INVESTIGATIONS AND DIFFERENTIALS OF HYPERGLYCAEMIC

EMERGENCIESDR ILERHUNMWUWA P.N

OUTLINE

• Investigations to confirm diagnosis and assess severity

• Investigations to establish precipitants

• Ancillary investigations

• Differentials

INVESTIGATIONS TO CONFIRM DIAGNOSIS AND ASSESS SEVERITY

DKA(mild) DKA( moderate) DKA( severe) HHS

Plasma glucose (mg/dl)

250 > 250 > 250 600

Urine ketones ++/+++ . May be negative.

++/+++ . May be negative.

++/+++ . May be negative.

+/Absent

Serum ketones * ++/+++ ++/+++ ++/+++ +/Absent

Serum osmolarity (mOsm/L)

Serum Osmolarity (in mOsm/L) = 2[Na++K] + plasma glucose + plasma urea

Normal Serum Osmolarity = 275 -300 mOsmol/L

Variable Variable Variable > 320

……contdDKA(mild) DKA(moderate) DKA(severe) HHS

Anion gap = (Na++K+) – (HCO3-+Cl-)*

Normal anion gap = 10–14 mmol/L

> 10. Typically above 14

> 12. Typically above 14

> 12 Variable. Typically normal.

Serum bicarbonate (mEq/L)*Normal value = 22 - 30

15 - 18 10 - 15 < 10 > 15

Arterial pH *Normal arterial pH = 7.35-7.45

7.25 – 7.30 7.00 – 7.24 < 7.00 > 7.30

* Used to assess severity

ANCILIARY INVESTIGATIONSInvestigations Comments

Full blood count with differentials • Anemia, leukocytosis typical and does not indicate infection• Leukocyte counts commonly between 10000 to 15000 cells

per uL• Leukocyte counts above 25000 suggests infection• Peripheral blood fiml important to establish infection

Electrolytes, urea and creatinine • Serum sodium typically normal or low in DKA but high in HHS

• Serum potassium may be elevated, normal or low.• Azotemia may result from dehydration, or indicate renal

failure as the precipitant.

Fasting lipid profile • Hypertriglyceridemia may account for pseudohypnatraemia and pseudonormoglycaemias

Serum lactate • Could be elevated in DKA• In the presence of normal plasma glucose, strongly suggests

lactic acidosis.

INVESTIGATIONS TO ESTABLISH PRECIPITANTS• Urine m/c/s• Sputum m/c/s• Blood culture• Cardiac enzymes• Chest x-ray• Brain imaging• Thyroid function tests• Toxicology screening

DIFFERENTIAL DIAGNOSES

• 1. Other causes of acute abdomen e.g peptic ulcer disease, acute cholecystitis

• 2. Other causes of altered sensorium e.g meningitis, cerebral malaria

• 3. Other causes of ketosis e.g starvation, alcohol ingestion

• 4. Other causes of high-anion gap metabolic acidosis e.g lactic acidosis

SUMMARY

• Investigations are needed to establish the type of hyperglycaemic emergencies as this will ultimately influence the line of management.

• There are many conditions that can mimic the presentation of hyperglycaemic emergencies and these must be sought for in the history and consequently investigations.

REFERENCE

• 1. Diabetes Care. 2009; 32(7): 1335- 1343.

• 2. Slovis CM, Mork VG, Slovis RJ, et al. Diabetic ketoacidosis and infection: leukocyte count and differential as early predictors of serious infection. Am J Emerg Med 1987; 5: 1-5.

• 3. Sheikh-Ali M, Karon BS, Basu A, et al. Can serum beta- hydroxybutyrate be used to diagnose diabetic ketoacidosis? Diabetes Care 2008; 31: 643-647.