It means paralysis of the lower limbs and is caused by lesions at various sites starting from cerebral cortex to spinal cord. Thus the causes of paraplegia can be classified as follows:
1. Cerebral cortex
(a) Tumor of falx cerebrie (Menigioma)
(b) Thrombosis of the superior sagittal sinus
(c) Congenital cerebral lesion (Littles disease)
(d) Occlusion of an unpaired anterior cerebral artery (Uncommon)
2. Spinal cord
(a) Compression of the spinal cord due to trauma, tumors of the spine and cord, secondary deposits, spinal caries, pagets disease.
(b) Acute transverse myelitis. Demyelinating disorders.
(c) Subacute combined degeneration of the cord. Progressive muscular atrophy, lathyrism, flourosis, haematomyelia.
(d) Cauda equina.
(e) Lesions of anterior horn cells – poliomyelitis
(f) Polyneuritis, acute infective polyneuritis
3. Disorders of muscles
(a) Hysterical paraplegia
(b) Myasthenia gravis, familial periodic paralysis
Investigations of a case of paraplegia
1. History of onset whether it is of sudden occurrence or slowly progressive. Sudden paraplegia follows trauma of the spine or infective conditions such as acute transverse myelitis. A paraplegia which comes slowly and has taken months to develop indicates a slow growing lesion. A spinal tumor generally starts unilaterally and then spreads to other side. Causes of slow onset of paraplegia shall include sub acute combined degeneration of the cord, Amyotrophic lateral sclerosis, lathyrism, flourosis, syringomyelia etc.
2. Age is significant since some diseases producing paraplegia are common in children such as cerebral diplegia, Spina Bifida and Meningitis. In adults important causes shall include caries spine, spinal tumor, motor neuron disease lathyrism, secondary deposits in spine etc.
3. There may be history of pain radiating down to legs in spinal tumor worsened by coughing. Rapid progression of the lesion suggests inflammatory pathology and malignancy.
4. Physical examination: When there is involvement of pyramidal tracts, spastic weakness of the limbs below the lesion results (spastic paraplegia). The features of this type of paraplegia are:
(a) Loss of voluntary power varying from slight weakness of one group of muscles to complete paralysis of both lower limbs
(b) Increase in tone in all group of muscles especially in extensors
(c) Exaggeration of tendon reflexes
(d) Spontaneous clonus of the extensor muscles in which the whole limb trembles
(e) Fibrillary twitching in motor neuron disease.
Sensations of the limbs is affected depending on the level at which the lesions is. The exact site of lesion may be several segments higher than the level of sensory loss.
Some important points to be considered are:
1. Anesthesia of all sensations on opposite side in extra medullary tumor.
2. Sensations are effected depending on the level of the lesion. In the mid dorsal region the pain and temperature fibers decussate completely one segment above the point of entry of roots while at higher levels crossing takes place more slowly and at all levels pain crosses more quickly then cold, then heat and touch last of all.
3. Dissociated anesthesia is specific for syringomyelia and intra meduallary tumours.
4. Posterior columns involvement results in loss of position and posture in lower limbs resulting in ataxia.
5. Sphincter involvement especially of bladder is common in traumatic and inflammatory lesions of the cord.
1. X-ray spine (AP and Lateral views) for evidence of fracture, caries, secondaries.
2. Myelography to confirm the lesion.
3. CT Scan