SAD - Chapter 17 - Nutritional Skin Dz Flashcards
Aromatic amino acids that influence hair color
phenylalanine, tryptophan, tyrosine
Essential polyunsaturated fatty acids for dogs? Cats?
linoleic acid and alpha-linolenic acid; cats – arachidonic acid, linoleic acid, alpha-linolenic acid
Where are the double bonds located with omega-3 fatty acids?
3-carbon position from the carboxyl end
Where are the double bonds located with omega-6 fatty acids?
6-carbon position from the carboxyl end
What omega-6 fatty acids are essential fatty acids?
linoleic acid and arachidonic acid (cat)
What omega-3 fatty acids are essential fatty acids?
alpha-linolenic acid
Why can’t cats synthesize enough arachidonic acid to meet their physiologic requirement?
low levels of delta-6 desaturase activity, which is used to convert linoleic acid into AA acid
What is the function of vitamin A in the skin?
important in cellular metabolism; required for normal maturation of skin and hair follicles; essential for normal epithelial tissue lining digestive, respiratory, and reproductive tracts; required for proper immune system functioning
Signs of vitamin A deficiency
epidermal hyperkeratosis and scaling, occlusion of sebaceous ducts, papules associate with follicular hyperkeratois, poor hair coat and alopecia; reproductive failure, retinal degeneration and night blindness; increased susceptibility to infections
Signs of vitamin A toxicity
epidermal scaling, unkempt hair coat, anorexia, weight loss, bone decalcification, liver damage
Functions of Vitamin D
required for normal calcium absorption and metabolism; essential for normal bone development. Vitamin D3 also has a role in regulation of keratinocyte proliferation and differentiation
Signs of vitamin D deficiency
rickets in young, osteomalacia in adults, chest deformity, poor eruption of teeth
Signs of vitamin D toxicity
increased blood calcium levels, soft-tissue calcification, diarrhea, kidney failure, death
Functions of Vitamin E
antioxidant, protect cells from oxidative damage; may have a role in normal immune function
Signs of Vitamin E deficiency
pansteatitis (seen in cats fed diets high in polyunsaturated fatty acids); seborrhea, muscular dystrophy; reproductive failure; intestinal lipofuscinosis, impaired immunity with predisposition to bacterial skin infections and demodicosis (dogs)
Signs of Vitamin E toxicity
anorexia
Functions of Vitamin K
formation of clotting factors and normal blood clotting
Signs of Vitamin K deficiency
hemorrhage, increased bleeding times (poor blood clotting)
Signs of vitamin K toxicity
none reported
Functions of vitamin C
antioxidant; formation and maintenance of matrix of bone, cartilage and connective tissue
Signs of Vitamin C deficiency
rickets, impaired wound healing, bleeding, anemia, increased susceptibility to infections
Signs of Vitamin C toxicity
none reported – dogs & cats do not require a dietary source of vitamin C (synthesize adequate levels)
Functions of thiamine (B1)
component of two coenzymes essential in carbohydrate metabolism and energy transfer; promotes natural health and digestion and normal nerve function
Signs of thiamine (B1) deficiency
anorexia, weight loss, vomiting, dehydration, ventral flexion of neck, paralysis, incoordination
Signs of thiamine (B1) toxicity
nontoxic
Functions of riboflavin (B2)
forms parts of two coenzymes with roles in energy transfer and protein metabolism; component of xanthine oxidase required for epithelial cell maturation
Signs of riboflavin (B2) deficiency
retarded growth, dry scaly skin, erythema, posterior muscle weakness, anemia, ocular lesions (pannus), glossitis, reduced fertility, testicular hypoplasia, fatty liver
Signs of riboflavin (B2) toxicity
nontoxic
Functions of niacin
component of two coenzymes with roles in energy transfer; required for metabolism
Signs of niacin deficiency
blacktongue (pellagra), pruritic dermatitis, diarrhea, dementia, anorexia, anemia, emaciation, death
Signs of niacin toxicity
cutaneous flushing, itching
Functions of pyridoxine (B6)
part of enzyme involved in protein metabolism; essential for normal metabolism of tryptophan
Signs of pyridoxine (B6) deficiency
dermatitis with dull, waxy, unkempt haircoat, alopecia and scaling, seizures, anemia, high serum iron, anorexia, weight loss, impaired growth
Signs of pyridoxine (B6) toxicity
nontoxic
Function of pantothenic acid (B5)
constituent of coenzyme A required for normal metabolism of carbohydrates, fats, and proteins
Signs of pantothenic acid (B5) deficiency
anorexia, stunted growth, hypoglycemia, uremia, gastroenteritis, seizures, fatty liver, coma, death
Signs of pantothenic acid toxicity
nontoxic
Functions of folic acid
required for normal red blood cell development and DNA synthesis
Signs of folic acid deficiency
anemia, leukopenia, stunted growth, glossitis
Signs of folic acid toxicity
nontoxic
Functions of biotin
required for metabolism of fats and amino acids, essential for skin and hair health, functions in enzyme systems
Signs of biotin deficiency
scaly dermatitis, alopecia, anorexia, weakness, diarrhea, progressive spasticity, and posterior paralysis
Signs of biotin toxicity
nontoxic
Functions of cobalamin
required for synthesis of nucleic acids; involved in purine synthesis and carbohydrate and fat metabolism
Signs of cobalamin (B12) deficiency
anemia, impaired growth, posterior incoordination
Signs of cobalamin (B12) toxicity
nontoxic
Functions of calcium
bone and tooth formationi, blood clotting, enzyme activation, muscle contraction, nerve impulse transmission
Signs of calcium deficiency
rickets in young and osteomalacia in adults, lameness, stiffness, constipation, anorexia, loss of teeth, tetany with acute deficiency
Signs of calcium toxicity
impaired skeletal development, secondary deficiencies of other minerals, especially zinc, phosphorous, and copper (interference with absorption); bloat
Functions of phosphorous
bone and tooth formation; component of enzyme systems, involved in energy transfer (component of high-energy bonds), part of DNA and RNA
Signs of phosphorous deficiency
rough hair coat, pica, anorexia, slow growth, rickets in young, osteomalacia in adults
Signs of phosphorous toxicity
impaired skeletal development, secondary deficiency of calcium, kidney damage
Functions of sodium
muscle contraction, maintenance of body fluid volumes, component of bile, muscle, and nerve function
Signs of sodium deficiency
salt hunger, pica, weight loss, fatigue, impaired milk secretion, polyuria, circulatory failure
Signs of sodium toxicity
thirst, pruritus, constipation, anorexia, seizures, hypertension (all unlikely if water is freely available)
Function of magnesium
enzyme activator, constituent of skeletal tissue, required for muscle and nerve function, roles in energy metabolism and protein synthesis
Signs of magnesium deficiency
calcification of soft tissues, retarded growth, spreading of toes, hyperirritability, seizures, excess salivation
Signs of magnesium toxicity
acute excesses may cause diarrhea; chronic excesses may contribute to urolithiasis, cystitis, and urinary tract disease in cats
Functions of zinc
essential component of many enzyme systems, including those involved in protein and carbohydrate metabolism; required for maturation of skin cells and healthy hair coat; required for normal immune function
Signs of zinc deficiency
impaired growth, scaly skin with parakeratosis, depigmentation of hair, infertility, testicular hypoplasia, impaired wound healing, increased susceptibility to infections
Signs of zinc toxicity
excesses may interfere with absorption of calcium and/or copper; acute toxicity may result in hemolytic anemia
Function of copper
roles in erythropoiesis, coenzymes, hair pigmentation, reproduction, collagen and elastin synthesis, iron utilization
Signs of copper deficiency
pica, stunted growth, diarrhea, depigmentation of hair, anemia, impaired bone growth
Signs of copper toxicity
inherited disorder of metabolism in some breeds leads to liver damage
Function of manganese
involved in carbohydrate and lipid metabolism, formation of cartilage
Signs of manganese deficiency
infertility, enlarged stiff joints, short brittle bones
Signs of manganese toxicity
infertility, partial ablinism (rare)
Function of iodine
required for thyroid hormone synthesis (involved in regulation of metabolism)
Signs of iodine deficiency
hypothyroidism, goiter, alopecia, infertility, lethargy, myxedema
Signs of iodine toxicity
excesses can also result in decreased thyroid function and signs similar to deficiency
Other than a diet deficient in fatty acids, how may fatty acid deficiency develop?
inadequate antioxidants (such as vitamin E), resulting in rancidity; intestinal malabsorption, pancreatic disease, chronic hepatic disease
What cutaneous changes can occur with fatty acid deficiency?
abnormal keratinization –> epidermal hyperplasia, hypergranulosis, orthokeratotic or parakeratotic hyperkeratosis
Why does abnormal keratinization occur with fatty acid deficiency?
arachidonic acid deficiency –> prostaglandin E2 deficiency -> aberrations in the ratios of epidermal cyclic adenosine monophosphate (cAMP) to cyclic guanosine monophosphate (cGMP) and in DNA synthesis
Why do cats require a dietary source of preformed retinol?
unable to synthesize it from its precursor, beta-carotene
Cats fed diets high in red tuna or other PUFA-rich foods, without receiving vitamin E supplements may develop what?
pansteatitis; lipid peroxidation –> necrosis and inflammation of subcutaneous and intraabdominal fat; lesions include firm, painful nodules in affected tisues
ceroid
product of lipid peroxidation
Syndrome I zinc-responsive dermatosis primarily occurs in what breeds?
Alaskan malamutes and Siberian huskies
What adverse effects have been reported with IV administration of zinc sulfate?
cardiac arrhythmias can occur if the drug is administered too fast
What adjunctive therapies can help with zinc absorption?
phytase – enhances the bioavailability of zinc by hydrolyzing phytates present in foods; low-dose corticosteroids– increase zinc absorption from the GI tract by induction of metallothionein
Syndrome II zinc-responsive dermatosis occurs in what situations?
rapidly growing puppies or young adult dogs that are fed zinc-deficient diets, diets high in phytates or minerals such as calcium or iron (interfere with zinc absoprtion), diet oversupplemented with other minerals and vitamins
Histopathological findings of zinc-responsive dermatosis
hyperplastic superficial perivascular dermatitis–eos and lymphocytes, marked diffuse and follicular parakeratotic hyperkeratosis, spongiosis
