E2L20, Soft Tissue Tumors Pathoma Flashcards
If a patient presents with S/Sx of dermatomyositis, what else should you look for or suspect?
Though the cause of this disease is unknown, it is associated with carcinoma–specifically gastric carcinoma (others possible)
Patient reports having trouble combing their hair and climbing stairs. They also have a rash of the upper eyelids and in malar distribution.
What are the hallmarks of this disease, and what other disease can be easily confused with this one?
This is dermatomyositis
Hallmarks: proximal muscle weakness, Anti-Jo-1 antibodies, perimysial inflammation with perifascicular atrophy
Easily confused with SLE because of the malar rash and a positive ANA
What is dermatomyositis and how is it treated?
Inflammation of the skin and skeletal muscle of unknown etiology
Treated with corticosteroids
What is the skin presentation of dermatomyositis?
Rash in 3 places:
1) Upper eyelids (heliotrope rash)
2) Malar
3) red papules on elbows, knuckles, knees (Gottron papules)
What is the outside covering of a muscle fascicle called?
Perimysium
What happens to the muscle in dermatomyositis?
Perimysial inflammation with perifascicular atrophy of the myofibrils
Patient has proximal muscle weakness and no signs of a rash. Biopsy shows necrotic muscle fibers and endomysial inflammation. What is the condition?
Polymyositis
Resembles dermatomyositis but does not involve the skin and the inflammation is endomysial instead of permysial
How is muscular dystrophy inherited? And what gene is involved, and what does it do?
X-linked
Dystrophin gene
Dystrophin anchors the muscle cytoskeleton to the extracellular matrix
What does the word dystrophy mean in muscular dystrophy?
replacement of skeletal muscle with adipose tissue
Patient presents with proximal muscle weakness as early as 1 year of age, seen later to develop pseudohypertrophy of the calf muscles.
What is the disease and what other S/Sx might be present and what is the outlook for the disease?
This is Duchenne muscular dystrophy
Involves a deletion of the dystrophin gene which is why Sx present early and are severe.
Labs would show elevated Creatinine Kinase
Death usually occurs from cardiac or respiratory failure
Compare Duchenne and Becker MD
Duchenne has a full deletion of the gene and show Sx sooner and more severe
Becker has a mutated gene and has milder Sx
Female patient complains muscle weakness that gets worse with use and better with rest. She also complains of seeing double and her eyelids seem to be droopy.
Diagnosis? What drug might relieve Sx? What procedure might help?
Myasthenia Gravis
Common in women b/c autoimmune
Anticholinesterase agents help
Can be caused by thymic hyperplasia or thymoma so resection can improve Sx
What is the pathogenesis of Myasthenia Gravis?
Explain why gets worse with muscle use and better with rest.
Autoimmune disease involving antibodies against postsynaptic Ach receptors
Having more Ach in the cleft outcompetes the antibodies
As muscles are used Ach is depleted from the presynaptic terminal and less Ach is released each time and less is available to outcompete the antibodies
Patient presents with proximal muscle weakness that improves with use. Administration of acetylcholinesterase inhibitors has no effect on Sx.
Diagnosis? What is a likely cause of this syndrome?
Lambert-Eaton Syndrome
Often caused by a paraneoplastic syndrome from small cell carcinoma of the lung
Describe pathophysiology and Sx of Lambert-Eaton syndrome and how it is cured
SCC of the lung produces a paraneoplastic syndrome that makes antibodies against the presynaptic Ca++ channels which prevents the release of Ach at the NMJ.
Proximal muscle weakness improves with use, eyes are spared, Ach-ase inhibitors have no effect.
Resection of the tumor cures.
