6: Special topics

Section 6 Special topics




Childhood and adolescence


Diabetes is one of the most common chronic diseases of childhood; 1 in 300 in Europe and North America develop diabetes by the age of 20 years. Over the past few decades the incidence has been increasing by 3–5% per year.


Type 1a (autoimmune) diabetes mellitus (T1aDM) accounts for the vast majority of children with diabetes. Newborn babies and infants rarely develop the disease (1 in 250 000 in those younger than 6 months) and the aetiology is usually monogenic, not autoimmune. T1aDM is believed to be caused by the interplay of genetic and environmental factors. The initial step is the development of islet autoimmunity, which is marked by the presence of islet autoantibodies. This is thought to be driven by one or more environmental triggers. After this initiation of islet autoimmunity, most patients have a long preclinical period that does offer the opportunity for secondary prevention of the progression to clinical diabetes. The presence of more than one of the autoantibodies combined with susceptibility human leukocyte antigen (HLA)-DR and HLA-DQ genotypes identifies those at high risk of developing diabetes.


Type 1b diabetes has the same clinical presentation as T1aDM, but islet autoantibodies are absent.


The diagnosis of diabetes in children is based on polyuria, polydipsia, weight loss, fatigue and random blood glucose level above 11.1 mmol/L (200 mg/dL). With the increased community recognition of diabetes, most children present with mild hyperglycaemia of short duration. However, 75% of children have the symptoms for more than 2 weeks, suggesting that the diagnosis could be made earlier in many cases. The diagnosis of diabetes should be considered in all sick children; urine or blood testing for glucose and ketones leads to an early diagnosis. Young children may have a non-specific presentation, possibly presenting with enuresis, vomiting or rapid breathing during the course of an infection. Nearly all patients admitted with severe diabetic ketoacidosis (DKA) have been seen hours or days earlier by health-care providers who missed the diagnosis. Most children do not require intravenous (IV) fluids or insulin infusion at the diagnosis of diabetes.


The availability of outpatient care centres has helped to decrease hospitalization at diagnosis. Admission with DKA is more often found among younger children and in children with lower socioeconomic status who encounter possible barriers in accessing medical care.


A family history of an autosomal dominant inheritance of diabetes appearing under the age of 25 years is highly suggestive of maturity-onset diabetes of the young (MODY). It is not uncommon for young people with MODY to be diagnosed when they present with an intercurrent illness.


The principal aims of treatment of diabetes in childhood are:



The difficulties posed by insulin treatment in children and adolescents mean that these ideals can be difficult to achieve. Emphasis should, however, be placed on the favourable prospects for the child with diabetes; diabetes should be a bar to few recreational activities or occupations.



Management of diabetes in childhood




Cerebral oedema


Subclinical cerebral oedema occurs in most children with DKA. Severe clinical oedema affects 0.5–1% and is fatal in over 20%. Neurological status should be monitored at frequent and regular intervals. Typically, cerebral oedema occurs at 4–12 hours and potential risk factors for symptomatic cerebral oedema in children include:



Signs and symptoms of cerebral oedema include headache, change in mental status or behaviour, incontinence, focal neurological findings, sudden normalization of heart rate in a previously tachycardic dehydrated patient, or a worsening clinical course in a patient with improved laboratory values. Bradycardia, hypertension and irregular respiration (Cushing triad) are signs of greatly increased intracranial pressure. Early intervention is essential and treatment includes:



Mannitol therapy may need to be repeated. IV hypertonic saline has also been used as an alternative to mannitol. Radiographic imaging (such as computed tomography of the head) should be obtained after, rather than during, treatment of cerebral oedema.



Insulin therapy


Injection regimens should be individualized and include:



Intermediate-acting insulins such as NPH are often mixed with soluble human (regular) or rapid-acting analogues (aspart, lispro or glulisine). Patients and families should be taught how to mix the insulin properly, in order to avoid contamination. It is generally taught to draw up clear (regular or short-acting) insulin before drawing up cloudy insulin (NPH).


Pre-mixed insulins contain a mixture of regular (or rapid-acting) insulin and NPH insulin in various fixed ratios. These preparations may be useful for children who do not want to draw insulin from separate vials before injecting. They may also be useful in reducing the number of injections when compliance is an issue, especially among teenagers. Pre-mixed insulins are also available for use in pen injector devices. The main disadvantage to using pre-mixed insulin preparations is the lack of flexibility in adjusting the separate insulin doses, which is often necessary with varied food intake or during illness or exercise.


Glargine or detemir insulins should not be mixed with any other insulin.



Insulin pump therapy


Insulin pump therapy is the best way to restore the body’s physiological insulin profile. Rapid-acting insulin analogues perform better in pumps than regular insulin, in terms of both mimicking the first-phase insulin release after meals and avoidance of postprandial hypoglycaemia. The user initiates bolus doses before meals and to correct hyperglycaemia. Even with the analogues, however, insulin has to be administered at least 10–15 min before a meal in order to reach effective levels in time. The pump delivers a variable programmed basal rate that corresponds to the diurnal variation in insulin needs.


Currently, the most frequent complications of insulin treatment include failures of insulin delivery because of a displaced or obstructed infusion set, local skin infections and DKA. Patients and their families must be instructed on troubleshooting and treatment of hyperglycaemia, particularly if ketones are present, as this may be an indication of pump malfunction. Syringes should always be available so that insulin may be administered via injection in the event of a pump failure.


Most clinical trials have demonstrated that, compared with multiple daily injections (MDI), pump therapy delivers better glycated haemoglobin (HbA1c), less severe hypoglycaemia, and can improve the quality of life in children.


Insulin pump treatment is significantly more expensive than regimens based on injections. For some patients, pumps may be too difficult to operate or comply with the multiple testing and carbohydrate counting requirements, or may be unacceptable because of body image issues or extreme physical activity (e.g. swimming, contact sports).




Education


Initial education should provide a basic understanding of the pathophysiology of diabetes and its treatment to ensure that families feel confident in providing diabetes care at home. In most centres where appropriate outpatient resources are available, diabetes education and initiation of insulin therapy can occur as an outpatient, which has been shown to be cost-effective.


In the first few months following diagnosis, close contact in the form of frequent outpatient visits, home visits, telephone communication and other methods of communication is essential to address the frequently changing requirements.


Diabetes education is a continuous process and must be repeated to be effective. It must be adapted and appropriate to the age of the child. Infants and toddlers often have unpredictable eating and activity patterns.


Needle phobia can present a significant issue with the perception of pain inflicted by the caregiver.


Hypoglycaemia is more common in this age group and the prevention, recognition and management of hypoglycaemia is a priority.


Education should also focus on age-appropriate stepwise handover of diabetes responsibilities. This becomes particularly important in adolescence, during which there is a critical balance between promoting independent responsible management of diabetes while maintaining parental involvement.


Once established, it is common practice for children to be seen in the diabetes clinic at least every 3 months; visits should be more often if the patient does not meet the treatment goals or treatment requires intensified, for example if insulin pump treatment is initiated. During these visits:



The advent of new technology, including downloadable glucometers, insulin pumps and continuous glucose sensors, has made it increasingly possible for the diabetes care team to gain insight into the home management of diabetes.


The dietitian should review dietary habits and provide ongoing nutrition education as needed.













Transition to the adult diabetes clinic


The terms ’transition’ and ’transfer’ have been used interchangeably in the literature when referring to adolescents moving between diabetes services. Transition may be interpreted as simply a process of physical transfer of a patient to a different service with a failure to acknowledge the psychosocial needs of the adolescent and family members/carers.


Adolescence is a period characterized by transition and change regardless of health status. Diabetes in adolescence is a life-changing condition requiring very careful and consistent management by a multidisciplinary team of clinicians, in addition to the support provided by the family unit/carers. Many young people with diabetes establish a long-term relationship with their paediatric health-care team and the transition to an adult diabetes service provider is an enormous event. The seamless transfer of adolescents with diabetes from paediatric to adult services is a challenge for diabetes teams.


Adolescence is a transitional stage of human development that:



During this time the adolescent is developing a sense of self and identity, establishing autonomy and understanding sexuality. It is usually accompanied by an increase in independence and generally less overall supervision. This is true too of adolescents transferring to an adult care service. The intention is to provide the adolescent with the practical and cognitive skills required for diabetes self-care and the capability to interact with others such as health-care providers. Age itself may not be a reliable indicator, as adolescents may have different needs and mature at different rates. The parents of the adolescent must also be prepared to relinquish some of the responsibility for diabetes care that they may have undertaken for many years. For some parents, this shift in responsibility can be a time of high anxiety. Fundamental to a successful transition programme is to work with parents to help them find a balance between shifting the responsibility to the adolescent and continuing to maintain an appropriate level of interest.


Transition should be planned, coordinated, and viewed holistically as opposed to focusing solely on the referral from one medical doctor to another. Transition should promote better management for adolescents with T1DM by developing their capacity to self-care through healthy choices.


A powerful predictor of good self-care is self-efficacy. Adolescents should be encouraged to have confidence in their capability to make decisions and take actions that demonstrate good diabetes self-care (see Appendix 6.1: Principles of dietary planning in children with diabetes).



Diabetes in the elderly


Diabetes, mainly type 2 diabetes, is particularly common in the elderly; more than 50% of patients in the UK are over 60 years of age (the majority having type 2 diabetes). In many countries diabetes affects 10–25% of elderly people (> 65 years), with particularly high rates in populations such as Pima Indians, Mexican Americans and South Asians. Glucose tolerance worsens with age, the main factor being impairment of insulin-stimulated glucose uptake and glycogen synthesis in skeletal muscle; progressive insulin resistance also contributes (Table 6.1). Symptoms of diabetes may be non-specific, vague or absent.


Table 6.1 Factors contributing to glucose intolerance in old age











Impaired glucose disposal and utilization

NIMGU accounts for 70% of glucose uptake under fasting conditions (primarily into the CNS) and for 50% of post-prandial glucose uptake (especially into skeletal muscle)
Impaired glucose-induced insulin secretion








Management of diabetes in women of childbearing age


An optimal outcome may be obtained from pregnancy in women with diabetes if excellent glycaemic control is achieved before and during pregnancy. However, type 1 and 2 diabetes are high-risk states for both the woman and her fetus. There is an increased risk of complications of diabetes, including severe hypoglycaemia and progression of microvascular complications.



There are also increased risks of obstetric complications, such as miscarriage, maternal infection, pre-eclampsia, premature labour, polyhydramnios and failure to progress in first or second stage. Fetal and neonatal complications include congenital malformation, later intrauterine death, fetal distress, hypoglycaemia, respiratory distress syndrome and jaundice. Rates of fetal and neonatal loss and congenital malformation are increased by at least 2–3-fold. The prevalence of type 2 diabetes is increasing in women of reproductive age, and outcomes may be equivalent or worse than in those with type 1 diabetes. Management before and during pregnancy should follow the same intensive programme of metabolic, obstetric and neonatal supervision.


An experienced multidisciplinary team, led by a named obstetrician and physician with an interest in diabetes, and including a diabetes specialist nurse, diabetes specialist midwife and dietitian, should provide comprehensive care from pre-pregnancy to postnatal review.



Pre-pregnancy and pregnancy care






Oral medication before and during pregnancy








Optimization of glycaemic control



Glucose monitoring


Optimal glucose control before pregnancy reduces congenital malformations and miscarriage, while during pregnancy it reduces macrosomia, stillbirth, neonatal hypoglycaemia and respiratory distress syndrome.


All women with pre-gestational diabetes should be encouraged to achieve excellent glycaemic control.


During pregnancy, preprandial testing and where appropriate postprandial testing may be advised. A reduced incidence of pre-eclampsia is associated with postprandial monitoring and targeting.


In women with gestational diabetes, measurement and targeting of postprandial glucose is associated with improved outcomes (including birth weight, reduced perinatal morbidity and macrosomia).


Postprandial glucose monitoring should be carried out in pregnant women with gestational diabetes and may be considered in pregnant women with type 1 or type 2 diabetes.



In women with type 1 or type 2 diabetes, as long as hypoglycaemia can be minimized, aim to achieve blood glucose:



There is limited evidence that continuous glucose monitoring may be of benefit to women during pregnancy.


Diabetes specialist nurses and midwives have an important role in educating women on the need for home blood glucose monitoring and intensive insulin regimens. Intensive basal bolus regimens are commonly used and insulin analogues are increasingly used, although research on their role and safety in pregnancy is limited.




Complications during pregnancy








Fetal assessment


An early pregnancy scan is considered good practice to confirm viability in women with pre-existing diabetes, particularly when changes in medication are required or diabetic control is suboptimal.


There is evidence of an increased incidence of congenital malformations in women with pre-existing diabetes (type 1 and type 2). In general, the sensitivity of ultrasound scanning for detecting structural abnormalities increase with gestational age. It is not possible to determine when during the second trimester scanning should take place to maximize detection rates. A detailed anomaly scan, including evaluation of the four-chamber heart and outflow tracts, undertaken at around 20 weeks (18–22 weeks) enables detection of many major structural abnormalities.


All women should be offered scanning to include:



In pregnancies complicated by maternal diabetes, the fetus is at risk of both macrosomia and intrauterine growth restriction (IUGR). The risk of macrosomia is greater when there has been poor glycaemic control. The risk of IUGR is greater in women with vascular complications of diabetes (retinopathy, nephropathy) or when pre-eclampsia develops.


Fetal monitoring includes cardiotocography (CTG), Doppler ultrasonography and ultrasound measurement of fetal growth and liquor volume. Although regular fetal monitoring is common practice, no evidence has been identified on the effectiveness of any single or multiple techniques, and therefore the clinical judgement of an obstetrician experienced in diabetic pregnancy is essential.


When IUGR is suspected, additional monitoring with serial ultrasonography and umbilical arterial Doppler velocimetry is associated with improved outcomes (fewer inductions of labour and hospital admissions, with a trend to improved perinatal mortality rates).


The evidence for the accuracy of ultrasonography in predicting macrosomia (birth weight above 4000 g) is mixed. The accuracy of fetal weight estimation in women with diabetes is at least comparable to that in women who are not diabetic. The negative predictive value of ultrasonography is high (80–96%), and therefore it is feasible that the true value of ultrasonography in the management of these women is its ability to rule out the diagnosis of macrosomia.


There is evidence to suggest that the incorrect diagnosis of a large-for-gestational-age fetus increases the induction and caesarean section rate without improving clinical outcome. Numerous studies have concluded that the reliability of ultrasound estimation of fetal weight is suboptimal. The ability to predict shoulder dystocia in the non-diabetic population is poor and evidence in the diabetic population limited. However, the determination of polyhydramnios is clinically useful as it may be associated with an adverse clinical outcome.


Trials report either equivalent outcomes or improved outcomes (birth weight, macrosomia, large-for-gestational-age infants) in women with gestational diabetes. Improved outcomes were associated with abdominal circumference (AC) being ascertained early (rather than late) in the third trimester and intensively managed thereafter. Where outcomes were equivalent this was achieved with fewer women requiring insulin or a change of treatment assignment. Although the rates of large-for-gestational-age infants were reduced with insulin therapy, there were no immediate clinical benefits observed from this reduction and there was an increase in the caesarean section rate.


Where IUGR is suspected, regular monitoring including growth scans and umbilical artery Doppler monitoring should be carried out.

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Mar 10, 2017 | Posted by in ENDOCRINOLOGY | Comments Off on 6: Special topics

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