BIS5130 Week 10 Lecture Part 2 Slides without answers (1)

Bell's Palsy Overview

• Definition: Bell's Palsy is a condition characterized by sudden weakness or paralysis on one side of the face, caused primarily by inflammation of the facial nerve (Cranial Nerve VII).

• Presentation: Symptoms typically include facial droop, inability to close the eye, loss of taste, and hyperacusis.

Case Study: Robert

Background

• Patient Details: Robert, a 41-year-old civil servant, presented with sudden facial weakness and loss of taste.

• Symptoms Prior to Diagnosis: Persistent headaches, tingling sensation in the face, slurred speech, and hyperacusis.

Diagnosis

• Initial Assessment: Concerns raised regarding potential stroke; ruled out by specialists.

• Confirmed Diagnosis: Bell's Palsy.

Sensory Functions Affected by Bell's Palsy

Taste

• Loss of Taste: The patient reported loss of taste, particularly with mustard (bitter taste).

• Key Point: Taste involves five basic qualities: sweet, sour, salty, bitter, and umami.

• Nerve Pathways: Taste signals are transmitted through cranial nerves VII (facial), IX (glossopharyngeal), and X (vagus) to the brain.

Hearing

• Hyperacusis: Robert experienced sensitivity to loud sounds, likely due to affected muscles in the middle ear (tympani and stapedius) that stabilize sound transmission.

Vision

• Inability to Blink: Difficulty closing the right eye leads to potential keratitis due to exposure of the cornea.

• Keratitis: Inflammation of the cornea, which can impair vision if untreated.

• Potential Impact on Vision from Keratitis: Can lead to blurry vision, discomfort, and long-term damage if not adequately addressed.

Treatment and Management

Immediate Treatment

• Steroid Therapy: Prednisolone prescribed within 72 hours of symptom onset; efficient for improving outcomes.

• Eye Care: Eye drops and ointments for dryness; taping the affected eye shut during sleep to prevent keratitis.

Long-term Prognosis

• Recovery Rates: Approximately 85% of patients recover fully within three weeks; long-term recovery rates are even higher.

• Physical Therapy: Recommended if some weakness persists after three months to assist in the recovery of muscle function.

Exam Preparation Notes

Key Points for Exam Answers

• Discuss the effects of Bell's Palsy on sensory functions, including taste, hearing, and vision.

• Mention the role of Cranial Nerve VII and the mechanisms by which Bell's Palsy induces sensory dysfunction.

• Link known causes (e.g., viral infections) and clarify distinctions from similar conditions (e.g., Guillain-Barré Syndrome).

• Provide detailed explanations of sensory pathways (taste receptors and hearing function), impacts of affected cranial nerves, and treatment protocols.