sachida
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I am confused with a question I read on usmle world.
Pseudotumor is managed first by weight loss, then acetazolamide
pathology is increased intracranial pressure in abcense of real tumor
normally when ICP is increased as evidenced by papiledema, lumber puncture is contraindicated due to fear of herniation.
I saw one question on usmle world where lumber puncter is management of psedotumor!!!
how does that make sense? answer also mentions that empty sella syndrome is often found in this patient possibly due to herniation into sella of brain tissue. so would not it be dangerous???
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| kpmle2
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if possible can u post the full Q.
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| hero
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CSF shunt rather than LP
http://www.emedicine.com/neuro/topic329.htm
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| Ivonne
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Sorry for copy and paste, hope this shine some light, source emedicine.
When a patient presents with bilateral disc edema, the diagnosis is presumably an intracranial mass until proven otherwise. A lumbar puncture should not be performed until the findings on neuroimaging studies have eliminated the possibility of a space-occupying lesion. A lumbar puncture performed in the presence of an intracranial mass may result in the fatal occurrence of herniation of the temporal lobe or the cerebellum. Thus, reviewing the images prior to performing a lumbar puncture is essential to avoid this outcome. In addition to ruling out a mass lesion, ensuring that patients with papilledema do not have a dural sinus thrombosis is important. Although a high-quality CT scan or MRI with infusion may eliminate this possibility, magnetic resonance venography is preferable.4 If the findings on neuroimaging studies are normal and a lumbar puncture indicates increased intracranial pressure in a patient with papilledema, long-term monitoring for progressive optic neuropathy is indicated. Diagnosis and long-term management of patients with IIH requires the performance of lumbar puncture, typically performed by neurologists or internists, and careful monitoring of visual status (most importantly peripheral visual field and fundus photography).
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| sachida
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Ivvone, thanks for that post.
It brings precisely to my question...
when intra cranial tumor is present, we dont do lumber puncture as herniation is feared.
but tumor is not found then lumber puncture becomes management..
why? how does tumor makes it more likely that brain will herniate?
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| Ivonne
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Because the tumor is inside of the brain while in pseudo-tumor is the outflow of CSF decreased. Different compartments 
CSF production rate (cc/min) should be equal to the CSF reabsorption rate.
If production exceeds absorption, ICP rises until it exceeds mean arterial pressure, which, if sustained, would be fatal.
I dont know just thinking...
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| hero
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Evaluation of papilledema should include CT or MRI to exclude the presence of brain tumor, sinus thrombosis, hydrocephalus, or optic masses. In some cases, MR venography is indicated to exclude sinus thrombosis. If the scan is normal, then an opening pressure should be measured by lumbar puncture manometry. If the opening pressure is elevated without apparent cause and CSF results are normal, a diagnosis of pseudotumor cerebri is made by exclusion.
Absolute contraindications to lumbar puncture are as follows:
Unequal pressures between the supratentorial and infratentorial compartments, usually inferred by characteristic findings on the brain CT scan:
Midline shift
Loss of suprachiasmatic and basilar cisterns
Posterior fossa mass
Loss of the superior cerebellar cistern
Loss of the quadrigeminal plate cistern
Infected skin over the needle entry site
Relative contraindications to lumbar puncture are as follows:
Increased intracranial pressure (ICP)
Coagulopathy
Brain abscess
Indications for brain CT scan prior to lumbar puncture include the following:
Patients who are older than 60 years
Patients who are immunocompromised
Patients with known CNS lesions
Patients who have had a seizure within 1 week of presentation
Patients with abnormal level of consciousness
Patients with focal findings on neurological examination
Patients with papilledema seen on physical examination with clinical suspicion of elevated ICP
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| mildus
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In IIH, there is slightly decreased reabsorbtion of CSF into arachnoid villi, and subsequent intracranial hypertension which is diffuse, and LP can give relief to the symptoms since it decreases amount of CSF.
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| mildus
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Of course, there are other treatment options as well, particularly weight loss as mentioned by sachida, inhibitors of carboanhidrase, shunt
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| drduck
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even i had the same Q in my mind when i saw this Q
but i forgot to ask.
i feel its a more of theoritical management and thats why they talk so much.
even in cases of bacterial meningitis or any case of headavhe, they give u the finding of CSF after the history,
this again is not possible, every case of raised ICT should be first confirmed by presence of papiloedema, follwed by other non invasive tests,
+ of pap'dema remains a C/I for LP, there are many exceptions to this but i think thats out of expectation.
so its only for the purpose of exams that they show us the CSF finding, but in real life situations, it is very difficult and dangerous to perform a LP on patient with raised ICT....u all know why.
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