History and exam

Key diagnostic factors

common

presence of risk factors for hyperglycaemia

Key risk factors for hyperglycaemia include stress (e.g., severe illness such as myocardial infarction), infection, corticosteroid use, and poorly controlled diabetes mellitus.

presence of risk factors for hypoglycaemia

Key risk factors for hypoglycaemia include insulin use, older age, malnourishment, cognitive impairment, or renal or hepatic failure.[3][21]​​

history of diabetes mellitus

In one study at a US community teaching hospital, 38% of all admitted patients had hyperglycaemia, comprising 26% with a known history of diabetes mellitus, and 12% with no prior diabetes diagnosis[5]

severe intercurrent illness or infection (hyperglycaemia)

Key risk factors for hyperglycaemia include physiological stress (e.g., severe illness such as myocardial infarction) and infection.

insulin use (hypoglycaemia)

Insulin therapy is a key risk factor for hypoglycaemia.

reduced level of consciousness/coma (hypoglycaemia and hyperglycaemia)

Can be a presenting feature of both severe hypoglycaemia and hyperglycaemia. Prompt recognition is critical for immediate management

sweating (hypoglycaemia)

May be a presenting feature of hypoglycaemia.

Prompt recognition of symptoms and signs of hypoglycaemia is essential for immediate management.

tachycardia (hypoglycaemia)

May be a presenting feature of hypoglycaemia.

Prompt recognition of symptoms and signs of hypoglycaemia is essential for immediate management.

unusual behaviour (hypoglycaemia)

May be a presenting feature of hypoglycaemia.

Prompt recognition of symptoms and signs of hypoglycaemia is essential for immediate management.

Other diagnostic factors

common

history of recent corticosteroid use

May suggest transient hyperglycaemia.

signs of diabetic retinopathy

Indicative of long-standing diabetes. Includes intraretinal haemorrhage, cotton wool spots, lipid exudates, venous beading, and intraretinal microvascular abnormalities.

signs of diabetic neuropathy

Indicative of long-standing diabetes. Includes loss of vibratory sensation; altered proprioception; impaired pain, light touch, and temperature sensation; gastroparesis, constipation, orthostatic hypotension, or resting tachycardia.

uncommon

polyuria, polydipsia, or unintentional weight loss

Hyperglycaemia is usually asymptomatic, but severe or prolonged type 2 diabetes may produce these symptoms.

May also suggest type 1 diabetes.

Risk factors

strong

severe illness (hyperglycaemia or hypoglycaemia)

Severe illnesses such as myocardial infarction, sepsis, and pneumonia are strong risk factors for hyperglycaemia.[24] In particular, sepsis can increase serum glucose levels by triggering hormonal changes that increase hepatic glucose production and reduce peripheral glucose uptake.

Patients at increased risk of hypoglycaemia include those with renal or hepatic impairment, heart failure, malignancy, infection, or sepsis.[1]​​​[3][21]​​

corticosteroid use (hyperglycaemia)

Corticosteroids oppose insulin action and stimulate hepatic gluconeogenesis. Higher body mass index and increased age increase the risk of corticosteroid-induced hyperglycaemia.[25]

poorly controlled diabetes mellitus (hyperglycaemia)

Patients with a known history of diabetes mellitus may present with hyperglycaemia.

insulin administration or use of insulin secretagogues (hypoglycaemia)

Insulin can induce hypoglycaemia, which may result in neuroglycopaenia. Insulin secretagogues (i.e., sulfonylureas, meglitinides) can also lead to hypoglycaemia. Physical activity increases this risk in patients taking insulin or insulin secretagogues, particularly if drug doses or carbohydrate intake are not appropriately adjusted.[1]

Hypoglycaemia is associated with adverse outcomes, especially in intensive care unit patients. Sedation or beta-blockers may mask symptoms of neuroglycopenia, and counter-regulatory responses may be impaired.

Compared with sliding scale insulin, basal-bolus insulin regimens are more frequently associated with hypoglycaemia.[26]

changes to corticosteroid or insulin regimen (hypoglycaemia or hyperglycaemia)

Iatrogenic causes of hypoglycaemia include sudden reduction in corticosteroid dosing, incorrect timing of short- or rapid-acting insulin relative to meals, and sudden decreases in intravenous dextrose (glucose) or parenteral nutrition infusion rates.[1]​​

poor nutritional intake (hypoglycaemia)

Malnourished people are at increased risk of hypoglycaemia.[1]​​[3][21]​ This risk is further heightened by changes in nutritional intake, such as reduced oral intake, inability to take food or medication orally, or unanticipated interruptions in enteral or parenteral nutrition.[1]​​​​[4]

older age or cognitive impairment (hypoglycaemia)

Associated with increased risk of hypoglycaemia.​[1][3]​​[21]​​[26]

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