What Is Hyporeflexia?

Hyporeflexia is a reduced or absence of reflex in response to a stimulus, like contact with a reflex hammer or medical instrument. It is a sign of a neurological problem, indicating that something is wrong with a patient’s sensory or motor neurons in the area of interest. This may be uncovered during a routine neurological evaluation or as part of testing to determine the extent and origins of a known medical problem. Treatment options can depend on why the patient’s reflexes are impaired.

Reflex testing involves checking for common automatic reflexes which are not controlled independently by the patient. The classic example is the jerking of the knee when the bone is gently tapped. When a neurologist checks for a reflex and the response doesn’t occur or isn’t as strong as it should be, it means the patient may have a medical issue. Testing is commonly repeated to make sure it was done correctly before definitively stating that the patient appears to have hyporeflexia.

Lesions along the spinal cord are a likely cause of this problem. A patient may have a slipped or compressed disc or pinched nerve, for example, that is interfering with the conduction of nerve signals. Injuries to the spinal cord such as those sustained in a bad car accident may be involved, as can progressive lesions caused by disease. Patients with multiple sclerosis, for example, can develop hyporeflexia as the condition eats away at the protective myelin sheaths coating the nerves.

When this problem is identified, the patient may need some medical imaging studies to learn more about what is going on inside the spinal cord. Additional nerve testing can also be recommended, along with an extensive patient interview if there isn’t an obvious cause for damage. Hyporeflexia in someone being evaluated after a car accident, for example, may be attributed to a spinal cord injury sustained in the crash, while the sudden appearance of reduced reflexes with no known cause may be another issue.

Some patients may need surgery to correct issues like nerve impingement. Medications can help control conditions that create spinal cord lesions. In other cases, treatment for hyporeflexia may be focused on managing symptoms and keeping the patient comfortable. Some injuries to the spinal cord are irreversible and cannot be corrected. Adaptations to address specific problems caused by lesions, like loss of bowel control, may be necessary to keep the patient healthy and functional for as long as possible.