What causes increased deep tendon reflexes?
What causes increased deep tendon reflexes?
If the lesion or injury involves the upper motor neuron (brain, brainstem, or spinal cord), an increased reflex will be present. In severe chronic cases, usually associated with spasticity, clonus can be seen. It is common in stroke, spinal cord injury, cerebral palsy, and multiple sclerosis.
What causes abnormal tendon reflexes?
Peripheral neuropathy is today the most common cause of absent reflexes. The causes include diseases such as diabetes, alcoholism, amyloidosis, uremia; vitamin deficiencies such as pellagra, beriberi, pernicious anemia; remote cancer; toxins including lead, arsenic, isoniazid, vincristine, diphenylhydantoin.
What happens to tendon reflexes in upper motor neuron lesion?
Reflexes are reduced in muscle disease. If there is an upper motor neurone lesion, the reflex is increased because inhibitory factors have been removed. Tendon reflexes are important because they provide an objective sign indicating abnormality and some indication as to the level of the abnormality.
What does it mean to have deep tendon reflexes?
muscle stretch reflexes
Deep tendon reflexes, more properly referred to as muscle stretch reflexes, are an integral part of the neurological examination. A stretch reflex is an involuntary reaction of a muscle to being passively stretched by percussion of the tendon. This reflex provides information on upper and lower motor neurons.
Why Deep tendon reflexes are exaggerated in UMN lesion?
Because of the loss of inhibitory modulation from descending pathways, the myotatic (stretch) reflex is exaggerated in upper motor neuron disorders.
Why is there Hypertonia in UMN lesion?
Hypertonia is caused by upper motor neuron lesions which may result from injury, disease, or conditions that involve damage to the central nervous system. The lack of or decrease in upper motor neuron function leads to loss of inhibition with resultant hyperactivity of lower motor neurons.
Why does UMN lesion cause hyperreflexia?
Hyperreflexia. Because of the loss of inhibitory modulation from descending pathways, the myotatic (stretch) reflex is exaggerated in upper motor neuron disorders. The stretch reflex is a major clinical diagnostic test of whether a motor disorder is caused by damage to upper or lower motor neurons.
How many deep tendon reflexes are in the reflex exam?
Reflex Exam (Deep Tendon Reflexes) The reflex exam is fundamental to the neurological exam and important to locating upper versus lower motor neuron lesions. There are five deep tendon reflexes and a number of superficial and visceral reflexes covered here. Introduction to the Reflex Exam
What is the difference between deep reflex and superficial reflex?
Deep reflexes involve receptor organs receptor organs embedded in the skin. With deep reflex- ulates the receptors in the muscle group. The aroused move. Deep reflexes include patellar, Achilles, plantar, tri- ceps, and biceps reflexes. With superficial reflexes, light muscle to twitch.
What can the DTR of the upper extremities tell us?
The DTR of the upper extremities can provide clues to the level of injury in the spinal cord. Increased reflexes can be normal, especially if bilateral. Children frequently have exaggerated reflexes (more prominent in upper extremities). Enhanced reflexes can be associated with an upper motor neuron lesion.
What type of reflex arc is the DTR?
The DTR is a monosynaptic reflex arc. It is monosynaptic because only two neurons are involved: a sensory and a motor neuron, with a single synapse. After the examiner taps the muscle’s tendon, the muscle fibers’ stretch is detected at the muscle spindle located within the muscle fibers.
