Miscellaneous Diseases

Chapter 12

Miscellaneous Diseases

Nutritional diseases

Disorders of nutrition range from malnutrition and vitamin deficiency to obesity and hypervitaminosis. In addition to inadequate intake, nutritional deficiency may be related to disorders of the liver, pancreas, and gastrointestinal tract that result in an inability of the body to digest and properly use proteins, carbohydrates, and lipids. In diabetes mellitus, the absence of insulin prevents entry of glucose into the cells and thus deprives the body of its major source of energy. Abnormalities of the pancreas, liver, and gastrointestinal tract that cause nutritional diseases are discussed elsewhere; this section deals with diseases caused by vitamin deficiency, malnutrition, and obesity.

Vitamin Deficiencies

Vitamins are an essential part of the enzymatic systems that are vital to the body’s cellular metabolism. Vitamins are formed (synthesized) only by plants, not by animals. Therefore, humans’ supply of vitamins comes directly from eating fruits and vegetables or from animals (including fish) that have eaten plants and have stored the vitamins. Vitamins are generally divided into two categories: fat soluble and water soluble. The fat-soluble vitamins (A, D, E, and K) can be stored within body tissues. Water-soluble vitamins (B and C) cannot be stored and must be a regular part of the diet to prevent a deficiency. The major B vitamins are thiamine, riboflavin, niacin, pantothenic acid, cobalamin (vitamin B12), and folic acid.

Vitamin deficiency diseases are rare in the United States but are all too prevalent in underdeveloped countries.

Beriberi (Thiamine Deficiency)

Beriberi results from a deficiency in thiamine (vitamin B1), a coenzyme essential for carbohydrate metabolism that promotes growth and maintains muscle tone and heart function. Beriberi occurs primarily in rice-eating countries, such as China, where the main staple is polished rice from which the vitamin-containing skin and germ have been removed. Infantile beriberi is common in breast-fed infants 2 to 4 months of age whose mothers have thiamine deficiency. Noninflammatory degeneration of the myelin sheath caused by thiamine deficiency produces a peripheral neuropathy characterized by weakness of the limbs and a “pins and needles” sensation in the extremities.

Pellagra (Niacin Deficiency)

Pellagra, caused by a deficiency of niacin viamin B3), is characterized by reddening and scaling of the skin on exposed parts of the body, vomiting and severe diarrhea, and nervous and mental disorders (ranging from chronic depression to violent, irrational behavior). The body requires niacin to complete the cellular process called respiration, in which nutrients and oxygen reach the cells through a series of chemical reactions. As a result of dietary supplements, epidemics of pellagra no longer exist; however, sporadic incidences occur among chronic alcoholics and people suffering from malabsorption.

Scurvy (Vitamin C Deficiency)

In patients with scurvy, the deficiency of ascorbic acid vitamin C) leads to an inability of the supporting tissues to produce and maintain vascular endothelium and the cementing substances that hold epithelial cells together (collagen, osteoid, dentin). Scurvy was classically a disease of sailors and explorers deprived of fresh fruit and vegetables containing vitamin C.

Weakening of capillary walls in scurvy often results in bleeding into the skin, joints, and internal organs. The gums are especially affected and bleed easily. The open lesions provide an entry for bacteria, leading to necrosis of gum tissue and tooth loosening and loss. Impaired synthesis of collagen leads to poor and delayed wound healing.

Radiographic Appearance: In children, disordered chondroblastic and osteoblastic activity cause radiographic bone changes that are most prevalent where growth is normally most rapid (especially about the knee and wrist). The bones are generally osteoporotic with blurring or disappearance of trabecular markings and severe cortical thinning. Widening and increased density of the zone of provisional calcification produce the characteristic “white line” of scurvy (Figure 12-2). A relatively lucent osteoporotic zone forms on the diaphyseal side of the white line. This osteoporotic zone is easily fractured, permitting the dense bone to become impacted on the shaft and to jut laterally beyond it, thus giving rise to characteristic marginal spur formation (Pelken spur). The epiphyseal ossification centers are demineralized and surrounded by dense, sharply demarcated rings of calcification (Wimberger’s sign of scurvy). If epiphyseal dislocations have not occurred, the appearance of the skeletal structures usually returns to normal after appropriate therapy.

Subperiosteal hemorrhage often occurs along the shafts of the long bones. Calcification of the elevated periosteum and underlying hematoma is a radiographic sign of healing.

Treatment of Vitamin Deficiencies

Any of the following three approaches can be used to treat vitamin deficiencies: (1) the patient’s diet is modified to include foods that contain the recommended daily requirements, (2) the patient is given synthetic oral supplements, and (3) vitamins are injected. Some deficiencies may be associated with absorption abnormalities resulting from a lack of the specific vitamins needed to absorb and process vitamins.

Dietary modifications for vitamin B deficiencies include increasing the intake of protein (meat), green leafy vegetables, and milk. For vitamin C deficiencies, an increase in consumption of fresh fruits and green leafy vegetables may help. Vitamin D deficiencies require the addition of cod liver oil, egg yolks, butter, and oily fish to the diet. Fortified milk and exposure to sunlight also provide vitamin D. To increase vitamin A, a diet including more liver, meat, eggs, milk, and dark green and yellow vegetables is of value. Eating more spinach, lettuce, broccoli, Brussels sprouts, and cabbage increases dietary vitamin K.


Long-term excessive intake of vitamin A produces a syndrome characterized by bone and joint pain, hair loss, itching, anorexia, dryness and fissuring of the lips, hepatosplenomegaly, and yellow tinting of the skin. This condition usually affects young children, who become irritable and fail to gain weight.

Protein-Calorie Malnutrition (Kwashiorkor)

Severe protein-calorie malnutrition (kwashiorkor) affects millions of young children (younger than 5 years) in developing countries (approximately 182 million in 2000) and produces abnormalities involving the gastrointestinal tract and nervous system. In those affected, an imbalance between the body’s supply of nutrients and its demand for energy causes a wasting away or emaciation. Fatty replacement of liver tissue and the resulting decreased levels of albumin lead to diffuse edema and ascites and the characteristic clinical appearance of a considerably protuberant abdomen. Damage to the pancreas and intestinal mucosa prevents proper digestion and absorption of nutrients.

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Apr 10, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Miscellaneous Diseases

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