Among the many challenges spinal cord injured persons need to deal with are body temperature regulation and sweating. Both are controlled by the autonomic nervous system of the body.
In order to understand the challenge experienced by SCI patients fully, let’s review how normal control of these bodily functions is achieved. The human nervous system comprises the central nervous system (brain and spinal cord) and the peripheral nervous system. Within the brain, the autonomic nervous system is regulated by the hypothalamus, an area just above the brain stem.
Autonomic functions include control of respiration, regulation of the heart rate (the cardiac control centre), regulation of the blood vessels (the vasomotor centre), and certain reflex actions such as coughing, sneezing, swallowing and vomiting. The autonomic nervous system has three branches: the sympathetic nervous system, the parasympathetic nervous system and the enteric nervous system.
The sympathetic nervous system is often considered the “fight or flight” system, whereas the parasympathetic nervous system is considered the “rest and digest” or “feed and breed” system. In many cases, both of these systems have opposite actions – one system activates a physiological response and the other inhibits it.
Temperature regulation might be affected after an SCI, as body temperature is controlled by the autonomic nervous system via hypothalamic regulation, and a spinal injury generally results in reduced sensory input regarding temperature received from below the level of injury. An injury at level T6 or above also results in a lack of descending sympathetic control, which responds appropriately to environmental changes in temperature.
As a result, patients may experience high or low body temperatures. Temperature dysregulation can occur acutely following SCI and can persist for a lifetime. People with higher levels of injury and complete injuries are more likely to experience these issues.
There are several patterns of temperature dysregulation found in SCI. These include:
High or low temperature secondary to environmental exposure
Patients with SCI can experience trouble regulating their temperatures in extremely hot or extremely cold weather. They will need to dress appropriately, and preferably have some sort of environmental control (air-conditioning) to stay warm and preserve body temperature in winter.
Fever without infectious source
This form of fever is more common in the first weeks or month after injury. One needs to be careful, however, as there might be many causes of fever that will need attention – typically, chest, skin or urinary infections need to be excluded as a cause of elevated temperatures, although deep vein thrombosis and heterotopic bone formation can also be the cause of a fever.
To avoid this condition, regulate exertion with exercise.
Sweating, too, is controlled by the autonomic nervous system, and people with SCI might experience sweating disturbance as a result of autonomic dysfunction. The most common pattern is increased sweating above the level of injury and minimal or no sweating below the level of injury.
Sweating can often be profuse and annoying to the point that someone would need to have several changes of clothing per day. Seek medical advice before assuming that this is indeed the result of autonomic dysfunction, because sweating can signal infection or even the development of a spinal cord cyst (syrinx), which would need urgent attention.
There are medications you can try to reduce excessive sweating.
Dr Ed Baalbergen is the medical officer at the Vincent Pallotti Rehabilitation Centre (Cape Town) and is a member of the International Spinal Cord Society and the Southern African Neurological Rehabilitation Association. email: email@example.com