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Neurology mnd for 5th year 2011


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MND for 5th year 2011.

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Neurology mnd for 5th year 2011

  1. 1. Motor neuron disease MND:ALS Dr. Mohammad Shaikhani.
  2. 2. Lou Gehrig’s Disease <ul><li>A well-known baseball player. </li></ul><ul><li>He was diagnosed with ALS. </li></ul><ul><li>Within a year, he could not walk or talk. </li></ul><ul><li>He died in 1941. </li></ul>
  3. 3. MND (ALS): <ul><li>A progressive disorder of unknown cause. </li></ul><ul><li>There is degeneration of motor neurons in the spinal cord,cranial nerve nuclei& pyramidal neurons in the motor cortex. </li></ul><ul><li>5% of cases are familial, AD, the genetic defect on ch 21, the enzyme involved superoxide dismutase (SOD1). </li></ul><ul><li>For the remaining 95% unknown cause, ? viral infection, trauma, exposure to toxins , electric shock. </li></ul>
  4. 4. MND (ALS): <ul><li>A relentlessly progressive disorder with incidence of 2/ 100,000 </li></ul><ul><li>Most cases are acquired or sporadic, 5- 10% inherited </li></ul><ul><li>20% with inherited ALS have a mutation in the superoxide dismutase gene( important mediator in free-radical pathways) lead to excessive free-radical damage to anterior horn cells. </li></ul><ul><li>Patients report progressive painless weakness, atrophy, fasciculations beginning in an arm or leg. </li></ul><ul><li>Patients do not have sensory loss, pain, or impairment in bowel &bladder function. </li></ul><ul><li>Combinations of LMN signs of atrophy& fasciculations&UMN signs,as hyperreflexia& extensor plantars, are typically seen. </li></ul><ul><li>20% have bulbar-onset ALS, characterized by slurred speech, difficulty swallowing&emotional lability. </li></ul><ul><li>As ALS progresses, patients develop weight loss& resp failure. </li></ul><ul><li>The presence of cognitive impairment, specifically frontotemporal dementia, is being increasingly recognized in some patients. </li></ul>
  5. 5. MND (ALS): <ul><li>Neurologic exam: limb weakness, fasciculations, atrophy, brisk deep tendon reflexes&extensor plantar responses. </li></ul><ul><li>Signs of bulbar impairment (such as slurred speech), tongue atrophy& fasciculations may also be evident. </li></ul><ul><li>MRI of the brain/spinal cord should be performed to exclude a structural lesion. </li></ul><ul><li>EMG is essential to rule out other disorders &to establish the extent / severity of denervation. </li></ul><ul><li>Pulmonary function tests&overnight pulse oximetry studies can establish the presence of respiratory insufficiency. </li></ul><ul><li>Patients with bulbar signs or symptoms require evaluation of swallowing function. </li></ul>
  6. 6. MND (ALS):Management <ul><li>Symptom based& referral to a multidisciplinary ALS clinic for ongoing care / support is beneficial. </li></ul>
  7. 7. MND (ALS): Management <ul><li>Interventions that improve survival: </li></ul><ul><li>1.Riluzole, a glutamate antagonist, is the only medication approved & can slow the decline of muscle weakness& prolong survival by a median of 83 days. </li></ul><ul><li>2.Noninvasive positive-pressure ventilation(NIV) with bilevel positive airway pressure has also been shown to prolong survival & improve quality of life. </li></ul><ul><li>Indications for ventilatory support: </li></ul><ul><li>Symptoms of nocturnal hypoventilation </li></ul><ul><li>A forced vital capacity < 50% </li></ul><ul><li>Nocturnal oxygen saturation < 90% for > 1 minute </li></ul><ul><li>A maximal inspiratory pressure of < 60 cm H2O </li></ul><ul><li>A maximal expiratory pressure of < 30 cm H2O. </li></ul>
  8. 8. MND (ALS): symptomatic trt <ul><li>1.Placement of a PEG improve the quality of life, when patients experience a 10% or greater weight loss, require 30 minutes or more to finish a meal, or have episodes of coughing&choking when eating. </li></ul><ul><li>2.Excessive salivation can be treated symptomatically with: </li></ul><ul><li>Anticholinergic agents, as glycopyrrolate,amitriptyline& benztropine. </li></ul><ul><li>Injection of botulinum toxin into the parotid or submandibular glands if above fail. </li></ul><ul><li>3.Excessive emotional lability can be treated with either TAD or SSRI. </li></ul><ul><li>4. Speech: augmentative & alternative communication devices can help preserve communication when speech becomes unintelligible. </li></ul>
  9. 9. MND (ALS):
  10. 10. Clinical features: <ul><li>A combination of lower &upper motor neuron signs without sensory involvement. </li></ul><ul><li>The presence of brisk reflexes in wasted fasciculating limb muscles is typical. </li></ul><ul><li>In many patients the clinical features are highly suggestive but alternative diagnoses need to be carefully excluded specially potentially treatable disorders as; </li></ul><ul><li>Diabetic amyotrophy. </li></ul><ul><li>Spinal disorders . </li></ul><ul><li>Multifocal motor neuronopathy. </li></ul><ul><li>CSF exam is usually normal, though a slight elevation in protein may be found. </li></ul>
  11. 11. Clinical features: <ul><li>Usually after 50 years </li></ul><ul><li>Very uncommon before 30 years </li></ul><ul><li>Affects males > females </li></ul>Onset
  12. 12. Clinical features: Symptoms <ul><li>Limb muscle weakness, cramps, occasionally fasciculation </li></ul><ul><li>Disturbance of speech/swallowing (dysarthria/dysphagia) </li></ul>
  13. 13. Clinical features: Signs Signs Signs <ul><li>Wasting and fasciculation of muscles </li></ul><ul><li>Weakness of muscles of limbs, tongue, face & palate </li></ul><ul><li>Pyramidal signs: spasticity, inc tendon reflexes, extensor plantar. </li></ul><ul><li>External ocular muscles intact. </li></ul><ul><li>Sphincters remain intact. </li></ul><ul><li>No objective sensory deficit. </li></ul><ul><li>No intellectual impairment in most cases until late . </li></ul>
  14. 14. Clinical features: course Signs Signs Symptoms often begin focally in one part & spread gradually but eventually become widespread
  15. 15. Clinical features: involvement patterns Signs Signs 1.Progressive muscular atrophy Predominantly spinal motor neurons affected Weakness / wasting of distal limb muscles at first Fasciculation in muscles Tendon reflexes may be absent
  16. 16. Clinical features: involvement patterns Signs Signs 2.Progressive bulbar palsy <ul><li>Early involvement of tongue, palate and pharyngeal muscles </li></ul><ul><li>Dysarthria/dysphagia </li></ul><ul><li>Wasting / fasciculation of tongue </li></ul><ul><li>+/- pyramidal signs. </li></ul>
  17. 17. Clinical features: involvement patterns Signs Signs 3.Amyotrophic lateral sclerosis <ul><li>Combination of distal & proximal muscle-wasting & weakness, fasciculation </li></ul><ul><li>Spasticity, exaggerated reflexes, extensor plantars </li></ul><ul><li>Bulbar & pseudobulbar palsy follow eventually </li></ul><ul><li>Pyramidal tract features may predominate </li></ul>
  18. 18. DD: Signs Signs
  19. 19. Management: <ul><li>The glutamate antagonist, riluzole, shown to have a small effect in prolonging life expectancy by about 2 month. </li></ul><ul><li>It is not clear at which stage of the illness this prolongation occurs, so may not be particularly helpful. </li></ul><ul><li>Other agents such as nerve growth factor show promise. </li></ul><ul><li>Psychological / physical support, with help from occupational / speech therapists / physiotherapists, are essential to maintain the patient's quality of life. </li></ul><ul><li>Mechanical aids such as splints, walking aids, wheelchairs / communication devices all help to reduce handicap. </li></ul><ul><li>Feeding by percutaneous gastrostomy may be necessary if bulbar palsy is marked. </li></ul><ul><li>Sometimes non-invasive ventilatory support may help distress from weak respiratory muscles although maintenance ventilation is usually not requested. </li></ul><ul><li>Relief of distress in the terminal stages usually requires the use of opiates & sedative drugs. </li></ul>
  20. 20. Management: <ul><li>The only drug currently available is riluzole (2-amino-6-[trifluoromethoxy]benzothiazole). </li></ul><ul><li>Riluzole blocks glutamic acid release, may slow disease progression by disrupting glutamate-mediated neurotoxicity. </li></ul><ul><li>Administered at 50 mg twice a day, </li></ul><ul><li>Riluzole is generally well-tolerated,but may cause nausea , general asthenia& methaemoglobinura in overdose. </li></ul>
  21. 21. Management:Future <ul><li>1.long-term ceftriaxone slowed the course of disease in a mouse model, if given in high doses at the onset of the disease, preserved grip strength, slowed weight loss, & increased the overall duration of survival from 122 - 132 days &the mechanism is by modulating glutamate transport. </li></ul><ul><li>2.Gene therapy </li></ul><ul><li>3. RNA silencing </li></ul>
  22. 24. Prognosis: <ul><li>It is progressive; the mean time from diagnosis to death is 1 year, with most patients dying within 3-5 years of the onset of symptoms. </li></ul><ul><li>Younger patients & those with early bulbar symptoms tend to show a more rapid course. </li></ul><ul><li>Death is usually from respiratory infection / failure& the complications of immobility. </li></ul>
  23. 27. TYPES OF SPINAL MUSCULAR ATROPHY Good Facial / bulbar weakness, proximal limb weakness, gynaecomastia X-linked Adult life, males only Bulbospinal Good, seldom disabling Distal weakness and wasting of hands and feet Autosomal dominant Early adult life Distal forms Slowly progressive disability Proximal weakness and wasting, EMG shows denervation Autosomal recessive Childhood, adolescence Kugelberg-Welander Poor Severe muscle-wasting/weakness Autosomal recessive Infancy Werdnig-Hoffmann Prognosis Features Inheritance Onset Type