Cerebellar Diseases

Other Types of Involuntary Movement

Tremor

Types of tremor. The main phenomenological distinction is between rest tremor and action tremor. The latter, in turn, is subdivided into postural tremor, isometric tremor (appearing when a muscle is contracted against constant resistance), and kinetic tremor (appearing only during movement). Intention tremor is a type of kinetic tremor that worsens as the limb approaches its target. Tremor can also be classified etiologically as parkinsonian tremor (discussed above), psychogenic tremor

(generally of highly variable severity, coarse, and demonstrative), alcoholic tremor (fine rest and intention tremor, worse after alcohol withdrawal, better after alcohol consumption), or essential tremor. The last named is often misdiagnosed as Parkinson disease.

Essential tremor is the most common type of tremor and often runs in families. It is a predominantly postural and sometimes also kinetic tremor of the hands; a pure intention tremor is seen in 15 % of patients (see p. 29). It may also affect the head in isolation (nodding tremor of the “yes” or “no” type), sometimes including the chin and/or vocal cords. It typically improves after the consumption of a small amount of alcohol and worsens

with nervousness or stress. It usually arises between the ages of 35 and 45. Genetic defects causing familial essential tremor have been found on chromosomes 2p22− p25 and 3q. “Essential tremor plus” is a combination of this entity with another neurological disorder (e. g., Parkinson disease, dystonia, myoclonus, polyneuropathy, restless legs syndrome).

Further types of tremor that will not be discussed here in any detail include autonomic (vegetative) tremor, hyperthyroid tremor, and the tremor of Wilson disease.

Treatment. If the tremor is severe enough to interfere with the patient’s everyday activities, a beta-blocker such as propranolol can be tried; this agent is particularly effective against essential tremor. Primidone, benzodiazepines, and clozapine are further alternatives. Deep brain stimulation through an electrode that has been stereotactically implanted in the nucleus ventrointermedius (V.im.) of the thalamus is highly effective but is reserved for severe and medically intractable cases.

Differential diagnosis. Involuntary movements arising from diseases of the basal ganglia must be differentiated from a variety of other movement disorders, which are listed in Table 5.3 (p. 71).

Cerebellar Diseases

Cerebellar disturbances present clinically with disequilibrium, truncal, and/or appendicular ataxia, impaired coordination, and diminished muscle tone (p. 80). Like disturbances of the cerebral hemispheres, they are usually due either to vascular processes (ischemia, hemorrhage) or to tumors. Multiple sclerosis is a further, common cause.

In this section, we will also discuss other diseases that may present primarily with cerebellar dysfunction, including infectious, parainfectious, (heredo-)degenerative, toxic, and paraneoplastic conditions, as well as cerebellar involvement in general medical diseases.

Acute cerebellitis is similar to the foregoing and affects both children and adults. In older patients, the clinical manifestations may persist.

Atrophie cérébelleuse tardive à prédominance corticale is a historic term encompassing a group of disorders that share the neuropathological finding of extensive loss of Purkinje cells, particularly in the vermian cortex. This is expressed clinically as unsteady gait, truncal ataxia, less severe appendicular ataxia, and nystagmus. The underlying disorder may be a cerebellar degeneration of genetic or (to date) unexplained etiology or a symptomatic involvement of the cerebellum, e. g., late cerebellar atrophy in chronic alcoholism or subacute paraneoplastic cerebellar cortical atrophy.

The More Common Diseases

of the Cerebellum

Acute cerebellar ataxia in childhood arises a few days or weeks after a chickenpox infection, less commonly after another viral illness. The patient is usually a school-aged child. Unsteady gait, ataxia, tremor, and nystagmus are the characteristic signs; they usually resolve spontaneously and completely within a few weeks.

blubber blubber

Cerebellar heredoataxias are of genetic origin. The enzymatic defects and pathophysiological mechanisms underlying each have not yet been determined, except in a few patients. These disorders are listed together with sporadic and symptomatic forms of cerebellar ataxia in Table 6.27.

Spinocerebellar ataxias involve not only the cerebellum, but also the spinal cord (cf. p. 153).

Intermittent cerebellar dysfunction has various causes, among which are pyruvate dehydrogenase deficiency, Hartnup disease, and familial periodic paroxysmal

Mumenthaler / Mattle, Fundamentals of Neurology © 2006 Thieme All rights reserved. Usage subject to terms and conditions of license.

135

6

Diseases of the Brain and Meninges

136	6 Diseases of the Brain and Meninges
		Table 6.27 Types of cerebellar ataxia
		Category	Disease	Clinical features	Remarks
		Autosomal	Friedreich ataxia	lumbering, broad-based, unsteady gait, pro-	GAA triplet expansion on
		recessive		gressive from the 1st or 2nd decade onward;	chromosome 9; impaired syn-
		hereditary		later, clumsiness of the hands, explosive	thesis of the protein frataxin
		ataxias		speech; typical Friedreich foot (see Fig. 7.13);
				scoliosis, hypotonia

Refsum disease (heredopathia atactica polyneuritiformis)

ataxia of gait and limbs beginning in childhood or adolescence, polyneuropathy with areflexia and sensory loss, hearing impairment, retinitis pigmentosa, mental abnormalities

lack of phytanic acid α-dehy- drogenase

A -lipoproteinemia (Bas-	progressive ataxia, nystagmus, ophthalmople-	low serum lipoprotein, choles-
sen−Kornzweig syndrome)	gia, polyneuropathy; acanthocytosis, low cho-	terol, and triglyceride values
	lesterol and triglyceride values; vitamin E defi-
	ciency

Ataxia telangiectasia	onset in infancy with ataxia and choreoatheto-
(Louis−Bar syndrome)	sis; frequent lung, ear, nose, and throat infecti-
	ons, slow eye movements; telangiectases in
	conjunctiva and joint creases

one of the chromosomal fragility syndromes

spinocerebellar ataxia

(different varieties, e. g., deficiencies of hexosaminidase, glutamate dehydrogenase, pyruvate dehydrogenase, ornithine transcarbamylase, or vitamin E

onset usually in the 1st decade, sometimes later, ataxia with variable accompanying deficits, e. g., mental retardation, visual or hearing impairment, polyneuritis, myoclonus, etc.; speech may be loud, deep, and harsh (“lion’s voice”)

Autosomal	cerebellar cortical atro-	onset at age 20 or later, with cerebellar signs	genetically heterogeneous,
dominant	phy (Holmes type = Har-		SCA 5 and SCA 6
hereditary	ding type III)
ataxias

	olivo-ponto-cerebellar
	atrophy (Menzel type =
	Harding type I)
	cerebellar atrophy (Harding
	type II)
Sporadic	nonhereditary ataxias
ataxias	“atrophie cérébelleuse tar-
	dive à prédominance corti-
	cale”
Symptomatic	tumor, infarct, hemorrhage,
ataxias	multiple sclerosis, infection,
	birth defect, chronic alcoho-
	lism, other toxic causes, vita-
	min E deficiency, hypothyroi-
	dism, malabsorption syn-
	drome, sprue, ataxia in gluten
	hypersensitivity, paraneoplas-
	tic, physical

onset at age 20 or later; cerebellar and noncerebellar signs including optic atrophy, basal ganglionic dysfunction, pyramidal tract signs, muscle atrophy, and sensory deficits, and sometimes dementia

onset after age 20 with cerebellar signs and retinal degeneration

onset in late adulthood with slowly progressive gait and truncal ataxia, later arm ataxia ; rarely, nystagmus, muscle hypotonia, and pyramidal tract signs

clinical features depend on cause

genetically heterogeneous, SCA 1−SCA 4; SCA 3 = Machado−Joseph disease

corresponds to SCA 7

symmetrical degeneration of Purkinje cells, predominantly in the vermis

often with accompanying involvement of other systems and organs

SCA = spinocerebellar ataxia

ataxia. The last named is a genetic disease, due to a defect on chromosome 19p, which responds to treatment with acetazolamide. Intermittent ataxia is also seen in many cases of multiple sclerosis.

Cerebellar dysfunction in other diseases is usually manifest as ataxia. Intoxication with diphenylhydantoin, lithium, organic mercury, piperazine, 5-fluorouracil, or

DDT is a common cause. Others include infectious diseases, such as mononucleosis, macroglobulinemia, myxedema, vitamin B deficiency, heatstroke, cerebellar tumors, and cranial polyneuritis (p. 175). There is also a form of gluten-induced ataxia, which may or may not be accompanied by gastrointestinal symptoms. Finally, cerebellar dysfunction may be the presenting manifestation of Creutzfeldt−Jakob disease.

Mumenthaler / Mattle, Fundamentals of Neurology © 2006 Thieme All rights reserved. Usage subject to terms and conditions of license.