๐ ็ธฝ็ฎ้ ๏ฝ ๐ ่ฑๆๅๆ๏ผๆฌ็ฏ๏ผ ๏ฝ ๐ ๅฎๆด็ฟป่ญฏ ๏ฝ โญ ็ฒพ่ฏ็ญ่จ
PATHOLOGY
Nutritional deficiencies generally occur in combination; therefore, the resultant pathologic changes are often very variable. Although nutritional diseases have been better studied biochemically than structurally, there are several helpful histologic clues, including necrosis of the upper one-third of the epidermis (see Fig. 51.12G). This distinctive reaction pattern has been reported in pellagra, acrodermatitis enteropathica, acquired zinc deficiency, and necrolytic migratory erythema. In the early stages, there is pallor and ballooning of the upper half of the epidermis. This stage is followed by the development of acanthosis, with confluent hyperkeratosis and degenerative features of the upper epidermal layers. In the late stages, the pallor of the upper epidermis is usually missing. In proteinโenergy malnutrition, nonspecific histologic features are seen, such as epidermal atrophy and hyperkeratosis.
Hair is a superb model of growth and differentiation. In some patients, histologic study of the hair matrix and hair shaft may provide evidence of moderate to severe degrees of proteinโenergy malnutrition.