Neurogenic shock

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Neurogenic shock
Other names: Vasogenic shock[1]
Cervical Spine MRI (T2W).jpg
Cervical spine MRI showing a C4 fracture and dislocation resulting in spinal cord compression
SpecialtySpinal surgery
SymptomsLow blood pressure, low heart rate, warm skin, abnormal body temperature[1]
ComplicationsOrgan dysfunction[2]
Duration4 to 12 weeks[3]
CausesSpinal cord injury above T4, spinal anesthesia, Guillain-Barre syndrome, autonomic nervous system toxins, transverse myelitis, other neuropathies[2][1]
Diagnostic methodBased on symptoms and medical imaging after ruling out other possible cases[1]
Differential diagnosisSpinal shock, hypovolemic shock, other types of circulatory shock[1]
TreatmentIntravenous fluids, C-spine motion restriction, norepinephrine[1]
FrequencyRelatively uncommon[4]

Neurogenic shock is a type of shock due to spinal cord injury.[1] Symptoms may include low blood pressure, low heart rate, warm skin, and abnormal body temperature.[1] It starts at the time of injury and may last for 4 to 12 weeks.[3] Complications can include organ dysfunction.[2]

The cause is generally a spinal cord injury above the fourth thoracic vertebrae.[2] Other causes may include spinal anesthesia, Guillain-Barre syndrome, autonomic nervous system toxins, transverse myelitis, and other neuropathies.[1] The underlying mechanism involves loss of sympathetic tone.[1] It is a type of distributive shock.[2] Diagnosis is based on symptoms and medical imaging after ruling out other possible cases.[1] It differs from spinal shock, which refers to loss of sensation, reflexes, and motor function, though may be associated with neurogenic shock.[1]

The initial treatment is generally with intravenous fluids and C-spine motion restriction.[1] If this is not sufficient norepinephrine is often used to keep the mean arterial pressure greater than 90 mmHg.[1] The slow heart rate may be treated with atropine.[1] Surgery may be required to stabilize the spine.[1] Neurogenic shock is relatively uncommon.[4] It occurs in about 19% of cervical and 7% of thoracic spinal cord injuries.[1][3]

Signs and symptoms

Causes

Neurogenic shock can result from severe central nervous system damage (brain injury, cervical or high thoracic spinal cord).[5] In more simple terms: the trauma causes a sudden loss of background sympathetic stimulation to the blood vessels. This causes them to relax (vasodilation)[6] resulting in a sudden decrease in blood pressure (secondary to a decrease in peripheral vascular resistance).

Neurogenic shock results from damage to the spinal cord above the level of the 6th thoracic vertebra.[7] It is found in about half of people who suffer spinal cord injury within the first 24 hours, and usually doesn't go away for one to three weeks.[7]

Pathophysiology

Neurogenic shock is diagnosed based on a person's symptoms and blood pressure levels.

Neurogenic shock's presentation includes:[8][9]

- warm and pink skin

- labored breathing

- low blood pressure

- dizziness

- anxiety

- history of trauma to head or upper spine.

- if the injury is to the head or neck, hoarseness or difficulty swallowing may occur.

Symptoms of neurogenic shock are differentiated from other forms of shock, by the lack of signs of the compensatory mechanisms triggered by the sympathetic nervous system on other forms of shock via the release of epinephrine and norepinephrine. Signs caused by these neurotransmitters are typically lacking in where shock is of neurogenic origin include: increased heart rate, faster breathing, and sweating, and adaptive vasoconstriction, which serves in other forms of shock to shunt blood away from the extremities and to the vital organs.

In neurogenic shock, the body loses its ability to activate the sympathetic nervous system so that only parasympathetic tone remains. The resulting loss of sympathetic tone, which plays a major role in other forms of shock is responsible for the unique and atypical features mentioned above.[8]

Treatment

References

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 Dave, S; Cho, JJ (January 2020). "Neurogenic Shock". PMID 29083597. Cite journal requires |journal= (help)
  2. 2.0 2.1 2.2 2.3 2.4 "Shock - Critical Care Medicine". Merck Manuals Professional Edition. Retrieved 5 January 2021.
  3. 3.0 3.1 3.2 Chhabra, Harvinder Singh (2015). ISCoS Textbook on Comprehensive management of Spinal Cord Injuries. Wolters kluwer india Pvt Ltd. p. 784. ISBN 978-93-5129-440-5.
  4. 4.0 4.1 Standl, T; Annecke, T; Cascorbi, I; Heller, AR; Sabashnikov, A; Teske, W (9 November 2018). "The Nomenclature, Definition and Distinction of Types of Shock". Deutsches Arzteblatt international. 115 (45): 757–768. doi:10.3238/arztebl.2018.0757. PMID 30573009.
  5. 4. Guly HR, Bouamra O, Lecky FE. The incidence of neurogenic shock in patients with isolated spinal cord injury in the emergency department. Resuscitation (2008) 76, 57-62
  6. "Dorlands Medical Dictionary:neurogenic shock".
  7. 7.0 7.1 Newman, Mark F.; Fleisher, Lee A.; Fink, Mitchell P. (2008). Perioperative Medicine: Managing for Outcome. Elsevier Health Sciences. p. 348. ISBN 978-1-4160-2456-9.
  8. 8.0 8.1 Mallek JT; Inaba K; et al. (2012). "The Incidence of Neurogenic Shock after Spinal Cord Injury in Patients Admitted to a High-Volume Level I Trauma Center". The American Surgeon. 78 (5): 623–626.
  9. Axelrad A, Pandya P, et al. (2013). "The Significance of Neurogenic Shock and Acute Spinal Cord Injury (Poster Session)". Critical Care Medicine. The Society of Critical Care Medicine and Lippincott Williams & Wilkins. doi:10.1097/01.ccm.0000439365.59627.b5.
  10. "Hypotension & Shock Treatment | health.am".
  11. Holtz, Anders; Levi, Richard (6 July 2010). Spinal Cord Injury. Oxford University Press. p. 63–4. ISBN 978-0-19-970681-5.

External links

Classification