In a case of a 30-year-old female with polyuria and hyperglycemia at 650 mg/dl, what is the most likely diagnosis?

The diagnosis of Hyperglycemic Hyperosmolar State (HHS) is most likely accurate in this scenario due to the significant hyperglycemia observed at 650 mg/dl combined with symptoms of polyuria. HHS typically presents in older patients and is characterized by extreme hyperglycemia, often exceeding 600 mg/dl, and a higher serum osmolality. In this case, the patient's young age doesn't entirely rule out HHS, particularly if there are other underlying health conditions such as insulin resistance or concurrent illness that may trigger this state.

In HHS, unlike Diabetic Ketoacidosis (DKA), there is typically a relative insulin deficiency rather than absolute deficiency and minimal or absent ketones in the blood, which supports high glucose levels without significant metabolic acidosis. The presence of polyuria suggests that the body is attempting to excrete excess glucose, which is consistent with HHS.

In this context, while DKA is often associated with younger patients and can also present with hyperglycemia, the pronounced level of hyperglycemia and the lack of a reference to ketoacidosis symptoms (such as metabolic acidosis or abdominal pain) lean more towards HHS as the main diagnosis. Hemolytic Uremic Syndrome (HUS