Endocrine Disorders Diabetes Mellitus The annual incidence of types 1 and 2 diabetes mellitus (DM) diagnosed prior to age 19 years has been increasing over the last few decades From 2011 to 2012, the incidence of type 1 DM was 21.7 cases per 100,000 youths per year, and the incidence of type 2 DM was 12.5 cases per 100,000 youths per year There were significant variations across racial and ethnic groups for both types 1 and 2.132 Cardiovascular complications are usually manifest later in the disease, and they are exceedingly rare in childhood.133 However, the pediatric cardiologist will encounter an increasing incidence of congenital cardiac malformations in the offspring of diabetic mothers Congenital structural cardiac anomalies occur in 3% to 6% of pregnancies complicated by insulin-dependent diabetes, with a predominance of conotruncal abnormalities Because these defects occur early in gestation and are associated with poorly controlled DM, with higher HbA1c increasing the risk, preconception counseling and treatment are very important.134 The most frequent neonatal cardiac complication of maternal diabetes is hypertrophic cardiomyopathy,135 produced by elevated levels of insulin and insulin-like growth factor I The most obvious complication, however, is macrosomia Even in the absence of congenital cardiac disease, infants of diabetic mothers have a host of problems This syndrome is seen both in mothers with established diabetes and in those who develop the disease during pregnancy The babies have a characteristic appearance, with high birth weight, plumpness, and puffy plethoric facies They are jittery, owing to hypoglycemia secondary to hyperinsulinism The organs, including the heart, are enlarged The babies are frequently tachypneic, but this may not be of cardiac etiology Respiratory distress syndrome is quite common Cardiac murmurs are frequent Approximately one-third have radiologic cardiomegaly The ECG is rarely diagnostic In diabetes-related cardiac hypertrophy, the ECG shows thickening of the right and left ventricular walls together with the septum Indeed, the ventricular septum is usually thicker than the free walls Septal thickness is generally most pronounced in those infants with CHF.136 Spontaneous improvement after birth is usual, and specific treatment of the hypertrophic cardiomyopathy is rarely needed Diuretics must be used judiciously, as the thickened myocardium requires a high preload, and β-blockade is sometimes advised to help diastolic dysfunction, but the benefit has not been proven The clinical and echocardiographic signs of hypertrophic cardiomyopathy usually resolve over the early weeks of life, but myocardial thickening can take up to 6 months to resolve.137 More important than diagnosis and treatment is prevention It is suggested that the most severely affected newborns are those in whom maternal control of diabetes has been poor.138,139 Pituitary Gigantism and Acromegaly Adenomas of the pituitary that secrete growth hormones cause gigantism in growing children and acromegaly in adults Cardiovascular complications are common and leading contributors to the morbidity and mortality of acromegaly Hypertension, early coronary artery disease, valve disease, arrhythmias, and acromegalic cardiomyopathy have all been described.140 Acromegalic cardiomyopathy results from elevated levels of growth hormone and the resultant elevated levels of insulin-like growth factor 1 The cardiomyopathy is characterized by biventricular and concentric involvement, which is progressive and may lead to CHF with myocardial fibrosis The severity of disease relates to the age of the patient Treatment with surgery or somatostatin analogues, which reduce growth hormone levels, is beneficial in terms of clinical symptoms and indexes of myocardial morphology and physiology.141 Disorders of Thyroid Function Hypothyroidism Congenital Hypothyroidism Congenital hypothyroidism has many etiologies The most common cause is congenital thyroid dysplasia, present in approximately 1 in 6000 live births There are rarer causes, including endemic deficiency of iodine, diminished responsiveness to thyrotrophin in familial goiter, and administration of antithyroid drugs to pregnant mothers The cardiac features of cretinism are not dramatic Normal to slow heart rates and radiologic cardiomegaly are usually the only manifestations The enlarged cardiac silhouette is usually caused by pericardial effusion, which is an extremely common feature (affecting approximately half of these patients142), but it is rarely hemodynamically important Cardiac performance is usually well preserved Abnormalities of heart rate and the pericardial effusions resolve when substitution treatment of the hypothyroidism is successful Juvenile Hypothyroidism As with congenital forms, juvenile hypothyroidism has multiple etiologies It is generally the result of autoimmune thyroiditis or Hashimoto disease Growth retardation is the most common form of presentation and can lead to delayed sexual maturation Cardiac signs and symptoms are few and cardiac failure is very rare Bradycardia, low pulse pressure, poor peripheral circulation, and nonspecific murmurs may be present Pericardial effusions with no evidence of pericarditis occur in some patients Tamponade is rarely seen because of the slow rate of fluid accumulation About half of the patients with pericardial effusions have associated pleural effusions Establishment of a euthyroid state reverses the cardiac manifestations Hyperthyroidism Juvenile Hyperthyroidism The most common cause of juvenile hyperthyroidism is diffuse toxic goiter, also known as Graves disease This is an autoimmune disease in which IgG immunoglobulins, which stimulate excessive production of thyroid hormones, can be demonstrated It is more common in girls, with a ratio of females to males of approximately 5 to 1 Its greatest incidence is between the ages of 11 and 19 years, and it is rarely seen in children under the age of 3 years Cardiovascular issues are present at presentation in approximately one-quarter of these patients.143 Other presenting symptoms include restlessness, poor performance at school, irritability, loss of weight, and occasionally diarrhea On examination, patients have warm skin and a fine tremor is visible in outstretched hands Enlargement of the thyroid gland is always present, and bruits are often audible over the enlarged gland because of its increased vascularity Exophthalmos is common but is not marked Cardiovascular involvement is secondary to an increased adrenergic drive and to direct myocardial stimulation by thyroid hormones The pulse is fast with a wide pulse pressure The systolic blood pressure is increased, and the apical impulse is hyperdynamic On auscultation,