What is Hyporeflexia?
Hyporeflexia is a condition characterized by the absence or diminished reflex in reaction to an applied stimulus. This condition is associated with the lower motor neuron defined by a deficit in the nerve that runs through the spinal cord going to the extremities.
Hyporeflexia is among the possible response in deep tendon test and is the reverse of hyperreflexia. The condition of hyporeflexia is an indication of a problem with the reflex arc itself whereas hyperreflexia represents a problem with the spine located on top of the reflex.
A reflex is an involuntary or automatic movement when a stimulus is applied. The reflex is governed by the stretch receptors in the muscle after it sends signal to the spinal cord via the sensory nerve of the spinal branch. The jerking of the extremity applied with stimulus is the result of the contraction signal sent from the spinal cord via the motor nerve.
Hyporeflexia in itself is mostly a symptom that indicates a bigger problem particularly at the spinal cord affecting the sensory and motor neuron of an individual. The onset of hyporeflexia is characterized by the absence or a diminished reflex when a stimulus is applied.
Hyporeflexia is among the sign of a neurological problem. It is an indication of a deficiency in the sensory or motor neurons. The existence of the condition is often discovered during a routine examination that includes a neurological evaluation to determine the extent of the underlying medical condition.
The general symptom of hyporeflexia is the diminished or the inability of the reflex to respond to the stimuli applied in certain areas of the body typically in the elbows and knees. Hyporeflexia is not a disease itself but is more of a sign and symptom indicating a bigger health problem particularly neurological problem.
The reflex of the body is governed by the stretch receptors in the muscle. It is an automatic or involuntary movement such as jerking of the extremity when a stimulus is applied. The level of the reflex is significant in the course of neurological evaluation as it may indicate a problem within the sensory or motor neurons of the spinal cord which may have been damaged or may be pressed by other matters.
The level of the reflex can be tested in any of the six primary location of the reflex arc. These include the tendons in the biceps, triceps and brachioradialis and the cervical nerves in the fifth, sixth and seventh vertebrae. The thoracic nerve is also included in the primary location of the reflex arc and which can be located in the eighth and all the way to the twelfth thoracic nerve. Reflex arc in the patellar tendon tests the second to fourth lumbar vertebrae while the Achilles’ tendon involves the first and second sacral tendon.
What are the Causes of Hyporeflexia?
The incidence of hyporeflexia is primarily due to the damage in the nerves that passes through the spinal cord and diverges to the extremities. The damage in the nerve causes the dysfunction of the nerve and such damage is particularly true in pinched nerves brought by several matters that can press the nerve and prevent it from functioning properly.
Hyporeflexia is commonly cause by the following:
- Radiculopathy such as spondylosis and osteoarthritis is the common cause of hyporeflexia
- Normal variant
- Peripheral neuropathy
It is less commonly cause by the following:
- Guillain-Barre syndrome
- Hyperacute spinal cord injury
- Disorders of the anterior horn cells
The treatment of hyporeflexia mainly depends on the underlying condition that caused the incidence. Hyporeflexia that resulted from pressure in the spinal cord can be managed with medicines and several therapies to alleviate the pressure.
In some cases, surgery may be necessary particularly if there is no improvement of the condition. The aim of surgery is to free the nerve from pressure and to restore the stability and proper function of the spinal cord.