Discuss about the Veterinary Terminology and Homeostatic System.
(Meaning, the body systems that controls homeostasis, what is negative feedback system, homeostatic mechanisms)
Homeostasis can be understood as a self regulating system which allows the maintenance of stability in biological systems, while adjusting to condition vital for survival. The stability is a state of dynamic equilibrium where a uniform set of conditions are maintained through continuous sets of changes (De Luca et al., 2014).
Homeostatic system consists of three components: receptor, control and effectors. The control can either be intrinsic or extrinsic. The Endocrine and the nervous system mostly act as control systems for homeostasis. (estrellamountain.edu, 2018).
Negative feedback system refers to a system where the information provided by the feedback causes a change that is reverse to the response (estrellamountain.edu, 2018).
Different types of variables are controlled by the homeostatic mechanism. These include: core body temperature, blood glucose, levels of respiratory gases in blood, blood oxygen levels, arterial blood pressure, level of calcium, concentration of sodium, concentration of potassium, fluid and osmotic balance, pH of blood, composition of cerebrospinal fluid, neurotransmission, neuroendocrine system, regulation of gene expression and energy homeostasis (Nakamura, 2011; Prabhakar & Semenza, 2015; bbc.co.uk, 2018).
Hyperadrenocorticism
Hypoadrenocorticism
Definitions
Hyperadrenocorticism is also called the Cushing’s Syndrome, characterized by a chronic excess of systemic cortisol (Lunn, 2018; Greco, 2018).
Hypoadrenocorticism is also known as Addison’s Disease characterized by a deficiency of adrenocortical hormones (Bruyette, 2018; Klein & Peterson, 2018).
Excessive and deficient conditions
Excess cortisol level
Deficient cortisol levels
Cause
Pituitary dependant Hyperadrenocorticism, Adrenal Tumor and Iatrogenic Hyperadrenocorticism. (Lunn, 2018; Vetfolio.com, 2018)
Caused due to the destruction or atrophy of the three adrenal cortical layers thereby resulting in the inadequate secretion of glucocorticoids and minerelocorticoids (Klein & Peterson, 2018).
Clinical Signs
Polyphagia, Polyuria/Polydispsia, abdominal enlargement, weakness of muscle, panting, Lethargy, Panting, Alopecia, Intolerance to heat, • Calcinosis cutis, Comedones, Thin skin, bruising, striae, Hyperpigmentation, • Testicular atrophy, Pseudomyotonia, Anestrus, • Seborrhea, pyoderma and Facial paralysis (Lunn, 2018).
Chronic gastroenteritis, changes in serum levels of potassium, sodium and chlorine; Hyponatremia; hypochloremia; Severe hyperkalemia; bradycardia; cute circulatory collapse; renal failure; hypotension; weakness; microcardia; progressive dehydration; hemoconcentration; Emesis; diarrhea; anorexia; weight loss; hypoglycemia; and skin hyperpigmentation (Bryutte, 2018; Klein & Peterson, 2018).
Diagnosis
Urine cortisol to Creatinine ratio; Adrenocorticotropic stimulation test; intravenous low-dose and oral dexamethasone suppression test; high-dose dexamethasone suppression test and Measurement of endogenous plasma Adrenocorticotropic concentrations (Greco, 2018). Complete Blood Count, Serum Biochemistry, Urianalysis. Diagnostic imaging techniques like: Abdominal radiograph, thoracic radiograph, abdominal ultrasound exam, brain CT scan or Magnetic Resonance Imaging (Lunn, 2018).
The condition can be diagnosed on the basis of compatible history, clinical signs, laboratory abnormalities, imaging studies and adrenocorticotropic hormone stimulation test results. Diagnostic imaging can include: thoracic radiograph, abdominal ultrasonography, electrocardiogram (Lottati & Bruyette, 2018).
Treatment
Surgical Intervention for adrenocortical tumours or pituitary tumours. Medical therapy: mitotane, trilostane, ketoconazole and l-deprenyl (vetfolio.com, 2018; Lunn, 2018).
Acute medical emergency is needed for adrenal crisis. The treatment should include: intravenous drip of saline solution; prednisolone sodium succinate or dexamethasone sodium phosphate (for shock); prednisone or prednisolone; minerelocorticoid replacement therapy; regular monitoring of renal function, electrolyte and glucose levels; administration of insulin (Bruyette, 2018).
Whether common in canine/feline/both
Canine
Hypercalcemia
Hypocalcemia
Hypercalcemia occurs when the concentration of serum calcium is more than 12mg/dL or ionized calcium is greater than 1.4mmol/L (Nelson, 2018).
This condition is characterized by low levels of calcium in blood due to vitamin D inadequacy, hypoparathyroidism or resistance to these hormones (Fong, 2012).
Excessive concentration of serum calcium or ionized calcium (Nelson, 2018).
Deficient levels of serum calcium
Acromegaly, adenocarcinoma of apocrine gland, Carcinoma, Iatrogenic disorders, Hypoadrenocorticism, Idiopathic hypercalcemia of cats, Lymphoma, Multiple myeloma, Metastatic or primary bone neoplasia, Primary hyperparathyroidism, Skeletal lesions and myeloproliferative disease (Peterson, 2018).
Renal disease, hypoproteinemia, pancreatitis, puerperal tetany, Phosphate Enema Toxicity (Peterson, 2018). Other causes include: Eclampsia, Hypoparathyroidism, and Certain types of poisoning, rickets and blood transfusions (Lee, 2018).
Polyuria/Polydispsia; anorexia, vomiting, constipation, pancreatitis, tranguria/pollakiuria, mental dullness, obtundation, coma, twitching, shivering, seizure, muscular weakness, lymphadenopathy, mass in the rectal wall, mammary masses, chronic renal failure, bradycardia with weak femoral pulses (Harkin, 2018).
Muscle cramps, diffuse encephalopathy, Papilledema, hyperreflexia, tetany, laryngospasm and generalized seizures; brittle nails, coarse hair, dry and scaly skin and cataracts (Lewis 2018).
Septum Parathyroid hormone test, Ultrasonography of parathyroid glands, and explorative surgery (Peterson, 2018).
Estimation or measurement of ionized calcium, magnesium, phosphate, parathyroid hormone, alkaline phosphatase, vitamin D in blood measurement of phosphate and cAMP in urine (Lewis, 2018).
Fluid therapy, glucocorticoid administration, Diuretics and miscellaneous agents like: bisphosphonate, mithramycin, Calcimimetics and calcitonin (Peterson, 2018).
Intravenous calcium gluconate for tetany, Oral calcium for postoperative hypoparathyroidism and Oral calcium and vitamin D for chronic hypocalcemia (Lewis, 2018).
Both
Hyperthyroidism
Hypothyroidism
Hyperthyroidism or Grave’s disease caused by an overactive thyroid gland, therefore resulting in an increase in thyroid hormones secretion (Medlineplus.gov, 2018).
Hypothyroidism is caused by an underactive thyroid gland resulting in the undersecretion of thyroid hormones (ncbi.nlm.nih.gov, 2018).
Excessive thyroid hormone production
Insufficient levels of thyroid secretion
It can be caused due to increased production of thyroid hormones (T3 and T4) from enlarged thyroid gland. The enlargement can be due to an adenoma (non-cancerous tumor) or thyroid adenocarcinoma (malignant tumors) (Komreich, 2018).
The most common cause is Lymphocytic thyroiditis and idiopathic atrophy of the thyroid gland (Peterson, 2018).
Weight loss, increased appetite, thirst and urination; vomiting, diarrhea, hyperactivity; unkempt/matted/greasy appearance of fur coat (Komreich, 2018). Other signs may include: restlessness, aggressiveness, rapid heart rate, difficulty breathing, weakness and depression (vetmed.wsu.edu, 2018).
Common signs may include: Hair loss, weakness, lethargy, slower heart rate, and drop in body temperature, mental dullness and obesity. Other symptoms may include Cushing’s syndrome
Checking the thyroid gland for enlargement (by palpating); checking the heart rate and blood pressure; measurement of thyroid hormone in blood; evaluation of general health, urinalysis, monitoring the function of kidneys and heart (Kornreich, 2018).
Measurement of the concentration of thyroxin in blood; Thyrotropin releasing hormone TRH and thyroid stimulating hormone TSH stimulation tests; Scintigraphy and ultrasonography of the thyroid gland. Other tests include: modified equilibrium dialysis test used along with TSH measurement test (Peterson, 2018).
Treatment can be in the form of medication, radioactive iodine therapy, surgery and dietary therapy. Medication can include: anti thyroid drugs, while surgery includes removal of thyroid gland and dietary therapy can include limiting dietary iodine intake (Kornreich, 2018).
Intravenous levothyroxine (for dogs in myxedema coma); Medications include: levothyroxine (oral); liquid thyroxin. Follow-up should be done to monitor the condition and to check for complications (Lathan, 2018).
Feline
Diabetes Mellitus is a disease that is characterized by consistently high levels of blood glues, and a reduction in the secretion of insulin or infectivity of the insulin hormone on the tissues of the body (diabetesjournals.org, 2018)
Type 1 diabetes mellitus is caused when the pancreas is unable to produce enough insulin, while type 2 diabetes mellitus is caused when the tissues of the body develop insulin resistance, and they fail to appropriately respond to the hormone (diabetes.co.uk, 2018). Type 1 can further be divided into immune mediated diabetes and idiopathic diabetes (diabetesjournals.org, 2018).
Causes of Diabetes include the autoimmune destruction of pancreatic beta cells, resistance to insulin (diabetesjournals.org, 2018). Several factors can increase the risks to diabetes and includes: family history of the disease; ethnicity; overweight/obesity; stress; some types of medications; pancreatic injury; autoimmune dysfunction; hypertension; high blood cholesterol levels; age; smoking and alcoholism and pregnancy (clevelandclinic.org, 2018).
Signs of diabetes are: increased hunger and thirst; dryness of mouth; urinating frequently; sudden loss of weight; blurring of vision; weakness; tingling and numbness in feet and hands; longer time for the healing of wounds; dryness of skin and yeast infections (clevelandclinic.org, 2018).
Treatment options are: diet change; oral medications; exercise; insulin treatment; identification and treatment of concurrent diseases (Kow, 2018).
Difference with diabetes insipidus: Diabetes Insipidus however is another type of diabetes that is caused due to inadequate production of Arginine Vasopressin hormone or an inability of the distal tubule/collecting ducts of the nephron to respond to it (Rossi & Ross, 2018).
References:
bbc.co.uk. (2018). BBC - GCSE Bitesize: Homeostasis. Bbc.co.uk. Retrieved 15 March 2018, from https://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway_pre_2011/ourselves/5_staying_in_ba
Bruyette, D. (2018). Hypoadrenocorticism - Endocrine System - Veterinary Manual. Veterinary Manual. Retrieved 15 March 2018, from https://www.msdvetmanual.com/endocrine-system/the-adrenal-glands/hypoadrenocorticism
clevelandclinic.org. (2018). What Is Diabetes Mellitus: Symptoms & Treatment | Cleveland Clinic: Health Library. Cleveland Clinic. Retrieved 17 March 2018, from https://my.clevelandclinic.org/health/diseases/7104-diabetes-mellitus-an-overview
D.umn.edu. (2018). Homeostatic Control Systems. D.umn.edu. Retrieved 15 March 2018, from https://www.d.umn.edu/~jkeener/hlth2040-1-su2012/pwreadings/pdf/1-3.pdf
De Luca, J., David, R., & Menani, J. (2014). Homeostasis and Body Fluid Regulation. Ncbi.nlm.nih.gov. Retrieved 15 March 2018, from https://www.ncbi.nlm.nih.gov/books/NBK200958/
Diabetes.co.uk. (2018). Diabetes Mellitus - Diabetes Type 1, Mellitus Symptoms, Risk Factors & Mortality. Diabetes.co.uk. Retrieved 17 March 2018, from https://www.diabetes.co.uk/diabetes-mellitus.html
diabetesjournals.org. (2003). Diagnosis and Classification of Diabetes Mellitus . Diabetes Care, 27(Supplement 1), S5-S10. https://dx.doi.org/10.2337/diacare.27.2007.s5
estrellamountain.edu. (2018). ANIMAL ORGAN SYSTEMS. Www2.estrellamountain.edu. Retrieved 15 March 2018, from https://www2.estrellamountain.edu/faculty/farabee/biobk/BioBookANIMORGSYS.html
Ferguson, D. (2018). Vetmed.illinois.edu. Retrieved 15 March 2018, from https://vetmed.illinois.edu/pet_column/hypothyroidism-dogs/
Fong, J. (2012). Hypocalcemia. ncbi.nlm.nih.gov. Retrieved 15 March 2018, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3279267/
Greco, D. (2018). Cushing Disease (Hyperadrenocorticism) - Endocrine System - Veterinary Manual. Veterinary Manual. Retrieved 15 March 2018, from https://www.msdvetmanual.com/endocrine-system/the-pituitary-gland/cushing-disease-hyperadrenocorticism
Harkin, K. (2018). Hypercalcemia in dogs and cats (Proceedings). dvm360.com. Retrieved 15 March 2018, from https://veterinarycalendar.dvm360.com/hypercalcemia-dogs-and-cats-proceedings
Klein, S., & Peterson, M. (2018). Canine hypoadrenocorticism: Part I. cbi.nlm.nih.gov. Retrieved 15 March 2018, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2797351/
Kornreich, B. (2018). Hyperthyroidism in Cats | Cornell University College of Veterinary Medicine. Www2.vet.cornell.edu. Retrieved 15 March 2018, from https://www2.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/hyperthyroidism-cats
Kow, K. (2018). Diabetes Mellitus In Dogs and Cats | Diagnosis, Treatment, Prognosis. Find a Vet Specialist. Retrieved 17 March 2018, from https://vetspecialists.com/diabetes-mellitus-in-dogs-and-cats-diagnosis-treatment-prognosis/
Lathan, P. (2018). Canine Hypothyroidism. Cliniciansbrief.com. Retrieved 16 March 2018, from https://www.cliniciansbrief.com/sites/default/files/attachments/Canine%20Hypothyroidism.pdf
Lee, J. (2018). Hypocalcemia in Dogs. Pet Health Network. Retrieved 15 March 2018, from https://www.pethealthnetwork.com/dog-health/dog-diseases-conditions-a-z/hypocalcemia-dogs
Lewis, J. (2018). Hypocalcemia - Endocrine and Metabolic Disorders - MSD Manual Professional Edition. MSD Manual Professional Edition. Retrieved 15 March 2018, from https://www.msdmanuals.com/professional/endocrine-and-metabolic-disorders/electrolyte-disorders/hypocalcemia
Lottati, M., & Bruyette, D. (2018). Canine Hypoadrenocorticism Overview, Diagnosis, & Treatment. Todaysveterinarypractice.navc.com. Retrieved 15 March 2018, from https://todaysveterinarypractice.navc.com/wp-content/uploads/2016/06/T1409F04.pdf
Lunn, K. (2018). Canine Hyperadrenocorticism (HAC; Cushing’s Syndrome). Cvm.ncsu.edu. Retrieved 15 March 2018, from https://cvm.ncsu.edu/wp-content/uploads/2016/04/May-4th-Katharine-Lunn-Canine-Cushings-Disease-1.pdf
Medlineplus.gov. (2018). Hyperthyroidism | Graves' Disease | Overactive Thyroid | MedlinePlus. Medlineplus.gov. Retrieved 15 March 2018, from https://medlineplus.gov/hyperthyroidism.html
Nakamura, K. (2011). Central circuitries for body temperature regulation and fever. American journal of Physiology-Regulatory, integrative and comparative Physiology, 301(5), R1207-R1228.
ncbi.nlm.nih.gov. (2018). Hypothyroidism - National Library of Medicine - PubMed Health. PubMed Health. Retrieved 15 March 2018, from https://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0022776/
Nelson, R. (2018). Hypercalcemia in Dogs and Cats: Etiology and Diagnostic Approach - WSAVA2002 - VIN. Vin.com. Retrieved 15 March 2018, from https://www.vin.com/apputil/content/defaultadv1.aspx?meta=&pId=11147&id=3846169
Peterson, M. (2018). Hypercalcemia in Dogs and Cats - Endocrine System - Veterinary Manual. Veterinary Manual. Retrieved 15 March 2018, from https://www.msdvetmanual.com/endocrine-system/the-parathyroid-glands-and-disorders-of-calcium-metabolism/hypercalcemia-in-dogs-and-cats
Peterson, M. (2018). Hypocalcemia in Dogs and Cats - Endocrine System - Veterinary Manual. Veterinary Manual. Retrieved 15 March 2018, from https://www.msdvetmanual.com/endocrine-system/the-parathyroid-glands-and-disorders-of-calcium-metabolism/hypocalcemia-in-dogs-and-cats
Peterson, M. (2018). Hypothyroidism - Endocrine System - Veterinary Manual. Veterinary Manual. Retrieved 15 March 2018, from https://www.msdvetmanual.com/endocrine-system/the-thyroid-gland/hypothyroidism
Prabhakar, N.R. and Semenza, G.L., 2015. Oxygen sensing and homeostasis. Physiology, 30(5), pp.340-348.
Rossi, T., & Ross, L. (2018). VetFolio. Vetfolio.com. Retrieved 17 March 2018, from https://www.vetfolio.com/internal-medicine/diabetes-insipidus
Vetfolio.com. (2018). VetFolio. Vetfolio.com. Retrieved 15 March 2018, from https://www.vetfolio.com/internal-medicine/overview-of-hyperadrenocorticism
vetmed.wsu.edu. (2018). Hyperthyroidism in Cats. Vetmed.wsu.edu. Retrieved 15 March 2018, from https://www.vetmed.wsu.edu/outreach/Pet-Health-Topics/categories/diseases/hyperthyroidism-in-cats