Type 1 Diabetes Mellitus Flashcards
Define Diabetes mellitus type 1
Chronic metabolic hyperglycaemic condition caused by absolute insufficiency of pancreatic insulin production, causing impaired carbohydrate, protein and fat metabolism.
What is the aetiology of T1DM
Destruction of the pancreatic insulin-producing β-cells, → absolute insulin deficiency
Often due to an autoimmune process (90%) against the β cells (GAD, insulin, IP2, ZnTB)
90% β cell destruction → hyperglycaemia
What is the epidemiology of T1DM
One of the most common chronic disease in childhood (<20)
Accounts for 5-10% of all diabetic patients and >85% of diabetes under 20
Can present at any age, but highest incidence is children 10-14
What are the symptoms of T1DM
Polyuria
Polydipsia
Weight loss
Nocturia
Fatigue, excessive tiredness
Blurred vision
± symptoms of complications
± other autoimmune diseases e.g. vitiligo, Addison’s, thyroid disease
What investigations should be done for T1DM
Bedside: BM, urine dip, urinary ketones (+ve = T1DM, -ve = T2), ECG, fundoscopy
Bloods
- Random plasma glucose: >11
- Fasting plasma glucose: >6.9
- HbA1c: >48 (glucose for 2-3 months)
- OGTT >11.1 (impaired = 7.9-11.1) - for borderline/GDM
- Plasma ketones: present (T1)
- Fasting C peptide: low or undetectable in T1DM
- Auto-immune markers (+ve): anti-GAD, ICA abs, IAA, IA-2A)
- Fasting lipid: often normal (Differentiate from T2DM)
- Renal function
What is the management for T1DM
MDT
Conservative: personalised care plan
- Nutritional advice (DAFNE - dose adjustment for normal eating): carbs (low glycaemic index), weight, CVD risk - NO RESTRICTION (still growing)
- Physical activity
- Self-monitoring
- Hypoglycaemia awareness education + avoidance
- CVD risk monitoring
- Complication monitoring
- Monitor HbA1c every 3-6 months
Pharmacological: Insulin therapy
What is the strategy for self monitoring in T1DM
capillary glucose monitoring (CGM) 5x a day at least
Real-time continuous glucose monitoring (rtCGM)
Intermittently scanned continuous glucose monitoring (isCGM)/ “flash”
Target:
5-7 mmol/l on waking and
4-7 mmol/l before meals at other times of the day
Hyperglycaemia:
- Offer blood ketone testing strips and a meter
- Test for ketonaemia if they are ill or have hyperglycaemia
Describe insulin therapy for T1DM
- Basal bolus insulin regimen (long acting + short acting before meals)
- Long acting = determir (2x daily) OR glargine
- Rapid (before meals) = lispro, aspart, glulisine - Continuous SC insulin infusion
- Mixed insulin regimen (unable to manage 3-4 injections daily)
- Sliding scale (hospital use) → metabolic stress → fluctuating glucose levels (adjustment of short acting insulin according to glucose levels every 4 hours)
Consider adding metformin if BMI >25
What should be monitored for in T1DM
Thyroid disease, at diagnosis then annually until transfer to adult services
Diabetic kidney disease via albumin:creatinine ratio (ACR) measurement, annually from 12 years
Hypertension, annually from 12 years
Retinopathy screening, from 12 years - refer to diabetic eye screening programme
Dental health reviews
Coeliac disease
Foot problems
What are the complications of insulin treatment
Weight gain (can predispose to diabulimia where diabetics do not take insulin due to fear of weight gain)
Fat hypertrophy at injection sites
Hypoglycaemia (missing meals, overdose)
What are the complications of T1DM
Long term hyperglycaemia → Vascular complications
- Microvascular complication: retinopathy, neuropathy, nephropathy
- Macrovascular complications: cardiovascular, cerebrovascular, peripheral vascular disease
- Hyperglycaemia → oxidative stress → endothelial dysfunction → allows LDL entry → atherosclerosis
Periodontitis
Juvenile cataracts
Necrobiosis lipoidica
Addison’s disease
DKA
Increased risk of other autoimmune diseases
What is the management for the following complications of T1DM:
Retinopathy
Nephropathy
Neuropathy
Gastroparesis
Erectile dysfunction
Foot care
Cardiovascular risk
Retinopathy: routine eye screening
Nephropathy: monitor albumin:creatinine ratio, ACEi/ABR
Neuropathy: autonomic neuropathy → duloxetine
Gastroparesis: mashed/purred food for symptomatic relief
Erectile dysfunction: phosphodiesterase-5 inhibitor
Foot care: X-ray/MRI feet
Cardiovascular risk: albuminuria, glucose control, BP, cholesterol
What is the prognosis for T1DM
Untreated - fatal due to DKA
Poor controlled T1DM is a risk factor for many chronic complications, including blindness, renal failure, foot amputation and heart attack
Intensive glycaemic control has been shown to decrease the incidence of microvascular and macrovascular disease in T1DM
Even a few years of intensive glucose control translate to reduced rates of microvascular and macrovascular complications 10 years later
Overall, cardiovascular disease is the major cause of death and a major cause of morbidity for patients with diabetes
What are the sick day rules for T1DM
insulin,: must not stop it due to the risk of DKA
check blood glucose more frequently, for example, every 1–2 hours including through the night
consider checking blood or urine ketone levels regularly
aim to drink at least 3 L of fluid (5 pints) a day to prevent dehydration
What are the rules for driving on insulin
Group 2 (HGV) licence: needs a VDIAB1I form
Can drive if:
- no severe hypoglycaemic event in the last 12 months
- Full hypoglycaemic awareness
- Regular monitoring at least 2x daily
- Understanding of hypoglycaemic risks
- No debarring complications of DM
