Myasthenia gravis history and symptoms

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

History: Female Gender, african/Americans race, evidence of coexisting autoimmune diseases, a positive history of: Heavy eyelids and double vision , eye movement problems

Photophobia , facial weakness, tongue weakness, chewing and swallowing problems, respiratory problems, limbs muscles weakness, Fatigue and urinary incontinency.symptoms: Ptosis and diplopia, gaze paralysis, photophobia, facial weakness, orbicularis oculi weakness, tongue weakness (chewing problems and dysphagia), respiratory problems, limbs muscles weakness, fatigue and pelvic floor weakness.

• The important points in the history of a patient suspected for MG are:
  • Age and Gender: The age of onset in Myasthenia gravis follows a bimodal distribution. The early type (before age of 50) is female predominant and the late type (after age of 60) is male predominant. Between the age of 50-60 there is no significant different between male and female.^[1]
  • Race: Some studies demonstrated that the incidence, prevalence and the severity of this disease is higher in African/Americans.^[2][3]
  • Evidence of coexisting autoimmune diseases^[4]
• A positive history of:
  • Heavy eyelids and double vision ^[5]
  • Eye movement problems ^[6]
  • Photophobia ^[7]
  • Facial weakness ^[8]
  • Tongue weakness, chewing and swallowing problems ^[9][10]
  • Respiratory problems ^[11][12]
  • Limbs muscles weakness ^{[13][14][15][16]}
  • Fatigue ^[17]
  • Urinary incontinency^[18][19]

• The importatnt point which we should keep in mind is that The hallmark of myasthenia gravis is Fluctuating weakness of specific muscles in limbs, bulbar, ocular and respiratory system which get worse with activity or using the muscle.^[20][21][22]

• The hallmark of myasthenia gravis is Fluctuating weakness of specific muscles in limbs, bulbar, ocular and respiratory system which get worse with activity or using the muscle.^[20][21][22]
• Symptoms of myasthenia gravis include:
• ptosis and diplopia
  • About 50 percent of patiens have ptosis and diplopia as their presenting sign. Ptosis is usually asymmetrical. The direction and degree of diplopia may change in a MG patients because of fatigable ocular motor paresis.^[5]
• Gaze paralysis
  • The ocular muscle weakness in MG can cause gaze paralysis and even mimic internuclear ophthalmoplegia or midline brain lesions.^[6]
• Photophobia
  • A lot of patients with myasthenia gravis complain that bright light bothers them and can even worsen the weakness of their eye muscles. Since this symptom is seen even in untreated patients, it’s not a complication of anticholinesterases treatment.^[7]

• Facial weakness
  • The facial weakness in MG occurs without sensation impairment of face. The sensation problems along with facial weakness suggest a different diagnosis like nasopharyngeal carcinomas.^[8]

• Orbicularis oculi weakness
  • If we try to keep the upper eyelid of a MG patient open, they cannot close it against our force because of the weakness of orbicularis oculi muscle.^[23]

• tongue weakness, chewing problems and dysphagia
  • The muscles of the tongue will become weak in MG patients especially after long speech. This can lead to unintelligible speech and dysphasia. Difficulty in swallowing can cause choking and nasal regurgitation. Furthermore the weakness of mastication muscles will cause chewing problem and can lead to weight loss.^[9][10]

• Respiratory problems
  • Inability to maintain a patent airway or respiratory insufficiency can occur in MG patients especially those who are in the MG crises.^[11]
  • Respiratory problems can cause inadequate sleep and day time somnolence.^[12]

• Limbs muscles weakness
  • Because the distal part of the limbs is warmer, they have less reserve of Ach and they will show more weakness.^[13]
  • The proximal muscles of upper extremities show weakness during hair brushing or dressing.^[14]
  • The proximal muscles of lower extremities show weakness during walking up stair^[15]
  • The distal muscle of limbs are more affected especially the finger extensors.^[16]

• Fatigue
  • MG patients experience fatigue after a period of mental or physical activity.^[17]

• Pelvic floor weakness
  • The weakness of pelvic floor muscles leads to urinary incontinency especially during cough or strain.^[18][19]

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