Quality Standards for Diabetes Care Toolkit

Introduction

Those with uncommon causes of diabetes need access to specialist expertise with experience in these conditions due to the specificity of the condition and differing treatment requirements. While there are many uncommon causes of diabetes, examples used for the purpose of this Quality Standard are monogenic, cystic fibrosis, thalassaemia and pancreatectomy.
Knowing and understanding monogenic diabetes including the differing forms of MODY means that the affected person can be treated in the most appropriate way possible. Advice can also be provided about how the disease will progress and what complications can be expected, and family/whānau members advised about the risks of inheriting the disease (New Zealand Society for the Study of Diabetes [NZSSD] 2012). The study advises consultant diabetes or endocrinology review for all molecular genetic testing of suspected cases due to the expense and the possible need for cascade testing of relatives.
Diabetes mellitus is a well-recognised complication of cystic fibrosis and, as survival in cystic fibrosis improves, so too does the prevalence of cystic fibrosis-related diabetes (The UK Cystic Fibrosis Trust Diabetes Working Group 2004). It is now a common and expected complication of cystic fibrosis as 10–30% of 15- to 25-year-olds with cystic fibrosis will develop diabetes (International Society for Pediatric and Adolescent Diabetes 2000). As people with cystic fibrosis-related diabetes (CFRD) survive longer, they are also at risk of developing diabetes-related complications, and their diabetes management becomes much more complex as the nature of the cystic fibrosis changes (The UK Cystic Fibrosis Trust Diabetes Working Group 2004). Management of diabetes in people with cystic fibrosis presents a different set of challenges to people with type 1 or type 2 diabetes and people with CFRD should be referred to a consultant with a specialty in managing patients with CFRD (The UK Cystic Fibrosis Trust Diabetes Working Group 2004).
Thalassaemia can lead to iron overload affecting beta-cell function and the decreasing insulin sensitivity of puberty contributes to the risk of diabetes. If iron levels remain high, treatment with high doses of insulin may be required (International Society for Pediatric and Adolescent Diabetes 2000). It is suggested that a long period of insulin resistance and hyperinsulinaemia might lead also to secondary beta cell failure (Li et al 2014). Impaired glucose tolerance in these people is common (up to 27%), and patients and health professionals should be aware of the high incidence. It is likely that the fatty replacement of the pancreas cells is irreversible, representing end stage pancreatic disease (Li et al 2014).
Pancreatitis, cancer and trauma can all harm the pancreatic beta cells or impair insulin production, thus causing diabetes. If the damaged pancreas is removed, diabetes will occur due to the loss of the beta cells. People who have had a pancreatectomy will not be able to produce any of their own insulin and will therefore need to take regular insulin injections in a similar way to people with type 1 diabetes. In the past, total pancreatectomy has been avoided due to the risks associated with post-operative brittle insulin dependent diabetes associated with hypoglycaemia, and malabsorption problems. However, with the advent of high quality enzyme formulations and advances in diabetes specialist care there has been a resurgence of interest in total pancreatectomy as a treatment as pancreatic insufficiency can now be managed safely (Crippa et al 2011).