Diabetes & Intercurrent Illness

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.¹ 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 non-ketotic state.²

• Education of 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
• Increase frequency of capillary-glucose monitoring to at-least 4-hourly
• Institute monitoring of urinary/capillary ketones in insulin-dependent diabetics
• Adjust insulin according to monitoring results, DO NOT ROUTINELY STOP IT
• Routinely discontinue metformin in acutely unwell patients or those with dehydration
• Adjust other anti-diabetic medication according to monitoring results and clinical condition
• Treat the underlying cause of the intercurrent illness sufficiently
• Anti-emetics may be useful for symptomatic treatment of vomiting but establish the likely cause of the symptoms first and admit if necessary
• Maintain carbohydrate intake using sugary drinks or fruit juice, soups or snack foods if the patient has difficulty eating
• Insulin-pump users should have injectable fast-acting insulin to hand to treat hyperglycaemia
• Keep a low threshold for regular follow-up or admission as the situation can deteriorate rapidly
• Consider admission for patients with anorexia or recurrent vomiting who cannot or will not take oral fluids/sugars
• Admit ill insulin-dependent diabetics who have significant ketosis despite supplemental insulin and optimal management
• For medicolegal reasons, keep a good record of how diabetes is being monitored and your follow-up arrangements
• Admit patient or seek advice from your local diabetes/acute medicine service if unsure

Metformin only²

• Increase blood glucose monitoring to 4 hourly
• Stop metformin in acute illness, restart slowly as illness subsides (e.g. 500mg od) and gradually build back to previous dose⁵
• Insulin may be the best temporary option in the event of sustained hyperglycaemia⁶
• Advise the patient to contact GP surgery/diabetes service if the home glucose monitoring result is over 13mmol/l and/or they are feeling unwell
• If control poor, consider sliding-scale fast-acting soluble insulin with regular monitoring
• Admission to hospital may be needed if no improvement, patient lives alone or is unable to manage such measures at home

Sulphonylurea only⁷

• Increase blood glucose monitoring to 4 hourly
• Consider increasing sulphonylurea up to maximum dosage if persistent hyperglycaemia, then reduce back to normal as illness subsides
• Advise to contact the GP surgery/diabetes service if home glucose monitoring gives a result over 13mmol/l and/or the patient is unwell
• If control poor, consider sliding-scale fast-acting soluble insulin with regular monitoring
• Admission to hospital may be needed if no improvement, patient lives alone or is unable to manage such measures at home

Metformin and sulphonylurea⁵

• Increase blood glucose monitoring to 4 hourly
• Stop metformin in acute illness, restart slowly as illness subsides (eg 500mg od) and gradually build back to previous dose
• If hyperglycaemic, consider increasing sulphonylurea up to maximum dosage according to glucose readings
• Advise to contact GP surgery if home glucose monitoring gives a result over 13mmol/l and/or the patient is unwell
• If control poor, consider sliding-scale fast-acting soluble insulin with regular monitoring
• Admission to hospital may be needed if no improvement, patient lives alone or is unable to manage such measures at home

Insulin ± metformin^1,5

• Ensure patients are supplied with reagent sticks to check urinary/capillary ketones
• Give a supply of fast-acting soluble insulin (particularly important for patients who are normally on insulin pumps or twice-daily combined insulin regimens)
• Increase blood glucose monitoring to 4 hourly and check ketones regularly
• Stop metformin in acute illness, restart slowly (eg 500mg od) and gradually build back to previous dose as illness subsides
• DO NOT STOP INSULIN - adjust dose as detailed below
• Severe illness: consider hospitalisation if blood glucose testing>15mmol/l, admit to hospital if there are significant levels of ketones and/or vomiting with inability to hydrate or take oral carbohydrates
• Advise to contact GP surgery if home glucose monitoring gives a reading over 13mmol/l and/or patient feels unwell

The scheme below can be used to help home self-management of motivated and well-informed diabetic patients who have sufficient support and insight. It needs to be backed up by regular follow-up (by phone or in person) with documentation of the continuing medical involvement.

Insulin regimen for self-management of ill insulin-dependent diabetic

• Firstly, calculate the total daily dose (TDD) of all types if insulin in standard units.
• For example, long-acting insulin 16 units once daily plus soluble insulin 8 units per meal, TDD = 16 + 8 + 8 + 8 = 40 units.
• Calculate 10% (in this example 4 units), 15% (in this example 6 units), 20% (in this example 8 units) supplements and give in addition to your normal insulin regimen according to the table below:

• Suspicion of underlying diagnosis that requires hospital admission, eg myocardial infarction, intestinal obstruction – admit immediately
• Inability to swallow or keep down fluids – admit if persists more than a few hours
• Significant ketosis in Type I diabetic despite optimal management and supplementary insulin
• Persistent diarrhoea
• Blood glucose persistently >20mmol/l despite best therapy
• Any clinical signs of ketosis or worsening condition, eg Kussmaul respiration, severe dehydration, abdominal pain
• 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