Which of the following clinical manifestations is most indicative of acute respiratory distress syndrome (ARDS)?

Correct Answer: C

Rationale: Rationale: - ARDS is characterized by severe hypoxemia and respiratory distress. - Tachypnea is a hallmark sign of ARDS due to the body's compensatory mechanism to increase oxygenation. - Hypoxemia refractory to supplemental oxygen signifies the inability to improve oxygen levels despite intervention. - Choices A, B, and D do not align with typical manifestations of ARDS, as they do not directly reflect severe hypoxemia or respiratory distress.

Correct Answer: B

Rationale: The correct answer is B: Disseminated intravascular coagulation (DIC). In DIC, there is widespread activation of coagulation leading to consumption of clotting factors, resulting in prolonged PT and aPTT, low fibrinogen levels, and elevated D-dimer. This pattern matches the laboratory findings in the patient. In liver cirrhosis (choice A), there is a decrease in clotting factors synthesis, leading to prolonged PT but not aPTT. Hemophilia A (choice C) is a genetic disorder that affects specific clotting factors, typically leading to prolonged aPTT but not PT. Vitamin K deficiency (choice D) impairs the synthesis of clotting factors, leading to prolonged PT but not aPTT and low levels of factors II, VII, IX, and X.

Correct Answer: C

Rationale: The correct answer is C: Meningitis. The patient's symptoms of severe headache, photophobia, neck stiffness, nuchal rigidity, and positive Kernig and Brudzinski signs are classic signs of meningitis. Meningitis is an inflammation of the meninges surrounding the brain and spinal cord, leading to these specific neurological symptoms. Migraine headache (A) typically presents with a throbbing headache, nausea, and sensitivity to light and sound, but does not typically cause neck stiffness or positive meningeal signs. Cluster headache (B) is characterized by severe unilateral headache with autonomic symptoms like tearing or nasal congestion, but does not typically cause neck stiffness or positive meningeal signs. Subarachnoid hemorrhage (D) presents with sudden severe headache often described as "the worst headache of my life," and may cause neck stiffness, but typically does not present with photophobia or positive meningeal signs like Kernig and Brudzinski signs.

Correct Answer: D

Rationale: The correct answer is D: Subarachnoid hemorrhage. This condition presents with sudden-onset severe headache, vomiting, and altered mental status due to bleeding in the subarachnoid space. This type of hemorrhage is typically noncontrast-enhancing on imaging. A: Ischemic stroke does not typically present with sudden-onset severe headache and vomiting. B: Subdural hematoma usually presents with a slower onset of symptoms and often develops after head trauma. C: Intracerebral hemorrhage presents with focal neurological deficits rather than altered mental status and vomiting. In summary, based on the sudden onset of symptoms, imaging findings, and clinical presentation, subarachnoid hemorrhage is the most likely diagnosis in this case.

Correct Answer: D

Rationale: The correct answer is D: Trigeminal neuralgia. This condition is characterized by recurrent, severe, stabbing pain in the trigeminal nerve distribution triggered by touch, chewing, or cold exposure. The key feature is the characteristic lancinating pain, which is not typical of migraine (choice A), cluster headache (choice B), or tension-type headache (choice C). Migraine typically presents with pulsating, moderate to severe headache associated with nausea and sensitivity to light and sound. Cluster headache is characterized by severe, unilateral pain around the eye associated with autonomic symptoms. Tension-type headache presents with bilateral, pressing or tightening pain without specific triggers. Therefore, based on the description of the symptoms in the question, trigeminal neuralgia is the most likely diagnosis.