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Polyneuropathy, Emergency Medicine

Basics

Description

- 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

- Pain control: - Parenteral or oral narcotics - Tricyclic antidepressants (amitriptyline) - Anticonvulsants (gabapentin)

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 abuseNutritional deficiencies (Thiamine, B12)HypothyroidismLiver failureKidney failureLung cancerChronic 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 dysfunctionRapidly progressive weakness and may lead to respiratory failureCIDM:Chronic illness of myelin dysfunctionSymptoms may recur or progress over months and years
  • Vasa nervosum compromise:Vascular supply to nerves compromised leading to nerve infarctionCauses:Chronic atherosclerosisVasculitisInfectionsHypercoagulable statesAxonopathyPrimary dysfunction of the axonMost often the result of toxic " “metabolic disorders:DiabetesNutritional deficienciesDrugs/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 extremitiesWeakness of extremitiesDifficulty walkingAutonomic symptoms:ConstipationLoss of bowel/bladder controlSexual dysfunctionOrthostatic dizzinessDry skinDecreased sweating

Physical Exam

  • Typically, findings are bilateral symmetrical and stocking glove distribution
  • Typical findings:Decreased sensationDecreased vibratory and position senseDecreased motor functionDecreased reflexesMuscle atrophyFasciculationsParalysis
  • Findings in specific types of polyneuropathy:Myelin dysfunction (Guillain " “Barre " “ acute and CIDP " “ chronic):Muscle weakness greater than expected for degree of atrophyParesthesiasGreatly diminished reflexesProximal and distal symptomsIschemia to nerve (atherosclerosis, vasculitis, infectious, hypercoagulable):Painful, burning sensory disturbancesDecreased pain and temperature sensationMuscle weakness proportional to atrophyReflexes sparedUsually spares proximal nervesCranial nerve involvement rarePrimary axon dysfunction (toxic-metabolic disorders):Have symptoms of either myelin dysfunction, ischemia, or combinedPainfulDistally symmetricalStocking gloveLower extremities before upper

Essential Workup

  • Thorough past medical history and physical exam should be obtained to guide testing
  • Initial lab testing:CBCElectrolytesGlucoseRenal and liver functionTSHESRANAVitamin B12FolateRPRHIVHepatitis B and CLymeCPKSerum protein electrophoresis
  • Subsequent lab testing based on history:Heavy metal levels (history of exposure)Genetic testing for genetic neuropathiesSerum 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 abnormalDiagnostic 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 deficiencyCancer/paraneoplasticToxinsLiver diseaseRenal failureGenetic disordersAmyloidosis
  • Other diseases with similar presentations:PolioPorphyriaSpinal muscular atrophyCatecholamine disordersPsychological 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 narcoticsTricyclic 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)