Neonatal & Pediatric Neuromuscular Disorders

DISORDER TYPE	Dysfunction
Neuronopathy	anterior horn cell - spinal muscular atrophies
Neuropathy	peripheral nerves
Myopathy	muscles - muscular dystrophies
Myasthenic Syndrome	nerve/muscle junction
Other	Reye's, Hypoxic- Ischemic, Spinal Cord Injury

· Neuronopathy -spinal muscular atrophy- 

1. Werding Hoffman
1. Pathophysiology: Atrophy of spinal musculature autosomal recessive
2. Signs & Symptoms: Inactive neonate, Frog-like positioning with limited limb movement.diaphragmatic breathing with intercostal retractions weak cry, pooling secretions otherwise alert
3. Diagnostic criteria: Electromyography -denervation pattern
4. Treatment:  Supportive
2. Juvinile Spinal Muscular Atrophy (SMA) (Kugelberg-Welander)
1. Pathophysiology: slow progressive trophy of spinal musculature
2. appears in later childhood & adolescense
3. normal life span
4. starts in pelvic girdle, then arms & legs
3. Poliomyelitis

· Neuropathy

1. Congenital Hypomyelinating Neuropathy
2. Guillain Barre Syndrome
1. Pathophysiology:  Inflammatory destruction of myelin sheath surrounding spinal roots & peripheral nerves.  Generally preceded by a viral infection/illness (mono, hepatitis, influenza, CMV.
2. Signs & Symptoms: Characterized by ascending weakness/paralysis starting in lower extremities.  Tingling, numbness, muscle weakness with distal to proximal progression. May affect diaphragm & airway muscles.
3. Diagnostic Criteria: Aforementioned S & S, lumbar puncture to determine protein in CSF and if CSF is acellular, EMG, nerve conduction velocity test.
4. Treatment: Supportive, plasmapheresis, and high dose immunoglobulin.
3. Chronic Inflamatory Polyneuropathy
4. Metachromic leukodystrophy

· Myopathy -muscular dystrophy largest group affecting children

1. Duchenne Muscular Dystrophy (Pseudohypertrophic Muscular Dystrophy)
1. Pathophysiology: Numerous types, Duchenne & Becker focus on children.  Duchenne caused by defective gene on the X chromosome.
2. Signs & Symptoms: Gait disturbances in child < 5 years old, frequent falling, muscular weakness later in course of disease, intellectual handicap in males. Difficulty running, biking & stairs. Fatty infiltration causes enlargement of clalves, thighs, upper arms. Disease ultimately affects diaphragm.
3. Diagnostic Criteria: Muscle biopsy – serum kinase level >5X normal
4. Treatment: Supportive resp. care – IPPB when VD drops below 80% of predicted cpap/bipap/ippb
5. Respiratory failure by 30 yrs of age
2. Myotonic dystrophy 1/3500 live births
3. Nonprogressive myopathy

· Myasthenic Syndrome

1. Infantile Botulism
1. Pathophysiology: Toxicity by Clostridium Botulinum endotoxin.  Prevents acytlcholine release from motor nerve endings, results in paralysis.  Muscles of the head first affected, time of onset 12-72 hours.
2. Signs & Symptoms: Flaccid paralysis, weak sucking response, “floppy baby syndrome”, respiratory complications.
3. Diagnostic Criteria: Blood sampling, pump GI tract, retain & test food samples (honey, Karo syrup, etc)
4. Treatment:  A, B, & E Trivalent horse anti-toxins, respiratory and cardiac support.
2. Juvenile Myasthenia Gravis
1. Pathophysiology:  Thought to be autoimmune response whereby the number of acytlcholine receptors in the neuromuscular junction is reduced,
2. Signs & Symptoms: Muscle weakness, fatigability, ptosis, diplopia, abnormal nasal speech, regurgitation through nose upon swallowing, failure of the mouth to close, dyspnea, inadequate mucus clearance, weak cough.
3. Diagnostic Criteria: Electromyography, plasma antireceptor antibodies, Tensilon Test (Tensilon & neostigmine given & transient return of strength noted),
4. Treatment: Anticholinesterase drugs, Azathioprine, plasmapheresis in crisis, Corticosteroids.
3. Transient Neonatal  Myasthenia Gravis
1. From mothrs who may be unaware of their disease
2. general weakness, depressed neuro signs, weak cry
3. Must differentiate from the congenital form of disease
4. Tetanus
1. endotoxin of Clostridium tetani - incubation <2 weeks
2. skin wound - endotozin causes defect in transmission at neuromuscular junction
3. may occur in delivery of neonate in contaminated surroundings
4. initially stiffness of neck and jaw muscles
5. progresses to limb righidity
6. difficult swallow, sensitivity to external stimuli
7. laryngospam and tetany of respiratory muscles make the patient prone to aspiration of retained secretions, pneumonia & atelectatis
8. prevent twith inoculation every 10 years

· Other

1. Reye’s Syndrome
1. Pathophysiology:  Toxic encephalopathy affecting chiefly the brain & liver. In liver causes enlarged mitochondria, which reduce hepatic capacity to convert ammonia to urea. Related to antigen/antibody response, asprin ingestion, parainfluenza, epstein-Barr, coxsackie, mumps, rubella, adeovisis, herpes simples, polio, influenza A& B, varicella. Generally age 2-11
2. Signs & Symptoms: Post upper respiratory infection or chicken pox recurring vomiting with worsening CNS function.  Decorticate posturing post cerebral involvement, later decerabrate posturing muscle flaccidity, apnea. – non-contageous
3. Diagnostic Criteria: Increased SGOT, SGPT, & LDH, percutaneous liver biopsy, decreased Prothrombin levels
4. Treatment: 
1. Stage 1:Early detection, supportive care, treatments of acid/base disbalance & cerebral edem
2. Stage 2: monitoring blood glucose, coagulation, temp  cpt & suctioning and pt. Sedation as necessary, 
3. Stage3 & 4: intubation, thiopental & paralysis.  ICP kept <20, pulmonary toilet, dialysis, transfuse to reduce blood ammonia
5. Neurogenic pulmonary edema, increase ICP.  Rx with pheonobarbitol coma.
2. Spinal Cord & Brainstem
1. neck injury at birth or in accident.
2. tumors, infection, brainstem atrophy (Joseph disease)
3. Diaphragm innervatedby phrenic from cervical plexus, from C 3,4 (primarily), & 5, 
4. tx- preseve neuro function & prevent further damage, maximize recovery, prevent intercurrent nonneuro complications, pulmonary toilet & airway maintenance
3. Hypoxic Ischemic, Bleeding & Swelling
1. Perinatal Asphyxia
2. Near Drowning - replace surfactant?
3. head trauma
4. control ICP, hyperventilate, 
4. Cerebral Cortex
1. Cerebral Palsy
1. cough, deep breathe, support
2. Retts, Leighs encephalopathy
5. Epilepsy & Seizures