title: Tonsillar Herniation After Lumbar Puncture in Idiopathic Intracranial Hypertension.
abstract: A 30-year-old woman with coexisting renal tubular acidosis and idiopathic intracranial hypertension (IIH), treated with acetazolamide, experienced coning (cerebellar tonsillar herniation) after a lumbar puncture (LP). Brain magnetic resonance imaging at initial diagnosis of IIH showed minor tonsillar descent and computed tomographic venography revealed hypoplasia of the left transverse sinus. The patient previously had three uneventful LPs, all of which showed high opening pressures and normal cerebrospinal fluid composition. In retrospect, it was noted that her serum bicarbonate had fallen to 9 mmol/L (normal: 22-28 mm/L) 1 week before the LP. We hypothesize that the combination of cerebral edema (due to worsening metabolic acidosis), poor venous drainage, and preexisting minor tonsillar descent contributed to her post-LP coning.
authors.affiliation: Department of Neurology (AAB, ARH, CJL), The Canberra Hospital, Canberra, Australia; and The Australian National University Medical School (AAB, ARH, CJL), Canberra, Australia.
authors.forename: Adeniyi A
authors.initials: AA
authors.lastname: Borire
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Hughes
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Lueck
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology; D004677:Encephalocele / Q000209:etiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D011559:Pseudotumor Cerebri / Q000175:diagnosis*; D012160:Retina / Q000473:pathology; D013129:Spinal Puncture / Q000009:adverse effects*; D041623:Tomography, Optical Coherence