Myasthenia Gravis Study Notes

Myasthenia Gravis PathophysiologyYesenia Signs and Symptoms Yesenia Labs/Diagnostics: Diana Medications Melody APIE: Everyone Case Study Patricia Pathophysiology Myasthenia Gravis (MG) is an autoimmune disease, a disease that mistakenly attacks its own parts. The problem with MG is that the communication between nerves and muscles is affected resulting in loss of voluntary muscle control. Generally nerves send signals to muscles across a synapse called the neuromuscular junction. ACH is then released and binds to acetylcholine receptors that trigger the muscle fiber to contract. This action is effortless in healthy people, but people with MG have antibodies that destroy the receptor sites thus blocking this nerve-muscle communication (Professional, n.d.) . The people most affected are middle aged women between the ages of 20-40 and men between the ages of 50-80. 1 in 10 cases occur in teenagers and the disorder is possible , but rare, in children. MG is generally not inherited. Pregnant women cannot pass MG to their infants. Some babies born to women with MD do develop a condition called neonatal myasthenia. Neonatal myasthenia presents with weak cry and sucking reflexes. Symptoms usually resolve within a few weeks and dont increase chances of the child developing MG in the future (Professional, n.d.). History of another autoimmune disease, infections, meds for malaria, arrhythmias, CA, history of surgical procedures, and thyroid disease all greatly increase the risk of someone developing MG. Autoimmune G is the most common form of this neuromuscular disease. The 2 types of autoimmune disease are ocular and generalized. Ocular autoimmune MG manifests as weakening of the muscles that move the eyes and eyelids. Generalized autoimmune MG affects the eye and other body parts (face, neck, arms, leg, throat). Half of people that are diagnosed with ocular MD progress to generalized MG within two years of the first symptom. MG is usually a lifelong disorder and has no cure available at the moment. Signs and Symptoms Two types of Myasthenia Gravis; ocular and generalized. With ocular, only eye muscles are involved causing diplopia and ptosis. For generalized form, patients experience weakness of muscles in the throat, limbs, and respiratory weakness (Medical- Surgical Nursing). Initial s/s come on suddenly. Muscles get weak when one is active and strength returns at rest. The intensity of muscle weakness can change from day to day. S/S include: ● ● ● ● ● ● ● ● ● ● Diplopia Ptosis Weakness in muscles of the face and throat Weak/hoarse throat Limb weakness Respiratory weakness/SOB Dysphonia Dysphagia Trouble walking Difficulty moving neck or holding head up A complication of MG is myasthenic crisis due to under medication or no cholinergic medication at all. Myasthenic crisis can happen due to progression of disease, emotional upset, systemic infections, meds, surgery or trauma. S/S of myasthenic crisis: ● Sudden onset of acute respiratory distress ● Inability to swallow or speak ● Increased HR, RR, BP ● Bowel and bladder incontinence LABS AND DIAGNOSTIC Common test to diagnose Myasthenia Gravis: ● Acetylcholine receptor (AChR) antibody test: o AChR antibody is a protein that can be found in the blood of people with MG o It is lab test to diagnose MG o Test is performed by obtaining a blood sample from the vein o Usually no special preparation is required prior to the test o Results: o Normal results: there is no AChR antibody in the bloodstream or can be less than 0.05nmol/L (depends on the laboratory) o Abnormal results: AChR antibody is found in the bloodstream. This confirms a diagnosis of MG, however, an absence of AChR antibody does not mean the person does not have MG. ● Acetylcholinesterase inhibitor test (Tensilon test): o No special preparation for test is necessary o Performed by administering a medication called Tensilon (also called edrophonium) o Medication is administered IV o 30 seconds after medication is administered, facial muscle weakness and droopy eyelids should resolve for around 5 minutes o Muscles that are weak will be tested before and right after Tensilon is given. o Positive test: diagnosis of MG is confirmed when there is immediate improvement in muscle strength. o Medicine used during this test can cause side effects such as: low heart rate, asystole, sweating, cramping, respiratory failure o Atropine should be available to control any possible side effects ● MRI Scan o An MRI can help identify an enlarged thymus gland, which may be present in people with myasthenia gravis. o The thymus gland is a site of production for acetylcholine receptor antibodies ● Ice pack test (noninvasive) o This test can help distinguish MG from other conditions o Inexpensive, safe, and quick to perform, can take between 3-5 minutes o Test is indicated for those with asthma or heart problems o Test involves holding and ice pack over the patient’s eyes x 2-3minutes o If a person has MG, the drooping of the eyelid should resolve temporarily after the ice pack has been applied Medications There is no cure for Myasthenia Gravis but medications can help alleviate symptoms ● Acetylcholine esterase (AChE) inhibitors are considered to be the f MG.basic treatment of myasthenia gravis (Medscape) ● Bronchodilators may be useful in overcoming the bronchospasm associated with a cholinergic crisis. (Albuterol & Salbutamol) ● Cholinesterase inhibitors (anticholinesterase) boost signals between nerves and muscles to improve muscle strength. ● Immunosuppressants & corticosteroids, decrease inflammation and reduce your body’s production of abnormal antibodies.(cleveland clinic) Anticholinesterase : Neostigmine and Pyridostigmine Corticosteroids: Prednisone Immunosuppressants: Azathioprine, Cyclosporine, Methotrexate, Mycophenolate mofetil APIE Assessment ● ● ● ● ● ● ● ● Droopy eyelids (ptosis) Double vision Difficulty swallowing Change in facial expressions Slurred or nasal speech Weakness of voluntary muscles (arms, hands, fingers, legs) Difficulty breathing Severe weakness related to MG can cause respiratory failure Planning: ● Assess for activity intolerance ○ Work with OT/PT ● VItal signs remain stable ○ O2 will stay above 92% ● Monitor oxygen level every 2-4 hours (RNpedia) ● Encourage deep breathing exercises Implementation: ● ● ● ● ● ● ● Monitor VS Evaluate and monitor ABG values Monitor the patient’s ability to swallow or cough Monitor respiratory status and suction airway when needed Auscultate breath sounds Administer medications according to regime Stick to eating routine ● Put pt in sitting position when eating & drinking to prevent choking or aspiration ● Educate on myasthenia gravis crisis ● Elevate HOB ● Assist pt to perform ADLs ● Perform neurological evaluation ● Encourage the patient to perform activities as tolerated ● Short activities during times of maximal muscle strength ● Educate patient to identify and avoid triggers (temperature extremes, stress, drugs, alcohol, infection, or caffeine) ● Maintain suction and emergency equipment at bedside ● Help pt with ROM exercises ● Have pt maintain adequate rest throughout the day ● Provide eye care Evaluation ● ● ● ● ● Patient maintained oxygen levels above 92% Patient denied any shortness of breath/difficulty breathing ABG levels remained within normal limits Pt ambulated with help without any difficulties ADL’s performed by patient with minimal help from nurse/staff without any difficulties Case Study Myasthenia Gravis is an autoimmune disease that affects middle aged women more than men (An Atypical Presentation:...). This autoimmune disease is caused by the neurotransmitter acetylcholine. In this case study, an 81 year old female patient was experiencing neck weakness, according to the article, patients with myasthenia gravis do not present with neck weakness. Older patients with neck weakness are usually diagnosed as stated in the case study, “Among elderly females, neck weakness could be a manifestation of degenerative joint disease, disk herniation, osteoporotic vertebral fractures, and metastases” (An Atypical Presentation:...). Meaning, that this patient was put through a lot of imaging and labs where it all came back normal, she was sent home due to the results coming back negative for everything. The patient did not get better after going home from the doctor, her neck was not getting better, she was brought back to the doctor where labs were drawn again and her acetylcholine levels were not normal. They were not sure if it was MG but she was started on anticholinesterases where as improvement was seen. Once the improvement was seen, then her diagnosis was confirmed. In the case study, it lets the reader know that sometimes autoimmune diseases are not as they seem and need further workup to rule out disease.