MDS PREP
What is the primary mechanism of action of antiphospholipid syndrome in promoting thrombosis?
1) Inhibition of protein C and protein S
2) Activation of platelets
3) Enhancement of fibrinolysis
4) Induction of antibodies against phospholipids
Antiphospholipid syndrome is an autoimmune disorder characterized by the presence of antiphospholipid antibodies. These antibodies can bind to phospholipids in cell membranes, leading to a prothrombotic state and an increased risk of thrombosis. The exact mechanism by which these antibodies induce thrombosis is complex and may involve interference with anticoagulant proteins like protein C and protein S, as well as platelet activation and endothelial damage. However, the primary mechanism is the presence of these autoantibodies.
A 35-year-old male comes to the clinic complaining of fever and malaise. Blood tests reveal a positive reaction to a tuberculin skin test. What is the most likely diagnosis?
(1) Active tuberculosis (TB)
(2) Latent TB infection
(3) BCG vaccine failure
(4) TB meningitis
A positive tuberculin skin test indicates a past exposure to TB bacteria, which has led to the development of an immune response. Latent TB infection is asymptomatic and does not imply active disease. Further tests are needed to rule out active TB.
A patient with a history of heart failure is prescribed digoxin. Which of the following is a common side effect of digoxin therapy?
(1) Hypertension
(2) Hyperkalemia
(3) Hypokalemia
(4) Hypercalcemia
Digoxin can cause hyperkalemia due to its effect on sodium-potassium ATPase pumps in cardiac cells, leading to increased intracellular sodium and decreased intracellular potassium. However, it is important to note that digoxin can also cause arrhythmias in the presence of high serum potassium levels.
In a patient with generalized muscle weakness following barium carbonate ingestion, what is the most likely underlying cause?
1) Hypermagnesemia
2) Hypokalemia
3) Hyperkalemia
4) Hypocalcemia
Barium carbonate can cause muscle weakness by increasing muscle sodium permeability and decreasing potassium permeability, leading to a large shift of extracellular potassium into muscle cells, resulting in hypokalemia.
A 65-year-old male with a history of hypertension is admitted for an acute exacerbation of chronic obstructive pulmonary disease (COPD). His current medication includes metoprolol. Which of the following is a possible adverse effect of metoprolol that could be relevant to his condition?
(1) Bronchospasm
(2) Peripheral edema
(3) Bradycardia
(4) Tachycardia
Metoprolol is a beta-blocker, which can cause bronchospasm as a side effect, particularly in patients with a history of respiratory conditions like asthma or COPD. It is important to monitor patients with respiratory diseases closely for signs of bronchospasm when prescribing beta-blockers.
What is the primary prevention strategy for pulmonary embolism in patients with heart failure and atrial fibrillation?
(1) Antiplatelet therapy
(2) Anticoagulation therapy with warfarin
(3) Physical prophylaxis with compression stockings
(4) Thrombolytic therapy
Patients with heart failure and atrial fibrillation are at high risk for pulmonary embolism due to venous thrombosis and intra-cardiac thrombus formation. The primary prevention strategy for these patients is anticoagulation therapy with warfarin, as it reduces the risk of thrombus formation and embolization. Warfarin is effective in preventing stroke and systemic embolism in patients with non-valvular atrial fibrillation and is also beneficial in the context of heart failure.
In Paget's disease of bone, which of the following is a characteristic finding in serum biochemistry?
(1) High serum alkaline phosphatase levels
(2) High serum calcium levels
(3) Low serum phosphorus levels
(4) High serum PTH levels
Paget's disease is characterized by excessive and abnormal bone remodeling, which results in increased bone turnover. This increased turnover is reflected in the serum by high levels of alkaline phosphatase, an enzyme involved in bone formation. While calcium and phosphorus levels may be affected in some cases, the hallmark biochemical abnormality in Paget's disease is elevated alkaline phosphatase.
A patient with a history of hypothyroidism presents with fatigue, cold intolerance, and weight gain. The most likely cause of these symptoms is:
1) Subclinical hypothyroidism
2) Hyperthyroidism
3) Thyroid cancer
4) Adrenal insufficiency
The symptoms of fatigue, cold intolerance, and weight gain are more consistent with hypothyroidism than hyperthyroidism. Subclinical hypothyroidism is a milder form of hypothyroidism where the patient may have a normal T4 level but an elevated TSH level.