CNS 5

Upper & Lower Motor Neuron Lesion

Corticospinal (upper) and neuromuscular (lower) loss of motor function This include Corticospinal tract & its neuron up to the anterior horn cell. Loss of voluntary control but no total loss of movement. Posture: arm flexed ,leg extended. Tone ↑. Reflexes ↑. Babiniski: present. Atrophy: possible. Fasciculation: absent. Lower: This include AHC , motor root , peripheral motor nerve , neuromuscular junction & muscles. Total loss of movement. Flaccid posture. Tone ↓. Reflexes ↓. Babinski: absent. Atrophy: possible. Fasciculation: possible.

UMNL Stroke in childhood: Obstruction of the blood flow may occur in arteries or veins & may be caused by local thrombosis or remobilization from distant site. Cerebral embolization occur within seconds & associated with focal seizure , headache & hemorrhagic infarction & the common sources are the heart and the carotid artery. T I A : it precede the cerebral thrombosis that produced its full deficits in hrs.

Etiology: Arteriopathy: as transient cerebral arteriopathy (TCA), postvaricella angiopathy, trauma. Cardiac Disease: Congenital: (cyanotic ≫ acyanotic)     Acquired: as catheterization/procedure, arrhythmia, endocarditis … Hematologic Abnormalities: as hemoglobinopathies, polycythemia, thrombocytosis, disorders of coagulation. Other including metabolic/genetic etiologies: Acute systemic illness (e.g., dehydration, sepsis, DKA) Chronic systemic illness (e.g., systemic lupus erythematosus, leukemia) Illicit drugs and toxins (e.g., cocaine) Neurofibromatosis type 1 Homocystinuria

Treatment : There is no treatment to repair the neurologic injury after the stroke, so prevention of future stroke must be the focus in children if the etiology can be identified. Treatment of strokes in evolution, recurrent TIA, or ongoing cerebral embolization: anticoagulants (heparin, warfarin). platelet antiaggregants (aspirin and dipyridamole). thrombolysis is not recommended for children treat underlying cause.

LMNL Disease of the lower motor unit produces progressive loss of strength with hypotonia and no abnormality of posture. Etiology: Anterior Horn Cell: as Spinal muscular atrophy( SMA). Peripheral Nerve: as Guillain-Barré syndrome (GBS). Neuromuscular Junction: as Myasthenia gravis (MG) Muscle: as   Duchenne (DMD) & dermatomyositis. Metabolic, Endocrine, and Mineral: as GSDII, thyroid excess or deficiency, potassium excess or deficiency (periodic paralysis)

SMA Etiology: 3 types Autosomal recessive. Progressive degeneration of anterior horn cells is the key manifestation of SMA. A genetic disease that may begin in intrauterine life or any time thereafter. 3 types Type 1: 25% “Werdnig-hoffmann disease (WHD)” severe infantile form. Type 2: 50% “Kugelberg-Welander syndrome” late infantile slowly progressive form. Type 3: 25% “Juvenile SMA” chronic form. Autosomal recessive. WHD: start as progressive proximal weakness , ↓spontaneous movement , floppiness , atrophy of muscles , loss of head control , drooling , ↓ facial expression ,loss of reflex , eyes remain bright open, tongue fasciculation (sleep), normal mentality , language & sensation Cause of death: respiratory infection , respiratory failure. Diagnosis: CPKN/↑, EMGfasiculation, muscle biopsy specimens show grouped atrophy. The diagnosis is established by DNA probe for SMA. Treatment: Symptomatic therapy. Prognosis: SMA1: most infants die withen the 1st 2 years. SMA2: may survive to adulthood. SMA3: slow progression & normal life expectancy.

GBS GBS is a postinfectious autoimmune polyneuropathy involving mainly motor but sometimes also sensory and autonomic nerves. This syndrome affects people of all ages. The paralysis usually occur about 10 days after respiratory or GIT infecftion ( especially Mycoplasma pneumoniae or Campylobacter jejuni, but also Helicobacter pylori) Symptoms: Numbness & parasthesia in the hand and feet then heaveness then weakness followed by inability to walk in a symmetrical fashion beginning in the legs and ascending to involve the arms, trunk, throat and the face either in rapid progression over hrs , days or wks. Chronic Guillain-Barré syndrome that recur intermittently or do not improve for a period of months or years. Sign: Areflexia, hypotonia, minor sensory loss, meningial irritation, bulber & respiratory insufficiency, normal bladder & bowel function, autonomic dysfunctions.

Diagnosis: CSF: is often normal in the first days of the illness, then shows elevated protein levels without significant pleocytosis. CK: mildly elevated or normal. NCV: slow. EMG: denervation. MRI with gadolinium: may reveal enhancement of the spinal nerve roots in >90% of patients.

Treatment : Patients in early stages of this acute disease should be admitted to the hospital for observation because the ascending paralysis can rapidly involve respiratory muscles during the next 24 hr. Therapy is symptomatic and rehabilitative. Rapidly progressive ascending paralysis is treated with intravenous immunoglobulin (IVIG) Plasma exchange and immunosuppressive drugs are alternative.

Prognosis: The clinical course is usually benign, and spontaneous recovery begins within 2–3 wk. Most patients regain full muscular strength, although some are left with residual weakness. The clinical features which predict poor outcome with sequelae: Cranial nerve involvement. Intubation. Maximum disability at the time of presentation.

Duchenne Dystrophy Etiology : Clinical Manifestations : X-linked recessive. The disease results from absence of a large protein called dystrophin. Clinical Manifestations : Start at about 2 to 3 years of age. boys develop an awkward gait and an inability to run properly. Some have an antecedent history of mild slowness in attaining motor milestones, such as walking and climbing stairs. Examination shows: calf hypertrophy. mild to moderate proximal leg weakness. waddling gait and inability to arise from the ground easily. The child typically arises from a lying position on the floor by using his arms to "climb up" his legs and body (Gower sign). Weakness progress to involve the arm and the child become confined to wheelchair at 12 yrs. Death due to pneumonia or CHF.

CK level is always markedly elevated. Laboratory and Diagnostic Studies : CK level is always markedly elevated. Blood PCR for the dystrophin gene mutation. Muscle biopsy specimen shows muscle fiber degeneration and regeneration. Cardiac assessment by echocardiography, ECG, and CXR is essential and should be repeated periodically. Treatment : Supportive care includes physical therapy, bracing, proper wheelchairs, and prevention of scoliosis. Treatment of cardiac dysfunction & respiratory infection. Steroid therapy can delay motor disability.

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