Neurological disorders imitating spinal stenosis in elderly patients. Series of clinical observations

Spinal stenosis is a pathological narrowing of the central spinal canal, lateral pocket, or intervertebral foramen due to age‑related changes, including pathology of the discs, facet joints, ligament hypertrophy, osteophyte formation and destruction of the arches. Clinically, the disease can manifest itself with pain, as well as numbness, or weakness in the arms or legs. The complexity of differential diagnosis is due to the lack of correlation between the degree of stenosis according to neuroimaging data and the severity of clinical manifestations. Spinal stenosis among 21 % of people may have an asymptomatic course. Spinal stenosis has to be differentiated from atherosclerosis of the vessels of the lower extremities, rheumatoid arthritis, piriformis syndrome, sacroiliitis, spondylitis/spondylodiscitis, amyotrophic lateral sclerosis, Guillain–Barré syndrome and other polyneuropathies. Isolated weakness should be of a particular concern in the clinical picture. Muscle hypotrophy, brisk tendon reflexes, the presence of pyramidal signs, muscle fasciculations, as well as patients’ complaints of simultaneous weakness in both the upper and lower extremities accompany them. We present and discuss three clinical cases of patients with a presumptive diagnosis of spinal stenosis. Two of them were held surgical treatment, which did not produce the expected result. Subsequently, it was found that the cause of progressive muscle weakness in the limbs was amyotrophic lateral sclerosis in two patients and the third one had Guillain–Barré syndrome, a form of acute demyelinating polyneuropathy.