A lumbar puncture would be contraindicated in a 68-year-old woman suspected of having Alzheimer’s disease if she has a history of which of the following?

Choice A reason: Acute lower back pain is not an absolute contraindication for lumbar puncture. While it may cause discomfort or technical difficulty, lumbar puncture can often still be performed safely with careful positioning and analgesia. Choice B reason: Osteoporosis is a relative concern for lumbar puncture due to potential fragility of vertebrae, but it is not an absolute contraindication. Special technique may be used to minimize risk. Choice C reason: Increased intracranial pressure is a major contraindication to lumbar puncture because removing cerebrospinal fluid in the presence of elevated pressure can precipitate brain herniation, which is life-threatening. This makes it a critical consideration before performing the procedure. Choice D reason: Decreased cardiac output is not a direct contraindication for lumbar puncture, though general hemodynamic instability may warrant caution. The primary concern is neurological safety rather than cardiovascular status.