Endocrine management: involving pet owners with diseases

Transcription

1 Vet Times The website for the veterinary profession Endocrine management: involving pet owners with diseases Author : Emma Gerrard Categories : Clinical, RVNs Date : January 16, 2017 ABSTRACT Endocrine diseases are commonly encountered in general practice and VNs are often at the forefront of assisting with treatment, discharge and follow-up appointments. It is important for VNs to understand the pathophysiology of each endocrine disease so they manage to involve and support the owner in its management. Due to the complexity of most endocrinopathies, care plans are an excellent way of involving clients in the home care requirements of these patients. This article aims to briefly discuss the main endocrinopathies and how the VN can involve the client in the management of an endocrine disease. Keywords: endocrine, management, client, home care, disease The endocrine system is a network of ductless glands that produce and release hormones delivered into the bloodstream, lymph or tissue fluid. The hypothalamus is the control centre of this system and sits at the base of the brain, connecting the endocrine system with the nervous system. The hypothalamus produces releasing hormones that control the pituitary gland. The pituitary gland (or hypophysis) responds to these by producing stimulating hormones, which are sent to individual organs. The pituitary gland is composed of an anterior and posterior section, both of which produce different hormones. Seven main endocrine glands exist: thyroid 1 / 10

2 parathyroid pituitary glands (anterior and posterior) adrenal glands (medulla and cortex) the pancreas (a mixed gland of both endocrine and exocrine functions, with the islets of Langerhans forming the endocrine tissue) ovaries testes Other organs such as the stomach, small intestine, kidney and placenta also produce hormones, but are not regarded as primary endocrine glands. Additionally, the pineal gland, which is found near the centre of the brain, is thought to be linked to sleep patterns. Many of the endocrine glands are linked to neural control centres by homeostatic feedback mechanisms. This article will discuss the top five glands previously listed and the main disease processes associated with them. Hypothyroidism The thyroid glands are a pair of elongated lobes of encapsulated tissue located on the lateral aspects of the trachea, caudal to the larynx, around the fifth to eighth cartilage rings. They are essential for maintenance of normal growth and metabolism, while also being an iodine store. Hypothyroidism is a progressive disease resulting from decreased secretion of thyroid hormones (thyroxine; T4) that causes a consequent slowing of metabolism affecting multiple systems. The cause is usually a result of the destruction of the thyroid gland, which is thought to be caused by the dog's own immune system killing the cells (lymphatic thyroiditis). Diagnosis of hypothyroidism can be difficult due to the varying clinical signs, and none of the laboratory tests available will diagnose the disease alone (Mooney and Peterson, 2004). The physiological effects of hypothyroidism can include: obesity lethargy dermatological abnormalities hypothermia reduced drug metabolism bradycardia hypotension Treatment of canine hypothyroidism is by drug therapy with levothyroxine sodium. VNs, meanwhile, will have a large supportive role during diagnosis, as well as in disease management. Patients will 2 / 10

3 be on lifelong therapy, so the nursing care plan should include regular weight and blood monitoring. It may also, depending on the individual, involve several requirements for example, ECG and/or skin checks. This will provide a VN with the opportunity to have regular contact with the patient and owner, so a holistic care plan can be developed, thereby ensuring compliance. Hyperthyroidism A thin hyperthyroid cat. IMAGE: Sarah Caney. Hyperthyroidism is caused by the overproduction of hormones T4 and triiodothyronine, which can result in multisystemic disease. It is one of the most common conditions in cats, with most affected patients aged 10 years or older (Caney, 2014). The physiological effects of hyperthyroidism can include: polyphagia tachycardia tachypnoea goitre vomiting hypertension nervous/aggressive behaviour 3 / 10

4 poor body condition score hypertrophic cardiomyopathy increased potential for catecholamine release underlying renal insufficiency The implementation of a nursing care plan and provision of home care will depend on the treatment agreed between the vet and owner. The three main treatment options are: medical (antithyroid drug therapy) surgical (thyroidectomy) radioactive iodine therapy Dietary management is also an option. Depending on the treatment or management of choice, VNs can take the lead on regular weight checks, blood sampling for monitoring and dietary management. The owner s involvement, meanwhile, will include administering antithyroid medications (if this option is chosen), observation for returning clinical signs and the side effects associated with the medication. Parathyroid glands The parathyroid glands are tiny glands found lying closely associated to the thyroid glands. They produce parathyroid hormone (PTH), which is responsible for controlling blood calcium concentrations. Diseases of the parathyroid are rare, but include: primary hypoparathyroidism primary hyperparathyroidism secondary hyperparathyroidism (nutritional or renal) Primary hypoparathyroidism is the complete absence or deficiency of PTH, which causes hypocalcaemia and hyperphosphataemia. This could be iatrogenic that is, accidental damage or removal during a thyroidectomy or by trauma to the neck. Clinical signs are those of hypercalcaemia, with treatment depending on the severity. This may include IV fluid therapy with calcium supplementation either parenterally or orally as directed by the vet. Long-term calcium supplementation will be required, too. Primary hyperparathyroidism, meanwhile, is the continuous excessive secretion of PTH, which causes hypercalcaemia and hypophosphataemia. This can be caused by a functional parathyroid tumour. When it comes to secondary hyperparathyroidism, this relates to either calcium/vitamin D malnutrition or chronic kidney disease. Secondary renal hyperparathyroidism, specifically, is a complication of chronic renal failure, while secondary nutritional hyperparathyroidism is caused by 4 / 10

5 excessive phosphorus intake, causing a total or relative calcium deficiency. This happens through a binding of calcium in the gut and decreasing its absorption. Fortunately, this latter condition is very rare now, mainly due to the availability of nutritionally balanced commercial diets. When considering nursing care plans and home care for parathyroid patients, it is important the owners understand the severity of hypocalcaemia. Nursing care plans will highlight the need for regular blood samples, lifelong monitoring of calcium, vitamin D supplementation and diet dairy products may be required to maintain the calcium intake, for example. Owner compliance is especially paramount when administering oral supplementation. Nutritional advice is also vital for new puppy owners specifically, those of large breeds to prevent metabolic bone disease. Hypoadrenocorticism Thyroid goitre palpation. IMAGE: Sarah Caney. Also known as Addison s disease, hypoadrenocorticism is primarily a disease of dogs and occurs when the adrenal glands are through damage producing insufficient corticosteroids, aldosterone and cortisol, hormones vital for maintaining blood volume and pressure and helping 5 / 10

6 with stress response. The physiological effects of the disorder are often vague and can wax and wane as a result, it is often underdiagnosed or misdiagnosed. Clinical signs include: gastrointestinal disorders polydipsia/polyuria hypovolaemia and hypotension poor tolerance to stress shivering and/or tremors muscle stiffness A new medication for the treatment of canine hypoadrenocorticism is desoxycorticosterone pivalate (DOCP). This prolonged release suspension is given once a month SC and controls serum electrolytes more effectively than fludrocortisone (Baumstark et al, 2014). Patients will also need daily prednisolone. At times, clinical signs may be of a sudden onset, with the resulting hormonal imbalances leading to severe hypovolaemic shock, collapse and renal failure this is referred to as an Addisonion crisis. The nurse s role when nursing an Addison s patient will include assisting the vet with the initial stabilisation once stable, this will extend to regular weight checks, bloods to monitor electrolytes and the administration of DOCP under the direction of the vet. The client, meanwhile, can be encouraged to complete a diary to monitor clinical signs so the veterinary team is notified of subtle changes. They can also be directed online ( where a logbook can be activated to keep a record of progress. Hyperadrenocorticism (Cushing s disease) Hyperadrenocorticism (HAC) is a common endocrine disease in dogs characterised by an overproduction of cortisol. This excess steroid can lead to muscle weakness, redistribution of fat to the cranial abdomen, generalised neuropathies and coagulation abnormalities. Three forms of HAC exist pituitary, adrenal dependent and iatrogenic. Clinical signs can include: weight gain polydipsia polyuria polyphagia pot-bellied appearance alopecia 6 / 10

7 HAC can be successfully managed with trilostane. VNs, meanwhile, can be responsible for the monitoring of HAC patients with adrenocorticotropic hormone (ACTH) stimulation tests under the direction of a vet at both 10 days and 28 days after starting treatment, which will reduce to threemonthly checks. Owners can become involved by monitoring polydipsia, polyuria, weight and skin lesions, and should be encouraged to take photographs of the skin lesions to monitor progress. Clients can also be directed to an interactive website ( to access a logbook to record and track treatment. Diabetes mellitus Diabetes is mainly seen in middle-aged dogs, particularly entire bitches. Diabetes mellitus (DM) is one of the most common endocrinopathies affecting the older pet, with as many as one in 200 dogs suffering. It is mainly seen in middle-aged dogs entire bitches, in particular and can be described as an endocrine disorder that results in the disruption of protein, fat and carbohydrate metabolism from an absolute or relative insulin deficiency. Insulin is a hormone produced in the pancreas and released into the cells in response to the digestive conversion of proteins into glucose in the bloodstream. Most food ingested is broken down into glucose a type of sugar in the blood and one of the body's main sources of energy. Normal insulin function will trigger the liver and muscles to take up 7 / 10

8 glucose from the blood cells, converting it to energy. Two main types of DM exist: Type one, insulin-dependent DM, is mostly seen in dogs. The beta cells of the pancreas fail to produce insulin, resulting in hyperglycaemia. Type two, insulin-resistant DM, is most common in cats and entire bitches. This occurs when the beta cells do not secrete sufficient insulin to reduce the hyperglycaemia. Clinical signs include: weight loss polyuria polydipsia polyphagia vomiting poor coat quality Diagnostic tests will indicate persistent hyperglycaemia and glucosuria/ketonuria, and to treat the condition successfully, the owner, vet and nursing team must work closely together. For one, diabetes-specific nurse consults are vital for clients with newly diagnosed and stable patients they can be tailored to individual clients and patients to ensure a holistic approach is adopted. DM clinics also provide a safe environment for owners to learn about diet and exercise, proper insulin injection techniques, and correct storage and disposal of insulin and needles. Clients are heavily involved in the monitoring and management of their diabetic pets, so they must be fully engaged. After all, treatment of DM will only succeed if the pet owner understands all aspects of its management. At home, they can perform daily urine testing and monitor and record parameters in a diary. This will allow subtle changes in behaviour and habits to be detected. VNs, meanwhile, will have the opportunity to see DM patients regularly to monitor blood glucose, perform curves and monitor fructosamine levels. Fructosamine and glycosylated haemoglobin are the two glycated proteins commonly used for monitoring diabetics, with the bonding of glucose to these proteins producing fructosamines. A single fructosamine measurement indicates the average glucose concentration over the previous two to three weeks. Doing these measurements in diabetes clinics is an ideal way to ensure optimal management of our patients, providing an excellent opportunity for VNs to specialise and develop a vital role in nursing and home care. The VN s involvement in client education in this endocrine disease from diagnosis to management is paramount. It is important to bear in mind instances of unstable diabetes could be due to owner factors, such as incorrect injection technique, storage of insulin and inappropriate dosage, or other concurrent diseases that can cause insulin resistance, such as pancreatitis, acromegaly and 8 / 10

9 hyperadrenocorticism. Furthermore, diabetes ketoacidosis (DKA) is a life-threatening complication of DM that can develop as a result of: long-standing undiagnosed cases insufficient insulin in diagnosed diabetics impaired insulin action and/or resistance caused by obesity, concurrent illness or pharmaceuticals Endocrine disorders are often complex and require a good level of understanding to ensure compliance. As a result of the lack of insulin, glucose cannot be used as an energy source, resulting in fats being broken down to provide energy. During this lipolysis, high levels of ketones are produced and ketosis and acidosis develop, accompanied by electrolyte imbalances. Clinical signs include: polyuria polydipsia anorexia vomiting and/or diarrheoa depression weakness or collapse shock poor body condition acetone smell on the patient s breath 9 / 10

10 Powered by TCPDF ( DKA is an emergency and treatment must be started as soon as possible under the direction of a vet. The treatment goals are to correct fluid deficits, acid-base balance and electrolyte balance, as well as lowering blood glucose and ketone concentrations, and recognising and correcting underlying and precipitating factors. Conclusion This article is a whistle-stop tour of the main endocrinopathies encountered in practice. Endocrine disorders are often complex and require a good level of understanding to ensure compliance. VNs and owners should work together when drawing up home care plans to ensure the most holistic care is provided. The main message is to encourage clients to keep a diary to log any clinical symptoms and changes in behaviour to aid patient monitoring. Encourage clients to keep a diary to log any clinical symptoms and changes in behaviour to aid patient monitoring. References This article was reviewed by Hannah Barfoot BVMedSci(Hons), BVM, BVS, MRCVS. Baumstark ME et al (2014). Use of plasma renin activity to monitor mineralocorticoid treatment in dogs with primary hypoadrenocorticism: desoxycorticosterone versus fludrocortisone, Journal of Veterinary Internal Medicine 28(5): 1,471-1,478. Caney S (2014). Feline hyperthyroidism advances and nurse s role in treatment and follow-up, VN Times 14(11): Mooney CT and Peterson ME (2004). BSAVA Manual of Canine and Feline Endocrinology (3rd edn), BSAVA, Gloucester / 10