Differentials
Diabetic ketoacidosis (DKA)
SIGNS / SYMPTOMS
Patients are often younger and usually with type 1 diabetes.
Abdominal pain is uncommon in HHS but frequently seen (>50%) in patients in DKA.[2][13]
Patients with ketosis-prone type 2 diabetes are mainly African-American or Hispanic in origin.[48]
INVESTIGATIONS
Venous pH <7.3.
HCO₃ <15 mEq/L.
Elevated serum or blood beta-hydroxybutyrate >3.0 mmol/L, or >3.8 mmol/L in children.[49]
Lactic acidosis
SIGNS / SYMPTOMS
May be clinically indistinguishable from HHS and DKA although most patients do not have a history of diabetes.
Sometimes occurs in association with HHS and DKA.
INVESTIGATIONS
Venous pH <7.3.
HCO₃ <15 mEq/L.
Lactic acid >5 mEq/L.
Serum glucose and ketones are normal.
Alcohol ketoacidosis
SIGNS / SYMPTOMS
A history of chronic alcohol abuse is present.
Produced by starvation due to poor food intake.
Peripheral signs of chronic liver disease, such as spider nevi, leukonychia, palmar erythema, bruising, jaundice, scratch marks, and hepatomegaly, are present.
INVESTIGATIONS
Venous pH is variable and can be normal.
HCO₃ <15 mEq/L; anion gap >12 mEq/L
Serum glucose is low or normal but serum ketones or beta-hydroxybutyrate is elevated.
Lactate levels are usually elevated but elevation is insufficient to account for acidosis.
Ingestion of toxic substances
SIGNS / SYMPTOMS
History of ingestion of ethanol, methanol, ethylene glycol (constituent of automobile antifreeze), and/or propylene glycol (diluent in many intravenous medications, such as lorazepam) is present.
Paraldehyde ingestion is suggested by its characteristic strong odor in the breath.[2]
Salicylate overdose
SIGNS / SYMPTOMS
A history of chronic salicylate ingestion or salicylate overdose is present.
INVESTIGATIONS
Serum salicylate levels will be elevated.
Seizures
SIGNS / SYMPTOMS
Patients may have a history of prior seizure events.
May present with widespread motor manifestations.
INVESTIGATIONS
Blood chemistry may be normal.
Electroencephalogram may show epileptiform activity.
Stroke
SIGNS / SYMPTOMS
In most cases, the symptoms of stroke appear rapidly, over seconds or minutes.
Patients may present with limb and/or facial weakness (typically affects face, leg, and arm equally); may show visual disturbance.
INVESTIGATIONS
Blood chemistries are normal.
Cranial CT or MRI demonstrates hemorrhage or attenuation.
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