Myasthenia gravis and Inflammatory myopathy Flashcards
Myasthenia gravis clinical presentation?
muscles commonly affected are extraocular and bulbar (mouth and throat, swallow) muscles
-neck and head, facial expression, altered speech or dysphagia and may progress into the limbs
muscle function improves with rest, worse with stress
Myasthenia gravis thymus?
hyperplasia and thyoma may be seen with this
Mysathenia gravis auto-antibody?
acetylcholinereceptors
Lambert-Eaton syndrome?
muscle weakness associated with cancer
symptoms start with proximal muscle weakness of leg
autoimmune attacks prevent presynaptic release of acetylcholne as antibiotics attack the voltage gated calcium channels
Cancer associated with Lambert-Eaton?
Small cell lung cancer (SCLC)
often have a history of smoking
What else may Lambert-Eaton affect?
Autonomics
-cause dry mouth, constipation, etc
thymus appears normal
Treat Lambert-Eaton?
Plasmaphoresis, Prednisone, azathiaprine, IVIG and others
must attend to the underlying malignancy too
Symptoms of Lamber-Eaton?
weakness or loss of movement that can be more or less severe, including:
-difficulty chew, climb stairs, lift objects, talking, drooping head, need to used hands to get up
-swallowing difficult, gagging, choking
blury vision, double vision, problems with steady gaze
Polymyositis/ Dermatomyositis?
idiopathic inflammatory myopathies
lymphocyctic infiltrate of skeletal muscle
patients present with symmetrical weakness in the proximal muscles of the upper and lower extremities
Immunologic features of Polymyositis/ Dermatomyositis?
Antinuclear antibody (ANA) and other autoantibody
CD8+ T cells and macrophage infiltrates
production of proinflammatory and cytotoxic cytokines
immune complexes and complement may contribute
Idiopathic inflammatory myopathies?
are rare diseases, polymorphism in HLA genes may contribute
subset of patients whose disease is triggered by infectious agents
associated/specific autoantibody, may include ANA
most common myositis-specific autoantibody?
antisynthetase autoantibody, Jo-1
only 20-30% patients have, if have is conclusive
Grotton’s papules?
violet colored inflammation over the nuckles in Polymyositis/ Dermatomyositis
Dematomyositis rash?
violaceous rash, more often seen in women
on the face, different from SLE
other characteristic skin chanes with dermatomyositis?
linear erythema scalp rash V-like sign shawl sign Mechanic's hands
Mechanic’s hands?
skin changes on lateral side of fingers
scaling, fishers on the radial side`
Lung probles with PM/DM? (Polymyositis/ Dermatomyositis?)
intersitial lung disease, a symmetric non-erosive arthritis of the hands and feet, associated with malignancy
Diagnosis of Polymyositis/ Dermatomyositis?
Proximal muscle weakness evidence of myositis from biopsy elevated enzymes in blood (ck, ast, alt, aldolase, LDH) EMG findings of myopathy charcteristic rash for DM
Treatment of DM?
corticosteroids
Associated cancer with Idiopathic inflammatory myopathies Polymyositis/ Dermatomyositis?
Lymphoma or solid tumors may occur 20-25%
Treatment of Myasthenia gravis?
Anti-cholinesterase, steroids, plasmapheresis
Proximal muscle weakness with ptosis, altered speech, dysphagia, improves with rest?
Myasthenia gravis
Proximal muscle weakness, dry mouth, cancer (SCLC) associated with smokeing?
Lambert-Eaton
Symmetrical proximal muscle weakness, difficult walking upstairs, standing, skin disease in DM?
Idiopathic Inflammatory Myopathies
