NUTRITIONAL PATHOLOGY By Dr.sujatha Udupa An adequate diet should provide Energy in the form of carbohydrates Essential and nonessential aminoacids ,and fatty acids to be used as building blocks Vitamins and minerals ,which function as coenzymes or hormones in vital metabolic pathways Malnutrition Primary: inadequate food intake Secondary: result of disease Causes of malnutrition Ignorance and poverty Chronic alcoholism Acute and chronic illness Self imposed dietary restriction Protein energy malnutrition(PEM) Range of clinical syndromes charercterised by an inadequate dietary intake of protein and calories to meet body’s needs A child whose weight is less than 80% of normal is called malnourished Protein compartment Somatic comparment:represented by skeletal muscles Visceral compartment:represented by protein stores in visceral compartment ,primarily liver Definitions of Malnutrition Kwashiorkor: protein deficiency Marasmus: energy deficiency Marasmic/ Kwashiorkor: combination of chronic energy deficiency and chronic or acute protein deficiency Marasmus Marasmus < 1 year Severe reduction in calorie intakecatabolism of and depletion of somatic protein compartment aminoacids act as source of energy Child suffers from growth retardation and loss of muscle mass Visceral compartment is depleted marginally >60%reduction in body weight Serum albumin levels are either normal or slightly reduced In addition to muscle proteins subcutaneous fat is also used as source of energyextremities are emaciated Anaemia and multivitamin deficiencies Immune deficiency,T cell mediated immunityconcurrent infections kwashiokar More severe form of malnutrition Occurs when protein deprivation is greater than reduction in total calories Seen commonly in Africaan children who have been weaned with exclusively carbohydrate diet Kwashiorkor Skin lesions,with alternating zones of hyperpigmentation,desquamatiuon,and hypopigmentationflaky paint appearence Severe loss of visceral protein compartmenthypoalbuminemiageneralized Soft pitting edema, starting in feet and legs Preserved fat layer, small weight deficit, ht may be normal Weight reduction is masked due to fluid retention Dry brittle hair, alternating bands of pale and darker hair, loss of firm attachment to scalp Anorexia, with vomiting and diarrhea Biologic differences Marasmus Weight loss Nl or low serum albumin No water retention Boarderline hgb, hct NL enzymes Kwashiorkor NO weight loss Very low serum albumin High extracellular water Low hgb, hct Low enzymes Morphology of PEM LIVER :enlarged and fatty in kwashiokar GIT:in kwashiokar small bowel shows in mitotic index in crypts and glands, associated with mucosal atrophy and loss of villiloss of enzymes Bone marrow:hypoplastic due to decreased number of erythrocyte precursorsdimorphic anaemia Brain:cerebral atrophy,reduced number of neurons,and impaired myelinization Thymic and lymphoid atrophy Deficiency of other nutrients like iodine and vitamins Diagnosis Evaluation of fat stores by measuring skin fold thikness(skin+subcutaneous fat) Evaluation of muscle mass by measuring mid arm circumferance Measurment of serum proteins like albumin and transferrin which indicate adequacy of visceral protein compartment Anorexia nervosa Resembles severe PEM Amenorrhea due to decreased secretion of GnRH Bradycadia intolerance Hypokalemia cardiac arrhythmia Bulimia Metaplasia and increased risk of neoplasia Electrolyte imbalance Cardiac arrhythmias Pulmonary aspiration of gastric contents Esophageal and stomach, cardiac rupture What are vitamins (“vital amines”)? Organic compounds distinct from fats, carbohydrates and proteins Natural components of foods usually present in minute amounts Essential for normal physiological function Absence causes specific deficiency syndromes Other useful terms: Vitamer - chemically-related family of compounds with same “vitamin activity” Pro-vitamin – a precursor which is metabolised to the active vitamin VITAMINS “VITAMIN” means “vital for life” * Nutrients required in very small amounts mg or µg VITAMINS are *Micronutrients which are necessary for everyday healthy functioning of the body Lipid soluble and water soluble vitamins Trace elements Thiamin Niacin Pantothenic acid Copper Iron Biotin Selenium Iodine Folate Vitamin E Manganese Zinc Vitamin C Molybdenum Cobalt Vitamin K Riboflavin Vitamin A Vitamin D Vitamin B6 Vitamin B12 Essential Micronutrients VITAMINS Two main categories Water soluble Fat Soluble B C A D E K Water soluble Cannot be stored in body - regular supply needed Excess is excreted in urine - no danger of toxic levels Unstable to heat and light, leach into cooking liquids Fat Soluble Can be stored in body regular supply not needed Can accumulate to toxic levels if large amounts ingested Fairly stable at normal cooking temperatures Fat soluble vitamins-properties Necessary for function or structural integrity of body tissues and membranes Can be retained in the body A polar hydrophobic compounds that can only be absorbed efficiently when there is normal fat absorption Vitamins, vitamers and pro-vitamins Vitamin Vitamin A Vitamin D Vitamin E Vitamin K Vitamin C Vitamin B1 Vitamin B2 Niacin Vitamin B6 Folic acid Biotin Pantothenic acid Vitamin B12 Vitamer retinol retinal retinoic acid cholecalciferol (D3) ergocalciferol (D2) -tocopherol -tocopherol phylloquinones (K1) menaquinones (K2) menadione (K3) ascorbic acid dehydroascorbic acid thiamin riboflavin nicotinamide nicotinic acid pyridoxal pyridoxal pyridoxamine Folic acid polyglutamyl folacins biotin pantothenic acid cobalamin Pro-vitamin -carotene -cryptoxanthin Vitamin deficiency • Primary deficiency (most common) due to malnutrition • Secondary due to: – Malabsorbation – Storage disturbance – Impaired metabolic conversion – Distorted blood transport VITAMIN A Vitamin A is a group of related natural and synthetic compounds Active forms of preformed vitamin A (retinoids): Retinol,retinal,retinoic acid Body can convert -carotene to retinol, thus called provitamin A. Retinol is stored in the liver, which makes it available to cells, which then convert it to the other two active forms Retinol (vit A) STORAGE AND TRANSPORT FORM B-carotene(provitamin) Intestinal mucosa Retinal(all-trans form) Isomer of visual pigment Irreversible oxidation Retinoic acid.affects growth and Differentiation of cell Retinal(cis form)visual pigment RICH DIETARY SOURCES Animal Foods Plant Foods Cod liver oil Sweet potato Liver & kidney Carrots Egg Cantaloupe Butter Spinach Milk & cheese Apricot Fish & meet Papaya •Animal sources of vit A: milk ,butter ,fish oils ,liver,meat, egg yolk •Vegetables: green leafy vegetables ,carrots •Fruits: mango , papaya •Oils : palm oil Vitamin A - normal function 90% stored in liver Maintaining normal vision in reduced light Potentiating differentiation of mucus producing epithelial cells Enhancing immunity to infections Antioxidative effect Photoprotective effect Visual Cycle (night vision) When light falls on retina Rhodopsin--conformational changealltrans retinol+opsin nerve impulse is generatedtransmitted to brain Some retinal is recycled and rhodopsin is re-formed,but most is lost Without adequate intake of vitamin A, one loses night vision (the first sign of vitamin A deficiency) Cell differentiation Vit-A plays a very important role in ordrely differentiation of mucus –secreating epithelium Mechanism: retinoic acid regulates the expression of the genes encoding a number of recetors and secreted proteins including rerceptors for growth factors Deficiency state :the epithelium undergoes squamous metaplasia Immunity Vit A plays a role in host resistance to infections It stimulates the immune system by forming a metabolite 14-hydroxyretinol during infections the bioavailability of vit –A is reduced Mechanism:Infectionsacute phase responsedecreases retinol binding protein in liverdepression of circulating levels of retinolreduced tissue availability of retinol Supplements of vitA during course of infections like measels will improve clinlical outcome Deficiency state Earliest manifestationimpaired vision during reduced light(night blindness) Persistant vit-A deficiency affect epithelium ocular changesxerophthalmia Dryness of conjunctivae(xerosis) dryness of conjunctivae as normal lacrimal and mucus secreting glands are replaced by keratinised epithlium Deposition of keratin debris Small opaque plaques(Bitot spot) Erosion of corneal surface(corneal ulcer) softening of cornea(keratomalacia) total blindness 1. Bitot 1. Fine line of Bitot spots spots 2. Wrinkled Conjunctiva 1. Bitot spots and rough Conjunctiva 1. Foamy Bitot spots Bitot spot Corneal ulcer Vitamin A Deficiency Xerotic Keratitis keratomalacia The epithelium lining the upper respiratory tract and urinary tract epithelium undergoes squamous metaplasia Loss of mucociliary epitheliumsecondary pulmonary infections Desquatiom of keratin debris in urinary tractrenal and bladder stones Avitaminosis-Aimmune deficiencyprone to common infections like measles, pneumonia, and infectious diarrhea Vitamin A toxicity 6.9.1 Acute hypervitaminosis Ingestion of large dose can give rise to transient signs and symptoms of toxicity, which are self limiting and completely reversible.. Common complaints include headaches and bulging fontanellae in young children. Nausea, vomiting, dizziness, headaches have been described in adults. Desquamation of the skin, bone pains and hair loss can occur in the following days. 9.2 Chronic hypervitaminosis Is due to ingestion of large doses on a daily basis. This can lead to hepatitis, cirrhosis, hair loss, dry scaly skin, hyperpigmentation, hyperostosis and bone pains, hepato-splenomegaly. It is therefore recommended not to exceed a daily intake of 3000 mcg in children and 7500 mcg in adults Vitamin E VITAMIN E The term vitamin E describes a family of 8 antioxidants, 4 tocopherols (,, , & d) and 4 tocotrienols. -tocopherol is the active form of vitamin E in the human body. Vitamin E Absorbed with dietary lipids Transported in LDL Stored in cell membranes,liver and muscle Mechanism It plays a role in termination of free radiclegenerated lipid peroxidation of chain reactions Protects cellular and subcellular membranes that are rich in polyunsaturated lipids Neurons with long axons are vulnerable to vit E deficiency because of their large surface area Mature red cells are also vulnerable because of oxidative injury during oxygenation of hemoglobin Functions Primary lipid-soluble antioxidant Protects polyunsaturated fatty acids in cell membranes, red blood cells, and lipoproteins from oxidative damage Especially important in cells exposed to oxygen - RBCs, lung, mitochondrial membranes Prevents the alteration of cell’s DNA and risk for cancer development Prevents LDL oxidation and risk for atherosclerosis Needed for normal nerve development May play a role in immune function Deficiency –morphology in nervous system Degeneration of axons in the posterior column of the spinal cord,with focal accumulation of lipopigment loss of nerve cells in dorsal root ganglia,and axonopathy Myelin degeneration in sensory axons of peripheral nerves In marked cases, degenerative changes in spinocerebellar tracts Morphology in erythrocytes Vit-E deficient erythrocytes are more susceptible to oxidative stress and have shorter half life in circulating blood VITAMIN -D The major function of vitamin-D is the maintenance of plasma levels of calcium and phosphorus It is required for the prevention of metabolic bone diseases and hypocalcemic tetany Vit D maintains correct concentration of ionised calcium in extracellular fluid Insufficient concentration of calciumcontinous exitation of muscleconvulsive statetetany Sources of Vitamin D Two possible sources :1)endogenous synthesis in skin 2)DIET Sunlight is the most important source which converts 7 dehydrocholesterol to vit D3 Fish liver oil Fish & sea food (herring & salmon) Eggs Plants do not contain vitamin D3,but contain its precursor ergosterol,which can be converted to vit D2 Sources of Vitamin D Two possible sources :1)endogenous synthesis in skin 2)DIET Sunlight is the most important source which converts 7 dehydrocholesterol to vit D3 Fish liver oil Fish & sea food (herring & salmon) Eggs Plants do not contain vitamin D3,but contain its precursor ergosterol,which can be converted to vit D2 VITAMIN D Vitamin D comprises a group of sterols; the most important of which are cholecalciferol (vitamin D3) & ergosterol (vitamin D2). Humans & animal utilize only vitamin D3 & they can produce it inside their bodies from cholesterol. Cholesterol is converted to 7-dehydrocholesterol (7DC), which is a precursor of vitamin D3. Metabolism of vitamin D Functions of vitamin D The maintenance of of normal plasma levels of calcium and phosphorus Is required for normal mineralisation of epiphyseal cartilage and osteid matrix Favours differentiation of osteoclasts from their precursors(monocytes)helps in resorptive function of bone increases synthesis of calcium binding proteins like osteocalcin and osteonectin Vitamin D deficiency •Deficiency of vitamin D leads to: Rickets in small children. Osteomalacia in adults Osteoporosis deficiency of vit-D hypocalcemia activates renal a1- hydroxylase in creasing active vit D and calcium absorption mobilises calcium from bone decreases renal calcium excretion Increases excretion of phosphorus GROUPS AT RISK •Infants •Elderly •Covered women •Kidney failure patients •Patients with chronic liver disease •Fat malabsorption disorders •Genetic types of rickets •Patients on anticonvulsant drugs Morphology An excess of unmineralised matrix Inadequate provisional calcificationovergrowth of epiphyseal cartilage Persistance of distorted irregular masses of cartilage Disruption of orderly replacement of cartilage by osteoid matrix,with enlargement of lateral expansion of osteochondral junction Deformation of skeleton due to loss of structural regidity of developing bones Skeletal changes in rickets Non ambulatory stage: head and chest sustain greatest stresses Occipital bone become flattened Parietal bone can be buckled in by pressure,which recoil back with the release of pressure(craniotabes) An excess of osteoid frontal; bossing and squared appearance of head Chest deformities Overgrowth of cartilage or osteid tissue at the costochondral junctionrichitic rosary Weakened metaphyseal areas of the ribs are subject to pull of respiratory musclespigeon breast deformity Inward pull at the margin diaphragmHarrison’s groove Ambulating child:lumbar lordosis,bowing of legs In adults vitamin D deficiency affects normal bone remodelling that occurs throughout life The newly formed osteid matrix is inadequately mineralisedproducing excess of persistant osteidosteomalacia The bone is weak and vulnerable to microfractures, especially of vertebral bodies and femoral necks Histopathology Unmineralized osteid appear as thickened layer of matrix ( appear pink in H and E) arranged about the more basophilic normally mineralized trabeculae TOXICITY •Hypervitaminosis D causes hypercalcemia, which manifest as: Nausea & vomiting Excessive thirst & polyuria Severe itching Joint & muscle pains Disorientation & coma.