6) Neurologically Mediated Disorders of Muscle Control Flashcards
1
Q
Cerebellum main function
A
- Motor control
- Enables smooth, well timed, proportional responses
- Speech, emotions, as well as pleasure and fear
2
Q
Cerebellum controls
A
- Unconscious posture and balance
- Coordination of smooth voluntary movement
3
Q
Lobes of the cerebellum
A
- Paleocerebellar (anterior)
- Flocculonodular (middle)
- Neocerebellar (posterior)
4
Q
Paleocerebellar (anterior) lobe function
A
- Unconscious posture, balance and proprioception
5
Q
Flocculonodular (middle) lobe (aka vestibulocerebellum) function
A
- Vestibular – unconscious equilibrium
6
Q
Neocerebellar (posterior) lobe function
A
- Receives input from cerebral motor cortex
- Coordinates voluntary skilled movements
7
Q
Cerebellum afferent input
A
- Cerebral cortex
- Vestibular tracts
- Spinocerebellar tract
8
Q
Cerebellum efferent input
A
- Integrates afferent “input” plus data from red nucleus and basal ganglia
- Relayed to cerebral motor cortex voluntary initiation of movement
9
Q
Somatotopic arrangement in vermis
A
- The unpaired, median portion of the cerebellum
- Connects the two hemispheres
10
Q
Dyssynergia
A
- Decomposition of movement
- Inability to perform voluntary movements smoothly
- Lack of normal coordination between agonists, and synergists
11
Q
Dyssynergia recognition
A
- Use of accessory muscles
- Wide arc of motion
- Asthenia
12
Q
Asthenia
A
- Weakness
- Lack of energy and strength
- Hyporeflexia
13
Q
Dysrhythmia
A
- Abnormal timing and coupling of movement
14
Q
Dysmetria
A
- Inability to gauge distance, speed, strength and velocity
- Excessive rebound
- Delay in initiation or cessation of movement
15
Q
Intention tremor
A
- Exacerbated at end of goal-related movement
- Medium frequency tremor
16
Q
Staccato speech
A
- Slurred, jerky or explosive
- Syllabic
- Clipped like speech
17
Q
Nystagmus
A
- Rapid jerky eye movements
18
Q
Signs of cerebellar damage
A
- Dysdiadokinesia / Dysmetria
- Ataxia
- Nystagmus
- Intention tremor
- Speech (slurred or scanning)
- Hypotonia
19
Q
Ataxic gait
A
- Wide based gait
- Slow, jerky cadence
- Stride length and foot placement vary with each step
- Frequent loss of balance
- Patient performs numerous “adjustments”
- Two-phase foot contact (heel then toe “double tap”)
20
Q
Cerebellum ataxic gait treatment
A
- Palliative (primary)
- Increase stability during ambulation
- Quad cane
- Walker
- Physical therapy
- Functional or accommodative orthoses
21
Q
Cerebellum clinical evaluation
A
- Carries unconscious proprioception
- Romberg’s Test
- Coordinates smooth volitional movements
- Heel to shin test
- Alternate patting test
- Gait analysis ataxic
22
Q
Ataxic gait clinical evaluation
A
- Paleocerebellar lesion
- Disturbance of equilibrium
- Neocerebellar hemispheres
- Classic signs of ataxic gait
23
Q
Basal ganglia
A
- Control intentional movement
- Responsible primarily for motor control
- Collection of nuclei deep within brain
24
Q
Basal ganglia nuclei
A
- Receive input from pre-motor cortex regarding “planned movement”
- Efferent pathways then control movement
25
Basal ganglia involved with movement
- Caudate
- Putamen
- Substantia nigra
26
Basal ganglia lesions result in
- Awkward unintentional movements
27
Striatum (caudate and putamen)
- Primarily inhibitory effect on thalamus
- Receive input from cerebral cortex
- Relay this input to globus pallidus
- Globus pallidus outputs to thalamus
28
Striatum (caudate and putamen) neurotransmitters
- Acetylcholine
| - γ-Aminobutyric acid (GABA)
29
Striatum (caudate and putamen) injury results in
- Hyperkinetic disorders
| of movement
30
Substantia nigra
- Communicates directly with striatum
- Deterioration results in hypokinetic disorders
- Neurotransmitter is dopamine
31
Substantia nigra primary function
- Eliminates excessive movement
- Keeps the body still when it needs to be still
- Allows the body to move without extraneous movements
32
Huntington's chorea
- Chronic progressive degenerative CNS disorder
| - Selective loss of caudate and putamen
33
Huntington's chorea incidence
- Autosomal dominant transmission
- Defect in chromosome 4
- Occurs in all ethnic and racial groups
- 5 to 10/100,000
34
Huntington's chorea characteristics
- Choreic (dance-like) involuntary movement
- Progressive dementia
- Psychiatric and behavioral disturbances
35
Huntington's chorea shows extensive hypertrophy of
- Basal ganglia
- Cerebral cortex
- Cerebellum
36
Huntington's chorea treatment
- No drug to attenuate the disease process
- Can only minimize symptoms
- Tetrabenazine (Xenazine)
- Deutetrabenazine (Austedo)
- Haloperidol
- Phenothiazines
- Antidepressants
37
Sydenham's chorea
- Sequella of Group A β-hemolytic strep infection
- Major diagnostic criteria for rheumatic fever
- Most important form of childhood chorea
38
Sydenham's chorea characteristics and incidence
- Autoantibodies target basal ganglia cells
- Peak incidence – 8 years old
- More common in females
39
Syndeham's chorea clinical recognition
- Insidious onset
- Emotional lability
- Facial grimacing
- Involuntary flinging movements
- Exacerbated with attempts to control movements and abate while sleeping
40
Sydenham's chorea diagnosis
- ASO titres
- ↑ acute phase reactants
- Acute-phase reactants, the erythrocyte sedimentation rate (ESR), and C-reactive protein levels (CRP) are usually elevated at the onset of Acute Rheumatic Fever
41
Huntington's disease vs. Sydenham's chorea
- Huntington's = progressive, and ultimately, fatal disease
| - Sydenham's chorea = treatable and curable
42
Sydenham's chorea treatment
- Penicillin or erythromycin
| - Must be continued for minimum of 10 days
43
Palliative treatment of Sydenham's chorea
- Valproic acid
- Carbamazepine or haloperidol
- Minimize external stimuli
44
Parkinsonism is characterized by
- Tremor
- Muscular rigidity
- Bradykinesia
- Alterations of posture and attitude of extremities
- Paralysis agitans
- Festination
45
Parkinsonism etiologies
- Exposure to environmental toxins
- Free radical generation
- Inheritance (?)
46
Parkinsonism prevalence
- 1% of population
| - 50,000 new cases per year
47
Parkinsonism disease progression
- Slow and gradual
| - With treatment – normal life expectancy
48
Parkinsonism pathology
- Loss of dopaminergic neurons in substantia nigra
| - 80% of neurons are lost before disease is evident
49
Parkinsonism clinical features
- Tremor (pill rolling)
- Rigidity
- Bradykinesia (slow movement)
- Gait and posture disturbances
50
Resting tremor (parkinsonism)
- “Pill rolling” – 4 – 6 Hz
- Initial complaint ~75% of time
- Begins one-sided – usually a hand
51
Cog-wheeling (Parkinsonism)
- A jerky feeling in your arm or leg
52
Rigidity (Parkinsonism)
- Stooped posture
| - Shuffling gait
53
Bradykinesia (Parkinsonism)
- Slowness with muscular fatigue – “freezing”
| - Akinesia or lack or “poverty of motion”
54
Loss of facial expression (Parkinsonism)
- Monotonous, stuttering, “deliberate” speech
| - Masked facies due to muscular fatigue
55
Parkinsonism gait disturbances
- Shuffling gait
- Development of a forward or backward lean
- Festination
- Retropulsion
56
Festination
- Correction of forward lean
- Sudden short shuffling steps
- Become progressively shorter and faster
57
Retropulsion
- Correction of backward lean
| - Rapid backwards steps
58
Parkinsonism pharmacologic intervention
- Replace dopamine (levodopa, carvidopa)
- Dopamine agonists (peroglide)
- Selegine (MAO inhibitor, delays need for levodopa)
- Amantadine
- Anticholindergics
- COMT inhibitors
59
Parkinsonism surgical intervention
- Globus pallidus pallidotomy (relieves dyskinesias)
- Deep brain stimulation (relieves tremors and dyskinesias, electrode placed within thalamus)
- Fetal nigral transplantation (implantation of fetal cells, experimental)
60
Wilson's disease
- Accumulation of copper in tissue
- Defect in ceruloplasmin (carries copper around your body to the tissues that need it)
- Autosomal recessive inheritance
61
Wilson's disease symptoms
- Basal ganglia disorders
- Hepatic cirrhosis
- Kayser-Fleischer Rings (RINGS AROUND THE IRIS)
- Arm flapping
62
Wilson's disease treatment
- C-penicillamine
63
Essential tremor
- Generally postural
| - Autosomal inheritance with incomplete penetrance
64
Essential tremor incidence
- Late adolescence
- Older adulthood
- Male to female – 1:1
65
Essential tremor clinical recognition
- Typically occurs when hands are in use
- Average tremor 6 – 8 Hz
- Physiologic and emotional stress exacerbate symptoms
66
Essential tremor treatment
- Symptoms relieved with alcohol
- Propranolol
- Anti-seizure medication
- Tranquilizers
- Botox injections
67
Cerebral palsy
- Chronic, non-progressive motor dysfunction
| - Evident within first two years of life
68
Cerebral palsy incidence
- 1.5 - 7.5 per 1000 live births
| - Greater incidence in low birth weight infants
69
Cerebral palsy (prenatal)
- Often idiopathic
- Genetic disease
- Maternal disorders (gestational diabetes, Rh incompatibility, toxemia)
- Fetal malformations
- Presence of more than one fetus (crowding)
70
Cerebral palsy (natal)
- Most common etiology
- Any process or insult at the time of delivery or within the first week
- The majority of CP (85%–90%) is congenital
71
Natal cerebral palsy common etiologies
- Prematurity
- Anoxia
- Respiratory distress
72
Postnatal cerebral palsy
- Injury from one week to two years of age
73
Kernicterus
- A type of brain damage that can result from high levels of bilirubin in a baby's blood
- It can cause athetoid cerebral palsy and hearing loss.
74
Postnatal cerebral palsy frequent etiologies
- Anoxia
- Encephalitis
- Infection
- Poisoning
- Seizures
- Trauma
- Intracranial Hemorrhage
- Periventricular Leukomalacia
75
Pyramidal cerebral palsy
- Spastic”
- Most common presentation – 64% of cases
- Lesion located in periventricular
76
Pyramidal cerebral palsy is characterized by
- Lesion in premotor cortex
- Upper motor neuron lesion
- Increased resistance to passive range of motion
- Delayed motor milestones
- Retention of primitive reflex responses
- Lesion location typically periventricular
77
Periventricular leukomalacia
- Affects the corticospinal tract, optic and acoustic radiations
- Intraventricular hemorrhage
78
Pyramidal CP hemiplegia (30%)
- Two limbs on same side of body
- Upper extremity more involved
- Spastic limbs are thinner and smaller
- Associated with leg length discrepancy
- Babinski sign present in post natal cases
79
CP Diplegia/paraplegia (20%)
- Paralysis of legs
| - Paraplegia may affect arms but to a lesser extent
80
CP quadriplegia (13%)
- Involves all four limbs equally
| - Double hemiplegia – arms more severely involved than legs
81
Extrapyramidal CP athetosis (11%)
- Post natal Kernicterus
- Undergo “athetoid” shift with bracing or surgery
- Snake like movement
82
Extramyramidal CP hypotonia (5%)
- Motor cortex lesion
| - Decreased or absent muscle tone
83
Extrapyramidal CP rigidity (5%)
- Lead pipe or cogwheel rigidity
| - Resistant to motion greatest with slow stretch
84
Extrapyramidal CP tremor (1%)
- Rhythmic, alternating movements
| - Occur with rest or voluntary movements
85
Extrapyramidal CP ataxia (5-10%)
- Cerebellar dysfunction
- Balance disturbance
- Presence of intention tremor
86
Pyramidal tract disease gait abnormalities
- Increased flexor tone
- Equinovarus foot deformities
- “Scissored” Gait
87
Scissor gait
- Internally rotated hips with adduction of leg
- Arms adducted at shoulders and flexed at wrists and knees
- Toe walking
88
Athetosis
- Slow serpentine movements
- Extreme postures vary between flexion with supination and extension with pronation
- Limb postures asymmetric
- Concomitant rotary movements of neck
89
Equinus
- Spastic Gastrocsoleus
- Most common deformity
- Treat with night splints, orthoses
Surgical intervention
90
Pes varus
- Continuous activity of posterior or anterior tibial muscle
- Swing phase activity of posterior tibial muscle
- Decreased peroneal activity
91
Cavus foot
- Calcaneal inclination angle > 25°
| - Complication of spastic gastrocsoleus correction
92
Forefoot equinus
- Dynamic muscular imbalance
| - Flexor stabilization secondary to spastic gastrocsoleus
93
Metatarsus adductus
- Spasm of adductor hallucis
94
Cerebral palsy treatment
- Physical and occupational therapy
- Bracing
- Botox
- Temporary relief of spasm
- Prevents exophytic release of acetylcholine
- Denervates muscle resulting in flaccid paralysis
- Toxic effects limited to peripheral nervous system!
95
Multiple sclerosis
- Focal or patchy destruction of myelin sheaths of central nervous system
- Recurrent attacks of focal or multi-focal neurologic dysfunction
96
Multiple sclerosis mechanism
- Autoimmune disease that destroys CNS elements
- Dysregulated autoreactive T-cells that cross into the CNS
- Works together with beta cells and macrophages
- Inflammatory reaction creates additional demyelination and tissue injury
97
Multiple sclerosis degeneration
- Primary cytodegeneration is the initial event
- Possibly focused on the oligodendrocyte myelin complex
- Highly antigenic constituents are released
- This is what causes CNS degeneration
98
MS onset
- Between third and fourth decade
| - Females: ~60%
99
MS genetic factors
- Positive family history → 8-fold increased risk
- Associated with histocompatibility loci
- Defect of chromosome 6
100
MS regional factors
- Higher latitude
| - Risk seems to be inversely proportional to sunlight exposure
101
MS autoimmune factors
- Molecular mimicry
- Anti-viral response against myelin
- Super antigenic stimulation of T-cells
102
MS additional factors
- Tobacco
- Vascular comorbidities
- Epstein Barr virus??
- Gut flora???
- Emotional or physiologic stress
- There is a correlation between the level of serum vitamin D and MS risk
103
MS classification
- Benign - 10%
- Relapsing-remitting – 40%
- Secondary chronic progressive – 40%
- Primary progressive – 10%
104
MS pathology
- Scattered areas of demyelination (plaques)
- Deficit from a few mm to several cm
- Often paraventricular areas of cerebrum, brainstem and spinal cord
- Affects white matter predominantly
- Peripheral nervous system is generally spared
105
MS first attack
- Single symptom – 45%
- Multiple symptoms – 55%
- Optic neuritis
- Generally unilateral
- 40% of patients
106
MS early symptoms
- Numbness
- Ataxia
- Muscular weakness
- Diplopia
107
MS diagnosis
- Two episodes of neurologic deficit
- Objective clinical signs of lesions at more than one site in the CNS
- CT or MRI confirming presence of second lesion
108
MS clinical presentation
- Ocular: Impaired vision, nystagmus
- Cerebellar: Ataxia, intention tremor
- Sensory: Dorsal column symptoms
- Motor involvement: Dependent upon location of lesion
109
Myasthenia gravis
- Acquired autoimmune disorder
| - Antibodies formed against acetylcholine receptors
110
Myasthenia gravis incidence
- 0.25 to 2 per 100,000
- Early onset: < 40 years (slightly higher in females, 60% HLA-B8 and DR3, thymus gland involvement)
- Late onset: > 40 years (slightly higher in males, no thymus gland involvement)
111
Myasthenia gravis clinical features
- Painless muscular fatigue and weakness
- Ocular: generally bilateral ptosis and diplopia
- Bulbar and facial weakness: reduced facial expression
- Limb weakness: more pronounced proximally
- Dyspnea on exertion
112
Lambert-Eaton Myasthenic Syndrome
- Acquired autoimmune disease
| - Number of acetylcholine “quantals” released is affected
113
Lambert-Eaton Myasthenic Syndrome incidence
- Males to females – 1:1
| - Often associated with small cell carcinoma of the lung (more than 50%
