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hypoglycaemia

hypoglycaemia

introduction

  • in diabetic patients, hypoglycaemia is usually defined as blood glucose concentration less than 3.5 mmol/L

clinical features of hypoglycaemia

  • Recurrent hypoglycaemia or long-standing diabetes can cause a dulling or loss of warning symptoms. This is referred to as “hypoglycaemia unawareness”. In this case, the first sign of hypoglycaemia may be unconsciousness.

early symptoms

  • sweating
  • irritability
  • palpitations
  • trembling
  • tingling of fingers and lips
  • headache

later symptoms

  • disturbance of concentration
  • slurred speech
  • aggressive behaviour
  • confusion
  • seizures
  • loss of consciousness
  • short periods of hypoglycaemia usually have a relatively full return to neurologic function

adults with prolonged hypoglycaemic coma and resultant hypoglycaemic encephalopathy

  • prolonged periods with GCS < 8 may result in potentially permanent or life threatening hypoglycaemic encephalopathy:
    • mortality rate despite prolonged ICU care may be around 40% while over a third have “good outcomes” (including moderate disability but independent living) by 1 yr follow up 1)
    • greater than 8 hours of hypoglycaemia appears to be associated with a poor outcome and duration of hypoglycaemia (rather than other features such as blood glucose level, a low lactate or presence of hypothermia2) ) appears to be a major determinant of outcome 3)
    • early seizures appear to be a good prognostic sign (although in rat models they were correlated with increased mortality)4)
    • variably induces early lesions of the internal capsule that may secondarily reach the white matter
    • CT scans if they show anything generally show bilateral changes in cortex, basal ganglia and white matter, while a normal CT can be seen as a good prognostic marker5)
    • EEG generally shows a slowed brain electrical activity
    • absence of lesions on the first early diffusion MRI was associated with good outcome
    • those with good pre-morbid health but who are not appearing to clinically improve, generally require a minimum of 10-15 days of ICU care before deciding upon treatment thresholds.

Mx of hypoglycaemia in diabetic patients

initial Mx if conscious and able to swallow

  • give rapidly absorbed simple carbohydrate ASAP:
    • 1 tube glucose gel (15g), or,
    • a small glass (150mL) of Lucozade, strong cordial, fruit juice (apple or orange juice) or soft drink (NOT sugar free)
    • if symptoms not settling, repeat in 5-10min.
  • follow with a long acting carbohydrate to maintain blood glucose level:
    • half a sandwich, or,
    • a piece of fruit, or,
    • a glass of milk, or,
    • 4-6 dry biscuits, or,
    • next meal if due

initial Mx if unable to swallow

  • place patient on their side
  • ensure clear airway
  • for adults, give 25-50mls 50% dextrose iv (can dilute to 25% or 12.5% to reduce venous irritation)
  • if iv access not available or difficult, give 1mg glucagon im (for adults)
  • ongoing 5% dextrose 100mL/hr infusion may be needed
  • give slow acting carbohydrate as above when able to swallow

recovery from hypoglycaemia

  • clinical symptoms generally resolve within 5 minutes of iv or im Rx as above, but complete recovery of symptoms may take hours, particularly if hypoglycaemia was prolonged or severe
  • watch for and Rx any recurrence of hypoglycaemia after initial Rx:
    • recheck BGL within 15-20min then if BGL > 3.9 re-commence qid checks
    • if patient had been unconscious, check dextrostix hourly for 4 hours
    • BGL may remain unstable for 24 hours
  • ensure patient education
Do NOT with-hold insulin in patients with type I diabetes as this may result in diabetic ketoacidosis (DKA)

identify and manage cause of hypoglycaemia

  • missed or delayed meal
  • insufficient carbohydrate
  • increased physical activity
  • excessive medication
  • renal impairment
  • hypothyroidism
  • adrenal insufficiency
hypoglycaemia.txt · Last modified: 2021/05/22 14:16 by gary1