Contraindications to performing a lumbar puncture include the following EXCEPT

Correct Answer: D

Rationale: A lumbar puncture (LP) is contraindicated when there is a risk of causing harm, such as brain herniation or introducing infection. Suspected mass lesions of the brain or spinal cord increase intracranial or intraspinal pressure, risking herniation if CSF is removed. Symptoms of impending cerebral herniation also contraindicate LP due to the danger of worsening pressure dynamics. Skin infection at the puncture site , however, is not an absolute contraindication; while it increasinfection risk, it can often be managed with alternative sitor sterilization, unlike the other conditions which pose immediate, severe risks. Thus, D is the exception and the correct answer, as it donot universally prohibit LP in the same critical way as A, B, or C.

Correct Answer: C

Rationale: CSF is primarily produced by the choroid plexus, with about 25% from extrachoroidal sourc, true. A child produc~20 mL/hr , and CSF flows from lateral ventriclvia the foramina of Monro to the third ventricle , both true. CSF is absorbed by arachnoid villi , also true. However, the total CSF volume in an infant is ~50-100 mL, not 150 mL , which is closer to adult levels. Thus, C is false and the correct answer, as it overestimatinfant CSF volume, misaligning with developmental physiology.

Correct Answer: B

Rationale: In simple febrile seizures, EEG is not routinely needed , spikduring drowsiness are common , and post-seizure EEGs may show slowing , all true. EEG helps classify epilepsy if present. However, an abnormal EEG donot reliably predict recurrence or epilepsy ; studishow it lacks specificity for prognosis in simple cases, making it the exception and correct answer. This reflects EEGs limited predictive value in febrile seizures, focusing its role on diagnosis rather than risk assessment.

Correct Answer: D

Rationale: Epilepsy surgery targets focal, resectable lesions in refractory cases, such as cortical dysplasia , tuberous sclerosis , polymicrogyria , and Sturge-Weber syndrome , where identifiable epileptogenic zon(e.g., tubers, malformations) can be removed. Degenerative problems , like Alzheimers or metabolic encephalopathies, are diffuse, progressive, and lack focal targets, making surgery inappropriate. This distinction focal versus diffuse pathology makes D the exception and correct answer, as surgery requira localized seizure focus.

Correct Answer: B

Rationale: NF-1 causlearning disabiliti, seizur, precocious puberty , and scoliosis via neurofibromas, gliomas, or hormonal dysregulation. Cataracts are linked to NF-2 (via lens opacities), not NF-1, which affects optic gliomas or Lisch nodulinstead. This specificity NF-1s ocular featurversus NF-2s cataracts make B the exception and correct answer, reflecting distinct genetic and phenotypic profiles.