This is the current release of the guideline.

Multifocal motor neuropathy

Diagnosis

Internal Medicine
Neurology

Physicians

• To develop a definition for the circumstances by which multifocal motor neuropathy can be diagnosed with a high level of confidence (definite multifocal motor neuropathy) or with only a moderate level of confidence (probable multifocal motor neuropathy)
• To provide clinicians with diagnostic guidelines for the most typical patients
• To propose diagnostic categories for research studies and clinical trials
• To stimulate further discussion about multifocal motor neuropathy

Adults with suspected multifocal motor neuropathy

1. Assessment of clinical symptoms and signs of multifocal motor neuropathy (e.g., weakness, sensory loss)
2. Sensory nerve conduction studies

Reliability and utility of diagnostic criteria

Searches of Electronic Databases

A Medline literature search was used to help develop the historical background and focus on the critical issues for which a consensus was required.

Not stated

Not stated

Not applicable

Review

Not applicable

Expert Consensus (Delphi)

A five-round modified Delphi process was used to develop these consensus criteria. The authors wrote an initial draft document, which was circulated for unsolicited comments from an expert panel. The expert panel was chosen from American Association of Electrodiagnostic Medicine (AAEM) members who had been authors of articles concerned with concepts relevant to multifocal motor neuropathy and who held divergent opinions at the start of the consensus development process. Based on the comments from the expert panel, and areas of apparent agreement and disagreement, the document was revised and re-circulated until consensus was reached.

Not applicable

A formal cost analysis was not performed and published cost analyses were not reviewed.

Internal Peer Review

The guideline was approved by the American Association of Electrodiagnostic Medicine (AAEM) Board of Directors in June 2002.

Definition

Multifocal motor neuropathy is a disease of lower motor neurons in adults that produces asymmetrical muscle weakness, often in association with fasciculations and cramping.

The diagnosis of multifocal motor neuropathy is a difficult one. Until further research clarifies the issue, the criteria for definitive and probable multifocal neuropathy listed below are proposed to serve as a guide for diagnosing this disease.

Criteria for the Diagnosis of Multifocal Motor Neuropathy

Criteria for Definite Multifocal Motor Neuropathy

1. Weakness without objective sensory loss in the distribution of two or more of the following nerves: median, ulnar, radial, peroneal, and tibial. During the early stages of symptomatic weakness, the historical or physical finding of diffuse, symmetric weakness excludes multifocal motor neuropathy.
2. Definite conduction block (for criteria for partial conduction block, see Table 1 in the original guideline document) is present in two or more nerves outside of common entrapment sites (median nerve at wrist; ulnar nerve at elbow or wrist; peroneal nerve at fibular head).
3. Normal sensory nerve conduction velocity across the same segments with demonstrated motor conduction block.
4. Normal results for sensory nerve conduction studies on all tested nerves, with a minimum of three nerves tested.
The absence of each of the following upper motor neuron signs: spastic tone, clonus, extensor plantar response, and pseudobulbar palsy.

Criteria for Probable Multifocal Motor Neuropathy

1. Weakness without objective sensory loss in the distribution of two or more of the following nerves: median, ulnar, radial, peroneal, and tibial. During the initial weeks of symptomatic weakness, the presence of diffuse, symmetric weakness excludes multifocal motor neuropathy.
2. The presence of either:
   1. Probable conduction block in two or more motor nerve segments that are not common entrapment sites or
   2. Definite conduction block in one motor nerve segment and probable conduction block in a different motor nerve segment, neither of which segments are common entrapment sites.
3. Normal sensory nerve conduction velocity across the same segments with demonstrated motor conduction block, when this segment is technically feasible for study (that is, this is not required for segments proximal to axilla or popliteal fossa).
4. Normal results for sensory nerve conduction studies on all tested nerves, with a minimum of three nerves tested.
5. The absence of each of the following upper motor neuron signs: spastic tone, clonus, extensor plantar response, and pseudobulbar palsy.

None provided

The type of supporting evidence is not specifically stated for each recommendation.

Appropriate diagnosis of multifocal motor neuropathy

Not stated

• The source guideline is provided as an educational service of the American Association of Electrodiagnostic Medicine (AAEM). It is based on an assessment of current scientific and clinical information. It is not intended to include all possible methods of care of a particular clinical problem or all legitimate criteria for choosing to use a specific procedure. Neither is it intended to exclude any reasonable alternative methodologies. The AAEM recognizes that specific patient care decisions are the prerogative of the patient and his/her physician and are based on all of the circumstances involved.
• Participants in the consensus process believe that multifocal motor neuropathy should be distinguished from chronic inflammatory demyelinating polyneuropathy but that sufficient empiric data and knowledge are not available at this time to determine if multifocal motor neuropathy is distinct from the other lower motor neuron syndromes described in the original guideline document. The expert panel had the greatest difficulty in reaching consensus on the issue of excluding the diagnosis of multifocal motor neuropathy in cases with minor abnormality on sensory nerve conduction studies.

An implementation strategy was not provided.

Getting Better
Living with Illness

Effectiveness

Not applicable: Guideline was not adapted from another source.

2003 Jan

American Association of Neuromuscular and Electrodiagnostic Medicine - Medical Specialty Society

American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM)

Not stated

Primary Authors Richard K. Olney, MD; Richard A. Lewis, MD; Timothy O. Putnam, MD; Joseph V. Campellone, Jr., MD

Not stated

This is the current release of the guideline.

None available

None available

This NGC summary was completed by ECRI on December 1, 2003.