Case 8: Jaw Trouble
Medical Mystery Case 8: Slurred Speech
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A man in his 70’s presents to the ED with slurred speech on and off for five days. In addition he has had some trouble swallowing and chewing that is worst at dinner. When you enter the room you notice the gentleman in position below. He states he needs to use his hand to hold his jaw closed because otherwise it just hangs open and he can’t stand it (try it. can you?) In addition he states he has had to use his hand in this way to help him chew his dinner. What is most likely to be causing his symptoms? What is in the differential diagnosis?
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Quick Essentials: Emergency Medicine
ANSWER:
Myasthenia Gravis. A Tensilon test was performed by the ED physician after informed consent. It was negative, even at the max dose. The patient was sent home without therapy because the neurologist was unconvinced that this was myasthenia. However, about 12 days later the test for acetyl-choline receptor antibodies came back positive.
Excerpt on Myasthenia Gravis from “Quick Essentials“
Sx/Sn: Fluctuation & Fatigue: diplopia c read, jaw weak, dysphagia, CN7, voice
Exam: pupil nl, ptosis; Weak: CN7, deltoid, neck flexion; may be asymmetric
Tests: Ice on eye>ptosis, ABG, CXR(thymus,ATX), tensilon, ACh Ab:75
Airway: Good sniff? FVC: <20/k:admit, <15/k:ICU, <12/k:ETT c high dose Succ
DDx: hyperthyroid, hypoK, lambert-Eaton, botulism, intracrainial mass
Rx: PLEX > IVIG, mestinon; NIF:-20 is OK; Worry: OP sx, RR>30, pCO2>50
Tensilon Test:
Contras: Known MG, OB, (asthma, cardiac dz). >Side Effects: Brady (rx=atropine), salivation
Prep: Consent, monitor, 10mg tensilon in TB syringe, pulse ox, crash cart
Dosing: Serial until (+) or 10mg total: 1mg>3mg>6mb. Alt. regimen: 2mg>8mg
Positive: improvement w/in 2min that lasts <5min. Negative: no improvement p total of 10mg. Does not rule out MG completely