Here are some of the most common questions which we receive about central pain, with answers as best we can supply them. The field is changing so rapidly that continual updating is necessary to try to obtain the most accurate information. This is not intended as medical advice, but is for educational purposes only.
What is Central Pain?
Central Pain is the name given to a generally agreed number of symptoms (in those with injury to the CNS) pertaining to loss of superficial sensibilities and associated pain of hypersensitization in those specific modalities, such as light touch and temperature sensing.
Burning dysesthesia, “like acid under the skin”, is the central symptom, but not all have it in a severe version. The same goes for the other central pains, which range from lancinating or shooting, electric like pains, to exaggerated pins and needles, cramping or tightening pain in the muscles, overfulness in any hollow organ such as gut or bladder, and marked increase in sensitivity to normal pain (hyperpathia).
The underlying problem in all these is nerve injury with hyperexcitation of those parts of the central nervous system which normally are in a state of balance between excitation and inhibition. Inhibition is knocked out in CP by the churning chemical production induced by NGF as well as inability of the injured neuron to produce the protein calcium carrier, KCC2, needed for sending inhibitory signal (described by Jeffrey Coull) All sensory signal from that time will be pain excitatory. Another word for this is torture.
Who gets Central Pain?
Anyone with an injury to the central nervous system, the brain and cord, is a candidate for Central Pain. This includes traumatic brain injury which involves the thalamus or certain other areas. Stroke and Multiple Sclerosis are examples of conditions which may lead to central pain. Other causes can be infectious, compression, or any other condition which interferes with blood flow to the cord or brain, SCI in particular. The interruption to blood flow is most commonly caused by compression of outflow (venous blood) from the cord. The blood backs up and new oxygenated blood cannot enter the watershed area cleared by that vein. Central Pain always involves more than just the pain tracts as a consequence. Arterial blood is under much higher pressure and occlusion of arterial blood is thought to be more rare. However, both arteries and veins in the central nervous system are very prone to go into vasospasm, so arterial blockage can occur. Trauma is the usual precipitator.
Is Central Pain Constant?
Classic burning dysesthesia has two components. One is