Diabetic Ketoacidosis (DKA): This condition is a common and serious complication of diabetes that occurs when the body produces high levels of blood acids called ketones. The sudden onset of uncontrolled glucose levels, especially in a diabetic patient, makes DKA a highly probable diagnosis due to its direct link with glucose metabolism and insulin deficiency or resistance.

Hyperosmolar Hyperglycemic State (HHS): Similar to DKA but without the significant production of ketones, HHS is another serious condition associated with very high blood glucose levels, often seen in type 2 diabetes. It can be precipitated by infections, certain medications, or other stressors.
Insulinoma: A rare tumor of the pancreas that produces excess insulin, leading to episodes of hypoglycemia. However, in the context of sudden uncontrolled glucose differential, an insulinoma could potentially cause erratic blood glucose levels if the tumor's insulin secretion is intermittent or if the patient's diet and activity levels significantly vary.
Glucagonoma: A tumor of the pancreas that secretes glucagon, causing hyperglycemia among other symptoms. Like insulinoma, it could lead to uncontrolled glucose levels, though it's less common.

Pituitary Apoplexy: A condition where there's sudden hemorrhage or infarction of the pituitary gland, which can disrupt the normal regulation of hormones, including those involved in glucose metabolism. Although rare, missing this diagnosis could be fatal.
Adrenal Insufficiency (Addisonian Crisis): A life-threatening condition that occurs when the adrenal glands do not produce adequate amounts of cortisol and, in some cases, aldosterone. It can lead to hypoglycemia or erratic glucose levels among other critical symptoms.
Pheochromocytoma: A rare tumor of the adrenal gland that secretes catecholamines, leading to episodes of hypertension, tachycardia, and potentially glucose metabolism disturbances due to the effects of these hormones on glucose release and insulin sensitivity.

Somatostatinoma: A rare tumor of the pancreas that secretes somatostatin, which can inhibit the secretion of insulin and glucagon, leading to diabetes.
VIPoma: A rare pancreatic tumor that secretes vasoactive intestinal peptide (VIP), causing a syndrome that includes diabetes due to the inhibition of insulin secretion and the stimulation of glucagon secretion.
Cushing's Syndrome: A condition caused by having too much of the hormone cortisol in the body, which can lead to hyperglycemia due to cortisol's effects on glucose metabolism. While not as immediately life-threatening as some other conditions, it's a significant diagnosis to consider in the context of uncontrolled glucose levels.