Key facts:
Authors: Kate Outterside, Sailesh Sankar, Ateeq Syed
Top Tips: Hypoglycaemia requires immediate action. Contact GP if on sulphonylurea
Key Differential Diagnoses
- All causes of abnormal behaviour, reduced conscious level, confusion, and seizures
Key Investigations
- FBC, ESR, CRP
- U+E, LFT, Bone, Glucose, HbA1C
- ECG, CXR
Key Treatment
- 15-20g fast acting carbohydrate; or biscuits etc (whatever to hand)
- IV 50% GLUCOSE 20 mls stat
Key Management Decisions
- ?Admit
- ITU
Background
If in doubt (eg not sure if drowsiness due to hypoglycaemia), treat
Introduction
- Is a plasma glucose of <4 mmol/l, associated with a typical symptom complex. It requires immediate treatment and zero tolerance
- Usually occurs in patients on Rx for diabetes mellitus (DM). Symptomatic hypoglycemia unrelated to treatment of DM is relatively rare, in part because the body has extensive counter-regulatory mechanisms to compensate for low blood glucose levels
- Mortality is 5% in drug-induced hypoglycaemia - ie, it can kill
- If in doubt, treat
Definition
- 'Plasma glucose of <4 mmol/l, associated with a typical symptom complex' is a reasonable definition
- There is no internationally agreed definition
- One is the ADA (USA) definition [Ref]
Causes
- Drug-induced (insulin or oral hypoglycaemics): accidental or intentional
- Reactive hypoglycaemia (missed meal, post prandial, gastric surgery)
- X Excess alcohol
- P Pituitary failure (especially acute necrosis)
- L Liver failure (rarely CCF/CRF)
- A Addison's (occasionally myxoedema)
- I Islet cell tumours (insulinoma)
- N Neoplasm - retroperitoneal fibrosarcoma, hungry neoplasm (hepatic carcinoma)
Risk Factors
- Previous hypoglycaemia
- Renal disease
- Liver disease
- Alcohol
Symptoms
- Sweaty, dizzy
- Palpitations
- Headache, hunger
- Confusion/aggression, if not treated
Key questions
- "How long have you had DM?"
- "What type of insulin do you take? Dose?"
- "What diabetic tablets to you take? Dose?"
- "Are you aware of 'hypos'?"
- "What and when did you last eat?"
Signs
- Sweating, tremor, pallor, cold, tachycardia
- Slurred speech, hemiparesis (hence can be confused for CVA ie pseudostroke)
- Peculiar behaviour
- Confusion/aggression, if not treated, then
- Reduced level of consciousness/seizures
Investigation
Beware sulphonylureas; they have long acting effects on BM
Blood
- FBC, ESR, CR
- U+E, LFT, Bone, Glucose, HbA1C
Note: patients with DM may experience symptoms of a 'hypo', despite normoglycaemia (especially if control poor) - ± ABG, if unwell
- ± INR/GGT, if liver failure
Other
- CXR
- ECG
Key investigation
- Glucose (BM)
Specialist investigations
- Insulin/c-peptide (if looking for insulinoma or intentional drug administration) before giving glucose
Note: low c-peptide and high insulin indicates endogenous insulin (eg insulinoma); high c-peptide and high insulin indicates exogenous
Differential diagnoses
- All causes of abnormal behaviour, reduced level of consciousness, confusion and seizure
- CVA (can present as pseudostroke too
- Subdural haematoma
- Liver failure (can be both)
- Drunk (can be both)
Note: or all four (liver failure, subdural haematoma, drunk and hypoglycaemic)
Treatment
Treatment (first line)
Drugs
- 15-20g fast acting oral carbohydrate (if conscious and aware); or sugar, sweets, biscuits .. whatever to hand
- IV 20 mls 50% GLUCOSE stat, slowly via small bore cannula into large vein; (immediate Rx if unconscious)
Note: recheck BM within 10 mins after intervention (target BM 4-7 mmol/L); patient should also regain consciousness within 10 mins; once regained consciousness, give a complex carbohydrate - ± IM GLUCAGON 1mg stat; can repeat
- ± IV PABRINEX 2 tds (to prevent precipitating Wernickes) if alcohol-associated or malnourished
- If liver failure, add PO LACTULOSE
- If ?Addison's, also give IV FLUIDS, IV HYDROCORTISONE and FLUDROCORTISONE
Procedures
- IV
Key management decisions
- ?Admit
- ITU
Stop
- Insulin/oral hypoglycaemic (in short-term)
- Beta-blockers (if masking symptoms of hypoglycaemia)
Treatment (second line)
Procedures
- If unwell (eg associated with liver failure), urinary catheter, CVP line, arterial line
Prescribing issues
- For emergency treatment of hypoglycaemia, 50% GLUCOSE should be administered slowly (eg 3 ml/min) via a small bore needle carefully placed in a large peripheral vein (to reduce risk of venous thromosis and phlebitis)
Admit?
- Usually
- If gets completely better after 2h, can go home; but may need adjustment to DM Rx regime, and early follow-up (eg community DM nurse)
Bed plan
- Medical admission ward or observation ward
- ± Endocrine ward, if hypoglycaemia recurrent
- ± ITU
- ± Liver, if liver failure
Referrals
Medical
- Endocrine
- Inpatient DM nurse
- ± ITU
Other
- DM nurse ± community DM nurse (on discharge)
The Rest
Complications
- Headache common on recovery
- Brain damage (especially by recurrent attacks)
- Patients with DM for >10y may not get 'warning symptoms' (eg sweating)
Follow-up
- Inpatient DM nurse ± Community DM nurse
Prognosis
- Good, if action is quick. In one study of drug-induced hypoglycaemia, mortality was 5%: [Ref]
Risk stratification (who can be managed as outpatient)
- If gets completely better in 1h, may not need admission
2° Prevention
+ Health promotion
- Early review by community DM nurse, with re-education
Don't forget
- Community DM nurse follow-up
- Driving precautions (advise patient to contact DVLA, and record that advice)
- Consider pychiatric review, if intentional
Red flags
- Recurrent episodes
