260 13 Painful Syndromes

Thoracic and Abdominal Wall Pain	back. Spondylolisthesis, the sliding of one vertebral body
	on another (with or without spondylolysis, i. e., a defect
Diseases of the internal organs are the most common	of the pars interarticularis of the vertebral arch), is a
	congenital anomaly that usually remains clinically
cause of pain in the thoracic and abdominal wall (see	silent until later in life. It sometimes becomes sympto-
“referred pain,” above). Chest pain is often due to dis-	matic after an accident.
eases of the heart and lungs. Band-like pain suggests a	Pathological changes of the sacroiliac joint typically
(possibly intraspinal) process irritating one of the spinal
nerve roots or segmental nerves. Abdominal wall pain	produce pain that worsens when the patient stands on
often arises from the internal organs, but may also be	one leg or hyperextends the leg on the affected side
due, for example, to compression of the ventral rami of	(Mennell maneuver).
the spinal nerve roots (e. g., compression of the caudal	Entrapment neuropathies are responsible for some
thoracic nerves in the rectus abdominis syndrome). The
rare Spiegel hernia (cf. Table 13.11) is another possibility,	cases of back pain of nonskeletal origin. Notalgia pares-
as is an abnormally mobile tenth rib.	thetica, for example, is a rare entrapment neuropathy of
	the sensory dorsal rami of the thoracic spinal nerves as
Back Pain	they pass through small apertures in the fascia (see
	p. 232).
Back pain is a very common problem that often pro-	Coccygodynia , i. e., intractable pain in the region of the
foundly affects the sufferer’s everyday life at work and	coccyx, can arise after local trauma (a fall on the but-
at home. The pain cannot always be fully explained	tocks) or spontaneously. In the latter case, the diagnos-
based on objectively demonstrable skeletal changes.	tic evaluation should include a search for tumors or in-
The extent of the visible structural changes is often not	fectious/inflammatory changes in the pelvis, as well as
commensurate with the intensity of the pain. The major	cysts of the lumbosacral nerve root sleeves (= Tarlov
causes of back pain are:	cysts).
Structural changes of the spine cause the vast major-	Groin Pain
ity of cases of back pain. Osteochondrosis leads to reac-
tive spondylotic changes and, therefore, increased stress	Pain in the groin can be caused not only by bladder con-
on the intervertebral joints. This, in turn, causes faulty
posture, reflex functional disturbances of the muscula-	ditions, gynecologic diseases, and inguinal hernias, but
ture, and, therefore, pain. A herniated intervertebral disk	also by peripheral nerve lesions. The ilioinguinal nerve
can compress a nerve root, producing acute pain radiat-	syndrome, a type of entrapment neuropathy, is de-
ing into the periphery (p. 210). Abnormal postures of the	scribed in Table 13.11. The pain of spermatic neuralgia is
spine, as in ankylosing spondylitis or scoliosis, often	felt in the scrotum. In general, when the cause of groin
cause intractable back pain because of the associated	pain is unclear, a pathological process should be sought
nonphysiological stress on the muscles of the trunk and	in the pelvis.

Leg Pain

Pain in the leg, like pain in the arm, has many causes. Common causes are degenerative and traumatic joint and soft tissue processes, lumbar disk herniation, and pathology in the lumbar spinal canal. Others include polyneuropathies, entrapment neuropathies, and restless legs syndrome.

Vascular diseases, too, play an important role, particularly arterial occlusive disease.

Pain in the hip is usually due to diseases of the hip joint, most often degenerative arthritis (coxarthrosis). A diagnosis that is often missed is periarthropathy of the hip: in this condition, the joint itself is not diseased, but the soft tissues around it give rise to intractable pain, which frequently lasts for months. In algodystrophy of the hip, local pain is followed, some time afterward, by the development of osteopenia of the femoral head. Both the pain and the osteopenia usually resolve spontaneously.

Thigh pain may be due to a local process such as a sarcoma. An upper lumbar disk herniation or other lesion causing nerve root irritation can produce referred pain in the thigh. Meralgia paresthetica, a type of entrapment neuropathy causing pain in the thigh, is described on p. 234. Acute thigh pain and femoral nerve palsy can be caused either by diabetic neuropathy or by a hematoma in the psoas sheath.

Knee pain is usually of orthopedic, rheumatological, or traumatic origin. A proximal lesion of the obturator n. produces referred pain in the popliteal fossa in Howship−Romberg syndrome (p. 236). Spontaneous or mechanically induced lesions of the infrapatellar branch of the saphenous n. are a further cause of pain in the knee.

Pain in the lower leg that is present only when the patient walks is typical of vasogenic intermittent claudication, a syndrome whose cause usually lies in the arteries, less commonly in the veins. Neurogenic intermit-

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Pseudoradicular Pain 261

tent claudication is caused by compression of the cauda equina in lumbar spinal stenosis (p. 213). Vasogenic intermittent claudication is worse when the patient walks uphill, while the neurogenic type is worse when the patient walks downhill. In the anterior tibial artery syndrome, pain develops acutely on the anterior aspect of the lower leg, particularly with exercise (p. 239). The saphenous n. can be caught in a fascial gap on the medial side of the lower leg, or, alternatively, in Hunter’s canal in the thigh; pain ensues in the cutaneous zone innervated by this nerve (entrapment neuropathy).

Pain in the foot is a common complaint. It is usually unilateral and caused by an orthopedic condition, or by trauma. Tarsal tunnel syndrome, which typically arises

after an ankle sprain, causes pain in the sole of the foot when the patient walks; it is described on p. 241. Morton’s metatarsalgia is described in the same section. Bilateral, burning pain in the feet characterizes erythromelalgia of vasomotor origin, otherwise known as burning feet syndrome. Similar symptoms may arise in polyneuropathy, but are then usually accompanied by objective neurological findings (loss of Achilles reflexes, distal sensory deficit). In “restless legs syndrome,” the restlessness, which is perceived as painful, forces the sufferer to stand up, walk around, and move the legs time and again, particularly at night or after prolonged sitting in a soft chair. This syndrome usually responds to small doses of L-DOPA, as well as to dopamine agonists.

Pseudoradicular Pain

This term denotes an etiologically heterogeneous collection of painful syndromes caused by a faulty synergy of the muscles and joints. The faulty synergy arises either from structural joint changes or from nonphysiological movements putting excessive stress on the musculoskeletal system.

Pathophysiology. The joints of the body have a continuous, dynamic relationship with the muscles that move them. Afferent nerve impulses arising in the joints are fed back to the muscles to regulate and coordinate the timing and strength of muscle contraction. Thus, pathological impulses arising from mechanically damaged or otherwise dysfunctional joints lead to nonphysiologic patterns of muscle activation. In addition, movements that are repeated monotonously or that put the joints in an unfavorable position (“nonergonomic” movements) cause pain of the participating anatomic structures through overuse. Different names are used for the resulting pain syndromes, depending on the specialty and school of thought of the physician or other expert consulted: tendomyalgia, tendomyosis, pseudoradicular pain, myofascial syndrome, muscular rheumatism, and so forth.

Clinical manifestations. Pseudoradicular pain can arise in many different regions of the body but is particularly common in the upper limb. The pain is chronic and difficult to treat, because it is constantly reactivated by the daily (over)use of the involved joints and muscles.

The general features of pseudoradicular pain are as follows:

the pain is of greater or lesser intensity,

usually radiates into a single limb,

is exacerbated by the use of this limb,

and causes an antalgic restriction of movement;

there are painful trigger points and painful tendon attachments;

there is no objectifiable sensory deficit, paresis, or reflex abnormality;

nonphysiologic, antalgic movement leads to the perpetuation, extension, and chronification of the pain.

Treatment and prognosis. This condition is difficult to treat. The most useful approach consists of good occupational hygiene (use of the affected muscles only up to the pain threshold), changing the illness-producing behavior (switch to a different task at work), and passive measures such as trigger-point therapy. Much patience is demanded of both doctor and patient.

Painful Syndromes

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