General Considerations



General Considerations





Definitions



  • Peripheral neuropathy, polyneuropathy: diffuse lesions of peripheral nerves, manifest by weakness, sensory loss, autonomic dysfunction.


  • Mononeuropathy: single nerve affected (trauma, entrapment).


  • Mononeuropathy multiplex: two or more nerves affected individually; can identify nerves by clinical pattern or nerve conduction studies.


  • Neuronopathy: motor or sensory neuron affected.


Classification by Symptoms and Signs



  • Predominantly motor: lead toxicity, dapsone or hexane intoxication, tick paralysis, porphyria, some cases of GBS, multifocal conduction block, anti-GM1 antibodies.


  • Predominantly sensory: thallium poisoning, acute idiopathic sensory neuronopathy or ganglioneuritis, pyridoxine (vitamin B6) deficiency, inherited sensory neuropathies, primary biliary cirrhosis, diabetes mellitus, amyloidosis, carcinoma, lepromatous leprosy.


  • Predominantly autonomic: acute or chronic autonomic neuropathy, amyloidosis.


  • Mononeuropathy multiplex: diabetes mellitus, periarteritis nodosa, HIV-1 infection, rheumatoid arthritis, brachial neuropathy, leprosy, nerve trauma, sarcoid compression. Asymmetric motor neuropathy in multifocal neuropathy.


  • Hypertrophic nerves: Charcot-Marie-Tooth (CMT) disease type 1, Dejerine-Sottas syndrome, Refsum disease, neurofibromatosis type 1, leprosy, amyloidosis, chronic demyelinating polyneuropathy, sarcoid, acromegaly (hyperpituitarism).


  • Fasciculations: spontaneous contractions of individual motor units; visible twitch of limb muscle under skin; also identified in EMG. Anterior horn cell diseases, multifocal motor neuropathy.



Etiology and Diagnosis

See Table 104.1.








Table 104.1 Classification and Evaluation of Most Common Polyneuropathies
































































































































































Cause or diagnosis Presentations Laboratory tests
Vitamin Deficiencies S, SM, SYM Vitamins B12, B6, B1
INfectious    
Lyme disease S, SM, SYM, MF, CN Serology, PCR
HIV-1 S, SM, SYM, MF, CN Serology, PCR
Hepatitis C S, SM, SYM, MF, CN Serology, PCR
Herpes Zoster S, radicular Serology, PCR
Cytomegalovirus SM, M, SYM, MF Serology, PCR, culture
Immune Mediated    
Guillain-Barré and variants SM, S, M, SYM, CN IgG anti-ganglioside antibodies (GM1,GD1a,GQ1b, GD1b), urine porphyrins
IgM antibody associated M, MF IgM anti-GM1, GD1a
  S, SM, SYM IgM anti-MAG, sulfatides, GD1b, GQ1b
Monoclonal gammopathy M, S, SM, SYM, MF Serum immunofixation electrophoresis, quantitative immunoglobulins
Autonomic neuropathy Autonomic dysfunction Anti-nicotinic acetylcholine receptor antibodies
Vasculitis SM, S, MF, SYM ESR, cryoglobulins, hepatitis C serology or PCR
Sarcoid SM, S, MF, SYM ACE, chest X-ray
Celiac disease S, SM, MF, SYM Anti-gliadin, endomysial, transglutaminase antibodies
CIDP Chronic motor or sensorimotor, demyelinating EMG, CSF
Rheumatologic diseases (Sjögren syndrome, lupus erythematosus, Wegener granulomatosis, rheumatoid arthritis) SM, S, MF, SYM SSA-Ro, SSB-La antibodies, ANA, ANCA (PR3, myeloperoxidase), dsDNA Ab, RNP, rheumatoid factor
Paraneoplastic    
Lung cancer S, SYM Anti-HU Ab, chest X-ray
Waldenström macroglobulinemia SM, S, M, SYM, MF Serum immunofixation electrophoresis
Myeloma SM, M, SYM, MF Serum and urine immunofixation electrophoresis, skeletal survey
Hereditary    
CMT1-1 Demyelinating, SM, SYM, MF DNA tests for PMP-22, MPZ, EGR2, Cx32
CMT-2 Axonal, SM, SYM DNA tests for NF-L, Cx32, MPZ
Mitochondrial NARP, SM, MF, MNGIE Serum lactate, thymidine phosphorylase (MNGIE), DNA testing
Other Axonal S, SM, amyloid, porphyria DNA test for transthyretin, periaxin; urine porphyrins; porphobilinogen, delta aminolevulinic acid; muscle nerve biopsy for amyloid.
Nutritional    
Alcoholism SM, autonomic  
Vitamin B1 deficiency SM, autonomic Serum B1
Vitamin B12 deficiency S, SM CBC count serum B12
Vitamin B6 deficiency S Serum B6
Vitamin E deficiency S Serum vitamin E
Metabolic/Toxic    
Diabetes S, SM, SYM, MF, CN Chem 7, HgbA1c, glucose tolerance test
Renal failure S, SM, SYM Chem 7
Thyroid disease S, SM, SYM, MF TSH, T4
Heavy metal toxicity S, SM, SYM Urine lead, mercury, arsenic
CN, cranial nerves; Cx32, connexin; EGR, early growth response protein; GM1, GD1a, ganglioside component of myelin; MPZ, myelin protein zero; NF-L, neurofilament light chain; M, motor; MF, multifocal; MNGIE, Myopathy with ophthalmoplegia, Neuropathy, and Gastro-Intestinal disease with Encephalopathy; NARP, neuropathy, ataxia, retinitis pigmentosa; PMP, peripheral myelin protein; PCR, polymerase chain reaction; RNP, ribonucleoprotein; S, sensory; SM, sensorimotor; SSA, SSB, antigens for Sjögren syndrome severe antibodies; SYM, symmetric.

Only gold members can continue reading. Log In or Register to continue

Related posts:

Default ThumbnailNerve Conduction Studies, Electromyography, and Magnetic Stimulation Default ThumbnailSpirochete Infections: Neurosyphilis Default ThumbnailCerebral Veins and Sinuses Default ThumbnailStructural Malformations Default ThumbnailGilles De La Tourette Syndrome Default ThumbnailMénière Syndrome

Stay updated, free articles. Join our Telegram channel
Tags:
Jul 27, 2016 | Posted by in NEUROLOGY | Comments Off on General Considerations

Full access? Get Clinical Tree
Get Clinical Tree app for offline access