Central Cord Syndrome

In a patient with severe radicular pain and central cord syndrome, the addition of lamotrigine 100-200 mg/day over a period of 6 weeks reduced pain intensity scores from 100mm down to 20mm and greatly improved quality of life [6]. 

Association of Pain, neuropathic pain is defined as pain initiated or caused by a primary lesion, dysfunction in the nervous system". Neuropathy can be divided broadly into peripheral and central neuropathic pain, depending on whether the primary lesion or dysfunction is situated in the peripheral or central nervous system. In the periphery, neuropathic pain can result from disease or inflammatory states that affect peripheral nerves (e.g. diabetes mellitus, herpes zoster, HIV) or alternatively due to neuroma formation (amputation, nerve transection), nerve compression (e.g. tumours, entrapment) or other injuries (e.g. nerve crush, trauma). Central pain syndromes, on the other hand, result from alterations in different regions of the brain or the spinal cord. Examples include tumour or trauma affecting particular CNS structures (e.g. brainstem and thalamus) or spinal cord injury. Both the symptoms and origins of neuropathic pain are extremely diverse. Due to this variability, neuropathic pain syndromes are often difficult to treat. Some of the clinical symptoms associated with this condition include spontaneous pain, tactile allodynia (touch-evoked pain), hyperalgesia (enhanced responses to a painful stimulus) and sensory deficits. 

Infants and children may require long-term ventilatory support due to three categories of diseases that may impair the ventilatory balance increased respiratory load (due to intrinsic cardiopulmonary disorders, upper airway abnormalities, or skeletal deformities), ventilatory muscle weakness [due to neuromuscular diseases (NMD) or spinal cord injury], or failure of neurological control of ventilation (with central hypoventilation syndrome being the most common presentation) (Fig. 1). 

Nociceptive neurons in the spinal cord as well as in higher centres such as the thalamus and cortex can also undergo alterations in activity following chronic peripheral changes and trauma (Table 1). These changes are typically long-term in nature and lead to the clinical syndromes of centrally maintained pain (secondary hyperalgesia, allodynia, spontaneous pain). Alterations... 

Neuropathic pain is defined as spontaneous pain and hypersensitivity to pain associated with damage to or pathologic changes in the peripheral nervous system as in painful diabetic peripheral neuropathy (DPN), acquired immunodeficiency syndrome (AIDS), polyneuropathy, post-herpetic neuralgia (PHN) or pain originating in the central nervous system (CNS), that which occurs with spinal cord injury, multiple sclerosis, and stroke. Functional pain, a relatively newer concept, is pain sensitivity due to an abnormal processing or function of the central nervous system in response to normal stimuli. Several conditions considered to have this abnormal sensitivity or hyperresponsiveness include fibromyalgia and irritable bowel syndrome. 

Fatigue accompanies viral infection, sepsis, trauma or major surgery. The cause of this fatigue is not known it may be peripheral, central or both. Studies on biopsy samples of patients with trauma show a reduction in the muscle ATP concentration, which could be responsible for peripheral fatigue, as explained above (Chapter 18 Table 13.3). Central fatigue has been identified in three different clinical conditions, post-polio syndrome, multiple sclerosis and after spinal cord injury, but has not been investigated in other conditions. 

The aminopyridines (4-aminopyridine 3,4-diaminopyri-dine) accelerate spontaneous exocytosis at central and peripheral synapses. There is also an increase in the number of transmitter quanta released by a nerve action potential. This is probably the result of increased Ca++ inflow at the terminals due to a reduction of K+ conductance and prolongation of the nerve action potential. Muscle strength is increased in patients with the Lambert-Eaton myasthenic syndrome and in others poisoned with botuUnum E toxin (discussed later). Improvement in uncontrolled spasms, muscle tone, and pulmonary function is noted in patients with multiple sclerosis or long-standing spinal cord damage. Side effects that limit clinical utility include convulsions, restlessness, insomnia, and elevated blood pressure. Of the two agents, 3,4-diaminopyridine is the more potent and crosses the blood-brain barrier less readily. 

This syndrome most often occurs as a result of the interaction of two or more drugs acting via different mechanisms to potentiate the central effects of serotonin at 5-HTi receptors in the brainstem and spinal cord (490). It consists of the following symptoms ... 

Spasticity is a central feature of multiple sclerosis (MS) and spinal cord injury (SCI). It consists of a velocity-dependent increase in tonic stretch reflexes with exaggerated tendon jerks, resulting from hyperexcitability of the stretch reflex as one component of the upper motor syndrome (Young 1994). Existing drug therapy is far from satisfactory in terms of efficacy and unwanted effects (Panegyres 1992). Tremor, ataxia and lower urinary tract symptoms are frequently troublesome in MS. Both neuropathic and nociceptive pain (dealt with in Sect. 2.3) are also common in MS and SCI, and dozens of very painful muscle spasms can occur each day. Small wonder that there is also a high incidence of anxiety and depression in these conditions. 

Figure 3 Percentage of users in each disease category by country. The symbol represents lung/ airways (COPD, cystic fibrosis, bronchiectasis, pulmonary fibrosis, and pediatric diseases) , chest wall deformities (kyphoscoliosis, old TB, OHS, surgical resection) and , neuromuscular disorders (muscular dystrophy, motor neuron disease, post-polio kyphoscoliosis, central hypoventilation, spinal cord damage, and phrenic nerve palsy). Abbreviations COPD, chronic obstructive pulmonary disease TB, tuberculosis OHS, obesity hypoventilation syndrome. Source From Ref. 15.

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