Evaluation of lower extremity mononeuropathy

Normal is <100 mg/dL. Prediabetes is 100-125 mg/dL. Diabetes is >125 mg/dL. Order after a minimum 8-hour fast. Confirm an elevated result with an HbA1c (which can be done on the same sample), a second fasting plasma glucose, or another diabetes diagnostic test.​​​[22]American Diabetes Association Professional Practice Committee. 2. Diagnosis and classification of diabetes: standards of care in diabetes - 2024. Diabetes Care. 2024 Jan 1;47(suppl 1):S20-42. https://diabetesjournals.org/care/article/47/Supplement_1/S20/153954/2-Diagnosis-and-Classification-of-Diabetes http://www.ncbi.nlm.nih.gov/pubmed/38078589?tool=bestpractice.com

More costly and inconvenient than fasting plasma glucose or HbA1c. A 2-hour value on a 75 g glucose tolerance test >199 mg/dL is diabetes. All diabetes tests need to be repeated to draw conclusions.

Accuracy increases with duration of symptoms; it is generally recommended that electrodiagnostic testing be done no sooner than 2-3 weeks after symptoms start. Assesses severity and chronicity, localizes the affected root(s), and guides therapy.[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms; it is generally recommended that electrodiagnostic studies be done no sooner than 2-3 weeks after symptoms start. Assesses severity and chronicity, localizes the affected root(s), and guides therapy.[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Enlarged epidural veins may be misinterpreted as herniated disk material.

Excludes femoral neuropathy, lumbosacral radiculopathy, or plexopathy. Sensory responses are often difficult to obtain even in normal people.

Excludes femoral neuropathy, lumbosacral radiculopathy, or plexopathy. Sensory responses are often difficult to obtain even in normal people.

Excludes lumbar radiculopathy. Guides therapy and additional testing by excluding structural or surgical etiologies.

Excludes lumbar radiculopathy. Guides therapy and additional testing by excluding structural or surgical etiologies.

Excludes compressive tumor or hematoma. Guides therapy and additional testing by excluding structural or surgical etiologies.

Excludes lumbosacral radiculopathy or plexopathy. Differentiates from sciatic, tibial, or length-dependent polyneuropathies. Gauges severity and acuity and monitors progression.

Excludes lumbosacral radiculopathy or plexopathy. Differentiates from sciatic, tibial, or length-dependent polyneuropathies. Gauges severity and acuity and monitors progression.

Excludes lumbar radiculopathy. Generally not needed, but helpful in the setting of superimposed radicular pain. Guides therapy and additional testing by excluding structural or surgical etiologies.

Excludes lumbar radiculopathy. Generally not needed, but helpful in the setting of superimposed radicular pain. Guides therapy and additional testing by excluding structural or surgical etiologies.

Excludes compressive lesion proximally. Rarely necessary, but helpful if lesion localizes proximal to fibular neck. Guides therapy and additional testing by excluding structural or surgical etiologies.

Generally not necessary, but useful if recovery is not as expected or unusual pain.

Excludes lumbosacral radiculopathy, distal tibial neuropathy, or length-dependent polyneuropathy.

Excludes other causes of foot pain, e.g., tendinitis, arthritis.

Assesses severity and chronicity, localizes the affected levels of the plexus, and guides therapy.[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Differs from radiculopathies in that sensory amplitudes are decreased. Assesses severity and chronicity, localizes the affected levels of the plexus, and guides therapy.[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Guides therapy and additional testing.

Guides therapy and additional testing.

Excludes femoral neuropathy, lumbosacral radiculopathy, or plexopathy. Gauges acuity and severity and monitors progression and/or resolution.

Excludes femoral neuropathy, lumbosacral radiculopathy, or plexopathy. Gauges acuity and severity and monitors progression and/or resolution.

Excludes lumbar radiculopathy. Guides therapy and additional testing by excluding structural or surgical etiologies.

Excludes lumbar radiculopathy. Guides therapy and additional testing by excluding structural or surgical etiologies.

Excludes compressive tumor or hematoma. Guides therapy and additional testing by excluding structural or surgical etiologies.

Excludes lumbosacral radiculopathy or plexopathy.

Excludes lumbosacral radiculopathy or plexopathy.

Guides therapy and additional testing by excluding structural or surgical etiologies.

Guides therapy and additional testing by excluding structural or surgical etiologies.

Guides therapy and additional testing by excluding structural or surgical etiologies.

Guides therapy and additional testing by excluding structural or surgical etiologies.[23]Yuen EC, So YT. Sciatic neuropathy. Neurol Clin. 1999;17:617-631. http://www.ncbi.nlm.nih.gov/pubmed/10393756?tool=bestpractice.com

Excludes lumbosacral radiculopathy or plexopathy. Differentiates from sciatic, tibial, or length-dependent polyneuropathies. Gauges severity and acuity and monitors progression.

Excludes lumbosacral radiculopathy or plexopathy. Differentiates from sciatic, tibial, or length-dependent polyneuropathies. Gauges severity and acuity and monitors progression.

Positive if there is a space-occupying lesion. Generally not needed, but helpful in the setting of superimposed trauma or surgery. Guides therapy and additional testing by excluding structural or surgical etiologies.

Excludes lumbosacral radiculopathy or plexopathy. Differentiates from sciatic, peroneal, or length-dependent polyneuropathies. Gauges severity and acuity and monitors progression.

Excludes lumbosacral radiculopathy or plexopathy. Differentiates from sciatic, peroneal, or length-dependent polyneuropathies. Gauges severity and acuity and monitors progression.

Excludes lumbar radiculopathy. Generally not needed, but helpful in the setting of superimposed radicular pain. Guides therapy and additional testing by excluding structural or surgical etiologies.

Excludes lumbar radiculopathy. Generally not needed, but helpful in the setting of superimposed radicular pain. Guides therapy and additional testing by excluding structural or surgical etiologies.

Excludes compressive lesion proximally. Rarely necessary, but helpful if lesion localizes at or proximal to divergence from deep peroneal nerve, or if there is unusual pain or incomplete recovery.

Accuracy increases with duration of symptoms. Assesses severity and chronicity, localizes the affected root(s), and guides therapy.[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.[24]Bowley MP, Doughty CT. Entrapment Neuropathies of the Lower Extremity. Med Clin North Am. 2019 Mar;103(2):371-82. https://www.sciencedirect.com/science/article/abs/pii/S0025712518301378?via%3Dihub http://www.ncbi.nlm.nih.gov/pubmed/30704688?tool=bestpractice.com

Accuracy increases with duration of symptoms. Assesses severity and chronicity, localizes the affected root(s), and guides therapy.[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.[24]Bowley MP, Doughty CT. Entrapment Neuropathies of the Lower Extremity. Med Clin North Am. 2019 Mar;103(2):371-82. https://www.sciencedirect.com/science/article/abs/pii/S0025712518301378?via%3Dihub http://www.ncbi.nlm.nih.gov/pubmed/30704688?tool=bestpractice.com

Positive if superimposed lumbar radiculopathy. Guides therapy and additional testing by excluding structural or surgical etiologies.

Positive if superimposed lumbar radiculopathy. Guides therapy and additional testing by excluding structural or surgical etiologies.

Guides therapy and additional testing by excluding structural or surgical etiologies.

Fasting plasma glucose is >125 mg/dL in diabetes mellitus. May also show glucose intolerance in prediabetes.

Also known as tomacula.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

False-negatives may occur during window period immediately after infection because antibodies to HIV have not yet been produced. A positive result should be confirmed with a Western blot or second ELISA.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

VCA-IgM in most patients is detectable with symptom onset, peaks at 2-3 weeks, and becomes unmeasurable by 4 months. VCA-IgG peaks at 2-3 months and persists for life. Antibodies to EA rise in acute stage, become undetectable by 3-4 months, and may reappear with reactivation of EBV infection. EA antibodies are also detectable in some clinically healthy people. EBNA antibodies rise in resolution phase, and remain detectable for life.[25]Hess RD. Routine Epstein-Barr virus diagnostics from the laboratory perspective: still challenging after 35 years. J Clin Microbiol. 2004;42:3381-3387. http://jcm.asm.org/cgi/content/full/42/8/3381 http://www.ncbi.nlm.nih.gov/pubmed/15297472?tool=bestpractice.com

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Approximately 90% of patients with a connective tissue disease and 20% to 30% of patients with either a primary systemic vasculitis or nonsystemic vasculitic neuropathy are positive for ANA.[26]Collins MP, Kissel JT. Neuropathies with systemic vasculitis. In: Dyck PJ, Thomas PK, eds. Peripheral neuropathy. 4th ed. Philadelphia, PA: Elsevier Saunders; 2005:2335-2404.[2]Gwathmey KG, Burns TM, Collins MP, et al. Vasculitic neuropathies. Lancet Neurol. 2014 Jan;13(1):67-82. https://www.thelancet.com/journals/laneur/article/PIIS1474-4422(13)70236-9/fulltext http://www.ncbi.nlm.nih.gov/pubmed/24331794?tool=bestpractice.com

Positive in vasculitis.[2]Gwathmey KG, Burns TM, Collins MP, et al. Vasculitic neuropathies. Lancet Neurol. 2014 Jan;13(1):67-82. https://www.thelancet.com/journals/laneur/article/PIIS1474-4422(13)70236-9/fulltext http://www.ncbi.nlm.nih.gov/pubmed/24331794?tool=bestpractice.com Antiproteinase 3 tests are used to detect a cytoplasmic pattern (c-ANCA). Antimyeloperoxidase tests are used to detect a perinuclear pattern (p-ANCA).

Reduced in vasculitis.[2]Gwathmey KG, Burns TM, Collins MP, et al. Vasculitic neuropathies. Lancet Neurol. 2014 Jan;13(1):67-82. https://www.thelancet.com/journals/laneur/article/PIIS1474-4422(13)70236-9/fulltext http://www.ncbi.nlm.nih.gov/pubmed/24331794?tool=bestpractice.com

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Anemia seen in 4% to 20%; leukopenia in 40%.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Quantitatively measures tears. A filter paper is placed in the lower conjunctival sac. The test is positive if <5 mm of paper is wetted after 5 minutes.[27]Ramos-Casals M, Brito-Zerón P, Sisó-Almirall A, et al. Primary Sjögren syndrome. BMJ. 2012 Jun 14;344:e3821. https://www.bmj.com/content/344/bmj.e3821/rr/650909 http://www.ncbi.nlm.nih.gov/pubmed/22700787?tool=bestpractice.com

Antibodies to the ribonucleoproteins 60 kD Ro and La are found in about 50% to 70% of patients with Sjogren syndrome.[27]Ramos-Casals M, Brito-Zerón P, Sisó-Almirall A, et al. Primary Sjögren syndrome. BMJ. 2012 Jun 14;344:e3821. https://www.bmj.com/content/344/bmj.e3821/rr/650909 http://www.ncbi.nlm.nih.gov/pubmed/22700787?tool=bestpractice.com Anti-60 kD Ro is not specific to Sjogren syndrome and is found in other autoimmune disorders, particularly lupus.[28]Scheinfeld N. Sjogren syndrome and systemic lupus erythematosus are distinct conditions. Dermatol Online J. 2006;12:4. http://escholarship.org/uc/item/0jp529zq http://www.ncbi.nlm.nih.gov/pubmed/16638372?tool=bestpractice.com

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Approximately 30% of RA patients are rheumatoid factor-negative.[29]Aho K, Palusuo T, Kurki P. Marker antibodies of rheumatoid arthritis: diagnostic and pathogenetic implications. Semin Arthritis Rheum. 1994 Jun;23(6):379-87. http://www.ncbi.nlm.nih.gov/pubmed/7524151?tool=bestpractice.com

Assesses severity and chronicity, localizes the affected levels of the plexus, and guides therapy.[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Differs from radiculopathies in that sensory amplitudes are decreased. Assesses severity and chronicity, localizes the affected levels of the plexus, and guides therapy.[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Sensitive, but not specific with respect to etiology.[2]Gwathmey KG, Burns TM, Collins MP, et al. Vasculitic neuropathies. Lancet Neurol. 2014 Jan;13(1):67-82. https://www.thelancet.com/journals/laneur/article/PIIS1474-4422(13)70236-9/fulltext http://www.ncbi.nlm.nih.gov/pubmed/24331794?tool=bestpractice.com

Sensitive, but not specific with respect to etiology.[2]Gwathmey KG, Burns TM, Collins MP, et al. Vasculitic neuropathies. Lancet Neurol. 2014 Jan;13(1):67-82. https://www.thelancet.com/journals/laneur/article/PIIS1474-4422(13)70236-9/fulltext http://www.ncbi.nlm.nih.gov/pubmed/24331794?tool=bestpractice.com

Guides therapy and additional testing.

Guides therapy and additional testing.

Assesses severity and chronicity, localizes the affected levels of the plexus, and guides therapy.[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Differs from radiculopathies in that sensory amplitudes are decreased. Assesses severity and chronicity, localizes the affected levels of the plexus, and guides therapy.[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Guides therapy and additional testing.

Guides therapy and additional testing.

Assesses severity and chronicity, localizes the affected levels of the plexus, and guides therapy.[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Differs from radiculopathies in that sensory amplitudes are decreased. Assesses severity and chronicity, localizes the affected levels of the plexus, and guides therapy.[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Guides therapy and additional testing.

Guides therapy and additional testing.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

May have thrombocytopenia from liver, bone marrow involvement; or pancytopenia from bone marrow involvement.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Guides therapy and additional testing.

Guides therapy and additional testing.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.

Accuracy increases with duration of symptoms. Assesses severity and chronicity and localizes the affected root(s).[1]Preston DC, Shapiro BE. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 3rd edition. Philadelphia: Saunders; 2012.