243

13 Painful Syndromes

Fundamentals .	. . 243		Painful Shoulder−Arm Syndromes (SAS) . . .				256
Painful Syndromes of the Head			Pain in the Trunk and Back . . .			258
and Neck . . .	244		Leg Pain . . .	260
Painful Syndromes of the Face . . .		252	Pseudoradicular Pain . . .		261

Fundamentals

Many conditions whose most prominent, or sole, symptom is pain lie within the neurologist’s area of expertise. In this chapter, we will discuss painful syndromes by location: headache, shoulder−arm pain, pain in the trunk, and pain in the lower limb. The etiological differential diagnosis of a painful syndrome cannot be restricted to neurological conditions but must always include diseases of nonneurological origin.

The generation and perception of pain. Pain is a type of unpleasant sensation. In terms of pathophysiology, it arises when specialized sensory end organs are excited by certain mechanical, thermal, or chemical stimuli of a potentially damaging (“noxious”) nature. The pain-re- lated (“nociceptive”) impulses are conducted centrally, mainly by way of thin, poorly myelinated fibers, through the posterior root and into the spinal cord. The nociceptive fibers cross the midline in the spinal cord at their level of entry. They then ascend in the spinothalamic tract to the thalamus and onward to higher centers in the brain, through which pain can be consciously felt (cf. p. 73). Biochemical factors also play an important role in pain perception. In the periphery, the intensity of pain is increased by a variety of biogenic amines, e. g., substance P. In the central nervous system, the intensity of pain is modulated by the production of opioid substances in certain areas of the brain. Finally, psychological factors—determined both by personality and by the sociocultural environment—affect the manner in which pain is experienced and processed.

General aspects of the clinical history in patients with pain. Many painful syndromes have their origin in the nervous system and many others, in which there is no evident dysfunction of the nervous system (e. g., most kinds of headache), are nonetheless traditionally evaluated and treated by neurologists. These facts justify the inclusion of painful syndromes in a textbook of neurology for medical students. It should be emphasized, however, that the physician must not merely analyze the symptom “pain” from the narrow viewpoint of his or her particular specialty, but must, rather, apply the full range of general medical knowledge.

This purpose is best served, first, by the taking of a systematic and directed pain history. Some important elements of the pain history are listed in Table 13.1. Further, specific questions will need to be asked depending on the nature and location of pain in the partic-

Table 13.1 Pain history

Where is the pain?

Precisely localized or diffuse?

Constant or varying localization?

Radiating?

How long has it been present?

For what length of time?

Since what precipitating event, if any?

Continuous or intermittent?

If continuous: of constant or variable intensity?

If intermittent: how long and how frequent are the episodes of pain?

Quality?

Hammering?

Throbbing?

Stabbing?

Dull?

Burning?

Intensity?

On a scale of 0 (no pain) to 10 (intolerable pain)

Precipitating and/or aggravating factors?

None?

Constant or variable factors—which, if any?

Dependence on posture?

Alleviating factors?

None?

Constant or variable factors—which, if any?

Medications—which ones, with what effect, lasting how long?

How severely is the patient impaired by the pain?

At work?

In the personal sphere?

Current complaints other than pain?

What is the patient’s own explanation for the pain?

Other medical history?

Living situation?

ular case and ancillary diagnostic tests may be necessary.

In the remainder of this chapter, we will discuss various major painful syndromes, classifying them by location.

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Painful Syndromes

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