Macroscopically no changes are seen in the central nervous system but histologically we often note chromatolysis with bulging of borders, eccentric nucleus and disappearance of tigroid substance in various nerve cells, especially those of the anterior horn, posterior ganglia, Clark’s column and Betz cells of cortex. There is an absence of chronic meningo-encephalitis and meningo-myelitis which should be present in the general type of protozoal infective lesions.
Degenerations in the posterior columns and crossed pyramidal tracts have been reported from certain autopsies.
The cell count of the cerebro-spinal fluid is normal and there is usually an absence of globulin increase with a negative Wassermann. The blood chemistry findings in pellagra appear solely to be low nonprotein nitrogen and urea values.
Symptomatology
There is probably no other disease which shows such a multiplicity of symptoms and such variations in these symptoms.
Upon questioning a patient who has developed a pellagra eruption in the spring months there is often obtained a history of more or less prolonged neurasthenic manifestations during the preceding winter, chiefly dizziness, insomnia, apprehension, occipital heaviness and muscular fatigue. There may also have been previous sensitiveness of the mouth and slight epigastric discomfort. Along with the appearance of the eruption we may have more marked alimentary tract disorders consisting of stomatitis, gastric disturbances, especially pyrosis, with a recurring diarrhoea. Upon examining the eruption we note localized, sharply delimited, strikingly symmetrical skin lesions of those parts of the body which are chiefly exposed to the sun’s rays.
This erythema is very similar to sunburn but often follows inadequate exposure to the sun and the erythema persists instead of fading. Desquamation continues for weeks or months instead of healing. The dry scaling area usually shows a striking pigmentation at the borders even after the central portions of the erythema have cleared up. The skin lesions instead of being dry and atrophic as is usual may more rarely be moist and oedematous.
From a vague neurasthenia we have now more distinct neurological manifestations such as variations in the reflexes, tremors, especially of tongue, head and upper extremities and a depressed mental state with lack of mental concentration or lapses of memory. Later on we may have a toxic psychosis in which mutism is often noted in a mental state characteristically melancholic.
