A 79-year-old woman with a history of Type 2 diabetes presents with confusion and a decreased conscious state. The following are her blood results on admission:

Parameter

Result

Normal Range

Barometric pressure

760 mmHg (100 kPa)

FiO2

0.4

pH

7.32

7.35 – 7.45

PCO2

36 mmHg (4.0 kPa)

35 – 45 (4.7 – 6.0)

PO2

90 mmHg (12.0 kPa)

Bicarbonate

18 mmol/L*

22 – 26

Lactate

4.8 mmol/L*

<2.0

Sodium

140 mmol/L

135 – 145

Potassium

3.9 mmol/L

3.2 – 4.5

Chloride

105 mmol/L

100 – 110

Urea

21.8 mmol/L*

3.0 – 8.0

Creatinine

0.22 mmol/L*

0.07 – 0.12

Glucose

40 mmol/L*

3.6 – 7.7

  • What is the most likely condition consistent with these results? Give the rationale for your answer.
  • List four potential complications of this condition.

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College Answer

a) 

  • Non-ketotic hyperosmolar state:
  • Marked hyperglycaemia – higher than usually seen in DKA
  • Hyperosmolar – approx. 342 mOsm/Kg
  • Relatively mild anion gap acidosis accounted for by raised lactate

b)

  • Cerebral oedema
  • Vascular thrombosis
  • Electrolyte derangement
  • Intercurrent events such as sepsis, AMI Hypotension and shock if inadequate resuscitation
  • Death


 

Discussion

Let us dissect these results systematically.

  1. The A-a gradient is high; 194 or 337.6mmHg depending on what FiO2 you think the Hudson mask is delivering.
    PAO2 = (0.4 × 713) - (36 × 1.25) = 240.2
    Thus, A-a = ( 240.2 - 90) = 150.2mmHg.
  2. There is acidaemia
  3. The PaCO2 is vaguely compensatory
  4. The SBE is not offered but the bicarbonate is 18, suggesting a metabolic acidosis
  5. The respiratory compensation is adequate - the expected PaCO2(18 × 1.5) + 8 = 35mmHg
  6. The anion gap is raised:
    (140) - (105 + 18) = 17, or 20.9 when calculated with potassium
    The delta ratio, assuming a normal anion gap is 12 and a normal bicarbonate is 24, would therefore be (17 - 12) / (24 - 18) = 0.83
    This suggests that there is a mixed high anion gap and normal anion gap metabolic acidosis here.
     

The glucose of 40, urea creatinine and the raised lactate are all giveaway clues.

Ths patient has HONK and uremic renal failure. The calculated osmolarity is (140 × 2 + 21.8 + 40) = 341.8 mOsm/L.

Complications of HONK, as listed in the abovelinked page, are as follows:

  • Cardiac arrest
  • Cardiovascular collapse
  • Myocardial infarction
  • Stroke
  • Cerebral oedema and brain injury
  • Venous thrombosis

I do not see how listing "death" as a complication earns any marks in this exam.

References

References

Hyperglycemic Comas by P. VERNON VAN HEERDEN from Vincent, Jean-Louis, et al. Textbook of Critical Care: Expert Consult Premium. Elsevier Health Sciences, 2011.

Oh's Intensive Care manual: Chapter 58  (pp. 629) Diabetic  emergencies  by Richard  Keays

Umpierrez, Guillermo E., Mary Beth Murphy, and Abbas E. Kitabchi. "Diabetic ketoacidosis and hyperglycemic hyperosmolar syndrome." Diabetes Spectrum15.1 (2002): 28-36.

ARIEFF, ALLEN I., and HUGH J. CARROLL. "Nonketotic hyperosmolar coma with hyperglycemia: clinical features, pathophysiology, renal function, acid-base balance, plasma-cerebrospinal fluid equilibria and the effects of theraphy in 37 cases." Medicine 51.2 (1972): 73-94.

Gerich, John E., Malcolm M. Martin, and Lillian Recant. "Clinical and metabolic characteristics of hyperosmolar nonketotic coma." Diabetes 20.4 (1971): 228-238.

Kitabchi, Abbas E., et al. "Hyperglycemic crises in adult patients with diabetes." Diabetes care 32.7 (2009): 1335-1343.

Kitabchi, Abbas E., et al. "Hyperglycemic crises in adult patients with diabetes a consensus statement from the American Diabetes Association." Diabetes care 29.12 (2006): 2739-2748.

Ellis, E. N. "Concepts of fluid therapy in diabetic ketoacidosis and hyperosmolar hyperglycemic nonketotic coma." Pediatric clinics of North America 37.2 (1990): 313-321.

Pinies, J. A., et al. "Course and prognosis of 132 patients with diabetic non ketotic hyperosmolar state." Diabete & metabolisme 20.1 (1993): 43-48.