Dr. Virender Sachdeva is a consultant in Pediatric ophthalmology, strabismus and neuro-ophthalmology
at L. V. Prasad Eye Institute, GMRV Campus, Visakhapatnam, India. He underwent a fellowship in
comprehensive ophthalmology and pediatric ophthalmology at L. V. Prasad Eye Institute, Hyderabad and
has been working at the LVPEI GMRV campus as a faculty since 2008. He also pursued a clinical research
fellowship in Neuro-ophthalmology at the Emory University, Atlanta, USA. He has been actively involved
in the teaching and research pertaining in fields of pediatric ophthalmology, squint and neuro-
ophthalmology. His special areas of interest include amblyopia, complex strabismus, visual field
abnormalities, pupil abnormalities, Optic neuritis, IIH and Neuroimaging. He is concentrating on clinical
research in the newer therapies for amblyopia, atypical forms of optic neuritis, pediatric optic neuritis,
idiopathic intracranial hypertension, and hereditary optic neuropathies in Indian populations. Dr.
Sachdeva has been a peer reviewer for many indexed journals in ophthalmology such as BJO, AJO,
Ophthalmology, Indian Journal of Ophthalmology, International Journal of Ophthalmology and is the
section editor of the BMC Ophthalmology, for pediatric ophthalmology and Strabismus.

I thank Dr. Tan for sharing an interesting and challenging case. From a review of the available information, it appears that the child was detected to have subnormal vision in the right eye (RE), and comprehensive eye examination revealed optic disc edema in both eyes. Given the presence of significant hypermetropia atleast in the right eye and anisometropia, a diagnosis of pseudopapilledema and anisometropic amblyopia seemed reasonable. Investigations such as confrontation visual fields, color vision, and B scan were normal / negative. However, only thing is a close look at the appearance of the optic discs does show obscuration of the peripapillary retinal nerve fiber layer (RNFL) and possible obscuration of the small vessels in both eyes especially nasally, which suggests that the disc swelling is more likely to be true papilledema. It is possible that it was asymmetric at the time of presentation more in the right eye than the left eye which is not unusual. Even OCT of the RNFL shows significant elevation of the RNFL thickness in both eyes, RE> LE, which is even greater than 130 microns, which is again suggestive of true disc edema as patients with pseudopapilledema usually do not have such high overall RNFL thickness. Of note there were no reported symptoms of elevated ICP, child was not obese and there was anemia which will make the diagnosis of elevated Intracranial pressure less likely.

At the same time, MRI brain was obtained which was reportedly normal. Still, CSF opening pressure and was obtained under nitrous oxide sedation and was 13.5 cm of H2O. therefore, a diagnosis of pseudopapilledema was entertained and patient was prescribed refractive correction and patching. However, serial follow-ups showed only slight improvement in best corrected visual acuity (BCVA) in RE and disc appearance was unchanged. Of note repeat evaluation with OCT showed continued increase in the overall RNFL thickness with time, which is conclusive of possible ongoing intracranial hypertension rather than pseudo-papilledema. Therefore, repeat work-up with MRI brain and MRV brain with contrast, and repeat lumbar puncture is totally justified. MRI and MRV brain were reportedly normal and CSF analysis was normal with opening pressure of 18 cm of H2O, which is not conclusive.
This raises the question of further workup as mentioned on slide 14. Various options such as CSF infusion study, formal ICP monitor, sleep study, visual electrophysiology and dural venous sinus manometry were discussed. Among these given normal visual function VEP is least likely to give any useful information. More invasive procedures such as ‘Formal ICP monitor’ might give us more accurate measurement of the CSF pressure than the CSF opening pressure however, all of these are more invasive procedures.

Given the presentation, my suggestions will be the following:

1) Thorough discussion with the neuro-radiologist about presence of subtle signs of elevated ICP, such as posterior globe flattening, vertical tortuosity of the optic nerves, and empty sella, which might be the only signs present in the young patients. Studies have shown that changes from chronic elevated ICP are unusual in pre-adolescent children, so even if these are absent pediatric IIH / intracranial hypertension cannot be completely ruled out.

2) Review of the MRI changes regarding cranio-cervical junction abnormalities that might impede the CSF outflow.

3) Another suggestion is reviewing the MRV brain again to look for flow voids in the cerebral venous sinuses and if suspicious to obtain MRV brain with contrast to avoid missing a CSVT albeit uncommon in this age.

4) Another useful discussion can be regarding the possibility of a dural AV fistula although again unusual to present with only papilledema. Existing literature does suggest such rare presentations and may not be completely rule out without conventional angiography.
– If all of these concerns are addressed, and if we have even subtle signs of elevated ICP on MRI, I will consider a diagnosis of presumed idiopathic intracranial hypertension (presumed IIH) and consider a trial of treatment with oral acetazolamide.
– This is so keeping in view demonstratable papilledema, worsening with time, continued normal visual function including visual fields, patient age and invasiveness of the various procedures.
– It is important to note that studies have shown that even in pre-pubescent children with elevated ICP due to IIH, BMI tended to be low and normal.
– Other treatment options in this case can be reserved based on the response to the treatment as the visual function is good despite disc edema.
– However, a discussion and documentation of the same with parents should be done and if they are still very keen further MRV with contrast, conventional angiography and formal ICP monitoring can be obtained.
As we see in the subsequent course of the patient, there is significant improvement and subsequent resolution of the disc edema following prolonged treatment with oral acetazolamide.

As regards the specific questions:

Q3) What do you feel is the etiology to his optic nerve swelling and what other investigations would you have liked in his workup?
As is clear from the above discussion, in my view the cause of disc edema in the given patient is most likely true papilledema and pediatric IIH is high in the differential diagnosis followed by chronic CSVT, and an indirect AV fistula. My work-up will be focusing on ruling out above and then entertaining a diagnosis of presumed IIH.

Q4) Please explain the value you place on a standard Lumbar Puncture in these situations. And do you ask for any special instructions in the way it is performed? (Anesthetics / nitrous / position etc.). Do you prefer CSF Infusion studies and / or formal ICP monitoring?
As regards the question of the value and accuracy of the lumbar puncture in such a case, it is a difficult situation, but we always try to obtain it under sedation in the standard lateral decubitus position, once the patient has stabilized under anesthesia. Our neurosurgeons and anesthetists usually use sevoflurane for the short anesthesia; however, the values usually do not differ much for nitrous oxide. Literature does suggest no major effect of nitrous oxide on the intracranial pressure. Timing of the lumbar puncture might be important for sevoflurane and nitrous oxide as these might reduce the CSF opening pressure after prolonged anesthesia and should be obtained as soon as patient is stabilized.
However, it is not still free from its own challenges and I have similar experience in 2 patients:
In the first patient, first lumbar puncture was traumatic and could not be relied upon, and the parents refused a repeat Lumbar puncture. Given other findings and after ruling out other considerations, patient was treated on oral acetazolamide and disc edema gradually improved.
In the second patient, where the CSF opening pressure was 16 mm Hg and there were only subtle signs of elevated ICP. Again, with similar considerations, diagnosis of presumed IIH was made and the patient responded well to oral acetazolamide.
If, however, I were to choose I will consider formal ICP monitoring in the workup of the patient after discussion with the parents.

Q5) How long do you follow these children for? When is it safe to discharge from regular follow up?
Overall these children and even adults require a prolonged follow-up. A useful dictum can be to follow-up these patients on active treatment until the disc edema completely resolves, and then gradually taper them of acetazolamide ensuring there is no recurrence of disc edema. On an average, most patients will need a treatment period of 12 to 18 months in my experience. Following this we can follow them up once every 3 months for one year, then every 6 months for a year and if completely free possibly once a year.
Fundus photographs, visual fields and OCT of the peripapillary RNFL can be very useful in the measurements in these patients and can be repeated every 1-2 months in the initial follow-ups.