Differentials
Hyperosmolar hyperglycemic state (HHS)
SIGNS / SYMPTOMS
Patients are typically older than patients with DKA and are usually patients with type 2 diabetes. Older nursing home residents with poor fluid intake are at high risk.
Symptoms evolve insidiously over days to weeks.
Mental obtundation and coma are more frequent. Focal neurologic signs (hemianopia and hemiparesis) and seizures are also seen. Seizures may be the dominant clinical features.[1]
INVESTIGATIONS
Serum glucose is >600 mg/dL. Serum osmolality is usually >320 mOsm/kg.
Urine ketones are normal or only mildly positive. Serum ketones are negative.
Anion gap is variable but typically <12 mEq/L.
Total chloride deficit is 5 to 15 mEq/kg.
ABG: arterial pH is typically >7.30, whereas in DKA it ranges from 7.00 to 7.30. Arterial bicarbonate is >15 mEq/L.
Lactic acidosis
SIGNS / SYMPTOMS
The presentation is identical to that of DKA. In pure lactic acidosis, the serum glucose and ketones should be normal and the serum lactate concentration should be elevated.
INVESTIGATIONS
Serum lactate >5 mmol/L.[1]
Starvation ketosis
SIGNS / SYMPTOMS
Starvation ketosis results from inadequate carbohydrate availability resulting in physiologically appropriate lipolysis and ketone production to provide fuel substrates for muscle.
INVESTIGATIONS
The blood glucose is usually normal. Although the urine can have large amounts of ketones, the blood rarely does. Arterial pH is normal and the anion gap is at most mildly elevated.[1]
Alcoholic ketoacidosis
SIGNS / SYMPTOMS
Classically, these are people with long-standing alcohol use disorder for whom ethanol has been the main caloric source for days to weeks. The ketoacidosis occurs when for some reason alcohol and caloric intake decreases.
INVESTIGATIONS
In isolated alcoholic ketoacidosis, the metabolic acidosis is usually mild to moderate in severity. The anion gap is elevated. Serum and urine ketones are always present. Blood alcohol may be undetectable and the patient may be hypoglycemic.[1]
Salicylate poisoning
SIGNS / SYMPTOMS
Can be differentiated by history and laboratory investigation. Salicylate intoxication produces an anion gap metabolic acidosis usually with a respiratory alkalosis.
INVESTIGATIONS
The plasma glucose is normal or low, ketones are negative, osmolality is normal, and salicylates are positive in blood and/or urine. It should be noted that salicylates may cause false-positive or false-negative urinary glucose determination.[1]
Ethylene glycol/methanol intoxication
SIGNS / SYMPTOMS
Methanol and ethylene glycol also produce an anion gap metabolic acidosis without hyperglycemia or ketones.
INVESTIGATIONS
Methanol/ethylene glycol serum levels are elevated. They can produce an increase in the measured serum osmolality.[1]
Uremic acidosis
SIGNS / SYMPTOMS
This is characterized by markedly elevated BUN and creatinine with normal plasma glucose. The pH and anion gap are usually mildly abnormal.
INVESTIGATIONS
Elevated BUN usually >200 mg/dL and elevated creatinine usually >10 mg/dL.[1]
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