Correct Answer: C

Rationale: The correct answer is dementia with Lewy bodies (DLB). Hallucinations, parkinsonian symptoms (like bradykinesia and limb rigidity), and fluctuating cognition are characteristic of DLB. Alzheimer's disease (Choice A) typically presents with memory loss as a prominent feature. Vascular dementia (Choice B) is associated with a history of strokes and step-wise cognitive decline. Frontotemporal dementia (Choice D) often presents with changes in behavior and personality rather than the parkinsonian symptoms seen in this case.

Correct Answer: C

Rationale: The correct answer is C, aortic dissection. Aortic dissection is characterized by sudden, severe chest pain that can radiate to the back. The discrepancy in blood pressure between the arms (higher in the right arm) is known as a 'pulse deficit' and is a classic finding in aortic dissection. This condition involves a tear in the inner layer of the aorta, leading to the abnormal flow of blood within the aortic wall. Acute myocardial infarction (choice A) presents with chest pain but typically does not cause discrepancies in blood pressure between arms. Pulmonary embolism (choice B) usually presents with chest pain and difficulty breathing but does not cause unequal blood pressures in the arms. Pericarditis (choice D) can cause chest pain exacerbated by breathing or lying down, but it does not typically lead to differences in blood pressure between arms.

Correct Answer: C

Rationale: The correct answer is C: 'It is usually triggered when the patient bends forward.' Benign positional vertigo is often triggered by changes in head position, such as bending forward. Choices A, B, and D are incorrect. A is incorrect because benign positional vertigo is not typically associated with headaches. B is incorrect because pupillary changes are not a common feature of benign positional vertigo. D is incorrect because nystagmus in benign positional vertigo usually stops when the eyes fixate on an object.

Correct Answer: A

Rationale: Primary aldosteronism is a common cause of secondary hypertension. In primary aldosteronism, there is an overproduction of aldosterone from the adrenal glands, leading to increased sodium retention and potassium excretion, ultimately resulting in high blood pressure. Essential hypertension (Choice B) is the most common type of hypertension, but it is considered primary hypertension, not secondary. White coat hypertension (Choice C) refers to elevated blood pressure readings in a clinical setting due to anxiety but not in daily life. Prehypertension (Choice D) is a condition where blood pressure levels are elevated but not high enough to be classified as hypertension.

Correct Answer: C

Rationale: Thyroid crisis in Graves' disease typically presents with hyperthermia (high body temperature) and tachycardia (rapid heart rate). These symptoms are a result of excessive thyroid hormone production and can lead to life-threatening complications if not promptly addressed. Choices A, B, and D are incorrect because constipation with gastric distension, bradycardia and bradypnea, and constipation and lethargy are not typical signs of a thyroid crisis in Graves' disease.