In-Depth Notes on Peripheral Nervous System Disorders chapter 38

Learning Outcomes

• Epidemiology: Describe the prevalence and demographic details of peripheral nervous system disorders.
• Pathophysiology: Explain mechanisms causing disorders like Myasthenia Gravis (MG), Guillain-Barré Syndrome (GBS), and Trigeminal Neuralgia.
• Clinical Manifestations: Correlate specific symptoms with underlying pathophysiological processes.
• Diagnosis: Identify relevant diagnostic tests confirming MG, GBS, and other conditions.
• Interprofessional Management: Discuss collaborative care plans for treating these disorders.
• Nursing Care: Develop detailed nursing care and teaching plans for patients with PNS disorders.

Key Concepts

• Caring: Emphasis on holistic support to alleviate patient suffering from neurological disorders.
• Comfort: Providing physical and emotional comfort to enhance patient well-being.
• Intracranial Regulation: Understanding how peripheral dysregulation affects overall health.
• Medication Management: Importance of timely and correct medication administration.
• Perioperative Care: Concerns regarding patients undergoing surgeries related to PNS disorders.

Essential Terms

• Acetylcholine (ACh): A neurotransmitter essential for neuromuscular junction transmission.
• Acetylcholinesterase (AChE): Enzyme that breaks down ACh, influencing neuromuscular activity.
• Myasthenia Gravis (MG): Autoimmune disorder leading to muscle weakness due to antibodies blocking ACh receptors.
• Guillain-Barré Syndrome (GBS): Acute inflammatory demyelinating disorder often preceded by infection.
• Neuromuscular Junction: The synapse where motor neurons communicate with muscle fibers.
• Thymectomy: Surgical procedure related to thymus gland, which can aid in MG treatment.

Case Study Synopsis: Stephanie Jordan's MG

• Patient Profile: 45-year-old female math teacher with a history of MG.
• Recent Health Issues: Upper respiratory infection leading to increased muscle weakness.
• Clinical Symptoms: Difficulty swallowing and chewing prompting emergency department visit.
• Medications: Pyridostigmine and prednisone.
• Emergency Management: Adjustments in medication dosages, admission to neuroscience unit.

Peripheral Nervous System Overview

• Central Nervous System (CNS): Includes the brain and spinal cord; peripheral nerves connect the CNS to limbs and organs.
• Divisions: Sensory (afferent nerves) and motor (efferent nerves). Motor division further divides into somatic and autonomic systems.
• Schwann Cells: Create myelin sheaths in PNS, essential for rapid neural conduction.

Myasthenia Gravis (MG)

• Definition: Autoimmune neuromuscular disorder leading to fluctuating muscle weakness.
• Pathophysiology: Antibodies against ACh receptors lead to diminished response to ACh, manifesting as muscle weakness.
• Epidemiology: More common in women; incidence 14-40 per 100,000 in USA; onset varies by gender.
• Clinical Manifestations: Ocular symptoms (ptosis, diplopia), bulbar symptoms (dysphagia), and generalized muscle weakness.
• Diagnosis: Utilizes serological tests (anti-AChR antibodies), electromyography, and edrophonium (Tensilon) test for muscle strength improvement.
• Management: Medications such as ACh inhibitors (pyridostigmine, neostigmine), corticosteroids (prednisone), and immunosuppressants (azathioprine, mycophenolate mofetil).
• Surgical Options: Thymectomy for patients with thymoma or hyperplasia.

Guillain-Barré Syndrome (GBS)

• Definition: Acute demyelinating polyneuropathy often triggered by an infection.
• Pathophysiology: Autoimmune response damaging myelin, leading to muscle weakness and potential respiratory failure.
• Incidence: Approximately 1 in 100,000; can follow viral infections like Campylobacter or Zika.
• Clinical Features: Ascending paralysis, pain, and potential cranial nerve involvement.
• Management: IV immunoglobulin (IVIG) or plasmapheresis to reduce symptoms and aid recovery.

Trigeminal Neuralgia

• Definition: Chronic pain disorder impacting the trigeminal nerve (CN V), leading to severe facial pain.
• Epidemiology: Incidence of 15,000 cases per year in the US; more common in women over 50.
• Pathophysiology: Pain may be idiopathic or related to vascular compression; triggers include light touch or certain activities.
• Management: Antiepileptic medications (carbamazepine, oxcarbazepine) are first-line; surgical options (microvascular decompression) available for severe cases.

Nursing Management

• Assessment: Regularly evaluate respiratory function, cranial nerve status, and muscle strength.
• Interventions: Administer medications as prescribed; educate patients on the importance of medication adherence and timing to maximize therapeutic effects.
• Patient Education: Encourage communication regarding symptoms and medication adjustments; involve families in care plans to optimize support.