Physiology & Biochemistry · patient case question
Which statement best describes the pathophysiology of multiple sclerosis?
Patient case: Family History and a Preoperative Workup
Patient: 26-year-old female
Chief Complaint: “My wisdom teeth need to come out and I want to make sure everything is safe first.”
Background: Multiple sclerosis diagnosed 2 years ago, currently in remission. Total thyroidectomy 6 months ago for papillary thyroid carcinoma, with persistent hoarseness since surgery. Her mother is a known carrier of Duchenne muscular dystrophy. Her brother has hemophilia A. She is planning a pregnancy within the next year.
Medications: Levothyroxine · Glatiramer acetate
Vital Signs: BP 114/70 mmHg · HR 76 bpm · RR 16 · T 98.4°F
Findings: Persistently breathy, hoarse voice. Well-healed anterior neck incision. Four impacted third molars planned for removal. Ibuprofen is planned for postoperative analgesia.
Show answer and explanation
Correct answer: B. Autoimmune destruction of oligodendrocytes causing demyelination in the central nervous system
- A. Incorrect. Schwann cells myelinate peripheral nerves. Autoimmune attack on peripheral myelin describes Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy.
- B. Correct. Multiple sclerosis is a T cell-mediated autoimmune attack on central nervous system myelin and the oligodendrocytes that produce it. Demyelinated plaques disseminated in space and time produce the characteristic relapsing-remitting pattern of neurologic deficits.
- C. Incorrect. Loss of dopaminergic neurons in the substantia nigra describes Parkinson disease, producing bradykinesia, resting tremor, and rigidity.
- D. Incorrect. Antibodies against the acetylcholine receptor describe myasthenia gravis, which causes fatigable weakness that worsens with sustained activity.
Note: Dental relevance: trigeminal neuralgia occurring in a young patient should raise suspicion of multiple sclerosis, since a demyelinating plaque at the trigeminal root entry zone is a recognized cause. Short morning appointments help, since fatigue and heat sensitivity worsen symptoms later in the day.
Practice Physiology & Biochemistry questions Physiology & Biochemistry study notes