79.EFFECT OF PAPILLOEDEMA DEPENTS UPON
A.SIZE
B.SITE
C.RATE OF GROWTH
D.INTRACRANIAL SPREAD
ANS:SIZE
Papilledema (or papilloedema) is optic disc swelling that is caused by increased intracranial pressure. The swelling is usually bilateral and can occur over a period of hours to weeks. Unilateral presentation is extremely rare. Papilledema is mostly seen as a symptom resulting from another pathophysiological process.
In intracranial hypertension, papilledema most commonly occurs bilaterally. When papilledema is found on fundoscopy, further evaluation is warranted as vision loss can result if the underlying condition is not treated. Further evaluation with a CT or MRI of the brain and/or spine is usually performed. Unilateral papilledema can suggest orbital pathology, such as an optic nerve glioma.
Papilledema may be asymptomatic or present with headache in the early stages. However it may progress to enlargement of the blind spot, blurring of vision, visual obscurations (inability to see in a particular part of the visual field for a period of time) and ultimately total loss of vision may occur.
The signs of papilledema that are seen using an ophthalmoscope include
venous engorgement (usually the first signs)
loss of venous pulsation
hemorrhages over and / or adjacent to the optic disc
blurring of optic margins
elevation of optic disc
Paton's lines = radial retinal lines cascading from the optic disc
On visual field examination, the physician may elicit an enlarged blind spot; the visual acuity may remain relatively intact until papilledema is severe or prolonged.
Diagnosis
Checking the eyes for signs of papilledema should be carried out whenever there is a clinical suspicion of raised intracranial pressure, and is recommended in newly onset headaches. This may be done by ophthalmoscopy or fundus photography, and possibly slit lamp examination.
Causes
Raised intracranial pressure: brain tumor, pseudotumor cerebri or cerebral venous sinus thrombosis, Intracerebral hemorrhage
Respiratory failure
Hypotonia
Accutane (Isotretinoin), which is a powerful derivative of Vitamin A, rarely causes Papilledema.
Hypervitaminosis A, in some people who take megadoses of nutritional supplements and vitamins.
Hyperammonemia, elevated level of ammonia in blood (including cerebral edema/intracranial pressure)
Guillain-Barré syndrome due to elevated protein levels
Foster Kennedy syndrome (FKS)
Chiari Malformation
Tumors of the frontal lobe
Acute Mountain Sickness and High Altitude Cerebral Oedema
Lyme disease (Lyme meningitis specifically, when the bacterial infection is in the central nervous system, causing increased intracranial pressure).
Malignant Hypertension
Medulloblastoma
Orbital A.Ocular venous drainage block:central retinal venous block, cavernous sinus trombosis B.Local lesion:optic neuritis, ischemia of the nerve head, toxin (methanol), infiltration of the disc by glioma,sarcoidosis and lymphoma
Acute Lymphocytic Leukemia (caused by infiltration of the retinal vessels by immature leukocytes)
Long periods of weightlessness (microgravity) for males
Pathophysiology
As the optic nerve sheath is continuous with the subarachnoid space of the brain (and is regarded as an extension of the central nervous system), increased pressure is transmitted through to the optic nerve. The brain itself is relatively spared from pathological consequences of high pressure. However, the anterior end of the optic nerve stops abruptly at the eye. Hence the pressure is asymmetrical and this causes a pinching and protrusion of the optic nerve at its head. The fibers of the retinal ganglion cells of the optic disc become engorged and bulge anteriorly. Persistent and extensive optic nerve head swelling, or optic disc edema, can lead to loss of these fibers and permanent visual impairment.
Treatment
The treatment depends largely on the underlying cause. However, the root cause of papilledema is the increased intracranial pressure (ICP). This is a dangerous sign, indicative of a brain tumor, CNS inflammation or idiopathic intracranial hypertension (IIH) that may become manifest in the near future.
Thus, a biopsy is routinely performed prior to the treatment in the initial stages of papilledema to detect whether a brain tumor is present. If detected, laser treatment, radiation and surgeries can be used to treat the tumor.
To decrease ICP, medications can be administered by increasing the absorption of Cerebrospinal fluid (CSF), or decreasing its production. Such medicines include diuretics like acetazolamide and lasix. These diuretics, along with surgical interventions, can also treat IIH. In IIH, weight loss (even a loss of 10-15%) can lead to normalization of ICP.
Meanwhile, steroids can reduce inflammation (if this is a contributing factor to increased ICP), and may help to prevent vision loss. However, steroids have also been known to cause increased ICP, especially with a change in dosage. However, if a severe inflammatory condition exist, such as multiple sclerosis, steroids with anti-inflammatory effects such as Methylprednisolone and prednisone can help.
Other treatments include repeated lumbar punctures to remove excess spinal fluid in the cranium. The removal of potentially causative medicines including tetracyclines and vitamin A analogues may help decrease ICP, however this is only necessary if the medication is truly felt to contribute to ICP increase.
