Correct Answer: C

Rationale: The correct answer is C: Autoantibodies. In Hashimoto's thyroiditis, the immune system mistakenly attacks the thyroid gland by producing autoantibodies against thyroid proteins such as thyroglobulin and thyroid peroxidase. These autoantibodies lead to inflammation and destruction of thyroid tissue. Antigen-antibody complexes (choice A) are not the main mechanism in Hashimoto's thyroiditis. Viral (choice B) and bacterial infections (choice D) do not directly cause autoimmune destruction of the thyroid in this condition. Autoantibodies targeting the thyroid gland are the key pathogenic factor in Hashimoto's thyroiditis.

Correct Answer: A

Rationale: The correct answer is A: Bacterial meningitis. Bacterial meningitis is the most significant form due to its potential severity and rapid progression, requiring urgent medical intervention with antibiotics. Bacterial meningitis can lead to serious complications such as brain damage or death if left untreated. Septic meningitis (choice B) refers to meningitis caused by a systemic infection spreading to the meninges. Aseptic meningitis (choice C) is typically viral or non-bacterial in origin, usually milder than bacterial meningitis. Viral meningitis (choice D) is less severe than bacterial meningitis and often resolves on its own without specific treatment.

Correct Answer: C

Rationale: The correct answer is C: platelets 18,000. A critically low platelet count can lead to life-threatening bleeding in the ICU. Normal platelet count ranges from 150,000 to 450,000. A count of 18,000 indicates severe thrombocytopenia. Immediate reporting is crucial for prompt intervention. Rationale for why other choices are incorrect: A: Hematocrit of 48% is within normal range (male: 42-52%, female: 37-47%). B: paCO2 of 38 mm Hg is within normal range (35-45 mm Hg). D: WBC count of 8000 is within normal range (4000-11000/uL). In critical care settings, it is vital to prioritize and address life-threatening conditions promptly, hence the urgent need to report the critically low platelet count.

Correct Answer: B

Rationale: The correct answer is B because in a normal Rinne test, air conduction is heard longer than bone conduction in both ears. This is due to the fact that air conduction involves the transmission of sound waves through the external auditory canal, middle ear, and inner ear, which is more efficient than bone conduction where the sound waves are transmitted directly to the inner ear through the bones of the skull. Therefore, when the tuning fork is placed on the mastoid bone (bone conduction) and then moved next to the ear (air conduction), the sound should be heard longer through air conduction. Choice A is incorrect because normal auditory acuity does not necessarily mean equal perception in both ears. Choice C is incorrect as bone conduction should be heard shorter than air conduction in a normal Rinne test. Choice D is incorrect as the test does not determine which ear perceives sound better, but rather the difference in duration between air and bone conduction.

Correct Answer: B

Rationale: The correct answer is B because a saturated and leaking dressing indicates a potential infection risk and compromised wound healing. The nurse should revise the plan of care and change the dressing immediately to prevent complications. Waiting until 1800 (choice A) could lead to further contamination and delay in treatment. Reassessing in 2 hours (choice C) might worsen the condition. Discontinuing the plan of care (choice D) is not appropriate without addressing the immediate issue.