CSF HYPOTENSION

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• The headache of low CSF pressure is characteristically orthostatic, developing or worsening when a person is upright & resolving or improving with recumbency

Etiology

• MC cause after LP– loss of CSF volume due to the removal of CSF

• Loss of CSF can result in brain sagging & traction on pain-sensitive structures– Bridging veins & sensory nerves

• Dilatation of intracranial venous structures

• Recumbency – Removes the effect of gravity & the traction headache is relieved

• The headache that occurs after a spinal tap usually resolves spontaneously within a few days

• Spontaneous recovery• 24% of Pt.within the first 2 days• 29% of Pt.within 3–4 days• 19% within 5–7 days

• Role of bed rest & good hydration– Healing process might be hastened

• Application of an epidural blood patch– When these conservative measures fail

• An epidural blood patch– 20ml

• The success rate of a single epidural blood patch is estimated between 70% & 98% (Turnbull & Shepherd, 2003)

Spontaneous intracranial hypotension• Spontaneous leak in CSF

– low-CSF pressure headache can occur when• MC location- thoracic region

Clinical features • MC manifestation -Orthostatic headache• Other common symptoms

– Auditory muffling– Tinnitus– Nausea &vomiting, & neck pain

• Not all orthostatic headaches are due to CSF leaks, and not all headaches in those with CSF leaks are orthostatic

• With chronicity- the orthostatic features reduces

Clinical features • Pt. with spontaneous intracranial hypotension • Causal relationship -uncertain• Recall having a very minor injury• Coughing, sneezing• Performing Valsalva just prior to onset of symptoms

• Pt.might have constant headaches or so-called “end-of-the-day” headaches

• Mokri, 2004

Initial diagnosis

• Brain MRI with gadolinium• MRI findings supportive

– Diffuse pachymeningeal Gd enhancement– Brain sagging

• Cerebellar tonsillar descent• Inferior displacement of the optic chiasm

– Flattening of the anterior aspect of the pons, & venous dilation

Axial T1-weighted MRI with Gd in a pt. with a spontaneous cerebrospinal fluid leak & orthostatic headache demonstrates diffuse pachymeningeal thickening & enhancement

103.2 Coronal T1-weighted MRI with Gd of a patient with orthostatic headache secondary to a spontaneous cerebrospinal fluid leak demonstrates subdural fluid collections & pachymeningeal enhancement

•Sagittal t1-weighted mri•Demonstrates brain descent•Low cerebellar tonsils•Crowding of the posterior fossa•Small prepontine cistern•Inferior displacement of the optic chiasm

• Subdural fluid collections (subdural hygromas & subdural hematomas) might occur in up to 50% of Pt.with intracranial hypotension due to spontaneous CSF leaks

(Schievink et al., 2005).

Diagnosis

• The patient with classical symptoms and classical brain

MRI findings of the disorder might not need additional

diagnostic tests prior to treatment with conservative

measures or epidural blood patch

Diagnosis• Diagnosis is uncertain additional testing• Spine MRI to assess for extra-arachnoid CSF collections• CT or MR myelography• Nuclear cisternography• Measurement of opening pressure via LP can be

diagnostic

• LP should be avoided when possible due to the risk of worsening intracranial hypotension following the procedure

• Importantly, a normal CSF opening pressure does not rule out a spontaneous CSF leak

Treatment

• Typical clinical & radiographic features of low-CSF pressure headache

• Conservative Treatment– Bed rest & hydration for 1 to 2 wks

• The efficacy of caffeine and theophylline ?• If this is either impractical or ineffective, treatment with a

blood patch is warranted • Epidural blood patches are effective in the majority of

patients• Some patients require 1 or 4-6 blood patches (Mokri,

2004)

Treatment

• Additional options include epidural injection of fibrin glue (translaminar or transforaminal)

• Combination of fibrin glue and homologous blood

• For resistant leaks that can be localized, surgical repair of the dural tear may be attempted

Other causes • Headache due to low pressure occurs uncommonly when

the CSF– Leaking through the cribriform plate– Petrous bones– Basal skull defect

• CSF rhinorrhea & especially CSF otorrhea may not be obvious to the patient, whose complaint may be postoperative or post-traumatic headache

• Spontaneously leakage when ICP is raised or when a tumor erodes through the base of the skull

• MC site -cribriform plate

Dignosis of CSF leakage• Imaging of the facial & cranial bones & by radioisotope

cisternography with nasal pledgets

• Placing numbered cotton pledgets in the nose next to the ostia of the sinuses detects leakage of CSF through the nasal sinuses

• Contamination of the pledgets by radioactivity enables the sinus through which the fluid is leaking to be identified

Dignosis of CSF leakage• Nasal discharge suspected to be CSF can be tested for

beta-2-transferrin

• Sensitivity ≈100%• Specificity ≈ 95% for detection of CSF

(Abuabara,2007)

Dignosis of CSF leakage

• CSF otorrhea is not easy to identify if the fluid is draining down the Eustachian tube when the eardrum is intact

• Scanning with a gamma camera after instillation of a radioactive tracer by LP may allow the leak to be identified

• Treatment is usually surgical repair of the bony& meningeal defect

MRI signs Major head MRI abnormalities• Diffuse pachymeningeal• Gadolinium enhancement without abnormal• Leptomeningeal enhancement• Sinking or sagging of the brain• Descent of the brainstem• Subdural fluid collections• Enlarged pituitary• Engorged cerebral venous sinuses• Decrease in size of the ventricles

• Diffuse pachymeningeal enhancement is the most prominent head MRI abnormality

• 3-Tesla MRI, the pachymeninges may appear more prominent

• Thank you