemiology
      • Autonomic Dysfunction Can Occur
    • Clinical
  • Neuraxial (Spinal) Anesthesia (see Spinal Anesthesia)
    • Physiology
      • XXXX
  • Transverse Myelitis (see Transverse Myelitis)
    • Physiology
      • XXXX
  • Traumatic Brain Injury (TBI) (see Traumatic Brain Injury)
    • Physiology
      • XXXX

Drug/Toxin-Associated Hypotension

  • Abacavir-Hypersensitivity Reaction (see Abacavir)
    • Pharmacology: peripheral vasodilation
  • Alcohol Intoxications
    • Ethanol (see Ethanol)
      • Pharmacology: peripheral vasodilation
    • Ethylene Glycol Intoxication (see Ethylene Glycol)
      • Pharmacology: peripheral vasodilation
    • Isopropanol Intoxication (see Isopropanol)
      • Pharmacology: peripheral vasodilation
    • Methanol Intoxication (see Methanol, [[Methanol]])
      • Pharmacology: peripheral vasodilation
  • All-Trans Retinoic Acid (ATRA)/Retinoic Acid Syndrome (see All-Trans Retinoic Acid, [[All-Trans Retinoic Acid]])
    • Pharmacology: peripheral vasodilation
  • Amiodarone (see Amiodarone, [[Amiodarone]])
    • Pharmacology: peripheral vasodilation (note: negative inotropy can also occur in patients with preexisting left ventricular dysfunction with EF <35%)
  • Benzodiazepines (see Benzodiazepines, [[Benzodiazepines]])
    • Pharmacology: peripheral vasodilation
  • Capsaicin (see Capsaicin, [[Capsaicin]])
    • Pharmacology: peripheral vasodilation
  • Cholinergic Intoxication (see Cholinergic Intoxication, [[Cholinergic Intoxication]])
  • Cigua Toxin Poisoning (see Cigua Toxin Poisoning, [[Cigua Toxin Poisoning]])
    • Physiology: dysfunction of calcium and sodium channels, resulting in peripheral vasodilation
  • Cyanide Intoxication (see Cyanide, [[Cyanide]])
    • Pharmacology: mitochondrial dysfunction
    • Clinical: hypotension occurs late in the course
  • Cytokine Release Syndrome (see Cytokine Release Syndrome, [[Cytokine Release Syndrome]])
    • Pharmacology: peripheral vasodilation
  • Dexmedetomidine (Precedex) (see Dexmedetomidine, [[Dexmedetomidine]])
    • Pharmacology: peripheral vasodilation
  • Dobutamine (Dobutrex) (see Dobutamine, [[Dobutamine]])
    • Pharmacology: myocardial β1-adrenergic receptor agonist (chronotropic/inotropic effects) and vascular β2-adrenergic/α1-adrenergic receptor agonist (if vascular β2-adrenergic effects exceed α1-adrenergic receptor agonist effects, some peripheral vasodilation may occur)
  • Endothelin Receptor Antagonists (ERA’s) (see Endothelin Receptor Antagonists, [[Endothelin Receptor Antagonists]])
    • Pharmacology: peripheral vasodilation
  • Envenomations
    • Types
      • Scorpion Sting (see Scorpion Sting, [[Scorpion Sting]])
      • Rattlesnake Bit (see Rattlesnake Bite, [[Rattlesnake Bite]])
      • Widow Spider Bite (see Widow Spider Bite, [[Widow Spider Bite]])
        • Epidemiology: hypertension is more characteristically seen in widow spider bites, hypotension occurs rarely
  • Estrogen (see Estrogen, [[Estrogen]])
    • Pharmacology: peripheral vasodilation
  • Glyphosate Ingestion (see Glyphosate, [[Glyphosate]])
    • Pharmacology: peripheral vasodilation
  • Hemoglobinopathies
    • Carboxyhemoglobinemia (see Carboxyhemoglobinemia, [[Carboxyhemoglobinemia]])
      • Pharmacology: mitochondrial dysfunction
    • Methemoglobinemia (see Methemoglobinemia, [[Methemoglobinemia]])
      • Physiology: peripheral vasodilation
  • Hexoprenaline (Gynipral) (see Hexoprenaline, [[Hexoprenaline]])
    • Pharmacology: β2-adrenergic receptor agonist
  • Hydrogen Sulfide Gas Inhalation (see Hydrogen Sulfide Gas, [[Hydrogen Sulfide Gas]])
  • Intravenous Immunoglobulin (IVIG) (see Intravenous Immunoglobulin, [[Intravenous Immunoglobulin]])
  • L-Arginine (see L-Arginine, [[L-Arginine]])
    • Pharmacology: nitric oxide induction, resulting in peripheral vasodilation
  • Magnesium Sulfate (see Magnesium Sulfate, [[Magnesium Sulfate]])
    • Epidemiology: with rapid infusion
  • Metal Intoxications
    • Agents
      • Arsenic Intoxication (see Arsenic, [[Arsenic]])
      • Iron Intoxication (see Iron, [[Iron]])
      • Manganese Intoxication (see Manganese, [[Manganese]])
      • Selenium Intoxication (see Selenium, [[Selenium]])
      • Thallium Intoxication (see Thallium, [[Thallium]])
    • Pharmacology: peripheral vasodilation
  • N-Acetylcysteine (Mucomyst, Acetadote, Fluimucil, Parvolex) (see N-Acetylcysteine, [[N-Acetylcysteine]])
    • Epidemiology: associated with oral administration
    • Pharmacology: peripheral vasodilation
  • Nerium Oleander Intoxication (see Nerium Oleander, [[Nerium Oleander]])
  • Neuroleptic Malignant Syndrome (NMS) (see Neuroleptic Malignant Syndrome, [[Neuroleptic Malignant Syndrome]])
    • Physiology: autonomic instability
  • Nitrites and Nitrates (see Nitrites and Nitrates, [[Nitrites and Nitrates]])
    • Pharmacology: nitric oxide induction, resulting in peripheral vasodilation
  • Ocrelizumab (Ocrevus) (see Ocrelizumab, [[Ocrelizumab]])
    • Epidemiology: may occur as a component of infusion reaction
  • Opiates (see Opiates, [[Opiates]])
    • Pharmacology: peripheral vasodilation
  • Papaverine (see Papaverine, [[Papaverine]])
    • Pharmacology: peripheral vasodilation
  • Phenytoin (Dilantin/)Fosphenytoin (Cerebyx) (see Fosphenytoin, [[Fosphenytoin]] and (see Phenytoin, [[Phenytoin]])
    • Pharmacology: peripheral vasodilation
  • Phosphodiesterase Type 5 (PDE5) Inhibitors (see Phosphodiesterase Type 5 Inhibitors, [[Phosphodiesterase Type 5 Inhibitors]])
    • Pharmacology: inhibits phosphodiesterase 5/PDE5 (the enzyme which degrades cGMP), resulting in enhanced NO-mediated smooth muscle relaxation and therefore, peripheral vasodilation
  • Propofol (Diprivan) (see Propofol, [[Propofol]])
    • Pharmacology: peripheral vasodilation
  • Prostaglandins with Vasodilatory Properties
    • Agents
      • Epoprostenol (PGI2, Prostacyclin, Flolan, Veletri) (see Epoprostenol, [[Epoprostenol]])
      • Iloprost (Ilomedin, Ventavis) (see Iloprost, [[Iloprost]])
      • Prostaglandin E1 (Alprostadil) (see Prostaglandin E1, [[Prostaglandin E1]])
    • Pharmacology: peripheral vasodilation
  • Protamine (see Protamine, [[Protamine]])
    • Pharmacology: peripheral vasodilation
  • Rasburicase (Elitek) (see Rasburicase, [[Rasburicase]])
    • Pharmacology: peripheral vasodilation
  • Ruxolitinib (Jakafi) Withdrawal Syndrome (see Ruxolitinib, [[Ruxolitinib]])
    • Epidemiology: occurs 1 day-3 wks after drug withdrawal
  • Salicylate Intoxication (see Acetylsalicylic Acid, [[Acetylsalicylic Acid]])
    • Pharmacology: peripheral vasodilation
    • Clinical : pseudosepsis with fever, tachypnea, metabolic acidosis, and hypotension
  • Scombroid (see Scombroid, [[Scombroid]])
    • Pharmacology: peripheral vasodilation
  • Serotonin Syndrome (see Serotonin Syndrome, [[Serotonin Syndrome]])
    • Pharmacology: peripheral vasodilation
  • Sevelamer (Renagel, Renvela) (see Sevelamer, [[Sevelamer]])
  • Tetrahydrocannabinol (THC) (see Tetrahydrocannabinol, [[Tetrahydrocannabinol]])
    • Pharmacology: peripheral vasodilation
  • Tetrodotoxin
    • Epidemiology: associated with ingestion of tetrodotoxin-contaminated pufferfish
    • Physiology: tetrodotoxin inhibits sodium channels on vascular smooth muscle
  • Theobromine (see Theobromine, [[Theobromine]])
    • Pharmacology: peripheral vasodilation
  • Thrombolytics (see Thrombolytics, [[Thrombolytics]])
  • Transfusion-Associated Acute Lung Injury (TRALI) (see Transfusion-Associated Acute Lung Injury, [[Transfusion-Associated Acute Lung Injury]])
  • Tricyclic Antidepressant Intoxication (see Tricyclic Antidepressants, [[Tricyclic Antidepressants]])
    • Pharmacology: peripheral vasodilation
  • Vancomycin-Associated Red Man Syndrome (see Vancomycin, [[Vancomycin]])
    • Pharmacology: peripheral vasodilation
  • Vasodilator Antihypertensives
    • Agents
      • α-Adrenergic Receptor Antagonists (see α-Adrenergic Receptor Antagonists, [[α-Adrenergic Receptor Antagonists]])
        • Pharmacology: α2-adrenergic receptor antagonism, resulting peripheral vasodilation
      • α-Methyldopa (Aldomet, Aldoril, Dopamet, Dopegyt) (see α-Methyldopa, [[α-Methyldopa]])
        • Pharmacology: α2-adrenergic receptor agonist, resulting in peripheral vasodilation
      • Angiotensin Converting Enzyme (ACE) Inhibitors (see Angiotensin Converting Enzyme (ACE) Inhibitors, [[Angiotensin Converting Enzyme Inhibitors]])
        • Pharmacology: angiotensin converting enzyme inhibition, resulting in peripheral vasodilation
      • Angiotensin II Receptor Blockers (ARB) (see Angiotensin II Receptor Blockers, [[Angiotensin II Receptor Blockers]])
        • Pharmacology: angiotensin II receptor inhibition, resulting in peripheral vasodilation
      • β-Adrenergic Receptor Antagonists (β-Blockers) (see β-Adrenergic Receptor Antagonists, [[β-Adrenergic Receptor Antagonists]])
        • Pharmacology: β-adrenergic receptor antagonism, resulting in decreased cardiac output and peripheral vasodilation
      • Calcium Channel Blockers (see Calcium Channel Blockers, [[Calcium Channel Blockers]])
        • Pharmacology: calcium channel antagonism, resulting in peripheral vasodilation (and additionally decreased cardiac output with some of the agents)
      • Clonidine (Catapres, Kapvay, Nexiclon) (see Clonidine, [[Clonidine]])
        • Pharmacology: α2-adrenergic receptor agonism, resulting in peripheral vasodilation
      • Hydralazine (see Hydralazine, [[Hydralazine]])
        • Pharmacology: peripheral vasodilation
      • Minoxidil (see Minoxidil, [[Minoxidil]])
        • Pharmacology: direct relaxation of arteriolar smooth muscle (possibly mediated by cAMP), resulting in peripheral vasodilation


  • Cirrhosis/End-Stage Liver Disease (see Cirrhosis, [[Cirrhosis]])
    • Physiology: characteristically produces a high cardiac output (CO)/low systemic vascular resistance (SVR) state
  • Hepatic Veno-Occlusive Disease (see Hepatic Veno-Occlusive Disease, [[Hepatic Veno-Occlusive Disease]])
  • Pregnancy (see Pregnancy, [[Pregnancy]])
    • Physiology: pregnancy increases plasma volume, increases cardiac output, increases stroke volume, increases heart rate, decreases blood pressure, and decreases SVR
  • Purpura Fulminans (see Purpura Fulminans, [[Purpura Fulminans]])
  • Systemic Arteriovenous Fistula (see Systemic Arteriovenous Fistula, [[Systemic Arteriovenous Fistula]])
    • Types
      • Femoral Arteriovenous Fistula: most common type of acquired arteriovenous fistula (due to the frequency of using the femoral site for percutaneous arterial or venous access)
      • Hemodialysis Arteriovenous Fistula (see Hemodialysis Arteriovenous Fistula, [[Hemodialysis Arteriovenous Fistula]])
    • Clinical: high output heart failure may occur
  • Systemic Mastocytosis (see Systemic Mastocytosis)
    • Physiology: peripheral vasodilation
  • Vasoplegic Syndrome (Post-Cardiac Surgery Vasodilation) (see Vasoplegic Syndrome)
    • Physiology: peripheral vasodilation following cardiac surgery
  • Vasovagal Syncope (see Vasovagal Syncope)
    • Physiology: peripheral vasodilation

Hemorrhagic Shock (see Hemorrhagic Shock)

Gastrointestinal Hemorrhage (see Gastrointestinal Hemorrhage, [[Gastrointestinal Hemorrhage]])

Hemoperitoneum (see Hemoperitoneum)

  • Various Etiologies

Intramuscular Hemorrhage (Into Thigh)

  • Various Etiologies

Intraoperative/Postoperative Hemorrhage

  • Various Etiologies

Retroperitoneal Hemorrhage (see Retroperitoneal Hemorrhage)

Severe Hemolysis (see Hemolytic Anemia)

Trauma with External Hemorrhage

  • Motor Vehicle Accident (MVA)
  • Traumatic Fall/Assault

Uterine/Vaginal Hemorrhage

  • Post-Partum Hemorrhage
  • Uterine Tumor
  • Vaginal Laceration


Hypovolemic Shock (see Hypovolemic Shock)

Dermal Fluid Loss

  • Altered Mental Status with Inadequate Fluid Intake
    • Intoxication
  • Burns (see Burns)
  • Diaphoresis (see Diaphoresis)
  • Heat Stroke/Environmental Exposure (see Heat Stroke)

Gastrointestinal Fluid Loss

Renal Fluid Loss

  • Excessive Diuresis
  • Hypoaldosteronism (see Hypoaldosteronism)
    • Epidemiology: although aldosterone normally acts to increase sodium retention, hypoaldosteronism is not usually associated with significant sodium wasting (except in young children)
      • This is due to the compensatory action of other sodium-retaining stimuli (such as angiotensin II and norepinephrine)
  • Pheochromocytoma (see Pheochromocytoma)
    • Epidemiology: occurs in some cases
    • Clinical Patterns
      • Episodic Hypotension: in rare cases where the tumor secretes only epinephrine
      • Pattern of Rapid Cyclic Fluctuation Between Hypertension and Hypotension (Cycling Every 7-15 min): unclear mechanism
      • Orthostatic Hypotension: due predominantly to decreased plasma volume
  • Salt-Wasting Nephropathy

Third-Space Fluid Loss

Obstructive Shock


Pulmonary Vascular


Arterial Line (see Arterial Line, [[Arterial Line]])

Bedside Ultrasound

Clinical Efficacy

Echocardiogram (see Echocardiogram)

Clinical Manifestations

Cardiovascular Manifestations

Neurologic Manifestations

Renal Manifestations