What Is It, Causes, Assessment Findings, Treatment, and More
Author: Ashley Mauldin, MSN, APRN, FNP-BC
Editors: Ahaana Singh, Ian Mannarino, MD, MBA
Illustrator: Aileen Lin
What is Cushing’s triad?
Cushing’s triad refers to a set of signs that are indicative of increased intracranial pressure (ICP), or increased pressure in the brain. Cushing’s triad consists of bradycardia (also known as a low heart rate), irregular respirations, and a widened pulse pressure. A widened pulse pressure occurs when there is a large difference between the systolic blood pressure (the blood pressure when the heart is contracting) and the diastolic blood pressure (the blood pressure when the heart is relaxing). Cushing’s triad is indicative of a medical emergency and medical attention is required.
What causes Cushing’s triad?
Increased ICP results in a lack of oxygen in brain tissue and a restriction of cerebral blood flow in the brain.
Increased ICP activates the Cushing reflex, a nervous system response resulting in Cushing’s triad.
As the ICP begins to increase, it eventually becomes greater than the mean arterial pressure, which typically must be greater than the ICP in order for the brain tissue to be adequately oxygenated.
The difference in pressure causes a decrease in the cerebral perfusion pressure (CPP), or the amount of blood and oxygen the brain is receiving, therefore leading to the brain not receiving enough oxygen (also known as a brain ischemia).
- As the pressure in the brain continues to rise, the brain stem may start to dysfunction, resulting in irregular respirations followed by periods where breathing ceases completely. This progression is indicative of a worsening prognosis.
What are the signs and symptoms of Cushing's triad?
Widened pulse pressure
Irregular respirations (also known as Cheyne–Stokes respirations)
Cheyne-Stokes respirations consist of periods of slow, deep breaths followed by periods of apnea, when breathing comes to a complete stop.
Changes in behavior or level of consciousness
What are the assessment findings of Cushing’s triad?
Procedural diagnosis is necessary to definitively diagnose Cushing’s triad by measuring ICP.
Clinical evaluation can be performed to help determine the underlying cause.
Medical history review
Imaging may be required to determine the underlying cause.
How do you treat Cushing’s triad?
Treatment is aimed at decreasing the ICP, as well as reversing the cause of the increased intracranial pressure. Prescribed treatment is often individualized and will depend on the severity of the symptoms.
Other medications often used in combination with mannitol:
Hyperventilation, or breathing very fast, is recommended to help lower ICP.
Drainage of the extra cerebrospinal fluid may be required to decrease the pressure.
Rarely, a craniotomy, or removal of a small portion of the skull, may be performed to alleviate the rising pressure.
If Cushing's triad is left untreated for too long,
- Infarction, or death of the brain tissue, can occur.
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Resources for research and reference
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Ciattei, J. (2018). ICP Monitoring: Direct: Department of Neurology and Neurosurgery. In Johns Hopkins Medicine. Retrieved October 3, 2020, from https://www.hopkinsmedicine.org/neurology_neurosurgery/centers_clinics/cerebral-fluid/procedures/icp-monitoring-direct.html
Del Maestro R. (2007). Harvey Cushing: A Life in Surgery. Canadian Journal of Surgery, 50(1): 70–71. Retrieved October 21, 2020 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2384244/
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Increased Intracranial Pressure (ICP) Headache. (n.d.). In Johns Hopkins Medicine. Retrieved September 28, 2020, from https://www.hopkinsmedicine.org/health/conditions-and-diseases/headache/increased-intracranial-pressure-icp-headache
Liferidge, A. (2020). UMEM Educational Pearls. In University of Maryland School of Medicine. Retrieved September 28, 2020, from https://umem.org/educational_pearls/133/