Page 203 Guide to Pain Management in Low-Resource Settings

Central Neuropathic Pain 191

For the diagnosis of central neuropathic pain, due to damage of the spinal cord itself or nerve roots.
the neuroanatomical location of the lesion should be In cases of nerve root damage, the pain may have uni-
determined (Fig. 1). A lesion in a brain hemisphere lateral predominance. Below-level pain is typically con-
causes abnormal fi ndings on the contralateral side of the stant, severe, and diffi cult to treat and represents central
body. A lesion in the brainstem causes abnormal cranial deaff erentation-type neuropathic pain. If the lesion is
nerve fi ndings on the ipsilateral side, whereas abnormal partial, the sensory fi ndings may be patchy, whereas in a
fi ndings in the limbs and trunk are due to a contralateral complete lesion there is total loss of sensation below the
lesion. A lesion in the spinal cord causes abnormal fi nd- level of the injury.
ings below the lesion level.
Central neuropathic pain may be present from Is all pain neuropathic in patients
the start of the neurological symptoms or appear with
a delay of days, months, or even years. In the delayed with spinal cord injury?
cases, a repeat neurological examination is mandatory
Patients with spinal cord injury and central neuropathic
to identify whether it is a new event or a progression of
pain may often have concomitant nociceptive muscu-
the previous disease (e.g., a new stroke, or syringomy-
loskeletal pain due to muscle spasms or overuse of the
elia with expanding sensory loss after the spinal cord in-
normally functioning parts of the body (e.g., the upper
jury). After it appears, central neuropathic pain tends to
limbs and shoulders in paraparesis). Examples of com-
become chronic, typically continuing for many patients
mon visceral nociceptive pains in these patients are pain
for the rest of their lives.
caused by bowel impaction or distension of the bladder.
Th ese symptoms are important to recognize in manage-
What is meant by traumatic ment of the patient with spinal cord injury.
spinal cord injury?

What is syringomyelia?
Various traumas may result in dislocation and fracture
of spinal vertebrae and cause spinal cord injury. In ad- Syringomyelia is a cystic cavitation of the central spinal
vanced countries, road traffi c accidents rank highest cord, most commonly in the cervical region. It can be
among the etiological factors for traumatic spinal cord developmental, as in Chiari I malformation, or acquired,
injury. According to an epidemiological study conduct- usually due to traumatic spinal cord injury. It is clinically
ed in Haryana, India, the predominant cause of injury characterized by segmental sensory loss, which is typi-
was falling from a height (45%), followed by motor vehi- cally of a dissociated type, in which thermal and pain
cle accidents (35%). Other causes of spinal cord trauma sensations are lost but tactile and proprioceptive sensa-
include sports injuries and acts of violence, primarily tions are preserved. Pain in cervical syringomyelia can
gunshot wounds. In people with asymptomatic cervical be located in the hand, shoulder, neck, and thorax, is
spinal stenosis, a fall or a sudden deceleration force can often predominantly unilateral (ipsilateral to the syrinx),
cause a contusion in the cervical cord, even without any and can be exacerbated by coughing or straining. Auto-
bone or joint trauma. Spinal cord injury can be partial, nomic symptoms such as changes in skin temperature
saving some motor or sensory functions or both, or it or sweating in the painful area can also be present. Pain
can be complete, causing paralysis and complete senso- may be the fi rst symptom, or it may appear after a long
ry loss below the level of the lesion. delay after the original lesion. Motor weakness may ap-
pear with the progression of the disease. Neurosurgical
What are the characteristics treatment is considered only in cases with recent and
of central neuropathic pain in quick progression.
spinal cord injury?
What is phantom limb pain?
Pain following spinal cord injury is divided into below-
level pain and at-level pain. Th e latter is located in a After traumatic amputation, at least half of patients
segmental or dermatomal pattern, within two segments experience phantom limb pain, which refers to pain
above or below the level of spinal cord injury. It may be experienced in the lost part of the body. It is related