Hypoglycaemia

Question 1

What is the most common cause of hypoglycaemia? Others?

Answer 1

Iatrogenic - accidental overdose of SC insulin or oral hypoglycaemic drugs

Late gastric dumping syndrome
Decompensated liver disease
Adrenal insufficiency

Question 2

What are the major risk factors for developing hypoglycaemia?

Answer 2

DM
Post-gastrectomy or gastric by-pass surgery
Alcohol excess or renal dialysis
Beta blockers

Question 3

What is gastric dumping syndrome? Management?

Answer 3

Complication of gastric bypass surgery

Early: (10-30) minutes post-prandial (meal) - sudden large passage of hypertonic gastric contents into small intestines resulting in an intraluminal fluid shift and subsequent intestinal distention. This causes nausea, vomiting, diarrhoea, hypovolaemia - leading to sympathetic response, predominating with tachycardia and diaphoresis (sweating)

Late: (1-3 hours post-prandial) - surge in insulin production following the dumping of food results in hypoglycaemia

Managed by small volume and more frequent meals, avoidance of simple carbs, separation of eating and drinking (to avoid heavy load on stomach)

Question 4

What are the clinical features of hypoglycaemia?

Answer 4

Sweating, tingling lips, extremities, tremor, dizziness, slurred speech

Signs:
Confusion, tachycardia, tachypnoea, focal neurology or reduced GCS

Patients on beta blockers may not exhibit signs/symptoms of hypo, w high are predominantly mediated by SNS
Also inhibit hepatic gluconeogenesis so increase risk fo hypoglycaemia

Question 5

What is the investigation for hypoglycaemia?

Answer 5

Capillary blood glucose (BM)

Question 6

How should hypoglycaemia be managed?

Answer 6

If conscious give oral glucose immediately and monitor capillary BM every 1-2hours until stable - ensure patient eats complex carbohydrates like bread to maintain BM

IF no improvement - IV glucose 1L 10% over 8 hours

If unconscious protect airway, high flow O2, gain IV access, give 100ml of 20% glucose stat. IF delayed, 1mg IM glucagon
Once stable 1L 10% glucose over 8 hours and monitor BM to ensure levels >5mmol

Question 7

What do diabetic patients require peri-operatively?

Answer 7

Intraoperatve glucose monitoring
BM taken every 30 minutes
Consider variable rate insulin infusion for duration of procedure
If BM < 4mmol at any point, increase IV glucose infusion rate and insulin infusion stopped. Any level <2mmol should be treated as hypoglycaemic emergency

Post op BM should be measured regularly.
Sliding scale should be continued until the patient is eating and drinking normally before resuming their normal therapy. For T1DM patients, continue IV sliding scale insulin for 30mins after normal SC insulin injections are given.