MDS PREP
What is the primary function of the gastrinoma in Zollinger Ellison syndrome?
1) Producing excessive gastrin
2) Inhibiting acid secretion
3) Stimulating pancreatic enzyme secretion
4) Promoting intestinal motility
A gastrinoma is a non-beta cell tumor that autonomously produces large amounts of gastrin, leading to hypergastrinemia and increased acid secretion in the stomach, resulting in severe peptic ulcers.
A patient with a history of liver cirrhosis develops a hemorrhagic tendency. Which coagulation factor is likely to be deficient?
1) Factor I (Fibrinogen)
2) Factor II (Prothrombin)
3) Factor V
4) Factor VIII
In liver disease, especially cirrhosis, there is a decrease in hepatic synthesis of clotting factors, particularly factor II (prothrombin). Vitamin K deficiency is also common in liver disease, which further contributes to hypoprothrombinemia. The deficiency of fibrinogen (factor I) would also result in a bleeding diathesis but is less common in liver disease. Factors V and VIII are also synthesized in the liver but are less frequently affected than factor II in such cases.
What is the principal cause of megaloblastic anemia other than vitamin B12 deficiency?
1) Folate deficiency
2) Iron deficiency
3) Vitamin A deficiency
4) Vitamin C deficiency
Megaloblastic anemia can be caused by either folate or vitamin B12 deficiency. Both of these nutrients are essential for DNA synthesis and cell division in the bone marrow.
A patient with chronic lymphocytic leukemia (CLL) is found to have a very high white blood cell (WBC) count. Which of the following is NOT a common physical examination finding in CLL?
1) Splenomegaly
2) Lymphadenopathy
3) Hepatomegaly
4) Fever
Chronic lymphocytic leukemia is characterized by the accumulation of mature-looking but functionally incompetent lymphocytes in the blood, bone marrow, and lymphoid tissues. Common physical examination findings include splenomegaly, lymphadenopathy, and hepatomegaly due to infiltration by leukemic cells.
What is the primary hormone responsible for the regulation of calcium homeostasis?
1) Parathyroid hormone (PTH)
2) Calcitonin
3) Vitamin D
4) Thyrocalcitonin
Parathyroid hormone (PTH) is the primary hormone that regulates calcium homeostasis in the body. It is secreted by the parathyroid glands and acts on the kidneys, bones, and intestines to maintain serum calcium levels within a narrow range. While vitamin D and calcitonin also play roles in calcium metabolism, PTH is the major player in this regulatory process.
What is the role of factor Xa in the coagulation cascade?
1) Activation of fibrinogen to fibrin
2) Conversion of prothrombin to thrombin
3) Activation of factor V
4) Activation of factor VIII
Factor Xa is a serine protease that plays a pivotal role in the common pathway of the coagulation cascade. It, along with factor Va, forms the prothrombinase complex that converts prothrombin (factor II) to thrombin (factor IIa), which in turn activates fibrinogen to form fibrin, leading to clot formation.
Which of the following is a congenital deficiency associated with a hemorrhagic diathesis?
1) Hageman trait
2) Parahemophilia
3) Hypoprothrombinemia due to liver disease
4) Hemophilia A
Hemophilia A is a congenital defect due to various abnormalities of the gene on the X chromosome that codes for factor VIII, leading to a hemorrhagic diathesis. Hageman trait is also congenital but does not directly cause a bleeding disorder.
Pinhead stippling of the skull is a radiological sign associated with which condition?
1) Rickets
2) Osteopetrosis
3) Hyperparathyroidism
4) Osteomalacia
Pinhead stippling of the skull is a sign of increased osteoclastic activity, which is characteristic of hyperparathyroidism. It represents resorption of the outer layer of the bone and is most prominent in the calvaria.