1. Describe the functional and supportive elements of the peripheral nervous system.
2. List the five etiologic categories into which peripheral neuropathies can be classified.
3. Identify the pathologic features of both axonal degeneration and segmental demyelination.
4. Compare and contrast the clinical, pathologic, and pathophysiologic features of acute idiopathic polyneuritis (Guillain-Barré syndrome) with diabetic distal sensory-motor neuropathy.
5. Explain the similarities and the differences between the pathologies of schwannomas and neurofibromas.
6. Describe the major clinical features of both neurofibromatosis types (1 and 2). Associate the known chromosomal abnormality with each type.
1. (Robbins 5th Ed., p. 1273-1285, 1351-1354) or (Robbins 6th Ed., p. 1269-1280, 1352-1355)
2. Images 1 and 2 are related to this case; 3-8 are for the study of other learning objectives.
This 59-year-old diabetic man complained to his doctor that he was "losing feeling" in his feet. He said that his feet often felt like they had "pins and needles" in them. "Oh, and another strange thing, is that my feet seem worse at night." He said that these unusual sensations had begun a few years before, but that they had not bothered him very much until now.
Physical examination revealed slight weakness of the lower extremities, absence of the ankle jerk reflex, and a 1 cm diameter ulceration on the heel of the left foot. The patient's doctor recommended a nerve biopsy and referred him to a surgeon.
The nerve biopsy revealed a depopulated segment of peripheral nerve (Image 1), and thickened vessel walls. The teased fiber preparation revealed several myelin ovoids (Image 2).
The doctor's advice was that, unfortunately, the only useful therapy for his condition was for the patient to maintain the best possible control of his diabetes, and that prognosis was uncertain.