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Fifth stage
Medicine
Lec-4
د.بشار
3/11/2015
MOVEMENTS DISORDERS
DISEASES OF EXTRAPYRAMIDAL SYSTEM
DISEASES OF BASAL GANGLIA
Parkinson Disease
Parkinson disease is an idiopathic, slowly progressive, degenerative disorder characterized
by resting tremor, stiffness (rigidity), slow and decreased movement (bradykinesia), and
gait and/or postural instability.
Parkinson disease (PD) affects about 0.4% of people > 40 yr, 1% of people ≥ 65 yr, and 10%
of people≥ 80 yr. The mean age at onset is about 57 yr.
Rarely, PD begins during childhood or adolescence (juvenile parkinsonism). Onset between
ages 21 and 40 yr is sometimes called early-onset PD.
Pathophysiology
Synuclein is a neuronal and glial cell protein that can aggregate into insoluble fibrils and
form Lewy bodies. The pathologic hallmark of PD is synuclein-filled Lewy bodies in the
nigrostriatal system.
In PD, pigmented neurons of the substantia nigra, locus ceruleus, and other brain stem
dopaminergic cell groups degenerate. Loss of substantia nigra neurons results in depletion
of dopamine in the dorsal aspect of the putamen (part of the basal ganglia) and causes
many of the motor manifestations of PD.
Etiology
A genetic predisposition is likely, at least in some cases. About 10% of patients have a
family history of PD. Several abnormal genes have been identified. Inheritance is autosomal
dominant for some genes and autosomal recessive for others. In genetic forms, age at
onset tends to be younger, but the course is typically more benign than that of later-onset,
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Symptoms and Signs
In most patients, the disease begins insidiously.
A resting tremor of one hand is often the first symptom. The tremor is characterized as
follows
Slow and coarse
Maximal at rest, lessening during movement, and absent during sleep
Amplitude increased by emotional tension or fatigue
Often involving the wrist and fingers, sometimes involving the thumb moving against
the index finger (pill rolling), as when people roll a pill in their hand or handle a small object
Usually, the hands or feet are affected first, most often asymmetrically. The jaw and tongue
may also be affected, but not the voice. Tremor may become less prominent as the disease
progresses.
Rigidity develops independently of tremor in many patients. When a clinician moves a rigid
joint, semirhythmic jerks due to variations in the intensity of the rigidity occur, producing a
ratchet-like effect (cogwheel rigidity.)
Slow movements (bradykinesia) are typical. Movement also becomes decreased in
amplitude (hypokinesia) and difficult to initiate (akinesia.)
Rigidity and hypokinesia may contribute to muscle aches and sensations of fatigue. The face
becomes masklike (hypomimic), with an open mouth and reduced blinking. Excessive
drooling (sialorrhea) may contribute to disability. Speech becomes hypophonic, with
characteristic monotonous, sometimes stuttering dysarthria. Hypokinesia and impaired
control of distal muscles cause micrographia (writing in very small letters) and make
activities of daily living increasingly difficult. Without warning, voluntary movement,
including walking, may suddenly halt (called freezing of gait.)
Postural instability may develop, resulting in falls, which occur later in PD. Patients have
difficulty starting to walk, turning, and stopping. They shuffle, taking short steps, holding
their arms flexed to the waist, and swinging their arms little or not at all with each stride.
Steps may inadvertently quicken, while stride length progressively shortens; this gait
abnormality, called festination, is often a precursor to freezing of gait. A tendency to fall
forward (propulsion) or backward (retropulsion) when the center of gravity is displaced
results from loss of postural reflexes. .
Dementia
Sleep disorders are common..
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Neurologic symptoms unrelated to parkinsonism commonly develop because
synucleinopathy occurs in other areas of the central, peripheral, and autonomic nervous
systems. The following are examples
Almost universal sympathetic denervation of the heart, contributing to orthostatic
hypotension
Esophageal dysmotility, contributing to dysphagia and increased risk of aspiration
Lower bowel dysmotility, contributing to constipation
Urinary hesitancy and/or urgency, potentially leading to incontinence (common)
Anosmia (common)
In some patients, some of these symptoms occur before the motor symptoms of PD.
Seborrheic dermatitis is also common.
Diagnosis
Mainly clinical evaluation, based on motor symptoms
Treatment
Carbidopa/levodopa (mainstay of treatment)
Amantadine
MAO type B (MAO-B) inhibitors, or, in few patients, anticholinergic drugs
Dopamine agonists
Catechol O-methyltransferase (COMT) inhibitors, always used with levodopa,
particularly when response to levodopa is wearing off
Surgery if drugs do not sufficiently control symptoms or have intolerable side effects
Exercise and adaptive measures.
Chorea, Athetosis, and Hemiballismus
Chorea
Movements are nonrhythmic, jerky, rapid, and nonsuppressible, primarily in distal muscles
or the face.
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Sometimes abnormal movements are incorporated into semipurposeful acts that mask the
involuntary movements.
Chorea often occurs with athetosis as choreoathetosis
Huntington disease, hyperthyroidism, hypoparathyroidism, paraneoplastic syndromes, SLE
affecting the CNS, other autoimmune disorders, rheumatic fever, tumors or infarcts of the
caudate nucleus or putamen
Pregnancy, often in women who had rheumatic fever
Senile chorea
Drugs that can cause chorea (eg, levodopa, phenytoin
,cocaine, oral contraceptives
Drugs that can cause tardive dyskinesia (eg, antipsychotics.)
Athetosis (slow chorea) is nonrhythmic, slow, writhing, sinuous movements predominantly
in distal muscles, often alternating with postures of the proximal limbs.
Huntington disease, encephalitis, hepatic encephalopathy
Drugs (eg, cocaine, amphetamines, antipsychotics)
Hemiballismusis unilateral rapid, nonrhythmic, nonsuppressible, wildly flinging movement
of the proximal arm and/or leg; rarely, such movement occurs bilaterally (ballismus).
Hemiballismus is a severe form of chorea
Dystonias
Sustained muscle contractions often distort body posture or cause twisting, repetitive
movements.
Primary (idiopathic)
Degenerative or metabolic disorders (eg, Wilson disease, various lipidoses, multiple
sclerosis, cerebral palsy, stroke, brain hypoxia)
Drugs that block dopamine receptors, most often antipsychotics (eg, phenothiazines,
thioxanthenes, butyrophenones) or antiemetics
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