6.3 Endocrine Disease & Diabetes

Diabetes Mellitus

Diabetes mellitus (DM) is a disorder of glucose homeostasis. The two main types are:

Diagnosis and HbA1c

HbA1c (glycated haemoglobin) reflects average blood glucose over the preceding 2–3 months.

• HbA1c >= 48 mmol/mol (6.5%) — diagnostic cut-off for diabetes (with symptoms, or two readings if asymptomatic).
• HbA1c 42–47 mmol/mol (6.0–6.4%) — pre-diabetes (impaired glucose regulation).
• Target for most adults with diabetes — 48–58 mmol/mol (6.5–7.5%), individualised by the diabetes team.

Hypoglycaemia

Hypoglycaemia is blood glucose < 3.9 mmol/L (or < 3.0 mmol/L by some definitions). It is the most common diabetic emergency in the dental chair and is usually caused by missed meals, excessive insulin, or exercise without carbohydrate adjustment.

Signs

• Early: tremor, sweating, palpitations, hunger, anxiety.
• Late: confusion, slurred speech, drowsiness, seizures, coma.

Management in the dental surgery

1. If conscious and able to swallow: give 15–20 g of fast-acting carbohydrate — for example 4–5 glucose tablets, 150–200 mL pure fruit juice, or 90 mL non-diet fizzy drink. Recheck glucose after 10–15 minutes and repeat if needed. Once recovered, give a long-acting carbohydrate snack (biscuits, sandwich).
2. If unconscious or unable to swallow safely: give IM glucagon 1 mg (subcutaneous or intramuscular), OR IV glucose 10% (e.g. 100 mL of 10% glucose) if venous access is available. Place in the recovery position, call 999, and do not give anything by mouth.
3. Reassess response within 10 minutes; glucagon may not work in malnourished patients or those with liver disease — use IV glucose if no response.

Hyperglycaemia and Diabetic Ketoacidosis

Hyperglycaemia presents with polyuria, polydipsia, fatigue, and eventually dehydration. Diabetic ketoacidosis (DKA) is a medical emergency, chiefly in type 1 diabetes, with ketosis, acidosis (pH < 7.3, bicarbonate < 15), and dehydration. If a patient in the chair has vomiting, abdominal pain, deep sighing respiration (Kussmaul), or drowsiness with a known high glucose, call 999.

Dental management of the diabetic patient

• Schedule morning appointments after breakfast, when the patient has eaten and taken usual medication — this minimises hypoglycaemia risk.
• Ask the patient to bring their glucose monitor and a hypoglycaemia remedy to every visit.
• Antibiotic cover is not given routinely for diabetic patients; reserve it for active infection (e.g. spreading odontogenic infection) and follow local antimicrobial guidance.
• Diabetes is associated with delayed healing, increased infection risk, periodontitis, xerostomia, and candidiasis.
• The diabetes–periodontitis bidirectional relationship is well established: poorly controlled diabetes worsens periodontitis, and effective periodontal treatment can reduce HbA1c by around 2–4 mmol/mol in the short term.
• For poorly controlled diabetes (HbA1c markedly above target), discuss timing of elective surgery with the diabetes team and optimise control first where possible.

Thyroid Disease

Hypothyroidism presents with fatigue, cold intolerance, weight gain, bradycardia, and dry skin. Hyperthyroidism (thyrotoxicosis) presents with weight loss, heat intolerance, palpitations, tremor, and anxiety.

Dental relevance

• Patients with untreated or unstable hyperthyroidism are at risk of thyrotoxic crisis (thyroid storm) — a rare but life-threatening hypermetabolic state precipitated by stress, infection, or surgery. Features include high fever, tachycardia, agitation, and cardiac failure. Call 999, give oxygen, and do not proceed with dental treatment.
• Severe untreated hypothyroidism can cause myxoedema coma with hypothermia and hypoventilation — also an emergency.
• Patients on stable replacement (levothyroxine) or antithyroid drugs (carbimazole, propylthiouracil) usually tolerate routine dental treatment well.

Adrenal Insufficiency

Primary adrenal insufficiency (Addison's disease) is autoimmune destruction of the adrenal cortex, causing reduced cortisol and aldosterone. Features include fatigue, weight loss, postural hypotension, hyperpigmentation, and salt craving. Secondary adrenal insufficiency results from pituitary disease or, more commonly, from long-term systemic corticosteroid therapy suppressing the HPA axis.

Adrenal crisis

Adrenal crisis is an acute severe cortisol deficiency, often triggered by infection, surgery, or stress. Features include hypotension, hyponatraemia, vomiting, and collapse. Treatment is IV/IM hydrocortisone and fluids — call 999.

Steroid cover for dental procedures

• Minor dental treatment under local anaesthetic usually does not require supplemental steroids in patients on long-term corticosteroids.
• For stressful or major procedures (multiple extractions, surgical extractions, general anaesthesia), consider perioperative hydrocortisone in consultation with the patient's GP or endocrinologist. A common regimen is hydrocortisone 100 mg IM/IV at induction for patients on long-term steroids.
• Patients with diagnosed Addison's disease should be managed per their endocrinology plan; never stop their steroids abruptly.

Practical Appointment Planning