Table 2.

Classic features of multifocal motor neuropathy and other neuromuscular disorders with similar clinical and electrodiagnostic features

Clinical features		Laboratory features	Electrodiagnostic	Treatment
Multifocal motor neuropathy
Asymmetric, distal > proximal, upper limb > lower limb weakness without sensory loss. Some patients with subjective sensory loss, pain, and fatigue		CSF protein usually normal 40%–50% of patients may have IgM ganglioside antibodies43	Multifocal demyelinating motor neuropathy with or without conduction block	IVIg, rituximab, and cyclophosphamide Does not respond to steroids or plasma exchange
Disorder	Overlapping features	Distinctive clinical features	Diagnostic features: laboratory and EDx	Treatment
Neuromuscular disorders with similar clinical and electrodiagnostic features
Multifocal acquired demyelinating sensory and motor neuropathy (MADSAM)	Asymmetric, distal > proximal, upper limb > lower limb involvement	Prominent sensory loss	CSF protein usually elevated with no pleocytosis EDx: Multifocal demyelinating sensory and motor neuropathy with conduction block	Steroids, IVIg, and plasma exchange Others include: azathioprine, cyclosporine, cyclophosphamide, and methotrexate
Multifocal acquired motor axonopathy (MAMA)	Asymmetric, distal > proximal weakness without sensory loss		Normal CSF studies EDx: Multifocal axonal motor neuropathy in the distribution of individual nerves with no demyelination or conduction block (closely mimics motor neuron disease)	IVIg? Close observation for signs of motor neuron disease
Hereditary neuropathy with predisposition to pressure palsy (HNPP)	Asymmetric weakness in the distribution of multiple named nerves, typically at common entrapment sites	Sensory loss, may have family history (autosomal dominant)	Genetic testing for PMP22 deletion EDx: Focal neuropathies at common sites of entrapment (may have underlying demyelinating neuropathy and occasionally closely mimics CIDP)	Supportive, avoid positioning/postures that lead to compression of susceptible nerves
Motor neuron disease	Asymmetric weakness without sensory loss	May have upper motor neuron signs and cognitive involvement, usually more prominent muscle atrophy	Clinical criteria supported by EMG fndings EDx: active and chronic motor axon loss and fasciculations in multiple regions	Supportive

Abbreviations: CIDP, chronic inflammatory demyelinating neuropathy; CSF, cerebrospinal fluid; EDx, electrodiagnostic; EMG, electromyography; IgM, immunoglobulin M; IVIg, intravenous immunoglobulin.