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Endocrine complications in thalassemia majorDiabetes mellitus Dr. K W Wong QEH 15th July 2004 Introduction • Part I – Classification – Epidemiology – Pathogenesis – Clinical presentation – Diagnosis – Management – DM complications Introduction • Part I – Associated endocrine problems – Survival • Part II – Diabetic thalassemic patients - a local hospital experience Classification • • • • Type I DM Type II DM Other specific types Gestational diabetes Classification • Other specific types – – – – – – – – genetic causes of impaired -cell function genetic defects of insulin action secondary to pancreatic disease e.g. thalassemia secondary to other endocrine disease secondary to drugs of toxins secondary to infection other forms of immune disorder rare genetic disorders Epidemiology • Limited data on prevalence of DM in thalassemic patients • Study in Italy: 2.3-24% • QMH study in 1995: 5.9% • QEH, PWH, PMH study in 2002: 8.6% • prevalence varies and higher if studies involving older patients Epidemiology • Age of onset of DM: teenagers • Male > Female Pathogenesis • Not completely understood • Combination of insulin deficiency and insulin resistance Pathogenesis (contributing factors): • Pancreatic dysfunction • Liver dysfunction – Fe deposition – Co-existing chronic liver disease – Hepatitis virus • Genetic factor –no distinct HLA typing can be found • Autoimmune factor Pathogenesis (Pancreatic dysfunction) Thalassemia Repeated blood transfusion Iron overload Damage pancreatic cells Pancreatic dysfunction Compensatory increase in insulin secretion cell exhaustion Insulin deficiency Pathogenesis (Liver dysfunction) • Fe deposition – Thalassemia Repeated blood transfusion Iron overload Damage hepatic cells ?? Insulin resistance • Co-existing chronic liver disease – well recognised association between cirrhosis and DM Pathogenesis (Liver dysfunction) • Hepatitis virus – 28% of patients with thalassemia major developed DM shortly after acute viral hepatitis De Sanctis V. Insulin Dependent Diabetes in thalassemia. Arch. Dis. Child 1988; 63: 58-62. – Prevalence of DM in thalassemia patients with positive HCV Antibody was higher (50%) than those with negative antibody (9.5%) Curyssoula. High prevalence of diabetes mellitus among adult beta thalassemia patients in chronic hepatitis C. Europe J. of gastroenterology & hepatology. 1999; 11:1033-1036. Pathogenesis (Autoimmune factor) The frequency of insulin cell antibodies positive subjects among diabetic thalassemic individuals (41.6%) was high Monge L.The possible role of autoimmunity in the pathogenesis of diabetes in betal thalassemia major. Diabetes Metab (Paris) 2001; 27: 149-154. CHO metabolism in thalassemia Normal insulin secretion Decrease in insulin secretion and decrease in insulin sensitivity Compensatory increase in secretion to maintain CHO homeostasis Insulin secretion fails to keep pase Normal IGT (present for months and can be up to 5 years) DM Clinical presentations • Asymptomatic : glycosuria, hyperglycemia • Classical symptoms: polyuria, polydipsia, unexplained weight loss • Acute complications: DKA Diagnosis In the absence of unequivocal hyperglycemia with acute metabolic decompensation, needed to repeat testing on a different day • Symptoms + random plasma glucose level >/ 11.1mmol/L • Fasting plasma glucose >/7mmol/L • 2-hr plasma glucose >/11.1 during OGTT test Screening No guideline • History taking • Urine monitoring of glucose every 4 weeks • Spot sugar annually Management • • • • Education Diet Exercise Medication – insulin (dosage similar as other DM patients) – oral hypoglycemic drugs • DM control Management-Oral hypoglycemic drugs • long term treatment with glyburide (glibenclamide) can reverse excessive insulin response to oral glucose Jones TW. Correction of hyperinsulinemia by glyburide treatment in nondiabetic patients with thalassemia major. Pediatr Res 1993; 33: 497-500 • improvement of OGTT in 73% of patients treated with glibenclamide versus 43% of patients on diet treatment Ladis. J.Glucose disturbance in regulation with glibenclamide in thalassemia. J. of Paed. Endo. & Metabolism. 1998; 11: 867-869 Management-DM control No guideline • spot sugar 3 monthly • fructosamine annually • annual complication DM screening – serum creatinine level – lipid profile – visual assessment by ophthalmologist – 24 hr urine for microalbumin Management-Prevention • Intensive chelation may be able to reverse islet cell damage and decrease insulin requirement DM Complications • Acute – hypoglycemia – DKA • Chronic – macrovascular : atherosclerosis – microvascular : retinopathy, nephropathy, neuropathy DM complications-retinopathy • 12/46 (26%) patients suffers from diabetic retinopathy in thalassemic patients with diabetes duration of 9+/4.5 years. • Less frequent and milder degree when compared with type I DM • Hypogonadism may be a protective factor Incorvaia C. Prevalence of retinopathy in diabetic thalassemic patients. J. of Paed. Endo. & Metab. 1998; 11: 879-883. DM complicationsnephropathy • 5/9 (58%) patients developed microalbuminuria after a mean duration of overt diabetes of 3.6+/-2years • Early development and accelerated course of diabetic nephropathy • Iron-derived free radicals cause high oxidative stress to kidney Loebstein. Diabetic nephropathy in hypertransfused patient with beta thalassemia with the role of oxidative stress. Diabetes Care 1998; 21(8): 1306-1309. Diabetic thalassemic patients: associated endocrine problems 23/29 have other endocrine problems • 5/23 hypoparathyroidism • 19/23 hypogonadism • 14/23 hypothyroidism • 14/23 hypoparathyroidism • 0/23 adrenal failure De Sanctis V. Insulin Dependent Diabetes in thalassemia. Arch. Dis. Child 1988; 63: 58-62. Diabetic thalassemic patients: survival • 14/29 patients died within 3 years of developing overt diabetes De Sanctis V. Insulin Dependent Diabetes in thalassemia. Arch. Dis. Child 1988; 63: 58-62. • 34% still alive 8 years after diagnosis of diabetes De Sanctis V. Multicentre study on prevalence of endocrine complications in thalassemia major. Endocrinology 1995; 42: 581-586 mainly caused by refractory heart failure