About Paraneoplastic Neurological Disorders (PND) >
Dorsal Root Ganglia and Peripheral Nerves >
The name sensory neuronopathy refers to the neurons from which the sensory nerves start. These neurons are clustered in the dorsal root ganglia which are located along the sensory nerve roots close to the spinal cord. Therefore, inflammation of these ganglia causes malfunction and degeneration of the neurons. This results in many sensory deficits and symptoms.
Symptoms of sensory neuronopathy usually start in an asymmetric fashion. This means, patients develop pain, numbness, or a sensation of pins and needles in one foot, or hand, and in a matter of days or weeks these symptoms progress to involve the other side. Eventually both sides are involved.
The symptoms most frequently described by patients include:
- lancinating pain (short-lasting, electric shock type of pain)
- a sensation of walking on sand
- cold numbness
- a feeling of burning in hands and feet
- sensation in the face, as well as the senses of taste and hearing can also be affected
At the advanced stage of the disease:
- all types of sensations can be severely diminished or lost including sensation of
- ability to know where the limbs are when the eyes are closed (Figure). This last problem makes it difficult to reach out for something or to walk and is called sensory ataxia
Patients with sensory neuronopathy usually have anti-Hu antibodies. These antibodies are important markers of several forms of paraneoplastic encephalitis or encephalomyelitis. In many patients the symptoms of sensory neuronopathy are the first symptoms of encephalomyelitis. Patients with anti-Hu antibodies usually have a small-cell lung cancer, although other cancers can also be associated.
The treatment of anti-Hu associated sensory neuronopathy should be focused to the tumor. Immunotherapy should be considered at initial stages of the disease, or when there are signs of symptoms of disease progression. Corticosteroids, plasma exchange and IVIg may be considered.
But results are usually mild and for the most part disappointing. There is some evidence that immunotherapy treatments directed at the T-cells (instead of only against the antibodies) may help some patients.