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What is Ptosis with weakness of orbicularis-oculi is an early feature of : and explain in detail?
B i.e. Myasthenia gravis Myasthenia gravis in a major cause of ptosis & diplopia Q. The distribution of muscle weakness has a characteristic pattern. The cranial muscles paicularly the lids and extraocular muscles are often involved early in the course Q of MG, and diplopia and ptosis are common initial complaints. Differential diagnosis of weakness of cranial (extra-ocular) musculature Myasthenia * It involves women in their 20-30's and men in their 50-60's gravis * Women are affected more than men (3:2) * The cardinal features are weakness and fatigability Q of muscles. The weakness increases during repeated use (fatigue) and may improve following rest or sleep. * The cranial muscles, paicularly the lids & extraocular muscles are often involved early in the course, & diplopia and ptosis are common initial complaints Q. Weakness in chewing, snarling expression on attempt to smile, difficulty in swallowing may be other complaints * The limb weakness (in 85% of all patients) is proximal & asymmetricalQ. Despite the muscle weakness, deep tendon reflexes are preserved Q and sensations are normal * Anti-acetylcholine receptor antibody Q (anti-Ach R antibody) is viually diagnostic but a negative test does not exclude the disease. The measured level of Anti-Ach-R antibody does not correspond well with the severity of MG in different patients. However, a treatment induced fall often correlates with clinical improvement in individual patient. * Anti-muscle specific kinase antibody Q (MUSK) is found in 40% of Ach R-antibody negative patients with generalized MG. It is not present in Ach R-antibody positive patients or in patients with MG limited to ocular disease * Repetitive nerve stimulation of weak or proximal muscle 6-24 hr after stopping anti Ach E medication; rapid reduction of >10-15% in amplitude of evoked response at 3Hz often provides helpful diagnostic evidence. Edrophonium may prevent or diminish this decrementa response (highly probable) * Single fiber electromyography : blocking & Jitter, with normal formal density; confirmatory, but not specific. * Edrophonium chloride (tensilon) 2 mg + 8mg IV (Anti cholinesterase test) is used most commonly for diagnostic testing because of rapid onset (-30 sec) and sho duration (-5min) of its effete. Diagnosis is highly probable if test unequivocally positive. * For ocular or cranial MG exclude intracranial lesion by CT or MRI.