Autonomic Dysreflexia

Excerpt

Autonomic dysreflexia is a condition that emerges soon after a spinal cord injury at or above the T6 level. This condition is generally defined as a syndrome in susceptible individuals with spinal cord injury, characterized by a sudden, exaggerated, inappropriate reflexive increase in blood pressure in response to a stimulus—typically bladder or bowel distension—originating below the level of the neurological injury. Clinical manifestations often include a severe headache, bradycardia, facial flushing, pallor, cold skin, and sweating in the lower part of the body. Autonomic dysreflexia is significant because it is a potentially lethal disorder that occurs in about half or more of the potentially susceptible individuals. However, it can typically be alleviated by prompt recognition and relatively simple corrective procedures by caregivers.

Autonomic dysreflexia is also referred to as autonomic hyperreflexia, hypertensive autonomic crisis, sympathetic hyperreflexia, autonomic spasticity, paroxysmal hypertension, mass reflex, and viscero-autonomic stress syndrome. In contrast, terms such as autonomic dysfunction, autonomic neuropathy, and dysautonomia describe general autonomic nervous system disorders and represent distinct clinical entities.

The higher the level of the spinal cord injury and its completeness, the greater the risk of developing autonomic dysreflexia. Up to 90% of patients with cervical or high-thoracic spinal cord injury are susceptible to the disorder. Dysregulation of the autonomic nervous system leads to an uncoordinated autonomic response that may result in a potentially life-threatening hypertensive episode when there is a noxious stimulus below the level of the spinal cord injury. In about 85% of cases, this stimulus is from a distended bladder, but a fecal impaction or other urological sources, such as a urinary tract infection, a distended bladder, or a clogged Foley catheter, may also cause the disorder. There is a significantly increased risk of stroke by 300% to 400%.

Autonomic dysreflexia can occur up to 40 times per day in susceptible individuals. Patients with traumatic spinal injuries who experience autonomic dysreflexia have a significantly higher death rate compared to similarly injured individuals without the disorder.

The initial presenting symptom is an acute, severe headache, typically described as throbbing. Susceptible individuals, such as patients with spinal cord lesions at or above T6 or those with a history of autonomic dysreflexia, who complain of an acute, severe headache should immediately have their blood pressure checked. If the blood pressure is elevated, a presumptive diagnosis of autonomic dysreflexia can be made. Prompt recognition and treatment of the disorder, often by irrigating or changing the Foley catheter, can be immediately life-saving.

Unfortunately, many nurses, emergency room staff, and physiotherapists lack familiarity with autonomic dysreflexia and may be unable to recognize or manage it promptly. This knowledge gap is quite concerning, as they are often the first healthcare professionals to witness such an event, where early recognition and immediate, appropriate intervention can mean the difference between life and death.

Fortunately, most episodes are relatively mild and can be managed at home by the patient and their usual caregivers without acute medical intervention. Severe, life-threatening episodes are rarely encountered by most medical personnel except those who work in specialized tertiary care centers. As a result, many medical professionals, including emergency personnel, may rarely encounter this condition in its most severe acute form, potentially leading to a lack of familiarity that delays early recognition and treatment.