Treatment of Myasthenia Gravis Treatment of Myasthenia Gravis and Tetanus.and Tetanus.

By: Dr. Premlata Das.

Myasthenia GravisMyasthenia GravisAcquired autoimmune disorder.

Skeletal muscle fatiguability & weakness.

Associated with production of IgG antibody against ACh receptors (Nm).

Pathogenesis: ↓ receptors → ↓ amplitute of EPP→ failure to trigger AP.

Symptoms:- Weakness of muscles & fatigue, that

worsens on exercise, but allayed on rest.

- No muscular pain.

- Initially– ptosis, diplopia, slurring of speech, difficulty in swallowing, weakness of extremities.

Diagnosis:1.Measurement of anti-ACh receptor titre by

immuno-precipitation assay.2.EMG recording of response to nerve

stimulation.3.Edrophonium test: use 1-2 mg i.v for test dose.

5- 8 mg i.v, If patient shows signs of improvement of muscle strength, then its MG.

4.Anti-striated muscle antibody.5.Thymoma identification & CT scan of thymus.

Treatment:1.Reversible anti AChE – intermediate duration

of action. Neostigmine – 15- 30 mg/ 6 hrly/ oral. Pyridostigmine– 60-120 mg/ 4-6 hrly/oral. Titrate doses during prolonged therapy to

prevent myasthenic/ cholinergic crisis.

S/E:Muscarinic: flushing, salivation, sweating etc.Nicotinic: Ms fasciculations, twitching, tremors.

Drugs that aggravate MG:Antibiotics : Aminoglycosides, Polymixin

Antiarrhythmics: Procainamide, Quinidine, propanolol

Morphine

Others: d-tubocurarine, Quinine, Lithium.

Other therapeutic measures:Glucocorticoids: 10mg OD/ alternate

days. Doses increased slowly.

Immunosuppressants: Azathioprine, Cyclosporine

Thymectomy .

Plasmapheresis

Tetanus Tetanus Neurologic disorder

Generalized, neonatal, localized forms.

Causative agent: Clostridium tetani.

Toxin: Tetanospasmin

Causes increased muscle tone & spasms.

Clinical manifestations:1st sign: ↑ tone of masseter ms – trismus

or lockjaw.

Dyaphagia, stiffness/ pain in neck, shoulder, back → rigid abdomen, stiff proximal limb muscles.

Gimace or sneer appearance, Opisthotonos.

Laryngospasm or sustained spasm of ventilatory muscles.

Death due to exhaustion, asphyxia or aspiration pneumonia.

Goals of treatment:Eliminate source of toxin.

Neutralize unbound toxin.

Prevent muscle spasm

Monitor patient in quiet room in ICU & provide support.

Cleaning & thorough debridement of wound necessary.

Antibiotic therapy:- To eradicate vegetative cells.- Benzylpenicillin 600 mg i.v/ 6 hrly.- Metronidazole 500 mg, q.i.d.- Erythromycin/ Clindamycin– if allergic.

Antitoxin – to neutralize circulating toxin & unbound toxin in wounds.

- Human tetanus immuneglobulin (TIG) – preferred.

- 3000- 6000 U, i.m., in divided doses.- Alternative: Equine tetanus antitoxin –

cheaper, shorter half life.

Control of muscle spasms:- Diazepam- In cases of unresponsive spasms:

nondepolarizing neuromuscular blocking agents.

Respiratory care: - Intubation or tracheostomy may be

required.- Provide mechanical ventilation.

Additional measures:- Hydration & nutritional requirements

should be met.- Physiotherapy.- Heparin.

Prevention: By active immunization.Immunize recovering patients

1st & 2nd dose – 4 – 8 weeks apart.3rd dose– 6- 12 months later.Booster dose– every 10 years.