Aetiology:
genetic susceptibility (DR3, DR4; chr.6),
environmental trigger (?CMV, reovirus),
autoimmune injury to beta cells (islet cell antibodies in 80%, )insulin autoantibodies in 18-20%
Presentation:
often in 'clusters',
weight loss, thirst, polydipsia, polyuria,
occasionally 'crisis' (ketoacidosis).
Diagnosis:
blood glucose - fasting >8mmol/l, postprandial >12mmol/l.
urinalysis - glycosuria.
1 Admission:
stabilise,
initiate/establish treatment,
familiarise with 'diabetic team',
familiarise with insulin, injections, skin pricks,
dietary advice.
? induce hypo attack.
Insulin: medium acting preparation, initially 0.5U/kg/day; 60% before b'fast, 40% before evening meal.
If weight loss, metabolic derangement severe -
insulin requirement upto 1.0U/kg/day.
Add short acting insulin (0.25-0.5U/kg/day).
2. Transition:
close supervision by diabetic health visitor.
5% experience 'honeymoon period'.
3. Follow-up:
close supervision,
educate and involve family.
1. Routine:
B.D. regimen (occasionally t.d.s.).
Mixed short and medium acting insulin,
dose approximately. 0.5-0.8U/kg/day.
Check skin, liver size, urine for protein, C&S.
2. Puberty:
Often difficult, especially girls.
Increased insulin requirements (1.5U/kg/day) due to surge in growth hormone.
3. Difficult pts:
Convert to Pen injections.
Continuous s.c. insulin infusion as last resort.
Semi residential special school.
4. Brittle diabetics:
Frequent ketoacidoses, usually due to:
§ Problem with diabetic management.
§ Concurrent illness.
§ Disrupted child/family dynamics.
Monitor:
Weight, growth.
Frequency of hypo attacks.
Sugars: 3-4/day twice a week or once daily,
- (more frequently if instable),
- use finger prick (BM stix) or autolets.
Urine glucose if needle phobic.
% HbA1 : normal=8%; 11-11.5% is acceptable
Serum fructosamine - measures % albumin glycation. quick, cheap but ? too sensitive to brief hyperglycaemic spells.
Ophthalmic review (if IDDM >10 years)
BP
1. Daytime: 10-15% will have at least one attack/year.
Frequency increases with tighter control.
Very rarely result in brain damage (even +fits).
2. Nocturnal: Potentially serious problem: - check BM late p.m, especially after busy day to obtain warning.
Partly due to surge in growth hormone at night.
May present with rebound hyperglycaemia first thing a.m. ('dawn phenomenon'/Somogyi effect).
Treatment:
Glucose drink, sweet etc.
Provide glucose buccal gel (Hypostop).
Provide (and instruct) glucagon injection.
Educate family, school etc.
1. History:
Short illness; insulin omitted
Vomiting, abdominal pain
Drowsiness, confusion, coma
2. Examination:
Dehydrated,
ketotic
decreased consciousness,
tachycardia
Kussmaul respiration
diffuse abdo tenderness
? signs of infection
3. Investigations:
Urinalysis: 3+ glucose; 3+ ketones,
BM stix 'high',
Blood glucose >15mmol/l (often much higher),
Na+ normal; K+ normal (initially); urea, creatinine raised,
osmolality raised: (2x(Na+ + K+) + urea + glucose).
FBC: Hb, white cell count raised.
Blood gas: pH, HCO3- low; pO2 normal/high; pCO2 low.
CXR
Blood cultures
1. CORRECT FLUID IMBALANCE
2. CORRECT ACIDOSIS
3. CORRECT ELECTROLYTE IMBALANCE
4. CORRECT HYPERGLYCAEMIA
5. TREAT PRECIPITATING CAUSE
1. Fluids:
If shock is present resuscitate with boluses of 10 ml/kg of 0.9% saline (or 5% albumin) IV over 30 minutes, and repeat whilst signs of shock remain.
Calculate the fluid requirement = maintenance + deficit
(a) Maintenance:
first 10 kg: 100 ml/kg/24h
next 10 kg: 50 ml/kg/24h
over first 20 kg: 20 ml/kg/24h
(b) Deficit = %dehydration × body weight (kg).
The total fluid requirement should be given evenly over 24 hours.
Fluid used as replacement:
- 0.9% (normal) saline until BM/glucose <15mmol/l,
- 0.18% saline/4% dextrose thereafter.
2. Acidosis:
- generally rehydration suffices.
- if pH <7.1 give 8.4% NaHCO3, 1ml/kg/dose.
3. Electrolytes:
- connect ECG monitor.
- as hydration proceeds, K+ moves into the cells to replace the net intracellular deficit resulting in hypokalaemia.
- add K+ to replacement fluids (depending on U & E).
4. Hyperglycaemia
- start insulin infusion.
- use rapid acting insulin.
- initially 0.1U/kg/hour.
- adjust according to sliding scale.
- repeated s.c. doses may replace infusion.
5. Monitoring in ketoacidosis
- Continuous ECG monitoring.
- Vital signs (pulse, BP, resp. rate, abdo tenderness) - hourly.
- BM stix, 2-4 hourly.
- Blood glucose, U & E (especially K+), 4 hourly.
- Blood gas - repeated if initial pH <7.1.
- Urinalysis - assess every sample for glucose, ketones.