MYASTHENIA GRAVIS

DEFINITION 

Myasthenia Gravis  is a progressive disease affecting neuromuscular transmission of impulses in voluntary muscles and due to insufficient amount of ACH.

Note:

Dxr  (disorder )

ACH  (acetylcholine )

MG  (myasthenia gravis )

NM(Neuromuscular). 

Note that it is more common in women cuz of their susceptibility to hormonal imbalances and depletion of neurotransmitters.

CAUSES /RISK FACTORS 

✔Depletion of ACH reception by an autoimmune attack. 

✔Emotional upset.

✔URTI

✔Surgery 

✔Trauma

✔ACTH Therapy 

✔Thyroid Dxr. 

✔Tumour of the thymus gland (Thymoma).

PATHOPHYSIOLOGY 

👉MG is a progressive dxr affecting NM transmission of impulses in voluntary muscles.

👉In MG,antibodies are attached to ACH receptor sites,block, destroy and weaken these sites thereby making them insensitive to ACH .

👉This insensitivity leads to an interference or blockage in NM transmission of impulse. 

👉This results in abnormal weakness and fatigue of skeletal muscles especially of the eyes,face,jaw and neck leading to speech impairment, drooping facial muscles,difficulty chewing ir swallowing. 

👉This May also involve muscles of the upper extremities and respiratory muscles leading to dyspnea.e.t.c.

👉If not managed properly,can result in Respiratory failure.

CLINICAL MANIFESTATIONS 

👀Abnormal weakness

👀Severe fatigue

👀Drooping facial muscles

👀Impaired chewing and swallowing. 

👀Dyspnea 

👀Sleepy mask like expression. 

👀Speech impairment(Dysarthria).

DIAGNOSTIC EVALUATION 

🔬History taking and physical examination. 

🔬EMG (Electromyography to reveal decreasing response to stimuli).

🔬Tensilon Test:Used to differentiate types of crisis (cholinergic crisis versus myasthenia crisis).

🔬Serum Test for ACH receptor antibodies is positive.

🔬CT Scan(Reveals thymus gland tumour).

There are 2 types of crisis in MG.

😣Cholinergic crisis:Can result from overuse of anticholinergic drugs,which release too much ACH at the NM junction. 

😣Myasthenia Crisis: Severe and persistent features of MG.

 MANAGEMENT. 

✏Medical mgt.

💊Anticholinesterase drugs .e.g. Neostigmine and Pyridostigmine (To enhance NM transmission).

💊Immunosuppressive drugs .e.g. Prednisone and azathioprine(used when weakness is not adequately controlled by anticholinergic medication).

💊Corticosteroids. E.g. Dexamethasone 

💊Plasmapheresis (To remove antibodies from the blood).

💊Thymectomy(For ppl with thymus gland tumour).

 NURSING MANAGEMENT . 

💉Assess for respiratory defect and promote measures to maintain adequate airway (Encourage and teach effective coughing, chest physiotherapy and suctioning secretions).

💉Monitor pulmonary function test.

💉Plan adequate rest periods throughoutthe day and help pt set realistic daily schedules, help pt perform ADLs.

💉Administer prescribed medications 30mins before activities or meals to facilitate chewing and swallowing.

💉Modify diet as needed to minimize risk of aspiration. E.g.Bland diet

💉Administer prescribed IV fluids and NG Tube feedings to pt in crisis or with impaired swallowing,elevate head of bed after feeding(to prevent risk for aspiration).

💉Suction the pt frequently if on a mechanical ventilator. 

💉Assess breathe sounds,check X-ray reports cuz aspiration is very common.

💉Encourage pt to speak in a slow manner to avoid voice strain,and teach pt to support the jaw to assist in speech.

💉Encourage use of writing materials for communication if speech is seriously affected. 

💉Change positions routinely  and encourage active and passive ROM exercises to prevent complications of mobility.

💉Emphasize the need for continued follow-up and compliance with treatment regimen.

💉Encourage pt to tape the eye open for short intervals to prevent problems associated with impaired vision.e.g.Ptosis.

💉Provide client and family teaching and coping strategies.e.g. avoid exposure to heat or cold,chew slowly.e.t.c.

COMPLICATIONS. 

😭Aspiration.

😭Decreased mobility. 

😭Respiratory Failure.

 NURSING DIAGNOSES 

👠Fatigue rt disrupted nerve impulses eb inability to complete ADLs.

👠Disturbed sensory perception(vision) rt facial muscle weakness eb drooping of eyelid.

👠Risk for aspiration rt facial muscle weakness. 

👠Social isolation rt dimished speech capabilities eb withdrawn attitude.