Basics
Description
A peripheral nerve disorder in which many nerves throughout the body malfunction simultaneously: ‚
- Acute polyneuropathy causes:
- Infectious (toxin producing bacteria, viruses)
- Autoimmune (Guillain " “Barre)
- Toxic (heavy metals):
- Drugs:
- Anticonvulsants (phenytoin)
- Antibiotics (chloramphenicol, nitrofurantoin, sulfonamides)
- Chemotherapy (vinblastine, vincristine)
- Sedatives (hexobarbital and barbital)
- Cancer (multiple myeloma)
- Chronic polyneuropathy causes:
- Diabetes (most common)
- Alcohol abuse
- Nutritional deficiencies (Thiamine, B12)
- Hypothyroidism
- Liver failure
- Kidney failure
- Lung cancer
- Chronic inflammatory demyelinating polyneuropathy (CIDM)
Epidemiology
Incidence and Prevalence Estimates
- In US, the prevalence of polyneuropathy is ¢ ˆ ¼2% in the general population
- It is 8% in patients >55 yr of age
- The most common cause in US is diabetes and it occurs in ¢ ˆ ¼50% of diabetics on insulin
Etiology
- Myelin dysfunction:
- Parainfectious immune response triggered by antigens that cross-react with antigens in the peripheral nervous system:
- Encapsulated bacteria (Campylobacter sp., diphtheria)
- Viruses (enteric or influenza viruses, HIV)
- Vaccines (influenza)
- Guillain " “Barre syndrome:
- Acute onset due to myelin dysfunction
- Rapidly progressive weakness and may lead to respiratory failure
- CIDM:
- Chronic illness of myelin dysfunction
- Symptoms may recur or progress over months and years
- Vasa nervosum compromise:
- Vascular supply to nerves compromised leading to nerve infarction
- Causes:
- Chronic atherosclerosis
- Vasculitis
- Infections
- Hypercoagulable states
- Axonopathy
- Primary dysfunction of the axon
- Most often the result of toxic " “metabolic disorders:
- Diabetes
- Nutritional deficiencies
- Drugs/chemicals
Diagnosis
Signs and Symptoms
- May be acute or chronic
- May be predominately sensory, motor, combined sensory " “motor, or autonomic dysfunction
History
- More commonly affects lower extremities than upper extremities and begins distally
- Typical complaints:
- Dysaesthesias " “ numbness, burning, or tingling of the extremities
- Weakness of extremities
- Difficulty walking
- Autonomic symptoms:
- Constipation
- Loss of bowel/bladder control
- Sexual dysfunction
- Orthostatic dizziness
- Dry skin
- Decreased sweating
Physical Exam
- Typically, findings are bilateral symmetrical and stocking glove distribution
- Typical findings:
- Decreased sensation
- Decreased vibratory and position sense
- Decreased motor function
- Decreased reflexes
- Muscle atrophy
- Fasciculations
- Paralysis
- Findings in specific types of polyneuropathy:
- Myelin dysfunction (Guillain " “Barre " “ acute and CIDP " “ chronic):
- Muscle weakness greater than expected for degree of atrophy
- Paresthesias
- Greatly diminished reflexes
- Proximal and distal symptoms
- Ischemia to nerve (atherosclerosis, vasculitis, infectious, hypercoagulable):
- Painful, burning sensory disturbances
- Decreased pain and temperature sensation
- Muscle weakness proportional to atrophy
- Reflexes spared
- Usually spares proximal nerves
- Cranial nerve involvement rare
- Primary axon dysfunction (toxic-metabolic disorders):
- Have symptoms of either myelin dysfunction, ischemia, or combined
- Painful
- Distally symmetrical
- Stocking glove
- Lower extremities before upper
Essential Workup
- Thorough past medical history and physical exam should be obtained to guide testing
- Initial lab testing:
- CBC
- Electrolytes
- Glucose
- Renal and liver function
- TSH
- ESR
- ANA
- Vitamin B12
- Folate
- RPR
- HIV
- Hepatitis B and C
- Lyme
- CPK
- Serum protein electrophoresis
- Subsequent lab testing based on history:
- Heavy metal levels (history of exposure)
- Genetic testing for genetic neuropathies
- Serum antibody testing for immune-mediated neuropathies
Diagnosis Tests & Interpretation
Imaging
Should be guided by history and physical findings ‚
Diagnostic Procedures/Surgery
- Electromyography (EMG)
- Nerve conduction studies
- Lumbar puncture:
- Increased CSF protein level abnormal
- Diagnostic of Guillain " “Barre syndrome and CIDP
- Skin or nerve biopsy
Differential Diagnosis
- Primarily to differentiate between various causes of polyneuropathy:
- Endocrine disease (diabetes)
- Infections (Guillain " “Barre, Lyme disease, HIV, syphilis)
- Vitamin deficiency
- Cancer/paraneoplastic
- Toxins
- Liver disease
- Renal failure
- Genetic disorders
- Amyloidosis
- Other diseases with similar presentations:
- Polio
- Porphyria
- Spinal muscular atrophy
- Catecholamine disorders
- Psychological disorders
Treatment
Pre-Hospital
Primarily supportive care for ABCs ‚
Initial Stabilization/Therapy
- ABCs
- Respiratory support for respiratory failure
Ed Treatment/Procedures
- Pain control:
- Parenteral or oral narcotics
- Tricyclic antidepressants (amitriptyline)
- Anticonvulsants (gabapentin)
- Plasma exchange or IV immune globulin for acute myelin dysfunction
- Corticosteroids or antimetabolite drugs for chronic myelin dysfunction
- Supportive care for autonomic dysfunction (IVF, pressors)
- Measure Negative Inspiratory Force (NIF) if concerned about respiratory compromise (Normal is < ¢ ˆ ’60 cm H2O)
Follow-Up
Disposition
Admission Criteria
Determined by medical condition and acuity of onset necessitating rapid diagnostic testing: ‚
- Respiratory failure
- BP instability
- Inability to walk or care for self
- Inadequate pain control
- Poor control of underlying disease process
- Rapidly progressing symptoms
Discharge Criteria
- Underlying medical condition stabilized
- No evidence or low risk of respiratory failure or autonomic instability
- Able to care for self
- Adequate pain control
- Access to outpatient follow-up for further testing or management
Issues for Referral
All patients require referral to primary care physician or neurology for ongoing testing and/or management ‚
Follow-Up Recommendations
- Primary care physician
- Neurology
- Physical therapy
Pearls and Pitfalls
- Understanding that the potential causes of polyneuropathy are broad and a comprehensive search for the underlying cause will aid in management
- Recognizing those few causes that are at risk for respiratory failure or autonomic instability
- For most causes, treatment consists of controlling underlying disease process
Additional Reading
- England ‚ JD, Gronseth ‚ GS, Franklin ‚ G, et al. Practice parameter: Evaluation of distal symmetric polyneuropathy: Role of autonomic testing, nerve biopsy, and skin biopsy (an evidence-based review). Report of the American Academy of Neurology, American Association of Neuromuscular and Electrodiagnostic Medicine, and American Academy of Physical Medicine and Rehabilitation. Neurology. 2009;72(2):177 " “184.
- Ralph ‚ JW. Assessment of polyneuropathy. In Minhas ‚ R, ed. Best Practice. BMJ Group. 2012.
- Rubin ‚ M. Peripheral Neuropathy. In: Porter ‚ RS, ed. Merck Manual Online. 2012.
- Tracy ‚ JA, Dyck ‚ PJ. Investigations and treatment of chronic inflammatory demyelinating polyradiculoneuropathy and other inflammatory demyelinating polyneuropathies. Curr Opin Neurol. 2010;23(3):242 " “248.
Codes
ICD9
- 356.9 Unspecified hereditary and idiopathic peripheral neuropathy
- 357.4 Polyneuropathy in other diseases classified elsewhere
- 357.7 Polyneuropathy due to other toxic agents
- 357.2 Polyneuropathy in diabetes
- 356.8 Other specified idiopathic peripheral neuropathy
- 357.5 Alcoholic polyneuropathy
- 357.81 Chronic inflammatory demyelinating polyneuritis
ICD10
- G62.2 Polyneuropathy due to other toxic agents
- G62.9 Polyneuropathy, unspecified
- G63 Polyneuropathy in diseases classified elsewhere
- E11.42 Type 2 diabetes mellitus with diabetic polyneuropathy
- G61.81 Chronic inflammatory demyelinating polyneuritis
- G62.1 Alcoholic polyneuropathy
- G62.89 Other specified polyneuropathies
SNOMED
- 42345000 Polyneuropathy (disorder)
- 193186008 Polyneuropathy associated with another disorder (disorder)
- 45600000 toxic polyneuropathy (disorder)
- 49455004 diabetic polyneuropathy (disorder)
- 128209004 Chronic inflammatory demyelinating polyradiculoneuropathy (disorder)
- 7916009 Alcoholic polyneuropathy (disorder)