neurologic disorders
Post–Lumbar Puncture and Other Low–Pressure Headaches
Introduction
Low-pressure headaches result from reduction in cerebrospinal fluid (CSF) volume and pressure due to lumbar puncture or spontaneous or traumatic CSF leaks. (See also Approach to the Patient With Headache .) Removal of CSF by lumbar puncture (LP) reduces CSF volume and pressure, as do spontaneous or traumatic CSF leaks. Headache after LP is common, usually occurring hours to a day or two afterward, and can be severe. Younger patients with a small body mass are at greatest risk. Using small, noncutting needles reduces risk. The amount of CSF removed and duration of recumbency after LP do not affect incidence. Spontaneous CSF leaks may result when a nerve root arachnoid diverticulum or cyst along the spinal canal ruptures. Coughing or sneezing may cause the rupture. CSF may leak after certain head or facial injuries (eg, basilar skull fractures). Headache results when head elevation while sitting or standing stretches the pain-sensitive basal meninges. Headaches are intense, postural, and often accompanied by neck pain, meningismus, and vomiting. Headache is alleviated only by lying completely flat. 