History and exam

Key diagnostic factors

common

history of diabetes mellitus

In one study, hyperglycemia was present in 38% of patients admitted to the hospital (26% had a known history of diabetes and 12% had no history of diabetes before admission).[5]

Poorly controlled diabetes mellitus is a key risk factor for the presence of hyperglycemia.

severe intercurrent illness or infection (hyperglycemia)

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

insulin use (hypoglycemia)

A key risk factor for hypoglycemia.

reduced level of consciousness/coma (hypoglycemia and hyperglycemia)

Can be a presenting feature of both severe hypoglycemia and hyperglycemia. Recognizing this presentation is essential to institute immediate management.

sweating (hypoglycemia)

May be a presenting feature of hypoglycemia.

Recognizing symptoms and signs of hypoglycemia urgently is essential to institute immediate management.

tachycardia (hypoglycemia)

May be a presenting feature of hypoglycemia.

Recognizing symptoms and signs of hypoglycemia urgently is essential to institute immediate management.

unusual behavior (hypoglycemia)

May be a presenting feature of hypoglycemia.

Recognizing symptoms and signs of hypoglycemia urgently is essential to institute immediate management.

Other diagnostic factors

common

history of recent corticosteroid use

May suggest transient hyperglycemia.

signs of diabetic retinopathy

May suggest long-standing diabetes. Includes intraretinal hemorrhage, cotton wool spots, lipid exudates, venous beading, and intraretinal microvascular abnormalities.

signs of diabetic neuropathy

May suggest 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

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

May also suggest type 1 diabetes.

Risk factors

strong

severe illness (hyperglycemia or hypoglycemia)

Particularly severe illnesses such as myocardial infarction, sepsis, and pneumonia are strong risk factors for hyperglycemia.[13] Sepsis can increase serum glucose levels through hormonal changes that increase hepatic glucose production and reduce peripheral glucose uptake. Patients at increased risk of hypoglycemia include those with renal or hepatic impairment, heart failure, malignancy, infection, or sepsis.[1]​​​[3][11]

corticosteroid use (hyperglycemia)

Corticosteroids oppose insulin action and stimulate hepatic gluconeogenesis. Higher body mass index and increased age increase the risk of corticosteroid-induced hyperglycemia.[14]

poorly controlled diabetes mellitus (hyperglycemia)

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

insulin administration or insulin secretagogues (hypoglycemia)

Insulin can induce hypoglycemia, leading to neuroglycopenia. Insulin secretagogues (i.e., sulfonylureas, meglitinides) can also lead to hypoglycemia. Physical activity in patients taking insulin or insulin secretagogues can lead to hypoglycemia especially if the drug dose or carbohydrate consumption is not adjusted accordingly.[1]​ Hypoglycemia 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 use is more frequently associated with hypoglycemia.[15]

changes to corticosteroid or insulin regimen (hypoglycemia or hyperglycemia)

Iatrogenic factors that may lead to hypoglycemia include sudden reduction in a corticosteroid dose, incorrect timing in relation to meals of short- or rapid-acting insulin, and reduction of intravenous dextrose infusion or parenteral nutrition rate.[1]​​

poor nutritional intake (hypoglycemia)

Malnourished people are at risk of hypoglycemia.[1]​​​[3][11]

Changes to nutritional intake may include reduced oral intake, not being able to take food or drugs orally, or unanticipated interruption of nutrition (enteral or parenteral).[1]​​[4]​​

older age or cognitive impairment (hypoglycemia)

Increased risk of hypoglycemia.[1][3]​​​[11]​​[15]

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