Importance of pituitary hormones in aetiology of diabetic ketoacidosis

Newly diagnosed T1 diabetes presenting with hypoglycemia due to simultaneous co-existence of Addison disease

Type 1 diabetes mellitus (TIDM) classically presents with symptomatic hyperglycemia and many patients develop diabetic ketoacidosis prior to their diagnosis. However, non-classical presentation or co-presentation with associated diseases may delay diagnosis or lead to challenges in acute, clinical management. An 18-yr-old girl presented to hospital with severe, symptomatic hypoglycemia. Clinical history and serum electrolyte concentrations suggested a diagnosis of adrenal insufficiency. She remained hypoglycemic until glucocorticoid replacement was commenced, at which point she developed persistent hyperglycemia requiring insulin therapy. Subsequent follow up confirmed the diagnosis of Addison's disease (AD), the treatment of which unmasked co-existing type 1 diabetes. Autoimmune diseases often cluster together in affected patients and first-degree relatives. Approximately 1 in 200 patients with T1DM develop AD. However, months or more commonly years usually elapse between the presentation of different autoimmune conditions. The co-diagnosis T1DM and AD in the acute setting is rare. Moreover, the first presentation of T1DM with severe hypoglycemia is even more exceptional. This case highlights the need for vigilance during the acute, emergency management of patients with autoimmune conditions and, in particular, to consider the possibility of concurrent antibody-mediated diseases which may need to be addressed during resuscitation.

Some hormonal influences on glucose and ketone body metabolism in normal human subjects

Control of glucose and ketone body metabolism is integrated by a variety of hormones. Insulin is the major anabolic hormone, and its actions are antagonized by rapidly acting catabolic hormones, such as glucagon and the catecholamines, and by others such as cortisol, growth hormone and the thyroid hormones, which generally have more delayed effects. In the normal human subject, the effects of catabolic hormones to raise blood glucose are limited by a compensatory increase in insulin secretion, and these effects are enhanced in insulin deficiency. Hyperketonaemic actions of the catabolic hormones may result from increased supply of non-esterified fatty acids from lipolysis, although glucagon has a major direct action to increase ketogenesis at the liver. As expected, these actions are also restricted in normal humans by the compensatory rise in insulin secretion. Hyperketonaemia does, however, occur with adrenaline (epinephrine) and noradrenaline (norepinephrine), even in the presence of mildly elevated insulin concentrations. These catecholamines may assume particular importance in mobilization of lipid fuels in milder forms of stress, when insulin secretion is normal or mildly increased. In severe stress, when there is catecholamine-induced suppression in insulin secretion, lipolytic and hyperketonaemic effects of all the catabolic hormones may be manifest. Starvation in humans also results in diminished insulin secretion and increased catabolic hormone secretion. The relative importance of individual hormones in lipid mobilization during starvation is uncertain, although glucagon, growth hormone, noradrenaline and, possibly, dopamine may all play a part.

Problems in the congenital lactic acidoses

The congenital lactic acidosis form a heterogeneous group of inborn errors that includes defects of gluconeogenesis, the pyruvate dehydrogenase complex, the Krebs cycle and the respiratory chain. These disorders are not easily classified because of the absence of specific metabolites, difficulties in providing suitable tissue specimens and technical problems with the enzyme assays. The commonest causes of lactic acidosis due to inborn errors are the deficiencies of glucose-6-phosphatase and fructose bisphosphatase, which present with hypoglycaemia, lactic acidosis and hepatomegaly. Pyruvate carboxylase and phosphoenolpyruvate deficiencies vary considerably in both clinical expression and biochemical findings. Neurological symptoms predominate in defects of the pyruvate dehydrogenase complex, and some cases of the spinocerebellar ataxias may be due to partial defects of the pyruvate and 2-oxoglutarate dehydrogenase complexes.

Immunoneutralization of endogenous glucagon with monoclonal glucagon antibody normalizes hyperglycaemia in moderately streptozotocin-diabetic rats

The role of glucagon in diabetic hyperglycaemia has been a matter of controversy because of difficulties in the production of selective glucagon deficiency. We developed a high-capacity (40 nmol/ml), high-affinity (0.6 x 10(11) l/mol) monoclonal glucagon antibody (Glu-mAb) and gave i.v. injections (4 ml/kg) to rats in order to study the effect of selective glucagon deficiency on blood glucose. Controls received a mAb against trinitrophenyl. Glu-mAb completely abolished the hyperglycaemic effect of 2.86 nmol/kg glucagon in normal rats (p < 0.05, n = 6). In moderately hyperglycaemic rats injected with streptozotocin as neonates (N-STZ), Glu-mAb abolished a postprandial increase in blood glucose (from 11.2 +/- 0.7 mmol/l to 17.3 +/- 1.8 mmol/l in controls vs 10.5 +/- 0.9 mmol/l to 9.3 +/- 1.0 mmol/l; cross-over: n = 6, p < 0.05). No significant effect of Glu-mAb treatment was observed in more hyperglycaemic N-STZ rats (cross-over, n = 4) and in severely hyperglycaemic rats injected with STZ as adults (n = 6), but after insulin treatment of the latter, at doses partially restoring blood glucose levels (12.7 +/- 4.3 mmol/l), Glu-mAb administration almost normalized blood glucose (maximal difference: 6.0 +/- 3.8 mmol/l; cross-over: n = 5, p < 0.05). In conclusion, our results provide strong additional evidence for the hypothesis that glucagon is involved in the pathogenesis of diabetes. The hormone plays an important role in the development of STZ-diabetic hyperglycaemia, but glucagon neutralization only leads to normoglycaemia in the presence of insulin.

Somatostatin analogues in diabetes mellitus

Growth hormone (GH) has long been considered to have importance in diabetes. With poor control in Type 1 diabetes GH levels are high and may aggravate poor metabolic control. Pharmacological suppression of GH release at this stage might reverse the metabolic changes, with the possible added benefit of lower plasma insulin concentrations. Diabetic patients with life-long GH deficiency rarely develop retinopathy, while pituitary ablation in patients with retinopathy often leads to improvement. Growth hormone release inhibiting factor, somatostatin, has a short plasma half-life, and multiple effects on the endocrine system and on the gastrointestinal tract, making it unsuitable for clinical use as a GH suppressant. Long-acting analogues have a long half-life, but remain non-specific in their effects. In Type 2 diabetes the analogue Octreotide suppresses insulin and glucagon release, leaving glucose levels either unchanged or somewhat elevated. Gastrointestinal side-effects have been common, but may diminish with long-term treatment. In Type 1 diabetes insulin requirement is decreased by Octreotide, but as in Type 2 diabetes GH suppression has been observed consistently only when the drug was given at bed-time. The decrease in insulin requirement may reflect suppression of glucagon release and/or gut effects. Amelioration of the 'dawn phenomenon' has not proved possible, and hypoglycaemia has proved a particular problem with Octreotide given subcutaneously at night. The lack of effective GH suppression (particularly in patients with proliferative retinopathy), lack of specificity, and the gut and hypoglycaemic side-effects, argue strongly against a clinical role for the current somatostatin analogues in diabetes mellitus.

Long-term follow-up of patients who underwent yttrium-90 pituitary implantation for treatment of proliferative diabetic retinopathy

Between 1960 and 1976 117 patients underwent pituitary implantation with yttrium-90 (90Y) for treatment of proliferative retinopathy at the Hammersmith Hospital, London. Mean age at operation was 35 +/- 11 years (mean +/- SD), and mean duration of diabetes 18.6 +/- 10.0 years. Mean insulin dosage prior to implant was 67.2 +/- 24 units, falling to 30.4 +/- 14.9 units post-implant. Thirty-two per cent of patients are still living, 60% are deceased and 8% are lost to follow-up. The 5-year survival rate was 82%. Of the causes of death, 21% died of infection, adrenal insufficiency or hypoglycaemia, 12% of renal failure, and 47% of myocardial or cerebral vascular disease. Ophthalmological follow-up was carried out on the 100 patients operated on between 1965 and 1976. The mean age of this group at implant was 35 +/- 10.5 years, and mean duration of diabetes 17.2 +/- 8.7 years. Visual acuity in the better eye at operation was 6/12 or better in 84% of patients, and this percentage remained similar at the time of the 5 and 10 year follow-up. Blindness (6/60 or worse) in both eyes was present in 12% of patients at the time of 5 and 10 year assessments. By 5 years new vessels on the disc had improved from a mean grading of 2.7 +/- 1.6 to 0.8 +/- 1.2 (p less than 0.001), and by 10 years there was no disc neovascularisation in any eye. There was a similar improvement in the grading of hard exudates, microaneurysms and haemorrhages, but there was an increase in fibrous retinitis proliferans.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of morning hyperglycaemia: determinants of fasting blood glucose concentrations in insulin-treated diabetics

A rise in blood glucose concentration at the end of the night, and consequent morning hyperglycaemia, are well recognized events in some diabetic patients. In 94 patients on twice daily insulin injections we have examined the prevalence and extent of morning hyperglycaemia, and its relation to control, insulin therapy, and insulin antibody levels. Blood glucose reached the highest level of the day before or after breakfast in 83% of patients, and in 50% this value was 2 mmol/l greater than any other time of day. Patients with higher fasting concentrations did not have worse blood glucose control over the rest of the day. No correlation was found between fasting blood glucose concentrations and the evening dose of intermediate acting insulin or the level of insulin antibodies. No consistent change in fasting blood glucose concentrations occurred with changes in antibody levels in patients switched between pork and beef insulin. Morning hyperglycaemia was as common with both insulin species. Pre- and post-breakfast hyperglycaemia is common and significant in insulin-treated diabetic patients. It is not directly related to diabetic control at other times of the day, and is independent of insulin species and insulin antibody levels.

Diabetic ketoacidosis

In the past decade, considerable advances have occurred in our understanding of the pathophysiology of this disorder, its metabolic sequelae, and its management, particularly with respect to continuous low-dose insulin infusion and the potential benefits of phosphate. This article reviews these advances as they pertain to children.

Glucose and ketone body kinetics in diabetic ketoacidosis

The hyperglycaemia and hyperketonaemia of diabetic ketoacidosis are initiated primarily by overproduction of these substrates; subsequent maintenance of hyperglycaemia occurs, in large part, due to impaired utilization of glucose, whereas overproduction of ketone bodies continues to be the major mechanism for maintenance of hyperketonaemia. Insulin deficiency results in increased rates of lipolysis and provides increased substrate (free fatty acids) for ketogenesis. Hyperglucagonaemia can augment ketogenesis further in the setting of insulin deficiency. It is likely that other counter-insulin hormones (growth hormone, catecholamines) also contribute to the pathogenesis of DKA, though their role is less well defined. Insulin corrects DKA largely via suppression of lipolysis (and thus ketone body production); insulin suppresses glucose production at lower levels than it does ketone body production.

Diabetic ketoacidosis--pathogenesis, prevention and therapy

Diabetic ketoacidosis is the principal cause of hospital admissions for diabetic patients under 20 years of age, and accounts for at least 4000 deaths per annum in the United States. Current mortality rates differ widely throughout the United States, ranging from 0-19 per cent, with an average of 10 per cent. The principal reason for this wide range in the percentage of mortality are the differing criteria for diagnosis and attributing deaths to diabetic ketoacidosis. There are many reported precipitating causes of diabetic ketoacidosis which may be reduced to four common pathways: insulin deficiency, stress hormone excess, dehydration and fasting. Infection is the most common precipitating cause in most reported series of diabetic ketoacidosis, but stress in any form can lead to metabolic decompensation. Omission of insulin is an unusual cause of ketoacidosis, and in approximately one-quarter of patients no cause can be identified. Each of the four common pathways through which these precipitating causes induce diabetic ketoacidosis results in a rise in ketone body and glucose production and/or concentration. Prevention of diabetic ketoacidosis has been underemphasized in the care of the ill diabetic patient. Prevention of metabolic decompensation in the stressed diabetic patient requires a knowledgeable physician and a cooperative patient. Appropriate physician management of insulin and suppression of stress hormones should prevent diabetic ketoacidosis in all patients who can ingest fluid. Recent studies suggest that if the mortality rate from diabetic ketoacidosis is to be significantly reduced, prevention of this complication is mandatory. Appropriate treatment of diabetic ketoacidosis is not difficult if the physician maintains an accurate flow chart and provides sufficient insulin, rehydration and potassium. We favour the use of low-dose insulin therapy, rehydration with isotonic saline, and aggressive potassium replacement. The administration of sodium bicarbonate is controversial and should be restricted to patients with an arterial pH of less than 7.0 and/or a patient in cardiogenic shock. The majority of complications encountered during the treatment of diabetic ketoacidosis are avoidable if proper care and attention is provided by the physician.

Intermediate acting insulin given at bedtime: effect on blood glucose concentrations before and after breakfast

Six C-peptide deficient diabetics receiving twice daily mixtures of short and intermediate acting insulins were selected for study because of persistently raised blood glucose concentrations before and after breakfast. They were investigated to assess the effect of moving their evening injection of intermediate acting insulin to bedtime. The patients' usual twice daily insulin treatment was optimised and compared with the bedtime regimen during inpatient metabolic studies and an outpatient crossover study. With the conventional injection regimen blood glucose concentration rose sharply from 0500 to reach a fasting mean value of 10 +/- SE 1 . 6 mmol/l (180 +/- 29 mg/100 ml) and 16 . 8 +/- 2 . 2 mmol/l (303 +/- 40 mg/100 ml) after breakfast. By contrast, when the evening dose of intermediate acting insulin was delayed until bedtime the nocturnal rise in blood glucose concentration started later and was significantly lower both fasting (7 . 5 +/- 1 . 1 mmol/l (135 +/- 20 mg/100 ml); p less than 0 . 02) and after breakfast (13 . 2 +/- 1 . 4 mmol/l(238 +/- 25 mg/100 ml); p less than 0 . 02). Fasting blood concentrations of ketone bodies (3-hydroxybutyrate) were also significantly decreased. Plasma free insulin concentrations showed the predicted changes in five of the six patients. Blood glucose profiles collected over four months during the outpatient study confirmed the beneficial effect of giving intermediate acting insulin at bedtime.

The role of "diabetogenic" hormones on carbohydrate and lipid metabolism following oral glucose loading in insulin dependent diabetics: effects of acute hormone administration

To evaluate the relative role of "diabetogenic" hormones as insulin antagonists in severe derangements of diabetic control, glucagon, cortisol, growth hormone and adrenaline were administered by continuous intravenous infusion, separately and in combination, to ketosis-prone insulin-dependent diabetics (n = 11). The amount of insulin required for the assimilation of a 50 g glucose load during the various hormone infusions was determined by means of an automated glucose-controlled insulin infusion system and used as an index of insulin effectiveness. Raising plasma hormone concentrations acutely into the range seen in severe diabetic states (glucagon 517 +/- 70 pg/ml; cortisol 32 +/- 3 micrograms/dl; growth hormone 14 +/- 3 ng/ml) did not alter significantly blood glucose profile and insulin requirement (control 11.3 +/- 1.1 U; glucagon 11.6 +/- 2.0 U; cortisol 11.1 +/- 0.4 U; growth hormone 12.9 +/- 1.4 U), except for adrenaline (plasma level 550 +/- 192 pg/ml), which caused a marked rise in blood glucose levels and a threefold increase in insulin demand (31.1 +/- 3.7 U). Combined infusion of all hormones did not potentiate significantly the latter effect (38.3 +/- 4.7 U). The effectiveness of metabolic control by insulin was assessed by a marked decrease in plasma nonesterified free fatty acids and ketone bodies upon its administration after glucose ingestion in all groups studied. It is concluded that from the hormones investigated within this study adrenaline exerts the strongest diabetogenic action during its short term administration followed by that of growth hormone. Whereas it may well be that over-insulinization of the patients by the glucose controlled insulin infusion system has overcome and disguised the smaller diabetogenic effects of cortisol and glucagon.

C-peptide blood levels in keto-acidosis and in hyperosmolar non-ketotic diabetic coma

For further evaluation of B-cell secretion in diabetic keto-acidosis (KA) and in non-ketotic hyperosmolar coma (NKHC), basal and post-i.v. tolbutamide blood CPR and IRI values were measured in 34 patients (22 KA and 12 NKHC). FFA, cortisol and HGH measurements were also performed. IRI was low in both KA and NKHC (0.07 +/- 0.01 and 0.082 +/- 0.01 nmol/l) as opposed to CPR which was significantly higher in NKHC (1.14 +/- 0.1 nmol/l) than in KA (0.21 +/- 0.03 nmol/l). After tolbutamide injection, CPR and IRI levels did not change in any of the KA cases, whereas they significantly increased in half of the NKHC cases. Cortisol and FFA values were similarly increased in both situations, as opposed to HGH which was significantly higher (6.1 +/- 1.2 ng/ml) in KA than in NKHC (1.9 +/- 0.2 ng/ml). These results suggest that B-cell function is less deficient in NKHC than in KA. Residual insulin amounts reaching the liver via the portal vein could partly account for the absence of ketosis in NKHC.

Prolactin response to TRH in diabetic ketoacidosis

The prolactin response to 200 microgram thyrotropin-releasing hormone (TRH) IV was studied in seven patients with diabetic ketoacidosis, at the start of the treatment, and again, in the same patients, five days after recovery, when the diabetes was well controlled. Normal basal prolactin concentrations and prolactin responses to TRH were found in both situations. There was no correlation between basal prolactin concentrations, or magnitude of prolactin responses to TRH, and any of the metabolic variables measured. These findings do no suggest a role for prolactin in the development of diabetic ketoacidosis.

Urinary excretion and plasma levels of norepinephrine and epinephrine during diabetic ketoacidosis

Sympathetic activity was determined in 13 ketoacidotic diabetics by evaluation of plasma and urinary catecholamines, before and in the course of medical management. Patients were divided into two groups. Group A (severe ketoacidosis, n = 5) and Group B (moderate ketoacidosis, = 8), depending on plasma glucose, pH and plasma bicarbonate levels. The results showed an enhanced sympathetic activity in all patients before treatment, with significant decrease during therapy. In Group A plasma catecholamines were higher than in Group B, both before and in the course of therapy. A significant correlation was found between basal plasma catecholamines and initial plasma glucose, plasma bicarbonate, hours of therapy and insulin dosage required to obtain plasma glucose levels below 150 mg/100 ml .These results, suggesting a close correlation between glycometabolic control and adrenergic activity, emphasize the role of the sympathetic nervous system as a powerful contrainsular factor in the pathogenesis and metabolic derangement of diabetic ketoacidosis.