Diabetes Mellitus - Type 1

Question 1

Define Type 1 Diabetes Mellitus

Answer 1

Chronic metabolic hyperglycaemic condition caused by absolute insufficiency of pancreatic insulin production, causing impaired carbohydrate, protein and fat metabolism

Question 2

Aetiology of Type 1 Diabetes Mellitus

Answer 2

Destruction of the pancreatic insulin-producing beta cells -> absolute insulin deficiency

Often autoimmune process against beta cells (90%)

Hyperglycaemia arises when 90% of the beta cells have been destroyed

Question 3

Epidemiology of Type 1 Diabetes Mellitus

Answer 3

Accounts for 5-10% of all diabetic cases
Accounts for >85% of diabetes cases under 20
Highest incidence children 10-14

Question 4

Symptoms of Type 1 Diabetes Mellitus

Answer 4

Patient: young, lean appearance

Polyuria, polydipsia
Weight loss
Nocturia
Fatigue
Blurred vision 

+symptoms of complications:
DKA (abdo pain, nausea + vomiting, drowsiness, confusion, coma)
Neuropathy (painless leg ulcers, loss of sensation)

Question 5

Signs of DKA and neuropathy due to Type 1 Diabetes Mellitus on examination

Answer 5

DKA: 
Tachypnoea, Kussmaul breathing (deep + rapid)
Ketotic breath
Dry mucous membranes
Reduced skin turgor 

Neuropathy:
Painless leg ulcers
Loss of sensation (monofilament+vibration)
Weak/absent dorsalis pedis pulse
Cranial nerve palsy 
Diplopia

Question 6

Investigations for Type 1 Diabetes Mellitus

Answer 6

Fasting plasma glucose >6.9
Random plasma glucose >11.1
Oral glucose tolerance test >11.1
HbA1c >48

Urinary ketones: T1DM 
ABPI: suggests PAD 
Urinary albumin excretion: may be increased (end-organ damage)
ECG: ?ischaemia
Fundoscopy: retinopathy 

Fasting C peptide: low or undetectable
Autoimmune markers: +ve
Fasting lipid profile: normal
Serum creatinine + eGFR: ?renal insufficiency

Question 7

Conservative Management for Type 1 Diabetes Mellitus

Answer 7

Smoking cessation
Physical activity 
Nutritional advice (DAFNE programme)
Self-monitoring of blood glucose levels (at least 4x a day)
Hypoglycaemia avoidance 

HbA1c monitoring every 3-6 months

Question 8

Medical management for Type 1 Diabetes Mellitus

Answer 8

Insulin therapy

1. Basal-bolus (2x daily insulin detemir) + rapid acting insulin before meals (lispro, aspart, glulisine)
2. Continuous SC insulin infusion (insulin pump_
3. Mixed insulin regimens
4. sliding scale (hospital use)

Question 9

Complications of Type 1 Diabetes Mellitus

Answer 9

Microvascular: retinopathy, neuropathy, nephropathy

Macrovascular: cardiovascular, cerebrovascular, peripheral vascular disease

Hypoglycaemia with insulin therapy

Diabetic Ketoacidosis

Question 10

What is hypoglycaemia define as and how is it managed

Answer 10

Plasma glucose < 3 mmol/L = severe

Able to swallow -> 50g oral fast-acting glucose e.g. lucozade, sugar, 3 dextrose tablets

Reduced consciousness -> IM glucagon ± IV glucose

No improvement after 10 mins -> IV glucose (dextrose)
-> when safe switch to oral carbohydrate

Question 11

What are the stages of Type 1 Diabetic retinopathy + their management

Answer 11

1. Background retinopathy
   Hard exudates | Microaneurysms | blot haemorrhages
   => Warn about warning signs + improve glucose control
2. Pre-proliferative
   Cotton wool spots/soft exudates
   => Pan-retinal photocoagulation
3. Proliferative
   Visible new vessels on disk or elsewhere
   => Pan-retinal photocoagulation
4. Maculopathy
   Hard exudates near the macula | microaneurysms | blot haemorrhages
   Can threaten direct vision
   => Grid photocoagulation

Question 12

Describe Type 1 Diabetic nephropathy and its management

Answer 12

HTN + progressively increasing proteinuria and deteriorating kidney function
Histological: mesangial expansion, BM thickening, glomcerulosclerosis

=> diabetic control | BP control | RAAS inhibition = ACEi | Smoking cessation

Question 13

Describe the different types of Type 1 Diabetic neuropathy

Answer 13

Peripheral: longest nerves supply the feet, common in taller people, no sense of injury -> infection -> does not heal

Mononeuropathy: sudden motor loss (wrist, foot drop, CN palsy)

Autonomic: loss of sympathetic/parasympathetic innervation to system

Mononeuritis multiplex: random combo of peripheral nerve lesions

Radiculopathy: pain over spinal nerve, often dermatomes

Question 14

Prognosis for Type 1 Diabetes Mellitus

Answer 14

Untreated = fatal due to DKA
Poor control = risk factor for many chronic complications
Intensive glycaemia control decreases complication rates, even if for a few years
Cardiovascular disease is the major cause of death