Pseudo Chiari type I malformation secondary to cerebrospinal fluid leakage

Abstract

Cerebrospinal fluid (CSF) leakage may occur spontaneously, iatrogenically or from spinal trauma. Postural headache is the cardinal symptom; dizziness, diminished hearing, nausea and vomiting are additional symptoms. In neurological examinations cranial nerve palsies may be found. Due to low CSF pressure neuroimaging studies may reveal dural enhancement and vertical displacement of the brain. We describe a patient with the history of an uncomplicated lumbar discectomy at the level L4-5 and the typical clinical symptoms of intracranial hypotension. MRI of the craniocervical junction showed typical features of a Chiari type-I malformation. After neurosurgical ligation of a CSF leak at L4-5 caused by lumbar disc surgery, the patient was free of orthostatic headache. A repeated MRI showed a striking reduction of the previous downward displacement of the cerebellar tonsils and pons.

Apparent diffusion coefficient measurements to support a diagnosis of intracranial hypotension

“…23 Brain sag is seen in more severe cases of ICH, although the imaging appearance of brain sag can be confused with Chiari 1 malformation. [24][25][26][27] Signs of brain swelling have been previously noted on imaging studies of ICH, with decreased ventricular size and subtle effacement of the sulci 16,21,28 (Figure 7). These findings may go unrecognized, particularly in young patients and patients without previous imaging studies for comparison.…”

Headache Rounds: Sudden Onset Chronic Daily Headache

“…The term pseudo‐Chiari or acquired Chiari is used when this displacement is caused by the depletion of CSF intracranial volume and subsequent loss of brain buoyancy . The clinical and radiological findings cannot be distinguished but usually in pseudo‐Chiari the orthostatic headaches precede the Valsalva headaches, like in our patient, and can be improved or even reversed once the CSF hypovolemia is treated …”

Audiovestibular impairments associated with intracranial hypotension

“…The patterns of spontaneous and positional nystagmus suggest brainstem or cerebellar dysfunction since spontaneous vertical nystagmus has mostly been reported in brainstem or cerebellar lesions [20], and various central patterns of positional nystagmus have largely been described in patients with lesions dorsolateral to the fourth ventricle or in the cerebellar vermis [21]. In patients with intracranial hypotension, compression or traction along the cranial floor of the brainstem or cerebellum due to a loss of CSF buoyancy may produce audiovestibular impairments, which may be the most prominent during supine or head hanging position [22][23][24]. However, pure vertical nystagmus without other ocular motor abnormalities suggestive of brainstem or cerebellar dysfunction can also be explained by the irritation or hypofunction of bilateral peripheral vestibular structures since both ears are subjected to the same effect of any change in intracranial pressure.…”