Diabetes Mellitus T1

Question 1

what is the def of T1DM

Answer 1

metabolic hyperglycaemic condition caused by absolute insufficiency of pancreatic insulin production

Question 2

what is the aetiology of T1DM

Answer 2

destruction of insulin-producing pancreatic beta-cells resulting in absolute insulin deficiency
autoimmune destruction - 90%
combination of genetically susceptible individuals & environmental triggers
polymorphisms such as HLA-DQB & HLA-DR increase risk of T1DM
pancreatic beta-cell autoantigens (glutamic acid decarboxylase, insulin) may play a role in initiation or progression of autoimmune islet injury

Question 3

what is the epi of T1DM

Answer 3

very common chronic disease in children
common in the west
8-17/100,000PA

Question 4

history & examination of T1DM

Answer 4

commonly juvenile onset (<30yrs)
polyuria/nocturia (osmotic diuresis caused by glycosuria)
polydipsia
tiredness
weight loss
signs of complications
-fundoscopy for diabetic retinopathy
-examination of the feet for neuropathy
-measure BP
signs of associated conditions
-vitiligo
-addison's disease

Question 5

what does osmotic diuresis caused by glycosuria mean

Answer 5

osmotic diuresis is the increase in urination frequency due to substances in the small tubes of the kidneys
by glycosuria meaning caused by glucose in the urine

Question 6

history & examination of diabetic ketoacidosis in T1DM

Answer 6

nausea & vomiting
drowsiness, confusion & coma
Kussmaul breathing (deep & rapid)
signs of dehydration

Question 7

what investigations would be performed in suspected T1DM

Answer 7

blood glucose (both positive results for diagnosis)
-fasting >7mmol/l
-random >11mmol/l
hba1c for blood glucose levels in past 2-3months
UEs monitor for nephropathy and high K caused by ACE inhibitors
urine for glycosuria, high ketones
CXR to exclude infection
ECG to look for acute ischaemic changes

Question 8

what investigations would be performed in suspected diabetic ketoacidosis in T1DM

Answer 8

bloods

• ABG (metabolic acidosis with high anion gap)
• blood/urinary ketones
• FBC (high WCC even without infection)
• UEs (high urea and creatinine from dehydration)
• amylase may be high

Question 9

management for T1DM

Answer 9

DKA if severe acidosis, hypotensive or oliguric - consider:
-HDU/ICU
-central line
-arterial line & urinary catheter
1 insulin
-50units of soluble insulin in 50ml 0.9% saline
-until capillary ketones <0.3, venous pH >7.3 & venous bicarbonate >18mmol/l
-at this point, if patient can eat & drink change to SC insulin, if not IV insulin sliding scale
2 fluids (500ml 0.9% saline) to raise SBP>100mmHg
3 potassium replacement
4 monitor blood glucose, capillary ketones & urine output hourly, UEs 4-hourly, VBG 2-hourly
5 patient education

GLYCAEMIC CONTROL
1 advice & patient education
-3x short-acting insulin (lispro, aspart, glulisine) before each meal
-1x long-acting insulin (isophane, glargine, determir)
2 insulin pumps may give better glycaemic control
3 patient education on carb intake & insuline dosage
4 monitor: symptoms with regular finger prick tests, hba1c <7%
5 treatment of hypoglycaemia
-if reduced consciousness 50ml of 50% glucose or 1mg glucagon IM
-if conscious 50g oral glucose followed by starchy snack

Question 10

why should insulin injection sites be rotated

Answer 10

to prevent lipoma

Question 11

complications of T1DM

Answer 11

DKA
-low insulin and high counter-regulatory hormones cause increased hepatic gluconeogenesis and decreased peripheral glucose utilisation
-renal reabsorptive capacity of glucose is exceeded causing glycosuria, osmotic diuresis & dehydration
-increased lipolysis leads to ketogenesis & metabolic acidosis
microvascular
-retinopathy
-nephropathy
-neuropathy
macrovascular
-peripheral vascular disease
-ischaemic heart disease
-stroke/TIA
more susceptible to infection (esp on feet)
insulin treatment complications
-weight gain
-fat hypertrophy at insulin injection sites

Question 12

prognosis of T1DM

Answer 12

dependent on early diagnosis, good control & compliance with screening & treatment
vascular disease & renal failure cause increased morbidity & mortality

Question 13

one unit of insulin

Answer 13

generally the amount needed to drop the blood glucose by 50mg/dl

Question 14

how is insulin used to treat hyperkalaemia

Answer 14

causes K to move into the cells

given with 100ml of 10% glucose to prevent hypoglycaemia