A thyrotoxic crisis is a complication of which disorder?

Choice A reason: Chronic asthma involves persistent symptoms managed over time, not an acute, life-threatening event. Status asthmaticus is an acute, severe exacerbation unresponsive to standard treatments, requiring urgent intervention, making this choice incorrect for describing status asthmaticus.

Choice B reason: An asthma attack triggered by exercise is exercise-induced bronchospasm, not status asthmaticus. Status asthmaticus is a severe, prolonged attack resistant to therapy, not defined by a specific trigger like exercise, making this choice incorrect.

Choice C reason: A mild asthma attack resolving with bronchodilators responds to standard therapy, unlike status asthmaticus, which is a severe, life-threatening attack unresponsive to bronchodilators and corticosteroids, requiring intensive care, making this choice incorrect for the condition.

Choice D reason: Status asthmaticus is a severe, prolonged asthma attack that does not respond to standard treatments like bronchodilators and corticosteroids. It causes critical airway obstruction and hypoxia, requiring aggressive medical intervention, accurately describing the condition and making this the correct choice.

Choice A reason: Coronary artery vasospasm causes transient vessel constriction, reducing blood flow to the myocardium, leading to ischemia and potentially infarction. This is a recognized cause, particularly in variant angina, making this a correct mechanism for myocardial infarction.

Choice B reason: A thrombus forming in a coronary artery, often due to plaque rupture, obstructs blood flow, causing myocardial ischemia and infarction. This is the most common cause of myocardial infarction, making this a correct mechanism.

Choice C reason: Chest wall bruising from trauma does not directly cause myocardial infarction, which requires coronary artery occlusion. Trauma may cause cardiac contusion but not infarction, making this choice incorrect for myocardial infarction development.

Choice D reason: An embolus, such as from a clot elsewhere, can block a coronary artery, stopping blood flow to the myocardium, causing infarction. Though less common than thrombosis, it is a valid mechanism, making this a correct choice.

Choice E reason: Systemic infection with hyperthermia does not directly cause myocardial infarction. It may increase cardiac demand, potentially exacerbating ischemia, but infarction requires coronary occlusion, not just fever, making this choice incorrect.