L21 Autoimmune Disorders Systemic Lupus Erythematosus (SLE) & Myasthenia Gravis (MG) Flashcards
Immune system except protect body from disease and compromise, what else does it trigger?
Temp elevation and mucus production
What are the 3 immune system disorders?
1.Hypersensitivity disorder (e.g. Asthma, Allergic Rhinitis, Food Allergies)
2.Immunodeficiency disease (e.g. AIDS)
3.Autoimmune disorder (Rheumatoid arthritis,
Type 1 DM, Systemic Lupus Erythematosus, multiple sclerosis, Myasthenia Gravis)
What is an autoimmune disorder?
immune system MISTAKENLY attacks the body’s own healthy cells and tissues, mistakenly recognise them as foreign invaders. Leading to inflammation, tissue damage(extensive) and impaired function of the affected organs
What could be the causes of autoimmune disorders?
Genetic factors, environmental changes, hormonal influences, immune system dysregulation, age
Common s/s of autoimmune disorders:
Fatigue
Joint pain and swelling
Muscle weakness
Skin changes(e.g. dry)
Fever
Numbness or tingling
Digestive issues
Hair loss(alopecia)
Swollen lymph nodes
Weight change
Difficulty concentrating/
Brain fog
Myasthenia Gravis is an acute or chronic autoimmune disease?
Chronic
For MG, what receptors are blocked or destroyed? And where do the receptors located?
nicotinic acetylcholine receptors at the neuromuscular junction
What is the consequence of blocked or destroyed receptors? (MG)
The ability of acetylcholine to stimulate muscle contraction is impaired, causing muscle weakness
What are the common population of MG?
Women under 40 years of age(especially during childbearing years) and men over 60
What is the pathophysiology of MG?
Antibodies attack the Acetylcholine (ACh) receptors, decreased the number of ACh receptor site at neuromuscular junction, making it unable to stimulate muscle contraction.
What are the two risk factors of MG (cause is still unknown)
Thymus gland abnormalities(e.g. thymus tumor) and hyperythyrodism
For the clinical manifestations of MG, what are the ocular symptoms?
Diplopia (double vision)
Ptosis(upper eyelid droop 下垂)
Dysarthia(slurring speech) and dysphagia that leads to probs of swallowing, choking and aspiration belong to which clinical manifestation of MG?
Bulbar symptoms, due to the weakness of bulbar muscle
Except for respiratory weakness(shallow and decreased vital capacity, accessory muscles using, cough difficulty), What else is the clinical manifestations of MG
Bowel and bladder sphincter weakness
MG does NOT affect…
Sensory
What are the diagnosis of MG?
Physical exams;
Electromyography EMG;
Blood test;
CT/MRI;
Screening for other autoimmune disease
What is the function of Electromyography/EMG?
It detects the speed and strength of electrical signals sent from nerves to the muscles
Why are CT/MRI used for diagnosing MG?
Check any thymoma/thymic hyperplasia
To check for ACh antibodies and thyroid function in MG patient, what test is useful?
Blood test
What is the reason of myasthenic crisis?
Complication of myasthenia gravis result from insufficient medication, emotional stress, trauma, infection or surgery
What are the s/s of Myasthenia crisis?
‑Sudden ↑BP and Pulse rate;
‑Cyanosis∵hypoxia
‑Respiratory distress
→intubation/
mechanical ventilation
‑Absent cough& gag reflex
‑Restlessness
‑Diaphoresis
‑↓urine output
‑Incontinence
(both bowel and bladder)
‑Dysarthria
(speaking difficulty)
What is the opposite condition of myasthenia crisis?
Cholinergic crisis, which is due to excessive medication given
For cholinergic crisis, what are the s/s related to muscle?
- Muscle twitching(esp. around mouth)
-Difficulty chewing, swallowing and speaking(muscle keep contracting)
-Advancing muscle weakness ~ 1hr after ANTIcholinesterase medication)
What are the other s/s for Cholinergic crisis (except for muscle-relating)
-nausea&vomiting
-diarrhea, cramp
-Increased secretion(e.g.salivary,
perspiration汗,lacrimal淚,bronchial)
-Headache
-Confusion
-Irritability, anxiety
-Syncope and respiratory distress–>respiratory arrest
