Chapter 26 Endocrine emergencies
EMERGENCIES IN PATIENTS WITH DIABETES
Diabetes is a disorder of glucose metabolism due to a relative (type 2) or absolute (type 1) insulin deficiency. With the rising rate of obesity in the community, diabetes is becoming increasingly common, and type 2 rather than type 1 diabetes is now often seen in young patients. Diabetic patients may present to the emergency department with acute life-threatening derangements of glucose metabolism, with complications related to long-standing diabetes, or with unrelated health problems which require concurrent management of their diabetes.
Diabetic ketoacidosis
Assessment
Patients with DKA commonly present with vomiting, polydipsia, polyuria, shortness of breath and abdominal pain. History and examination should be directed at identifying the precipitating event and assessing the degree of dehydration. Most commonly, DKA is precipitated in patients with type 1 diabetes by intercurrent infection, although other causes should be considered (see Box 26.1). It occurs infrequently in patients with non-insulin-dependent diabetes.
Management
Fluid and electrolyte therapy
Potassium depletion is a feature of DKA, even in the presence of an initial elevated serum K+. Serum potassium should be measured as soon as possible and is often available on the initial blood gas. The administration of intravenous fluids and insulin will rapidly lower the measured K+. If the initial K+ is > 5.5 mmol/L, the level should be rechecked every 30–60 minutes as it will inevitably fall as a consequence of rehydration. Table 26.1 outlines the rate of potassium replacement. Monitoring of K+ levels every 1–2 hours is essential during the initial phase of treatment.
Serum K+, mmol/L | Replacement therapy |
---|---|
> 5.5 | Nil—repeat test in 1 h |
3.5–5.5 | KCl 5–10 mmol/h |
< 3.5 | KCl 20 mmol/h, cardiac monitoring and central line |
Phosphate and magnesium levels are commonly low in DKA; however, there is no evidence to support the routine replacement of these electrolytes. Intravenous bicarbonate is of no proven benefit in patients with DKA as the acidosis usually improves with rehydration and insulin therapy. Bicarbonate should not be given without consulting a critical care specialist or endocrinologist. The measured sodium level should be corrected for the elevated glucose (true sodium = measured sodium + [glucose (mmol/L) ÷ 4]) as the high BSL will artefactually dilute the sodium.
Ongoing management
Cerebral oedema is a rare but life-threatening complication of DKA that is more common in children and usually occurs in the first 12 hours of therapy. Symptoms such as a falling level of consciousness, progressive headache, bradycardia and a rising blood pressure may indicate cerebral oedema and patients with any of these symptoms require urgent senior medical review.
Hyperosmolar hyperglycaemic non-ketotic state (HHNS)
Assessment
HHNS is characterised by non-specific signs such as confusion, vomiting and weight loss, developing over days to weeks in elderly patients with undiagnosed or poorly controlled diabetes. Polyuria and polydipsia are not universally present. There are many possible precipitating events which are summarised in Box 26.2. These patients often have multiple comorbidities and may be on multiple medications.
Box 26.2 Precipitants of HHNS
Infection—urinary tract, respiratory, CNS, skin
Cardiovascular events—AMI, CVA/intracranial haemorrhage, mesenteric ischaemia
Other—gastrointestinal haemorrhage, pancreatitis, renal failure, diuretic therapy