An ankle clonus is a movement disorder characterized by involuntary waves of muscle contractions in the ankle, occurring in response to stretching the muscles in and around the ankle. It is usually a sign of a neurological disorder, as the body normally prevents such contractions from occurring. People being screened for neurological problems can be tested for ankle clonus and patients who report this system may be evaluated for other signs of neurological problems. This will assist a doctor in arriving at a diagnosis.
A classic method used in testing for this condition involves flexing the foot upwards and then releasing it. In a healthy individual, the ankle will return to a normal position. In someone with ankle clonus, a series of five or more uncontrolled muscle contractions and relaxations will occur, causing the ankle to jerk repeatedly. This is a form of reflex tremor, an involuntary movement occurring in response to a reflex stimulus.
In people with ankle clonus, the muscle spasms can interfere with the ability to walk steadily. When the patient places weight on the affected foot, it can jerk and twitch, throwing the patient off balance and potentially causing a fall. Ankle clonus can be associated with limps and other abnormal gaits and can also be uncomfortable for the patient, as the spasms can be painful. Repeated sessions of spasms can cause lingering muscle soreness and pain in the patient.
This diagnostic sign rarely occurs alone. Other symptoms can be used to confirm that a patient has a neurological injury and to determine the level of the injury. Sometimes ankle clonus is associated with damage to the spinal cord, as may occur as a result of an accident. In other cases, it is caused by higher level damage in the brain itself. This condition can be common in people with cerebral palsy and can be seen in other people with damage in the areas of the brain that control muscle movement.
Treatments available for a patient with this reflex tremor vary, depending on the cause. Some patients find using canes, braces, and other assistive devices helpful for stability while they walk. Others may benefit from treatments designed to address the damage associated with the clonus, such as spinal surgery to address a pinched or damaged nerve. A neurologist is usually involved in care, and patients may work with other medical specialists like rehabilitation therapists as well.