We assume that at that time of the neurological examination there was no limb muscle atrophy or weakness and that tone and reflexes were within normal limits in all four extremities.
71 year old lady has isolated progressive isolated dysarthria and dysphagia since June of 2008. The available reports show no clinical evidence of any upper or lower motor neuron involvement in the extremities. Limited EMG study did not fulfill the electro-diagnostic El Escorial criteria for a motor neuron disease. With the current available information she does not fulfill the clinical El Escorial criteria for possible, probable, or definite ALS. However, the clinical history is worrisome for very early motor neuron disease.
The differential diagnosis of isolated swallowing and speaking difficulties include, but not limited to:
- Early motor neuron disease; detailed examination checking for jaw jerk, tone and reflexes would be helpful. Performing a detailed needle EMG study including the thoracic paraspinal and tongue muscles would be also beneficial. EMG should be repeated every 6 months or sooner if weakness or spasticity develops in the limb muscles.
- Cranial neuropathies; MRI with concentration on the base of skull and the nasopharyngeal area, serum ACE levels, and a lumbar puncture would be reasonable.
- Myopathies; less likely since CK levels are normal and there is no limb weakness. Certain muscular dystrophies, such as oculopharygeal muscular dystrophy has been described in Italian families and can cause weakness limited to the nasopharyngeal muscles and eyelids.
- Neuromuscular junction disorders; although single fiber EMG is normal, checking anti Ach receptor and anti MuSK antibodies would be reasonable.
- Neurodegenerative movement disorders such as progressive supranuclear palsy; less likely in the absence of other typical findings on exam.
1- Repeat detailed EMG study of bulbar muscles, limb muscles. It is important to also check thoracic paraspinal muscles and tongue muscles.
2- Brain MRI with and without gadolinium with focus on the base of the skull and the nasopharyngeal area.
3- Consider lumber puncture if EMG does not show more widespread motor neuron abnormalities.
4- Additional blood work: Vitamin B12, Folate, PTH, Copper, ACE levels, Anti Ach receptor antibodies, and anti MuSK antibodies.
5- Continue Riluzole 50 mg bid for now assuming early ALS, continue checking liver function tests every month for 3 months and then every three months. Consider stopping Riluzole if a diagnosis other than ALS has been confirmed.
6- Pulmonary function tests.
7- Baruim swallow study.
8- Speech and swallowing consultation and training to prevent aspiration.
9- Monitor and maintain weight.