Principles

The stress of illness can increase basal insulin requirements in all types of diabetic patients. Being ill may also render the diabetic patient unable to monitor and manage their condition as they would normally. Some diabetics may associate insulin dosing with eating, so during a period of anorexia or vomiting they may feel that they do not need to take their normal insulin regimen, whereas they ought to maintain it, or even increase the dose. There is also a need to keep up carbohydrate intake. These measures help reduce the risk of diabetic ketoacidosis and poor diabetic control. Patients taking metformin should receive special attention as continuing this medication during periods of dehydration or acute illness can increase the risk of lactic acidosis or a hyperosmolar nonketotic state.^[1]

Cornerstones of diabetes management during intercurrent illness (patients on oral antidiabetics and/or insulin)^[2][3]

• Education of the patient as to the correct action to take when ill.
• Consider what arrangements need to be made to monitor blood glucose in patients who do not normally do so - may require education of the patient and/or carer, or involvement of community services.
• Patients should Increase the frequency of glucose monitoring to 4-hourly or more as necessary.
• Treat the underlying cause of the intercurrent illness sufficiently.
• Maintain carbohydrate intake using sugary drinks or fruit juice, soups or snack foods if the patient has difficulty eating.
• Fluid intake is important and patients should be advised to have a glass of water every hour, aiming for 3 litres in 24 hours.
• Antiemetics may be useful for symptomatic treatment of vomiting but establish the likely cause of the symptoms first and admit if necessary.
• For medicolegal reasons, keep a good record of how diabetes is being monitored and your follow-up arrangements.

Sick-day supplies

Advise patients to keep a 'sick-day supply box' which might contain:

• Long-life fruit juice
• Bottle of ordinary Lucozade® or non-diet fizzy drink
• Two 2 L bottles of still water
• Soup
• Ice-cream
• Unopened box of blood glucose monitoring strips
• Unopened box of ketone strips (if on insulin)

All items should have their expiry dates checked (especially the last two items) every six months. Written information on sick-day rules should be kept with these, such as those available at the Diabetes UK website.^[4]

Patients on oral antidiabetics^[1][5]

• The patient should take their tablets and normal dosage, providing carbohydrate intake continues in solid or liquid form (see above) and glucose monitoring continues at least four-hourly.
• If glucose level increases beyond 13 mmol/L and/or the patient feels unwell, medical advice should be sought.
• Metformin should be stopped if the patient is becoming dehydrated. Hospital admission/sliding scale insulin may need to be considered (see Indications for hospital admission, below).

Patients on insulin^[2][4][5]

• INSULIN SHOULD NOT BE STOPPED - hyperglycaemia can arise from intercurrent illness irrespective of the patient's calorie intake.

• There are no hard and fast rules regarding insulin dosage as response depends on the individual patient's metabolism and the type of insulin they are taking (long-acting insulin will have a slower response time than fast-acting). Sick-day rules should follow those agreed with consultants/specialist units at the time of initiation of insulin or follow local guidelines. In the absence of these the following rule of thumb could be followed:
  • Blood glucose less than 13 mmol/L - continue with current dosage
  • Blood glucose 13-22 mmol/L - patient should increase by 2 units each injection, even if unable to eat
  • Blood glucose greater than 22 mmol/L - patient should increase by 4 units each injection, even if unable to eat
  • Return dose to normal when blood glucose returns to normal
• Glucose and ketone monitoring should continue until the glucose level returns to 13 mmol/L or below, a normal diet is being taken and ketones are absent from the urine.
• Patients should stick test for ketonuria once or twice a day, more frequently if ketones are present.

When patients should ask for medical advice^[2]

Patients should be advised to seek medical advice if:

• They are unable to eat or drink
• Have persistent vomiting or diarrhoea
• Have a blood glucose higher than 25 mmol/L despite increasing insulin
• Have very low glucose levels
• Have persistent ketones or large amounts of ketones in the urine
• Become drowsy or confused (make sure carers are aware of this)
• Any other concern

Indications for hospital admission (patients on oral antidiabetics and/or insulin)^[6]

Hospital admission should be considered in the following circumstances:

• A suspicion of underlying diagnosis that requires hospital admission, eg myocardial infarction, intestinal obstruction – admit immediately
• Inability to swallow or keep down fluids – admit if this persists for more than a few hours
• Significant ketosis in a type I diabetic despite optimal management and supplementary insulin
• Persistent diarrhoea
• Blood glucose persistently >20 mmol/L despite best therapy
• Any clinical signs of ketosis or worsening condition, eg Kussmaul's respiration, severe dehydration, abdominal pain
• The patient who is unable to manage adjustment of normal diabetes care
• Patients who live alone and have no support who may be at risk of slipping into unconsciousness