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: C

Rationale: The correct answer is C: Macrophages. Macrophages are antigen-presenting cells that engulf pathogens and present their antigens to T cells, initiating an immune response. They express major histocompatibility complex (MHC) molecules necessary for T cell recognition. B cells also present antigens but primarily to B cells for antibody production. NK cells are involved in killing infected cells, not antigen presentation. Eosinophils are mainly involved in allergic responses and defense against parasites, not antigen presentation.

Correct Answer: B

Rationale: The correct answer is B: IgA. In multiple myeloma, there is a proliferation of abnormal plasma cells, leading to a decrease in normal antibody production. IgA is the most abundant immunoglobulin in mucosal secretions and plays a crucial role in mucosal immunity. Therefore, a deficiency in IgA is common in patients with multiple myeloma. IgG is the most abundant immunoglobulin in the blood and is typically less affected in multiple myeloma. IgM is the first antibody produced in response to an infection and is less likely to be deficient in this case. IgE is primarily involved in allergic responses and is not typically affected in multiple myeloma.

Correct Answer: C

Rationale: The correct answer is C: Hyponatremia. SSRI medications can lead to the syndrome of inappropriate antidiuretic hormone secretion (SIADH), causing hyponatremia. This occurs due to increased levels of serotonin affecting the hypothalamus, leading to excessive ADH release. Hyponatremia can result in neurological symptoms and must be closely monitored. A: Bradycardia is not a common adverse effect of SSRIs. B: Hyperkalemia is not typically associated with SSRIs. D: Hypertension is not a common adverse effect of SSRIs; they may actually lower blood pressure.

Correct Answer: B

Rationale: The correct answer is B: osteoporosis. Osteoporosis is a condition characterized by weakened bones, making individuals more susceptible to fractures, especially with minor trauma or falls. In the context of a patient prone to fractures, nurses should be particularly cautious about fall prevention. A: The aging process alone does not necessarily lead to an increased risk of fractures. While aging is a risk factor for osteoporosis, it is not the direct cause of fractures in this case. C: Changes in vision can contribute to an increased risk of falls, but it is not the primary reason for the patient being prone to fractures in this scenario. D: Hematologic conditions may affect bone health, but they are not typically the primary cause of increased fracture risk in patients.