Page 69 - Retail Pharmacy November/Decemeber 2020

68 CPD ACTIVITY THE LOW-DOWN ON HYPOGLYCAEMIA Sofia Cabrera BPharm (Hons) AACPA Accredited Pharmacist B Pharm (Hons), Grad Cert Diabetes Education and Management, AACPA, MACP LEARNING OBJECTIVES After completing this CPD activity, pharmacists should be able to: • Describetheriskfactorsof hypoglycaemia. • Discussthesymptomsof hypoglycaemia and how they arise. • Counselpatientsatriskof hypoglycaemia about how to manage the condition. 2016 Competency Standards: 3.1, 3.3, 3.5. Accreditation Number: A2011RP1 (Exp. 31/10/2022). Hypoglycaemia significantly affects quality of life, is a financial burden to the healthcare system, causes recurrent morbidity and sometimes (through rarely) can be fatal.1,2 Hypoglycaemia is clinically defined as a blood glucose concentration of less than 4mmol/lt.3 An episode of hypoglycaemia is colloquially known by patients as a ‘hypo’.3 Hypoglycaemia can be further defined as non-severe or severe. In the case of the former, it can be self-treated without the assistance of a third party, whereas severe hypoglycaemia requires assistance from a third party to recover.3 Hypoglycaemia causes a series of unpleasant symptoms and, if left untreated, severe hypoglycaemia can lead to seizures, loss of consciousness and brain injury due to lack of glucose supply to the central nervous system.3 Hypoglycaemia is most commonly iatrogenic (induced by medications) in patients with diabetes. Other causes of hypoglycaemia are uncommon. It’s estimated that for type 1 diabetes, all hypoglycaemia (both non-severe and severe) has an incidence of 42.9 episodes per patient year and for type 2 diabetes patients treated with insulin the incidence is 16.4 episodes.4 The incidence of severe hypoglycaemia is 1.15 episodes per patient year for type 1 diabetes and is 0.35 for type 2 diabetes treated with insulin.4 The clinical challenge Achieving euglycaemia is difficult in diabetes due to the risk of hypoglycaemia.5,6 Tighter controls of blood glucose levels have been associated with benefits in microvascular complications and some macrovascular complications.5,6 However, tighter glycaemic control in patients can result in an increased incidence of hypoglycaemia in both type 1 and type 2 diabetes as seen in the ‘UK Prospective Diabetes Study’ and the ‘Diabetes Control and Complications Trial’.5,6 Glycaemic targets should be individualised for patients to optimise blood glucose control but minimise hypoglycaemia.7 Pathophysiology The body has compensatory mechanisms to avoid hypoglycaemia and achieve euglycaemia. In times of low blood glucose, in the first instance, insulin release by beta pancreatic cells is reduced.8 When insulin release is reduced, gluconeogenesis (glucose production by the liver) and glycogenolysis (glycogen break-down in the liver to release glucose) are both stimulated.8 In the next phase, glucagon is released by alpha pancreatic cells.8,9 An increase in glucagon causes a rise in blood glucose through two mechanisms: glycogenolysis and gluconeogenesis.10 The third stage is stimulation of the autonomic nervous system including adrenomedullary adrenaline secretion.8,9 Adrenaline stimulates glycogenolysis, gluconeogenesis and lipolysis and causes a reduction in insulin secretion and glucose utilisation.11 Growth hormone and cortisol play a role in prolonged hypoglycaemia and are released after the above counterregulatory steps.10 Insulin release reduction will typically start occurring when blood glucose levels are 4.4mmol/lt, whereas glucagon and adrenaline release will occur below physiological blood glucose levels at 3.8mmol/lt.10 Growth hormone is released at 3.7mmol/lt and cortisol at 3.2mmol/lt.10 High insulin levels can supress the counter-regulatory response.12 In the case of type 1 diabetes where there is no endogenous insulin production, the first step in the response to hypoglycaemia (insulin reduction) is not possible and glucagon release is hindered due to the high amounts of insulin.10,12 Additionally, the blood glucose threshold for adrenaline release is often lower, meaning that symptoms of hypoglycaemia can be delayed.10,12 Risk factors for hypoglycaemia Hypoglycaemia commonly is an unwanted consequence of diabetes treatment and is uncommon in those not being treated for diabetes.13 See Table 1 for a list of possible causes of hypoglycaemia in a patient without diabetes. There are a number of important risk factors for hypoglycaemia in patients with diabetes. It’s important to understand not only the ongoing risk factors, but the immediate risk factors that could be considered as acute precipitants of hypoglycaemia. Table 1. Possible causes of hypoglycaemia in a patient without diabetes14,15,16 Non medication related causes Drugs associated with hypoglycaemia (other than antihyperglycaemic drugs and alcohol) Critical illness Moderate quality evidence: Alcohol Cibenzoline Malnourishment Cinafloxacin Cortisol deficiency Gatifloxacin Non-islet cell tumours Glucagon (in endoscopy) Endogenous hyperinsulinism Indomethacin Pentamidine Accidental, surreptitious, or malicious hypoglycaemia Quinine Low quality evidence: Artesunate/ artemisin/ artemether Chloroquineoxaline sulfonamide IGF-1 (Insulin-like Growth Factor-1) Lithium Propoxyphene and dextropropoxyphene RETAIL PHARMACY • NOV/DEC 2020 3 CPD CREDITS