Differential Diagnosis for Asymmetric Axonal and Demyelinating Motor and Sensory Polyneuropathy
Single Most Likely Diagnosis
- Multifocal Motor Neuropathy (MMN): This condition is characterized by asymmetric motor weakness, often with some sensory involvement, and is typically more severe in the arms. The presence of conduction block on electrophysiological studies can support this diagnosis. The asymmetric nature and the specific involvement of the left arm, along with some sensory findings, make MMN a strong consideration.
Other Likely Diagnoses
- Chronic Inflammatory Demyelinating Polyneuropathy (CIDP): Although CIDP typically presents with a more symmetric pattern, there are variants that can present asymmetrically. The presence of both demyelinating and axonal features, along with joint swelling, could suggest an inflammatory process like CIDP.
- Lewis-Sumner Syndrome: A variant of MMN, it presents with multifocal demyelinating neuropathy, often with both motor and sensory involvement, and can have an asymmetric distribution.
- Vasculitic Neuropathy: This condition can cause an asymmetric polyneuropathy due to inflammation of the blood vessels supplying the nerves. The presence of joint swelling could suggest a systemic inflammatory condition, and vasculitis should be considered, especially if there are other systemic symptoms.
Do Not Miss Diagnoses
- Lyme Disease: Although less common, Lyme disease can cause a neuropathy that might present with asymmetric features, including radiculopathy or mononeuritis multiplex. Given its potential for serious consequences if untreated, it's crucial not to miss this diagnosis, especially in endemic areas.
- Sarcoidosis: This systemic disease can cause neuropathy among its myriad presentations. Neurosarcoidosis can lead to various neurological symptoms, including neuropathy, and the presence of joint swelling could support this diagnosis.
- Amyloidosis: A condition where abnormal proteins (amyloid) accumulate in various tissues, including nerves, leading to neuropathy. It can present with asymmetric sensory and motor findings, and systemic symptoms might include joint involvement.
Rare Diagnoses
- Tangier Disease: A rare genetic disorder affecting lipid metabolism, leading to neuropathy among other symptoms. The neuropathy can be asymmetric and affect both motor and sensory nerves.
- Neuropathy associated with Paraproteinemia: Conditions like POEMS syndrome (Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal gammopathy, and Skin changes) can cause a demyelinating neuropathy, often with systemic symptoms. The presence of joint swelling and neuropathy might suggest a paraproteinemic condition, although these are rare.
- Inherited Neuropathies with Late Onset: Certain forms of Charcot-Marie-Tooth disease or other inherited neuropathies can present later in life and might show asymmetric features, especially if there's a superimposed injury or other condition affecting the nerves.