Hypoglycaemia

Clinical definition and risk

Hypoglycaemia is an abnormally low blood glucose concentration. Severe or prolonged hypoglycaemia can cause seizures, coma, irreversible neurological injury, and death.

Always consider hypoglycaemia in any patient with impaired consciousness, lethargy, coma, seizures, severe acute illness, severe malnutrition, diabetes treatment, heavy alcohol use, or unexplained neurological symptoms.

Measure blood glucose whenever possible, but if hypoglycaemia is clinically suspected and a test is not immediately available, give glucose or another rapidly available sugar empirically.

Neonatal hypoglycaemia requires a dedicated newborn protocol and should be managed under obstetric/newborn guidance.

Clinical features

• Symptoms usually begin rapidly and may be non-specific: hunger, fatigue, tremor, sweating, pallor, anxiety, palpitations, tachycardia, headache, blurred vision, or difficulty speaking.
• Neuroglycopenic signs include confusion, unusual behaviour, drowsiness, focal neurological signs, convulsions, lethargy, coma, or respiratory compromise after a seizure.
• Infants, malnourished children, older adults, septic patients, intoxicated patients, and people taking sedatives may show few warning symptoms.
• Symptoms may recur after initial correction if the cause continues, insulin or oral hypoglycaemic medicine remains active, intake is poor, or glycogen reserves are low.

Diagnosis and thresholds

Use a capillary blood glucose reagent strip when available. If symptoms resolve after sugar or glucose where testing was unavailable, the clinical diagnosis is strongly supported.

• Repeat glucose testing after treatment, because clinical improvement can be temporary.
• If the patient does not improve after correction, reassess for meningitis, severe malaria, sepsis, epilepsy, poisoning, alcohol intoxication, adrenal insufficiency in children, stroke, head injury, or another cause of coma/seizure.

Emergency treatment

Treat immediately according to consciousness and swallowing safety. Protect airway and breathing in any patient with coma, seizure, or reduced consciousness.

• If ready-made 10% glucose is unavailable for a child, prepare it by removing 100 ml from a 500 ml bag of 5% glucose and adding 50 ml of 50% glucose to the remaining 400 ml, producing 450 ml of 10% glucose.
• Neurological signs may improve within minutes after IV glucose; oral sugar usually improves symptoms within about 15 minutes.
• After stabilisation, give a meal or snack rich in complex carbohydrate and observe for several hours.
• If full alertness does not return after severe hypoglycaemia, continue regular blood glucose monitoring and search for another cause.

Aetiological treatment

• Treat severe acute malnutrition, neonatal sepsis, severe malaria, sepsis, acute alcohol intoxication, prolonged fasting, vomiting, or poor intake.
• End prolonged fasting and provide reliable carbohydrate intake after emergency correction.
• Review medicines that can induce or worsen hypoglycaemia, including insulin, oral antidiabetics, IV quinine, pentamidine, ciprofloxacin, enalapril, beta-blockers, high-dose aspirin, and tramadol.
• When a hypoglycaemia-inducing medicine cannot be stopped, anticipate the risk. For example, quinine infusion requires glucose-containing fluid and close monitoring.
• In adults with suspected alcohol-related illness or vitamin B1 deficiency, give thiamine at the same time as glucose and continue replacement afterward.

Diabetic patient review

• Ask about insulin or oral antidiabetic dose, timing, missed meals, vomiting, increased physical activity, renal disease, alcohol, weight loss, new medicines, and previous hypoglycaemia episodes.
• Avoid missed meals and increase carbohydrate intake when physical activity, poor intake, or intercurrent illness increases risk.
• Adjust insulin based on blood glucose pattern, food intake, activity, renal function, infection, and clinician review.
• Adjust oral antidiabetic medicines with attention to drug interactions and renal or hepatic impairment.
• Provide clear return precautions and a prevention plan before discharge.

Monitoring and follow-up

• Monitor consciousness, airway, respiratory status, pulse, blood pressure, temperature, oral intake, vomiting, and recurrent neuroglycopenic symptoms.
• Repeat capillary glucose after 15 minutes, then continue checks according to severity, treatment used, recurrence risk, and medicine half-life.
• Observe severe cases for several hours after apparent recovery, especially after insulin or sulfonylurea exposure, malnutrition, sepsis, malaria, alcohol intoxication, renal failure, or poor intake.
• Document the lowest glucose value, treatment given, response time, recurrent episodes, suspected cause, and discharge plan.

Complications, prevention, and referral

• Complications include seizure, aspiration, traumatic injury, coma, arrhythmia, recurrent hypoglycaemia, permanent neurological injury, and death.
• Prevent recurrence by treating the underlying illness, ensuring regular feeding, correcting malnutrition, reviewing diabetes medicines, planning sick-day diabetes care, avoiding alcohol-related fasting, and educating caregivers on early symptoms.
• Refer or admit for coma, seizure, recurrent or persistent hypoglycaemia, inability to eat, severe malnutrition, severe malaria, sepsis, poisoning, suspected adrenal insufficiency, pregnancy, infancy, renal failure, unsafe home setting, or uncertain cause.
• Handover should include glucose values and times, clinical signs, sugar or IV glucose given, response, recurrent episodes, medicines taken, last meal, comorbid illness, pregnancy status, and suspected cause.