1) Identify on Physical Examination, Or on Review of Tissue Slides Or Photographs, Tissue
Pathology
Lecture 19 Nutritional Disease
1) Identify on physical examination, or on review of tissue slides or photographs, tissue alterations resulting from deficiencies of:
A. Total calories – Marasmus is a deficiency of almost all nutrients but mostly proteins and calories with multiple vitamin deficiencies. Present when a malnourished child’s weight fall to <60% of normal for sex and age. It results in stunted growth, muscular atrophy, and loss of subcutaneous fat.
B. Protein – Kwashiorkor is caused purely by a protein deficiency. Often occurs when children are weaned and eat primarily carbohydrates. Hypoalbuminemia results in severe edema. Fatty liver, anemia, and malabsorption due to intestinal atrophy are also present. Characterized by stunted growth and muscle wasting with preservation of subcutaneous fat.
C. Fat soluble vitamins
1. Vitamin A – aids in differentiation of mucus epithelial cells, enhances immunity to infections, and maintains normal night vision. In Vitamin A deficiency, corneal epithelium is replaced by keratinizing epithelium in small plaques (Bitot spots), which will erode the cornea resulting in blindness.
2. Vitamin D – maintains normal calcium and phosphorous levels in the plasma. Deficiency results in hypocalcemic tetany, osteomalacia in adults, and rickets in children. Excess unmineralized bone matrix is deposited in epiphyseal plates (disrupting growth) and microfractures occur from weakened bone.
3. Vitamin E – is a scavenger of free radicals. Insufficiency, although rare, occurs with fat malabsorption, abetalipoproteinemia, immature liver and GI tract in infants, and genetic impaired vitamin E metabolism. Damage occurs in the nervous system causing axonal degeneration in the dorsal root ganglia and erythrocytes causing a shorter half-life.
4. Vitamin K – is a cofactor for liver microsomal carboxylase which converts glutamyl residues to gamma-carboxyglutamates. Clotting factors VII, IX, and X require this conversion for activation and insufficiency causes bleeding disorders. Deficiency results from fat malabsorption, antibiotic destruction of K-synthesizing bacteria, the neonatal period, and diffuse liver disease.
D. Water soluble vitamins
1. Thiamine – functions in ATP synthesis, the pentose phosphate pathway, and neural membrane maintenance. Thiamine deficiency, beriberi, targets the peripheral nerves, heart and brain. Dry beriberi attacks peripheral nerves resulting in atrophy. Wet beriberi attacks the heart. Wernicke-Korsakoff syndrome occurs in chronic alcoholics and is characterized by ataxia, confusion, and memory loss due to grey matter and mamillary body damage.
2. Riboflavin – is a coenzyme component for redox reactions. It manifests as cheilosis (skin fissures at the angles of the mouth), glossitis, corneal vascularization, and suborrheic dermatitis of the face, scrotum, or vulva.
3. Niacin – is a coenzyme component for NAD and NADP required for metabolic processes. Deficiency results from lack of niacin and tryptophan (niacin precursor). Manifests as pellagra, characterized by the “three Ds”: dementia, dermatitis (exposed areas: face, neck, hands and feet), and diarrhea.
4. Vitamin B6 (pyridoxine) – is a coenzyme in metabolic reactions involving lipids, amino acids, and the immune response. Deficiency may develop with increased demand in pregnancy or hyperthyroidism, in alcoholics due to degredation, and with use of antagonistic drugs (isoniazid, estrogens, and penicillamine). Manifests as seborrheic dermaititis, cheilosis, glossitis, peripheral neuropathy, convulsions, anemia, and diminished immune function.
5. Pteroylmonoglutamic acid (folic acid)[folate] – is an essential cofactor for nucleic acid synthesis. Can be depleted in cooked and processed foods. Pregnant women, alcoholics, embryos, and methotexate patients are at the greatest risk. Manifests as megaloblastic anemia, neurologic damage, and filiform papillary atrophy of the tongue, gingival inflammation, and stomatitis.
6. Vitamin B12 (cobalamin) – is important in nucleic acid synthesis. Absorption is dependant on intrinsic factor (IF). Vegans, post-gastrectomy patients, the elderly and HIV patients are at the greatest risk. Manifests as megaloblastic anemia, neurologic damage, dementia, and infertility.
7. Vitamin C (ascorbic acid) – is a cofactor for hydroxylation and an antioxidant. Vitamin C deficiency, scurvy, is characterized by bone disease in children and hemorrhages and healing defects in both adults and children. Wound healing and hemorrhage are due to impaired collagen synthesis.
E. Minerals
1. Iron – serves to transport oxygen in hemoglobin. Impaired absorption, increased requirement, and chronic blood loss put a person at risk. It is the most common deficiency, manifesting as hypochromic microcytic anemia, reversible impaired cognative function, decreased bacteriocidal activity of neutrophils, reduced cell-mediated immune function, reduced endurance, and abnormalities in thermoregulation.
F. Trace elements
1. Zinc – is a component of >200 metalloenzymes. Populations at risk are growing children, patients with high volume diarrhea, and those with high output GI fistulas. Manifests as acrodermatitis enterpathica of the eyes, nose, mouth, anus, and distal limbs, anorexia with diarrhea, growth retardation, poor wound healing, hypogonadism, altered immune function, impaired night vision, depressed mental function, and increased congenital malformations.
2. Iodine – hypothyroidism – is an essential element of thyroid hormones. Manifests as hypothyroidism, goiter, impaired mental function, retarded physical development, abortions, stillbirths, and congenital abnormalities.
2) Describe pathological tissue alterations related to common nutrient deficiencies using appropriate medical terminology.
Liver – enlarged and fatty in kwashiorkor.
Small intestine – decreased mitotic index of the crypts of the glands in kwashiorkor associated with mucosal atrophy, loss of villi, and loss of digestive enzymes.
Bone marrow – erythropoietic cells are decreased in kwashiorkor and marasmus resulting in hypochromic microcytic anemia.
Bone – derangements occur in both rickets and osteomalacia resulting in excess unmineralized matrix deposition, thinning of bone, and buckling.
PNS – degeneration of axons in the posterior columns of the spinal cord, with focal accumulation of lipopigment and loss of nerve cells in the dorsal root ganglia (vit E).
CNS – dementia can result from degeneration of neurons in the brain due to niacin deficiency. Cerebral atrophy can result from protein-energy malnutrition.
Skin – many changes can occur with riboflavin deficiency. Cheilosis fissures radiating from the corners of the mouth. Glossitis results in an atrophic cyanotic tongue. Keratitis can result in corneal opacities. Scaly, greasy dermatitis can occur over the nasolabial folds and also on the vulvar and scrotal regions. Pellagra results from niacin deficiency and presents as dermatitis on exposed areas.
GI – diarrhea can be caused by niacin deficiency, which results in atrophy of the columnar epithelium of the mucosa.
3) List three nutrition-related clinical conditions likely to be seen in normative clinical practice and define the likely categories of patients that will manifest these disorders.
A. Vitamin B1 (thiamine) deficiency – usually associated with alcoholism (Wernicke-Korsakoff syndrome) and fad diets.
B. Vitamin C deficiency – those at risk include smokers, young children and the elderly due to restrictive diets.
C. Iron deficiency – occurs with gastrointestinal blood loss in men and postmenopausal women.