Diabetes & Glucose

Type 1 Diabetes Mellitus (T1DM)

•    Autoimmune destruction of pancreatic β-cells → absolute insulin deficiency

•    Typically presents in childhood/adolescence

•    Features: polyuria, polydipsia, weight loss, ketosis, DKA

•    Associated with other autoimmune diseases (e.g. coeliac, thyroid)

•    Requires lifelong insulin therapy

•    Antibodies: anti-GAD, anti-IA2, ZnT8

Type 2 Diabetes Mellitus (T2DM)

•    Combination of insulin resistance and relative insulin deficiency

•    Risk factors: obesity, family history, sedentary lifestyle, South Asian/Afro-Caribbean ethnicity

•    Often asymptomatic or mild osmotic symptoms

•    Management (stepwise):

1.    Lifestyle modification

2.    Metformin (1st-line, unless contraindicated)

3.    Add SGLT2 inhibitor or GLP-1 RA (if CVD/weight loss benefit)

4.    Add insulin or SU/DPP4i if needed

Diagnosis of Diabetes

•    Any one of the following (in symptomatic patients):

o    HbA1c ≥ 48 mmol/mol (6.5%)

o    Fasting glucose ≥ 7.0 mmol/L

o    2h glucose ≥ 11.1 mmol/L on OGTT

o    Random glucose ≥ 11.1 mmol/L with symptoms

•    If asymptomatic: confirm with second abnormal test

Secondary Diabetes

•    Pancreatic: chronic pancreatitis, haemochromatosis, pancreatic cancer

•    Endocrine: Cushing’s syndrome, acromegaly, phaeochromocytoma, glucagonoma

•    Drug-induced: steroids, antipsychotics, thiazide diuretics

MODY (Maturity-Onset Diabetes of the Young)

•    Monogenic (AD) form of non-insulin dependent diabetes

•    Onset <25 years, strong FHx, not obese

•    Often misdiagnosed as T1/T2

•    Subtypes:

o    HNF1A/4A: sensitive to sulfonylureas

o    GCK: mild stable fasting hyperglycaemia, no treatment needed

Complications of Diabetes

•    Microvascular:

o    Retinopathy: background → pre-proliferative → proliferative ± maculopathy

o    Nephropathy: microalbuminuria → proteinuria → CKD

o    Neuropathy: distal symmetrical sensory loss ("glove and stocking")

•    Macrovascular:

o    ↑ risk of MI, stroke, PAD

•    Autonomic neuropathy:

o    Gastroparesis, erectile dysfunction, postural hypotension, bladder dysfunction

•    Prevention: tight glucose, BP, lipid control; annual screening

Diabetes in Pregnancy

•    Includes gestational diabetes and pre-existing diabetes

•    Risks: macrosomia, pre-eclampsia, neonatal hypoglycaemia

•    Insulin is treatment of choice

•    Oral hypoglycaemics usually stopped (some units use metformin)

•    Monitor closely with growth scans and glucose targets