Diabetes mellitus

Definition

Diabetes mellitus (DM) is a group of metabolic disorders in which persistent hyperglycaemia (random plasma glucose more than 11.1 mmol/L) is caused by deficient insulin secretion, resistance to the action of insulin, or both

Classification

• Type 1 diabetes: absolute insulin deficiency typically the result of autoimmune destruction of the pancreatic islet β-cells causes persistent hyperglycaemia.
• Type 2 diabetes: insulin resistance and relative insulin deficiency result in persistent hyperglycaemia.
• Gestational diabetes: hyperglycaemia develops during pregnancy but usually resolves postpartum.
• Other specific types of diabetes include monogenic diabetes, diabetes secondary to pancreatic disease e.g. pancreatitis, malignancy, trauma, cystic fibrosis, or haemochromatosis, diabetes secondary to endocrine disorders e.g. acromegaly, Cushing's syndrome, hyperthyroidism, or phaeochromocytoma & diabetes secondary to drug treatment (usually corticosteroids).

Diagnosis
Diagnosis of type 1 diabetes:
Based on clinical grounds in adults presenting with hyperglycaemia (random plasma glucose more than 11 mmol/L).

Adults with type 1 diabetes typically present with one or more of the following:

• Ketosis.
• Rapid weight loss.
• Age of onset younger than 50 years.
• Body mass index (BMI) below 25 kg/m2.
• Personal and/or family history of autoimmune disease.

Suspect type 1 diabetes in a child or young person presenting with hyperglycaemia and the characteristic features of:

• Polyuria.
• Polydipsia.
• Weight loss.
• Excessive tiredness.

Diagnosis of type 2 diabetes:
Suspect a diagnosis of type 2 diabetes in patients with persistent hyperglycaemia that may or may not be accompanied by the following features:

• Polydipsia
• Polyuria
• Blurred vision
• Unexplained weight loss
• Recurrent infections
• Lethargy
• Acanthosis nigricans
• Presence of risk factors

Diabetes should not be diagnosed on the basis of a single abnormal HbA1c or plasma glucose result. Repeat testing to confirm the diagnosis is advised.



Complications of diabetes

Acute metabolic osmotic emergencies

• Diabetic ketoacidosis (DKA)
• hyperosmolar hyperglycaemic state (HHS, previously termed HONK)

Macrovascular
Ischaemic heart disease

• Angina
• Myocardial infarction

Cerebrovascular ischaemia

• TIA
• Stroke

Peripheral vascular disease

• intermittent claudication
• Acutely ischaemic limbs
• distal limb ischaemia e.g. toes
• foot ulcers

Microvascular
Autonomic neuropathy

• Resting tachycardia, postural hypotension, cardiac ischaemia, sudden cardiac death
• Gastroparesis, constipation/diarrhoea, oesophageal dysmotility
• Erectile dysfunction, neuropathic bladder

Mononeuropathies

• cranial neuropathies, entrapment and pressure neuropathies and radiculopathies.

Diabetic peripheral neuropathy

• Sensory dysfunction (typically in glove and stocking distribution)
• Foot ulceration
• Charcot joint's

Diabetic nephropathy

• Renail impairment (CKD)

Diabetic retinopathy

• Blindness

Infections

---

Hypoglycaemia

Definition

Hypoglycaemia is a lower than normal blood-glucose concentration. It is defined by NICE as blood glucose <3.5 mmol/L. The RCEM advises a blood glucose level below 4.0 mmol/L in diabetic patients should prompt treatment for hypoglycaemia.

True hypoglycaemia is defined by Whipple's triad and requires all three of the following:

• Signs and symptoms of low blood glucose
• A low blood plasma glucose concentration
• Relief of symptoms after correcting low blood glucose

Signs & symptoms

Treatment options in adults
If able to take oral medication:

• Oral carbohydrate: 15-20g of a quick acting carbohydrate should be followed by a long acting carbohydrate. Soft drinks such as Lucozade may be used but the carbohydrate content should be checked carefully.
• Buccal Glucose Gel: Absorbed more quickly than complex carbohydrates and is easily administered. The patient should be able to swallow in order for it to be fully effective.

If oral route or oral medication not available:

• Glucagon: Glucagon 1 mg IV, IM or SC. Useful in situations where behaviour, co-operation or other neuroglycopenic symptoms make oral or IV routes difficult. Repeated doses are not advised. Glucagon will be less effective in those with depleted glycogen reserves e.g. sulphonylurea treatment, malnourished, or excessive alcohol consumption.
• Dextrose: 10-20% dextrose (glucose) may be used. Typical doses are 75-80 ml 20% glucose or 150-160 ml of 10% glucose. 50% dextrose is highly irritant and risks extravasation injury.

Glucose levels should be re-checked 15 minutes after treatment. Treatment may be repeated following 10-15 minutes.

Treatment options in children

If able to take oral medication:

• Glucose 5-20 g in liquid form (Glucogelµ, Dextrogelµ, or Rapiloseµ) or granulated sugar or sugar lumps. May be repeated after 10-15 minutes if required. Patient should be fed to prevent recurrence of hypoglycaemia.

if sugar cannot be given by mouth and IV access unavailable:

• Glucagon (if child aged < 8, body weight < 25 kg dose is 500 microgram)
• If not effective in 10 minutes give IV glucose

if sugar cannot be given by mouth and IV access available:

• 2 mL/kg of 10% glucose IV as bolus followed by 10% glucose IV infusion at a rate of 5 mL/kg/hour
• Carbohydrates should be given as soon as possible after treatment

Treatment of neonatal hypoglycaemia

• Treat with glucose IV infusion 10% given at a rate of 5 mL/kg/hour.
• An initial stat dose of 2 mL/kg over five minutes may be required if hypoglycaemia is severe enough to cause loss of consciousness or fitting.
• Mild asymptomatic persistent hypoglycaemia may respond to a single dose of glucagon.