A 45-year-old woman presents with fatigue, pruritus, and jaundice. Laboratory tests reveal elevated bilirubin and alkaline phosphatase levels. Imaging shows a normal common bile duct but dilated intrahepatic bile ducts. What is the most likely diagnosis?

Correct Answer: A

Rationale: The most likely diagnosis for the 45-year-old woman with fatigue, pruritus, jaundice, elevated bilirubin and alkaline phosphatase levels, and dilated intrahepatic bile ducts is Primary Biliary Cirrhosis (PBC). PBC is an autoimmune liver disease that primarily affects middle-aged women, leading to bile duct destruction and liver damage. The elevated alkaline phosphatase levels and presence of pruritus are typical in PBC due to impaired bile flow. Imaging showing dilated intrahepatic bile ducts supports the diagnosis of PBC as it indicates bile duct damage. Summary of other choices: B: Primary sclerosing cholangitis typically presents with strictures and beading of bile ducts on imaging. C: Gallstones would typically present with a common bile duct obstruction and not dilated intrahepatic bile ducts. D: Pancreatic cancer would typically present with different imaging findings and symptoms such as

Correct Answer: A

Rationale: The most likely diagnosis for a 60-year-old man with fatigue, polyuria, polydipsia, hyperglycemia, and ketonuria is Type 1 diabetes mellitus. The key clues are the presence of ketonuria, which indicates the body is breaking down fats for energy due to lack of insulin in Type 1 diabetes. Additionally, the acute onset of symptoms in an older individual suggests an autoimmune destruction of pancreatic beta cells seen in Type 1 diabetes. Type 2 diabetes is less likely due to the acute presentation and ketonuria. Diabetes insipidus presents with polyuria but not hyperglycemia or ketonuria. Hyperthyroidism typically presents with symptoms such as weight loss, tremors, and heat intolerance, not the classic symptoms seen in this case.

Correct Answer: A

Rationale: The most likely diagnosis is A: Primary biliary cirrhosis. This is supported by the patient's symptoms of fatigue, pruritus, jaundice, elevated bilirubin and alkaline phosphatase levels, and dilated intrahepatic bile ducts. Primary biliary cirrhosis is an autoimmune liver disease that primarily affects middle-aged women, leading to destruction of intrahejson hepatic bile ducts. The normal common bile duct rules out obstruction from gallstones or pancreatic cancer. Primary sclerosing cholangitis typically presents with strictures in the bile ducts, which is not seen in this case. Therefore, the combination of symptoms, lab findings, and imaging results point towards primary biliary cirrhosis as the most likely diagnosis.

Correct Answer: A

Rationale: The correct answer is A: Hypothyroidism. In this scenario, the patient has symptoms of hypothyroidism (fatigue, weight gain, cold intolerance) along with high TSH and low free T4 levels, indicating primary hypothyroidism. TSH is elevated as the body is trying to stimulate the thyroid to produce more thyroid hormones. Free T4 is low as the thyroid is not able to produce enough hormones. Hyperthyroidism (choice B) would present with low TSH and high free T4 levels. Thyroiditis (choice C) typically presents with symptoms of hyperthyroidism followed by hypothyroidism. Thyroid cancer (choice D) usually does not cause these specific symptoms and lab findings. Therefore, based on the symptoms and lab results, hypothyroidism is the most likely diagnosis.

Correct Answer: A

Rationale: Step 1: Symptoms of fatigue, polyuria, polydipsia point to diabetes. Step 2: Hyperglycemia and ketonuria suggest uncontrolled diabetes. Step 3: Onset in a 30-year-old woman is more common in Type 1 diabetes. Step 4: Type 1 diabetes is characterized by autoimmune destruction of pancreatic beta cells leading to insulin deficiency. Step 5: Treatment for Type 1 diabetes involves insulin therapy. Summary: - Choice B (Type 2 diabetes) is less likely due to the acute presentation and ketonuria. - Choice C (Diabetes insipidus) does not involve hyperglycemia or ketonuria. - Choice D (Hyperthyroidism) does not typically present with hyperglycemia and ketonuria.