Question 21.3

Created on Wed, 05/13/2015 - 02:51
Last updated on Tue, 08/11/2015 - 18:40
Pass rate: 93%
Highest mark: 10

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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+3.9) - (105+18) = 20.9
    The delta ratio suggests that there is a pure high anion gap metabolic acidosis here.
    (20.9 - 12) / (24 - 18) = 1.48

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

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.