150 7 Diseases of the Spinal Cord

	Hemorrhage in or Adjacent to the Spinal	coagulated patients, or they can be caused by ruptured
		vascular malformations or trauma. They usually pro-
	Cord
		duce intense pain and more or less pronounced neuro-
	The function of the spinal cord can be affected by an in-	logical deficits, depending on their site and extent.
		Hemorrhage in or adjacent to the spinal cord requires
	tramedullary, subdural, or epidural hemorrhage. These	immediate diagnostic evaluation and, in some patients,
	types of hemorrhage can arise spontaneously in anti-	emergency neurosurgical decompression.

Infectious and Inflammatory Diseases of the Spinal Cord

The spinal cord and spinal nerve roots, like the brain, can be infected by bacteria, viruses, and other pathogenic organisms. Combined infection of the brain and spinal cord is common: simultaneous manifestations of encephalitis, meningitis, myelitis, and radiculitis (cf. pp. 116 ff.) can be caused by spirochetes (borrelia, leptospira, treponemes; cf. pp. 209 ff.) and by many viruses. Acute anterior poliomyelitis, on the other hand, affects only the motor neurons of the anterior horns of the spinal cord.

Any infectious or inflammatory disease of the spinal cord, whatever its etiology, is called myelitis. The causes of myelitis include direct infection, secondary autoimmune processes in the wake of an infectious disease, and chronic autoimmune inflammatory disease of the central nervous system, such as multiple sclerosis.

The main causes of acute myelitis include viruses (measles, mumps, varicella-zoster, herpes simplex,

Fig. 7.11 Myelitis (T2-weighted MR image). A spindle-shaped signal anomaly extends from C3 to C5 and expands the spinal cord (which is wider here than the normal cervical enlargement).

HIV), as well as rickettsiae and leptospira. Postvaccinal and postinfectious myelitis have also been described, as has myelitis in the setting of granulomatous disease. The clinical manifestations range from progressive spastic paraparesis to partial spinal cord transection syndrome. Myelitis can be visualized by MRI (Fig. 7.11).

Transverse myelitis affects the entire cross-section of the spinal cord, producing a complete spinal cord transection syndrome. It has a variety of causes. Often, the neurological manifestations are preceded by nonspecific flulike symptoms one to three weeks before onset. The spinal cord deficits usually arise acutely or subacutely and become maximally severe within a few days. Fever, back pain, and myalgia accompany the acute phase. The cerebrospinal fluid displays inflammatory changes (lymphocytic pleocytosis, elevated IgG and total protein concentrations). A neuroimaging study (usually MRI) must be performed to rule out a mass or ischemic event. The responsible organism is treated specifically if it can be identified; otherwise, only symptomatic treatment can be given. The spinal cord transection syndrome persists, or resolves less than completely, in two-thirds of all patients.

Acute Anterior Poliomyelitis

Etiology and epidemiology. This disease, caused by a poliovirus, almost exclusively affects the motor neurons of the anterior horn of the spinal cord. Its incidence in countries with a well-developed public health system has been reduced nearly to zero by prophylactic vaccination. The disease is transmitted by the fecal−oral route under conditions of poor sanitation.

Clinical manifestations. After an incubation period ranging from three to 20 days, nonspecific prodromal manifestations arise, consisting of fever, flulike symptoms, and, in some patients, meningeal signs. The prodrome may resolve without further consequence or be followed, within a few days, by a paralytic phase (likewise accompanied by fever). Over the course of a few hours or days, flaccid paralysis arises in various different muscles or muscle groups; it is asymmetrical, often mainly proximal, and of variable extent and severity. There is no sensory deficit, but the affected muscles may be painful and tender.

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Syringomyelia and Syringobulbia 151

Diagnostic evaluation. The diagnosis is based on the typical course and physical findings, combined with an inflammatory CSF pleocytosis: at first, there are several hundred cells per microliter, often mainly polymorphonuclear granulocytes. Later, there is a transition to a predominantly lymphocytic picture. The responsible organism (poliovirus) can be identified in the patient’s stool.

Treatment. There is no specific etiologic treatment; the most important aspect of treatment is the management of respiratory insufficiency (if present).

Prognosis. Brain stem involvement and respiratory paralysis confer a worse prognosis; in the remainder of patients, paralysis may regress partially or completely in a few weeks or months. There is usually some degree of residual weakness.

Postpolio syndrome. This term refers to two different syndromes. Some authors use it for a symptom complex seen a few years after the acute illness in polio patients with residual weakness, characterized by fatigability, respiratory difficulties, pain, and abnormal temperature

regulation (with negative polio titers). Others use it for a syndrome with progressive worsening of residual weakness occurring decades after the acute illness. Before this problem can be ascribed to the earlier polio infection, other possible causes of weakness must be ruled out, e. g., compression of the spinal cord or spinal nerve roots because of secondary degenerative disease of the spine.

Spinal Abscesses

Spinal abscesses are most often epidural, less often subdural, and only rarely intramedullary. The most common pathogen is Staphylococcus aureus, which reaches the spinal canal from a site of primary infection outside it by way of the bloodstream (hematogenous spread). The typical clinical features are general signs of infection (fever, elevated erythrocyte sedimentation rate, leukocytosis, chills in some cases), pain, and neurological deficits referable to the spinal nerve roots or spinal cord, depending on the specific anatomic situation. Spinal abscesses usually require prompt surgical treatment, followed by weeks of high-dose antibiotics.

Syringomyelia and Syringobulbia

Syringomyelia, a condition coming under the general heading of spinal dysraphism, is sometimes seen in combination with other congenital defects such as the Arnold−Chiari syndrome or spina bifida. It has several different causes; it can be classified into primary syringomyelia and symptomatic forms due to (for example) hemorrhage, infection, or a tumor.

Syringomyelia is defined by the pathological finding of a tubelike or cleftlike cavity (syrinx) within the spinal cord, often lined by ependyma, and usually extending over several spinal segments. The cavity may reach all the way up to the medulla, or even the midbrain (syringobulbia, syringomesencephaly). Mere widening of the central canal of the spinal cord is called hydromyelia.

Clinical manifestations of syringomyelia depend on the location of the syrinx within the spinal cord and on its

vertical extent; they usually arise in the patient’s second or third decade. The typical signs and symptoms are summarized in Table 7.2.

Diagnostic evaluation. Syringomyelia can be diagnosed from its typical symptoms and physical findings; the characteristic picture is of a dissociated sensory deficit combined with trophic disturbances. The diagnosis must then be confirmed with neuroimaging, specifically MRI (Fig. 7.12).

Clinical course. Syringomyelia is usually slowly progressive.

Treatment. Neurosurgical methods are occasionally successful. The options include the Puusepp operation (opening the posterior aspect of a large syrinx into the subarachnoid space), drainage of the syrinx with a shunt, or operation of an accompanying Arnold−Chiari malformation at the craniocervical junction.

7

Diseases of the Spinal Cord

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152 7 Diseases of the Spinal Cord

Table 7.2 Common symptoms and signs of syringomyelia

Symptoms/signs	Localizing significance	Remarks
Spastic paraparesis/	pressure of syrinx cavity on the pyramidal tracts	may be unilateral or asymmetric
aspastic quadriparesis

Muscle atrophy

Sensory level

Unior bilateral dissociated sensory deficit below a given level

Segmental loss of all modalities of sensation

Pain

Segmental dissociated sensory deficit

Autonomic disturbances

Trophic disturbances

Kyphoscoliosis

Associated anomalies

loss of anterior horn ganglion cells

pressure of syrinx cavity on all ascending sensory pathways

unior bilateral involvement of the ascending spinothalamic tract

syrinx involving posterior root entry zone

involvement of entering sensory fibers or ascending spinal cord pathways

syrinx involving the anterior spinal commissure, thereby interrupting the decussating fibers of the spinothalamic tract

involvement of the intermediolateral tract in the upper thoracic spinal cord, or of the lateral horns

as above

secondary to weakness of the paravertebral muscles

part of a disorder of prenatal development

segmental, usually unilateral

differential diagnosis: extramedullary lesion compressing the spinal cord

highly characteristic

usually unilateral or asymmetrical; predisposes to burns and other types of mutilating injury

segmental, bilateral, less commonly unilateral

impaired sweating, succulent edema, osteolytic bone lesions, arthropathy

severe spondylosis, mutilation of the fingers

usually later in the course of the disease; rarely congenital

basal impression, Arnold−Chiari malformation, spina bifida, hydrocephalus

a

b

Fig. 7.12 Thoracic syringomyelia (MRI). a The axial image reveals the expanded central canal as a cavity (syrinx) in the middle of the spinal cord. b The sagittal image shows the syrinx extending from T4 to the lower border of T8.

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