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Emergency And Acute Medicine – Polyneuropathy
Polyneuropathy is a peripheral nerve disorder in which multiple nerves throughout the body malfunction simultaneously. It may present acutely or chronically and may involve sensory, motor, autonomic, or mixed dysfunction. Acute causes include infections (such as toxin-producing bacteria and viruses), autoimmune conditions like Guillain–Barré syndrome, toxic exposures including heavy metals such as lead and mercury, medications such as phenytoin, chloramphenicol, nitrofurantoin, sulfonamides, vincristine, vinblastine, and certain sedatives, as well as malignancies like multiple myeloma. Chronic polyneuropathy is most commonly caused by diabetes mellitus, but may also result from chronic alcohol use, nutritional deficiencies (particularly thiamine and vitamin B12), hypothyroidism, liver failure, kidney failure, lung cancer, and chronic inflammatory demyelinating polyneuropathy (CIDP).
Polyneuropathy affects approximately 2% of the general U.S. population and up to 8% of individuals over age 55. Diabetes is the most common cause in the United States and occurs in roughly half of insulin-dependent diabetics. Pathophysiologically, polyneuropathy may result from myelin dysfunction, vascular compromise to the vasa nervorum, or primary axonal injury. Myelin dysfunction is often immune-mediated, triggered by infections such as Campylobacter, diphtheria, influenza, or HIV, and may follow vaccination. Guillain–Barré syndrome presents acutely with rapidly progressive weakness and may lead to respiratory failure, whereas CIDP follows a more chronic or relapsing course. Vascular compromise from atherosclerosis, vasculitis, infection, or hypercoagulable states may cause ischemic nerve injury. Axonal injury is most commonly due to toxic-metabolic conditions such as diabetes, nutritional deficiencies, or drug and chemical exposure.
Clinically, polyneuropathy usually begins distally in the lower extremities and progresses proximally in a symmetrical “stocking-glove” distribution. Patients often report numbness, burning, tingling, weakness, and difficulty walking. Autonomic symptoms may include constipation, urinary retention or incontinence, sexual dysfunction, orthostatic dizziness, dry skin, and decreased sweating. On examination, findings are typically bilateral and symmetrical, including decreased sensation, impaired vibration and position sense, diminished motor strength, reduced reflexes, muscle atrophy, and sometimes fasciculations or paralysis. In demyelinating disorders such as Guillain–Barré syndrome and CIDP, weakness may be disproportionate to atrophy and reflexes are markedly diminished. Ischemic neuropathies often cause painful burning sensations with preserved reflexes and distal involvement. Toxic-metabolic axonopathies are typically painful and distally symmetric.
Evaluation begins with a thorough history and physical examination. Initial laboratory testing should include complete blood count, electrolytes, glucose, renal and liver function tests, thyroid-stimulating hormone, erythrocyte sedimentation rate, antinuclear antibody, vitamin B12, folate, rapid plasma reagin, HIV, hepatitis B and C serologies, Lyme testing, creatine phosphokinase, and serum protein electrophoresis. Additional tests such as heavy metal levels, genetic studies, or immune-mediated antibody testing are guided by clinical suspicion. Electromyography and nerve conduction studies are essential diagnostic tools. Lumbar puncture demonstrating elevated cerebrospinal fluid protein with normal cell count supports Guillain–Barré syndrome or CIDP. Nerve or skin biopsy may be considered in selected cases.
Emergency management focuses on airway, breathing, and circulation. Respiratory compromise is a critical concern in acute demyelinating neuropathies; measurement of negative inspiratory force (normal approximately −60 cm H₂O) helps assess impending respiratory failure. Patients with respiratory weakness require prompt ventilatory support. Pain management may include narcotics, tricyclic antidepressants such as amitriptyline, and anticonvulsants such as gabapentin. Plasma exchange or intravenous immunoglobulin is indicated for acute demyelinating neuropathies, while corticosteroids or other immunosuppressive agents are used in chronic demyelinating conditions. Supportive care, including intravenous fluids and vasopressors, may be necessary for autonomic instability.
Admission is warranted for patients with respiratory failure, blood pressure instability, inability to ambulate or care for themselves, inadequate pain control, rapidly progressive symptoms, or poorly controlled underlying disease. Stable patients without respiratory or autonomic compromise who can manage self-care and have adequate outpatient follow-up may be discharged. All patients require referral to primary care and neurology for ongoing evaluation and management, and many benefit from physical therapy. Recognizing potentially reversible causes and identifying patients at risk for respiratory failure or autonomic instability are essential priorities in emergency and acute care.
Polyneuropathy is a peripheral nerve disorder in which multiple nerves throughout the body malfunction simultaneously. It may present acutely or chronically and may involve sensory, motor, autonomic, or mixed dysfunction. Acute causes include infections (such as toxin-producing bacteria and viruses), autoimmune conditions like Guillain–Barré syndrome, toxic exposures including heavy metals such as lead and mercury, medications such as phenytoin, chloramphenicol, nitrofurantoin, sulfonamides, vincristine, vinblastine, and certain sedatives, as well as malignancies like multiple myeloma. Chronic polyneuropathy is most commonly caused by diabetes mellitus, but may also result from chronic alcohol use, nutritional deficiencies (particularly thiamine and vitamin B12), hypothyroidism, liver failure, kidney failure, lung cancer, and chronic inflammatory demyelinating polyneuropathy (CIDP).
Polyneuropathy affects approximately 2% of the general U.S. population and up to 8% of individuals over age 55. Diabetes is the most common cause in the United States and occurs in roughly half of insulin-dependent diabetics. Pathophysiologically, polyneuropathy may result from myelin dysfunction, vascular compromise to the vasa nervorum, or primary axonal injury. Myelin dysfunction is often immune-mediated, triggered by infections such as Campylobacter, diphtheria, influenza, or HIV, and may follow vaccination. Guillain–Barré syndrome presents acutely with rapidly progressive weakness and may lead to respiratory failure, whereas CIDP follows a more chronic or relapsing course. Vascular compromise from atherosclerosis, vasculitis, infection, or hypercoagulable states may cause ischemic nerve injury. Axonal injury is most commonly due to toxic-metabolic conditions such as diabetes, nutritional deficiencies, or drug and chemical exposure.
Clinically, polyneuropathy usually begins distally in the lower extremities and progresses proximally in a symmetrical “stocking-glove” distribution. Patients often report numbness, burning, tingling, weakness, and difficulty walking. Autonomic symptoms may include constipation, urinary retention or incontinence, sexual dysfunction, orthostatic dizziness, dry skin, and decreased sweating. On examination, findings are typically bilateral and symmetrical, including decreased sensation, impaired vibration and position sense, diminished motor strength, reduced reflexes, muscle atrophy, and sometimes fasciculations or paralysis. In demyelinating disorders such as Guillain–Barré syndrome and CIDP, weakness may be disproportionate to atrophy and reflexes are markedly diminished. Ischemic neuropathies often cause painful burning sensations with preserved reflexes and distal involvement. Toxic-metabolic axonopathies are typically painful and distally symmetric.
Evaluation begins with a thorough history and physical examination. Initial laboratory testing should include complete blood count, electrolytes, glucose, renal and liver function tests, thyroid-stimulating hormone, erythrocyte sedimentation rate, antinuclear antibody, vitamin B12, folate, rapid plasma reagin, HIV, hepatitis B and C serologies, Lyme testing, creatine phosphokinase, and serum protein electrophoresis. Additional tests such as heavy metal levels, genetic studies, or immune-mediated antibody testing are guided by clinical suspicion. Electromyography and nerve conduction studies are essential diagnostic tools. Lumbar puncture demonstrating elevated cerebrospinal fluid protein with normal cell count supports Guillain–Barré syndrome or CIDP. Nerve or skin biopsy may be considered in selected cases.
Emergency management focuses on airway, breathing, and circulation. Respiratory compromise is a critical concern in acute demyelinating neuropathies; measurement of negative inspiratory force (normal approximately −60 cm H₂O) helps assess impending respiratory failure. Patients with respiratory weakness require prompt ventilatory support. Pain management may include narcotics, tricyclic antidepressants such as amitriptyline, and anticonvulsants such as gabapentin. Plasma exchange or intravenous immunoglobulin is indicated for acute demyelinating neuropathies, while corticosteroids or other immunosuppressive agents are used in chronic demyelinating conditions. Supportive care, including intravenous fluids and vasopressors, may be necessary for autonomic instability.
Admission is warranted for patients with respiratory failure, blood pressure instability, inability to ambulate or care for themselves, inadequate pain control, rapidly progressive symptoms, or poorly controlled underlying disease. Stable patients without respiratory or autonomic compromise who can manage self-care and have adequate outpatient follow-up may be discharged. All patients require referral to primary care and neurology for ongoing evaluation and management, and many benefit from physical therapy. Recognizing potentially reversible causes and identifying patients at risk for respiratory failure or autonomic instability are essential priorities in emergency and acute care.
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