What Is Tetraplegia?
Tetraplegia is the loss of motor and/ or sensory function in all the four limbs (arms and legs) as well as trunk and pelvic organs due to the damage at the cervical segments of the spinal cord.
It does not include brachial plexus injury or injury to any peripheral nerve outside the neural canal.
Approximately 250,000 to 500,000 people become paralyzed every year globally. Individuals between the age of 20 to 40 years often represent this population. Spinal cord injury at the cervical level leading to tetraplegia is approximately 50 percent.
Causes Of Tetraplegia
- Road traffic accidents: This constitutes a major cause of tetraplegia. Direct or indirect force during road traffic accidents results in displacement, dislocation, or fractures of cervical vertebrae which will lead to cord damage. Hyperflexion with rotation movement can also cause damage to the cervical vertebrae and the spinal cord.
- Work-related accidents: Accidents from mining, construction works, or due to the fall of any heavy objects on the head or neck can lead to tetraplegia.
- Sports and recreational injuries: Uncontrolled accidents during activities like parachuting, diving, surfing, rock climbing, formula racing can cause injury to the cervical spine which leads to tetraplegia.
- Fall: Falls affect the older population. Fall from a height is also a cause of cervical and spinal cord injuries.
- Violence: Riots leading to stab injury and gunshot injuries are also a common cause for spinal cord injuries.
- Surgical procedures: Surgeries performed in and around the spinal cord can damage the cord.
- Pathological conditions: Diseases like transverse myelitis, syringomyelia, amyotrophic lateral sclerosis, multiple sclerosis, Tuberculosis of the spine (Pott’s disease), and space-occupying lesions like spinal tumors can compress the cord.
Symptoms Of Tetraplegia
- The symptoms depend on the level of injury. Injury on the higher level of spinal cord results in more dysfunction.
- In a complete injury, there is no sensory or motor function below the level of injury.
- Injury to the higher cervical levels (C1 – C4) of the spinal cord leads to more severe impairments. The sensory and motor loss causes weakness of the diaphragm and paralysis of all the four limbs (arms and legs) and trunk leading to breathing inability and complete loss of body movements. Ventilatory support is required in such cases.
- Injury to the lower cervical levels (C5 – C8) of the spinal cord preserves the breathing ability. Partial movements of the upper limb are present as some of the nerves controlling the upper limb movements are preserved.
- Complete injury at any cervical level leads to loss of normal bowel and bladder control.
- In an incomplete injury, some sensory and motor functions are present below the level of injury including the lower sacral segments (S4 and S5)
Some patterns of incomplete injury are:
- Brown-Sequard Syndrome: This occurs from the damage to one side of the spinal cord caused due to penetration wounds or stab injury. There will be paralysis and sensory loss in the ipsilateral side (same side) below the level of the lesion. And also loss of proprioception, light touch, tactile localization, and two-point discrimination on the same side due to damage to the lateral corticospinal tract. Loss of pain, temperature, and crude touch on the contralateral side (opposite side) due to damage to the spinothalamic tract. This variation occurs because the lateral spinothalamic tracts ascend two to three segments on the same side before crossing.
- Anterior Cord Syndrome: This occurs from the damage to the anterior portion of the spinal cord and anterior spinal artery. It is frequently caused due to hyperflexion injury of the cervical region. This syndrome is characterized by loss of pain and temperature sense and loss of motor function below the level of the lesion caused due to the damage of the spinothalamic tract and corticospinal tract respectively. Deep sensations are preserved as they are mediated by the dorsal spinal column with vascular supply from posterior spinal arteries.
- Central Cord Syndrome: This occurs from the damage to the central portion of the spinal cord mainly caused due to hyperextension injuries. This syndrome is characterized by more involvement of the upper limbs than the lower limbs. There is a loss of pain and temperature sensations in the proximal part whereas the sacral part is preserved. Bowel and bladder functions are retained.
Complications And Associated Conditions
- Spinal shock: Spinal shock is the period of areflexia immediately following the spinal cord injury. It is characterized by loss of all the reflex activity, loss of tone, loss of sensory and motor function below the level of lesion, and autonomic regulation impairments (hypotension). The initial period of spinal shock can last for approximately 24 hours. It usually resolves within 24 to 48 hours. The presence of bulbocavernosus reflex is the first indicator of the resolution of spinal shock.
- Autonomic Dysreflexia: Also referred to as autonomic hyperreflexia. It is a pathological autonomic reflex that is observed in lesions in the higher spinal level (above T6). It is characterized by hypertension, headache, bradycardia, profuse sweating, increased spasticity, restlessness, nasal congestion, piloerection, constricted pupils, vasoconstriction below the level of lesion and vasodilation (flushing) above the level of the lesion. These responses usually occur in response to any noxious stimuli.
- Spasticity: Spasticity is more common in people with injury at the cervical level. It is characterized by the increased tone in the muscles (hypertonicity), increased tendon reflexes (hyperreflexia), and clonus. it is velocity dependent and increases in resistance to passive stretch. spasticity gradually increases during the first six months after the injury and reaches a plateau by one year.
- Impairment of temperature control: Persons with cervical level injuries and complete injuries have more impairment with temperature control. The ascending tract carrying the information about peripheral temperature to the hypothalamus will be cut due to spinal cord damage. Hence the thermoregulation with the response to heat or cold will not be controlled. initially, after the injury hypothermia may occur due to peripheral vasodilation. Hyperthermia is more likely to occur later due to the loss of sympathetic control of sweat glands.
- Bowel and bladder dysfunction: The disconnection of the sacral segments to the brain leads to loss of voluntary bowel and bladder control. Damage above the micturition center (S2, S3, S4) causes Automatic or Reflex bladder, and Reflex or Spastic bowel is seen in lesions above S2.
- Respiratory impairment: Higher cervical lesions leads to loss of phrenic nerve innervation which results in denervation of diaphragm and loss of spontaneous respiration. An artificial ventilator is required in such cases. In lower cervical injuries, partial innervation of the diaphragm is preserved. the severity of respiratory impairments depends on the level of lesion, preserved respiratory muscles, and associated injuries to the chest.
- Sexual dysfunction: Physiological erection remains intact in lesions above S2, S3, S4 segments. Ejaculation may be affected in case of complete injury.
Secondary Complications Of Tetraplegia
- Pressure sores: Pressure sores are caused due to continuous unrelieved stress on certain parts of the body. Ulcerations can develop over any bony prominence which is subjected to excessive pressure mainly due to prolonged immobilization. The common sites are heels, sacrum, ischial tuberosity, greater trochanter, elbow, and scapula.
- Deep vein thrombosis (DVT): The lack of immobility and active muscle contractions of the lower limb leads to stasis of blood which results in the development of thrombus. The thrombus can get dislodged and float freely in the blood leading to pulmonary embolism. It is fatal and can result in death.
- Contractures: Prolonged shortening of the soft tissues across the joint results in contractures. Initially, muscles are affected followed by ligaments and capsules. The contractures are developed due to muscle imbalance, spasticity, or improper positioning of the person on bed or wheelchair for a prolonged period.
- Heterotropic (Ectopic) ossification: It is the abnormal growth of bones (osteogenesis ) in soft tissues below the level of injury. It commonly occurs in hip and knee joints. The early symptoms include pain, swelling, redness, reduced movement (ROM), and warmth over the area.
- Pain: Pain is common following spinal cord injury. The pain can be Nociceptive which can be musculoskeletal, caused due to poor posture, improper positioning, and muscle imbalance. Neuropathic pain is the sharp, burning, shooting type of pain caused due to nerve damage.
- Osteoporosis: There is a reduction in bone mineral density in patients with spinal cord injury. It can be due to limited muscle activity or lack of weight-bearing by the person. This may precipitate fractures.
- Urinary tract infections: Urinary retention and the use of catheter increases the risk of bacterial growth leading to urinary tract infections. The person is also prone to renal calculi due to the increased levels of calcium in the urine.
Along with the physical examinations, imaging studies (X-ray, MRI) should be used to rule out the location, extent of the injury, and to identify any associated injuries.
ASIA impairment scale is used to assess the neurological level of the injury. It is also used to classify the spinal cord injury into complete or incomplete injury. It is based on the ability of the patient to feel sensations on multiple points of the body (dermatomes) and also tests motor function (myotomes).
Treatment Of Tetraplegia
- Management should start from acute trauma care itself. When spinal cord injury is suspected, active and passive movements of the spine should be avoided to reduce further damage to the spine.
- Movements of the spine should be avoided by using immobilizer or supporting cervical collar to prevent further neurological damage.
- Then the primary focus should be on ventilation, circulation, and fracture fixation if needed.
- Muscle reconstructive surgery can be opted to improve the movements.
- Physical therapy management plays an important role in persons with tetraplegia to improve their quality of living.
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