Diabetes Mellitus

Answer: A
Explanation: Diabetic ketoacidosis (DKA) is most common in type 1 diabetes due to the absolute insulin deficiency. Davidson explains that without insulin, the body shifts to fat metabolism, producing ketones and leading to metabolic acidosis. Harrison adds that DKA can occur in type 2 diabetes under extreme stress, but it is far less common.

Reference: Davidson 23rd; P-748

Reference: Davidson 23rd; P-749

Reference: Davidson 23rd; P-746

Reference: Davidson 23rd; P-746

Stem Breakdown:

Polyuria, polydipsia, and nocturia: These are classic symptoms of diabetes mellitus, indicating hyperglycemia leading to osmotic diuresis.
Fasting blood glucose of 170 mg/dL and haemoglobin A1c of 8.2%: These results confirm persistent hyperglycemia and meet the diagnostic criteria for diabetes mellitus (fasting blood glucose ≥126 mg/dL, A1c ≥6.5%).
Option Analysis:

A) Type 1 diabetes mellitus: Type 1 diabetes usually presents in younger individuals with an acute onset of symptoms (polyuria, weight loss) and often requires insulin from the onset. This patient’s presentation, age, and gradual development of symptoms are more consistent with type 2 diabetes.
B) Type 2 diabetes mellitus: This is the correct diagnosis. Davidson and Harrison explain that type 2 diabetes is the most common form of diabetes, typically occurring in middle-aged or older adults, often with a gradual onset. It is characterised by insulin resistance and relative insulin deficiency, leading to elevated fasting blood glucose and A1c levels.
C) Diabetes insipidus: Diabetes insipidus is characterised by polyuria and polydipsia, but it results from a deficiency of antidiuretic hormone (ADH) or renal insensitivity to ADH. Blood glucose levels would be normal, not elevated.
D) Hyperosmolar hyperglycaemic state (HHS): HHS is a life-threatening complication of type 2 diabetes, characterised by extreme hyperglycemia (>600 mg/dL), dehydration, and altered mental status. The patient in this case has elevated glucose but is not in HHS.

(Ref : Davidson 23rd ,p-703 )

Reference: Davidson 23rd; P-746

Reference: Davidson 23rd, Page: 760
Explanation: Median nerve compression is more common in diabetes causing carpal tunnel syndrome.

Reference: Davidson 23rd, Page: 746 , Box : 20.26

Stem Breakdown:

Polyuria, polydipsia, and weight loss: These symptoms indicate uncontrolled hyperglycemia, suggesting diabetes mellitus.
Fasting blood glucose of 230 mg/dL and HbA1c of 10.5%: These levels confirm the diagnosis of diabetes, with an HbA1c >6.5% indicating poorly controlled blood glucose.
Option Analysis:

A) Insulin: Insulin is used in type 1 diabetes and in type 2 diabetes when oral agents fail to achieve glycaemic control. However, for most newly diagnosed type 2 diabetes patients, oral hypoglycemic agents are first-line unless there are signs of diabetic ketoacidosis or severe hyperglycemia.
B) Metformin: This is the correct answer. Davidson and Harrison both recommend metformin as the first-line therapy for type 2 diabetes, as it effectively lowers blood glucose by improving insulin sensitivity and reducing hepatic glucose production without causing significant hypoglycemia. It is typically used in patients who are overweight, as it does not promote weight gain.
C) Sulfonylureas: Sulfonylureas (e.g., glipizide, glyburide) are effective in lowering blood glucose but are associated with weight gain and a higher risk of hypoglycemia compared to metformin. They are often used as second-line agents if metformin alone is insufficient.
D) DPP-4 inhibitors: DPP-4 inhibitors (e.g., sitagliptin) help increase insulin secretion and reduce glucagon secretion but are generally used as add-on therapy to metformin. They are not as effective as first-line treatment for most patients with type 2 diabetes.

Reference: Davidson 23rd; P-746

Explanation: Metformin is used as first-line therapy for type 2 diabetes, irrespective of body weight

Reference: Davidson 23rd, Page: 736 , Box : 20.15

Reference: Davidson 23rd, Page: 733 , Box : 20.9

Reference: Davidson 23rd, Page: 756, Box: 20.36

Whipple’s triad confirmed
Patient had symptoms of hypoglycaemia
Low blood glucose measured at the time of symptoms
Symptoms resolved on correction of hypoglycaemia