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Hyperosmolar hyperglycaemic state with an infected obstructed kidney76-year-old woman, 60 kg, for urgent cystoscopy and left ureteric stent for an infected, obstructed kidney

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Know this first

  • Calculated osmolality = 2[Na] + glucose/18 + BUN/2.8; above 340 causes obtundation.
  • Corrected sodium: add 1.6 per 100 mg/dL of glucose above 100.
  • HHS: fluid first, 1–2 L saline in the first hour if the heart allows; insulin only after initial volume.
  • Correcting hyperosmolarity too fast risks cerebral oedema.

The patient

76-year-old woman, 60 kg, for urgent cystoscopy and left ureteric stent for an infected, obstructed kidney. Type 2 diabetes, taking metformin and a thiazide; 5 days of polyuria and thirst, now confused and very dry. Labs: glucose 1010 mg/dL, Na 138 mmol/L, K 3.9 mmol/L, BUN 56 mg/dL, pH 7.32, HCO3 19 mmol/L, ketones trace, lactate 3.1 mmol/L. Vitals: BP 92/54, HR 116, SpO2 95% on air, RR 22, temp 38.9 °C.

The examiner asks

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  1. Consider

    What are the issues?

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    • A 76-year-old with a hyperosmolar hyperglycaemic state and urosepsis from an obstructed kidney, for an urgent stent. Patient
    • At 76 her heart limits how fast I can fill her, so I reassess after every bolus.
    • Her polyuria is an osmotic diuresis from glucose; diabetes insipidus would give urine under 200 mOsm/kg. Disease
    • Glucose over 1000, trace ketones and pH 7.32: this is HHS, not DKA.
    • Metformin stops; dehydration and sepsis raise her lactic acidosis risk.
    • The infected obstructed kidney is driving her sepsis, so source control can't wait long. Surgery

  2. Prepare

    How do you assess and resuscitate her?

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    • Calculated osmolality: 2 × 138 + 1010/18 + 56/2.8, about 352; that explains her confusion. (Disease)
    • Corrected sodium: 1.6 for each 100 mg/dL above 100, so about 153. She's short of water.
    • Saline 1–2 L over the first hour if her heart tolerates it, then slower, replacing a third in 6–8 hours.
    • Insulin once fluid is running and K is above 3.3: 0.1 units/kg/h, cut to 0.02–0.05 near 250–300 mg/dL.
    • K 3.9: 20–40 mEq in each litre once urine flows, keeping K between 4 and 5.
    • Her blood is thick and clot-prone: enoxaparin 40 mg daily once bleeding risk allows.
    • Antibiotics for her urosepsis within the hour of recognising it.

  3. Plan

    How do you manage her anaesthetic?

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    • A short anaesthetic for source control once she's partly resuscitated; the stent can't wait for full correction. Surgery
    • Confused and at aspiration risk: rapid sequence, with propofol under 1.5 mg/kg for her age and volume. Airway
    • Arterial line; noradrenaline 0.05–0.5 mcg/kg/min if her MAP stays below 65 after fluid. Disease
    • Glucose, sodium and osmolality checked hourly, aiming for a slow, steady fall.
    • ICU afterwards: her sepsis, osmolality and sodium need close, hourly attention. After surgery

  4. Crisis

    Eight hours into treatment, after a switch to 0.45% saline, her glucose is 380 mg/dL and sodium 131 mmol/L. She has a generalised seizure; SpO2 88%. How do you respond?

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    • A seizure during correction: cerebral oedema from a too-rapid osmolality fall, or low sodium. Crisis
    • Airway first: 100% oxygen, jaw thrust, suction, on her side, and a bedside glucose.
    • Midazolam 1–5 mg IV to stop the seizure.
    • Corrected sodium fell from 153 to 136 in 8 hours: back to 0.9% saline, insulin slowed.
    • If cerebral oedema is likely: mannitol or hypertonic saline, with neurocritical care input.
    • Recurrent seizures: fosphenytoin 15 mg/kg, no faster than 150 mg/min.
    • Not waking: intubate, CT head, and ICU. After surgery

Fatal mistakes

  • Letting her osmolality fall rapidly.
  • High-dose insulin before fluid replacement.
  • Delaying source control indefinitely while correcting her chemistry.

Checked against: Stoelting 8e · Miller 10e · Barash 9e · Surviving Sepsis Campaign: international guidelines for sepsis and septic shock (2021)

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