Peripheral Neuropathy Clinical Presentation

Peripheral Neuropathy: Clinical Presentation

• Distal sensory loss, burning, stinging, and "pins and needles" sensation
• Symptoms: ulcers or slow healing wounds, sensitivity to touch, lack of sensation, increased falls, and tingling or numb feet
• Sensory changes are the most common manifestation

Classifications of Peripheral Neuropathies

• Mononeuropathy: involves one nerve
• Polyneuropathy: involves multiple nerves
• Mononeuropathy Multiplex: involves one nerve in multiple places

Mononeuropathies

• May occur due to injury, compression, angulation, or stretching of a nerve
• Entrapment neuropathy: compression of a nerve by neighboring anatomic structures
• Examples: carpal tunnel syndrome, compression/entrapment nerve, ischemia, leg crossing, high boots
• Acute compression neuropathy: no treatment is necessary, complete recovery generally occurs within 2 months
• Chronic compressive or entrapment neuropathies: avoidance of aggravating factors and correction of underlying systemic conditions are important

Polyneuropathies

• Typically symmetric and distal
• Associated with Diabetes Mellitus (DM); also known as "stocking-glove" neuropathy

Mononeuropathy Multiplex

• Simultaneous malfunction of two or more peripheral nerves in separate areas of the body
• Can be caused by infection (e.g., HIV)
• Neuropathic pain: burning, dull, and poorly localized
• Allodynia: pain due to a stimulus that does not normally provoke pain
• Hyperpathia: a painful syndrome characterized by an abnormally painful reaction to a stimulus

Timeline

• Acute: days to 4 weeks
• Subacute: 4-8 weeks
• Chronic: >8 weeks
• Course: monophasic, progressive, or relapsing

Upper Motor/sensory Neuron Involvement

• Hyperreflexia, spasticity, Babinski sign
• Most common cause: vitamin B12 deficiency
• Other considerations: copper deficiency, HIV

Physical Examination

• Sharp/Dull
• Deep ankle reflex
• Foot evaluation for ulceration

Diagnostic Workup

• Electrodiagnostic Studies (EDx): nerve conduction studies (NCS) and needle electromyography (EMG)
• Nerve Conduction Studies (NCS)
• Needle Electromyography (EMG)
• Nerve Biopsies (NBx): less widely performed, primary indication is suspicion for amyloid neuropathy or vasculitis

Treatment

• Protect anesthetic extremities from injury
• Patient education: daily foot inspection, use of a mirror if needed, and proper shoe fitting
• Physical therapy: prevents contractures, and maintains a weak extremity in a position of useful function
• Pain management: simple analgesics (e.g., aspirin, NSAIDS), gabapentin, or pregabalin

Carpal Tunnel Syndrome

• Mononeuropathy: affects only the median nerve
• Causes: repetitive wrist activities, pregnancy, diabetes mellitus, rheumatoid arthritis
• H&P: initial symptoms, subtle disparity between affected-opposite sides, Tinel sign, Phalen sign, and carpal compression test
• Diagnostic studies: US, EDx, and NCS
• Treatment: relieve pressure on median nerve, splinting, oral corticosteroids, NSAIDs, methylprednisolone injections, and surgery

Guillain-Barré Syndrome

• Rapidly progressive weakness or paralysis
• Associated with mild respiratory or intestinal infection, swine flu immunizations
• Common in 20-50 years old
• Treatment: plasmapheresis and/or IVIG

Complex Regional Pain Syndrome (CRPS)

• Rare disorder characterized by autonomic and vasomotor instability
• Cardinal symptoms and signs: pain, swelling, disturbances of color and temperature, dystrophic changes, and limited range of motion
• Most cases preceded by surgery or direct physical trauma
• Syndrome phases: pain, swelling, skin color/temperature changes, and dystrophy
• Treatment: NSAIDs, prednisone, invasive therapies, and early mobilization after injury or surgery

Charcot-Marie-Tooth (CMT)

• Inherited neuropathies
• Clinical presentation: foot deformities or gait disturbances in childhood or early adult life
• Slow progression leads to typical features of polyneuropathy
• No medical treatment, but physical and occupational therapy are key

Neuropathies Associated with Systemic & Metabolic Disorders

• Diabetes Mellitus
• Chronic alcohol overuse
• Nutrition deficiencies
• Pregnancy

Neuropathies Associated with Infection & Inflammatory Disorders

• HIV/AIDS
• Sarcoidosis
• Rheumatoid Arthritis

Neuropathies Associated with Toxin Exposure

• Chronic alcohol overuse
• Chemotherapy
• Heavy metals exposure (e.g., lead, arsenic)
• Environmental (e.g., vibration-induced nerve damage, loud sounds, prolonged cold exposure, hypoxemia)

Autonomic Neuropathies

• Resulting from diseases of the peripheral autonomic nervous system, a significant complication of diabetes mellitus
• Characterized by changes in:
  • Skin and hair texture
  • Itching
  • Edema
  • Loss of nails
  • Sweating abnormalities
  • Dryness of mouth and eyes
  • Excessive salivation

Cardiovascular Impacts

• Cardiac arrhythmias
• Orthostatic hypotension
• Sleep apnea

Gastrointestinal Impacts

• Dysphagia
• Constipation
• Gastroparesis

Genitourinary and Neuroendocrine Impacts

• Urinary retention or incontinence
• Bladder urgency
• Sexual dysfunction

Key Clinical Sign

• Orthostatic fall in blood pressure without an appropriate increase in heart rate
• Measured through orthostatic hypotension test

Important to Know

• Autonomic nervous system regulates involuntary physiologic processes, including heart rate, blood pressure, respiration, digestion, and sexual arousal
• Autonomic nervous system disorders can occur on their own or as a result of progression of other peripheral nervous system disorders