Differential Diagnosis
The patient's presentation of confusion, rapid breathing, increased urination, abdominal pain, fatigue, and somnolence, along with the laboratory results, suggests a complex metabolic and possibly infectious process. The following differential diagnoses are considered:
Single most likely diagnosis
- Diabetic Ketoacidosis (DKA): The patient's high glucose level (450 mg/dL), metabolic acidosis (low bicarbonate), and increased urination are consistent with DKA. The recent history of a viral illness could have triggered the onset of DKA, especially if the patient has a predisposition to diabetes.
Other Likely diagnoses
- Viral or bacterial sepsis: The patient's initial symptoms of rhinorrhea, cough, and fever, followed by abdominal pain and somnolence, could indicate a severe infection. However, the absence of a high fever and the specific laboratory findings make this less likely than DKA.
- Acute kidney injury: The elevated creatinine level and abdominal tenderness could suggest kidney involvement, but this would not fully explain the patient's hyperglycemia and metabolic acidosis.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Meningitis or encephalitis: Although the patient's symptoms have evolved, the initial presentation of fever and the current confusion could suggest central nervous system infection, which is a medical emergency.
- Adrenal insufficiency: The patient's hypotension, abdominal pain, and fatigue could be indicative of adrenal insufficiency, which would require immediate treatment.
Rare diagnoses
- Hyperosmolar Hyperglycemic State (HHS): While similar to DKA, HHS typically presents with more severe hyperglycemia and less pronounced ketosis. The patient's glucose level is high but not typically as high as seen in HHS.
- Toxic ingestions: Certain toxic ingestions could lead to metabolic acidosis and altered mental status, but there is no specific indication of this in the patient's history.
- Mitochondrial disorders: These are rare genetic disorders that can affect energy production and lead to metabolic crises, but they would be unusual in this context without prior suggestive history.