My Publications

Throughout my medical career, I’ve had the opportunity to research and report on a broad range of topics and fields in neuro ophthalmology and ocular motility. I’ve written many articles on different topics concerning the medical world. My acclaimed works have been published and are well-respected by medical professionals all over the world. Read some of my written works below.

Eye Trial Frame

Neuro Ophthalmology

August 2017

Assessment of optic nerve appearance and functions is a daily routine in neuro-ophthalmology. Following a recent high profile court case there has been a significant increase in the amount of referral to ophthalmology departments to assess the optic nerve and its functions and rule out optic nerve swelling. The aim of this review is to provide an overview of optic nerve anatomy and functions, as well as a discussion of optic nerve swelling, its features and its possible causes. The review will be split over two articles. The first will discuss the basic optic nerve anatomy, functions and various features on optical coherence tomography (OCT) scans and differentiating true from pseudo optic nerve swelling. This article will also discuss unilateral optic neuropathy. The second article will discuss features of bilateral optic nerve swelling as well as our experience and protocols of management in Manchester Royal Eye Hospital.

Eye Test Glasses

Neuro Ophthalmology 2

October 2017

In this second article we will discuss bilateral optic nerve swelling, its aetiology, various investigations and possible treatments. We will also discuss various protocols used in the management of suspected optic nerve swelling cases.

Eye

Different pupil size (Anisocoria)

March, 2018

Anisocoria means the presence of difference in the size of the right and left pupils. It is a sign of an abnormality in the efferent pathway. The first question facing the ophthalmologist is to ascertain if anisocoria is present or not. The second question to answer is which pupil is the defective one.


Question 1: is there anisocoria?

Look at both pupils in ambient room light conditions and measure size of the pupil in each eye. It is also important to note any obvious abnormalities in the shape of the pupil. Having ascertained the presence of anisocoria, the ophthalmologist needs to answer the next question: which is the abnormal pupil?

Question 2: is the smaller or the larger pupil abnormal?

In order to answer this question, pupil size needs to be measured in different light conditions by changing the level of light in the examination room.


Anisocoria more in darkness

  1. Physiological anisocoria: the difference in size is usually 0.5-1.0mm, the difference is usually similar in light and dark conditions but could be a bit more obvious in dark conditions. It is estimated that up to 20% of the population will have some form of anisocoria. Looking at old photos could help with the diagnosis.

  2. Inhibition of the sympathetic pathway (Horner’s syndrome) – Figure 1: features of this include miosis, subtle ptosis, lower lid reverse ptosis, apparent enophthalmos, dilation lag and anhidrosis. Other features include iris depigmentation in congenital cases. Various pharmacological agents could be used to confirm the diagnosis and try to localise the site of the lesion. Cocaine dilates the normal pupil but not the affected pupil so it increases the anisocoria. Hydroxyamphetamine can be used to localise the lesion causing Horner’s syndrome. Putting this agent into a central or preganglionic Horner’s will cause pupil dilation, however, using this agent in a postganglionic Horner’s pupil will not change the size of the pupil. Due to difficulties in access to these agents, ophthalmologists could use Apraclonidine (Iopidine) to confirm Horner’s syndrome. The pupil develops hypersensitivity (after three to seven days) and installing Iopidine into both eyes will cause reversal of anisocoria as the affected pupil will dilate compared to the normal pupil. It does not localise the lesion. Due to that, most acquired Horner’s syndrome pupils will need neuro imaging to the whole sympathetic chain to rule out compressive lesions or carotid dissection.

  3. Sympathetic hypersensitivity: this could manifest itself as benign episodic unilateral dilation (usually in young migraine sufferers), tadpole pupil, and whiplash injury (causing unilateral sympathetic irritation). This also could be caused by pharmacological stimulation to pupil dilator muscle in one eye. Examples include cocaine, eye whitening drops and some pulmonary treatment agents.

Anisocoria more in light

Inhibition of the parasympathetic pathway: depending on the site of the lesion, this could cause an isolated dilated pupil, a combination of iridoplegia and cycloplegia (internal ophthalmoplegia) or internal and external ophthalmoplegia (oculomotor palsy).

  1. Tonic pupil: this is caused by damage to the ciliary ganglion or short ciliary nerves. Features include light – near dissociation, tonic near response, parasympathetic hypersensitivity and focal iris paralysis (vermiform movements). The cause of this nerve damage could be localised to the eye and the orbit or part of widespread neuropathy. Holmes – Adie pupil is a subcategory of the tonic pupil.

  2. Oculomotor nerve palsy – Figure 2: this would cause various external ophthalmoplegic features depending on the extraocular muscles affected. This includes reduced adduction, elevation, depression and possible ptosis. Most of these patients would have diplopia. It is imperative to assess these patients with full orthoptic assessment and if third nerve palsy is suspected, urgent neuroimaging is necessary especially to rule out aneurysms.

  3. Damage to the iris sphincter: surgical or traumatic, this could be examined on the slit-lamp.

  4. Pharmacological dilation of the pupil: this usually fails to constrict to pilocarpine 1%.

Conclusion

In practical terms, when faced with anisocoria, ophthalmologists need to confirm the finding by measuring pupil size in each eye in ambient room light. Then the pupils need to be measured in different light conditions (dark and bright light). It is also important to note any other obvious features such as ptosis.

If the anisocoria is worse in darkness then it is usually the small pupil not dilating and it is important to rule out or confirm Horner’s syndrome using Iopidine 1% then arrange relevant neuroimaging. If the anisocoria is worse in light then it is usually the large pupil not constricting and it is important to rule out third cranial nerve palsy by assessing ocular motility.


Other conditions such as Adie’s pupil, physiological anisocoria and benign episodic pupil dilation pose less of risk if not diagnosed instantly. 

Image by Robina Weermeijer

IV cranial nerve palsy (vertical double vision)

November 2017

Aetiology:

Trochlear nerve palsy can be divided into acute or congenital. Congenital trochlear nerve palsy is usually noted in childhood with development of abnormal head posture. Various pathologies can lead to acute IV nerve palsy, most commonly trauma. Other causes include vascular (ischaemic), inflammatory (demyelination), neoplastic and aneurysms.

Signs and symptoms:

It is very important to differentiate acute IV cranial nerve (CN) palsy from longstanding but decompensating one. Patients usually present with sudden onset, intermittent or constant vertical diplopia. Full orthoptic assessment is essential to confirm the condition. The assessment will show that the affected eye is hypertropic and this hypertropia increases on contralateral gaze and on ipsilateral head tilt (3 step test). It is also important to obtain a Hess chart as well as assessing the patient on the synoptophor looking for subjective torsion. Fundus photography looking at the position of the fovea relative to the optic nerve head is a way of detecting objective torsion.

“It is important to have a period of stable measurements of at least six months before embarking on surgery.”

Common features of longstanding IV nerve palsy:

  1. Extended vertical fusion range

  2. Lack of subjective torsion

  3. Development of muscle sequelae on Hess chart

  4. Longstanding head tilt to the contralateral side.

Common features of bilateral IV cranial nerve palsy:

  1. Reversal of the vertical deviation on side gazes

  2. Torsion of more than 10 prism dioptres in primary gaze

  3. V pattern

  4. Chin up position instead of head tilt.

Investigations:

Once confirmed as acute onset, several investigations are recommended including neuro imaging (MRI), blood tests such as ESR, CRP, FBC, glucose, lipids, U&Es. Other tests for autoimmune antibodies, ACh-R antibodies are done if felt necessary.

Management options:

It is important to fully investigate the patient and treat any pathology if possible or control risk factors for vascular disease. Symptomatic treatment to address diplopia includes patching, prisms and surgery.

Non-surgical options:

These include patching one eye or using Fresnel prisms in order to avoid diplopia, it is also important to tell patients to avoid driving and inform the DVLA about their diplopia.

Knapp classification:

This is a useful way of classifying IV nerve palsy as it helps planning surgical treatment options.

Class I: greatest hypertropia in ipsilateral inferior oblique (contralateral up) field

Class II: greatest hypertropia in ipsilateral superior oblique (contralateral down) field

Class III: greatest hypertropia in entire contralateral field

Class IV: greatest hypertropia in entire contralateral field and across the lower field

Class V: greatest hypertropia across lower field

Class VI: bilateral IV palsy

Class VII: traumatic paresis combined with Brown’s syndrome.

Surgical options:

It is important to have a period of stable measurements of at least six months before embarking on surgery. The surgical option depends on the angle of deviation in primary position, area of maximum deviation and presence of torsion.

Torsion can be corrected by the Harada Ito procedure, Knapp class I can be addressed by ipsilateral IO recession, class II can be addressed by ipsilateral SO tuck, class III can benefit from either options and class IV and V might need also a contralateral inferior rectus recession. It is important to counsel the patient about the possibility of unmasking a bilateral IV palsy following surgery on one eye then needing further surgical intervention. Adjustable sutures could be utilised in adults’ surgery.

Complications:

It is important to avoid over corrections by staging the surgery or using adjustable sutures. Other specific complications include inducing a Brown syndrome following SO tuck and it is important to counsel patients regarding this possibility. IR muscle surgery can induce lower lid malposition.

Image by Harpreet Singh

It's not always GCA

December, 2020

Giant cell arteritis (GCA) is an immune mediated granulomatous inflammatory disease that affects muscular middle or large sized arteries. It is considered as a continuation of polymyalgia rheumatica (PMR) when the severity of the disease has increased.

It is the most common of all the vasculitides. Common signs and symptoms include headaches, shoulder pain, fever and night sweats, jaw claudication, raised inflammatory markers, mild anaemia, temporal tenderness and blurred or double vision.

GCA and ophthalmology

Many ophthalmologists and emergency eye clinics are the first port of call for GCA suspects. This is due to the fact that the loss of vision in GCA is severe and irreversible. GCA has several ocular manifestations. These include:

Ischaemic optic neuropathy: this is the most severe form and can usually lead to permanent and severe loss of vision. This could be anterior (AAION) which is the more common type or posterior (PION) which is far less common.

Central retinal artery occlusion (CRAO): can happen in the context of GCA if the inflammatory process affects the central retinal artery and lead to severe loss of vision.

Ocular ischaemia syndrome (OIS): can happen if the inflammatory process affects the ophthalmic artery and can lead to retinal ischaemia, anterior chamber inflammation and neovascularisation.

Ocular motility abnormalities: such as cranial nerve (CN) palsies, most commonly VI CN palsy but also III and possibly IV cranial nerve palsies.

Other rare manifestations: such as scleritis.

Dilemmas in GCA diagnosis

GCA is a clinical diagnosis. The clinician can overrule any investigation result if the clinical suspicion is high. The problem with signs and symptoms of GCA and its diagnostic tests is that most of them are non-specific and can be positive in various conditions.

Headaches and GCA: if you ask almost any person if they have headaches, the answer almost certainly is yes. It is the character of the headache that can point the clinical towards GCA type headaches or common migraine and tension headaches.

Raised inflammatory markers and GCA: raised erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) can happen in any inflammatory, infectious or malignant condition. It is important to ask patients if they have any infection anywhere in their body such as urinary infections, respiratory infections, sinusitis, diabetic ulcers, etc.

Jaw claudication and GCA: it is important to ask specific and clear questions when investigating GCA. Jaw claudication is not jaw pain such as the one noted in temporomandibular joint (TMJ) problems.

Swollen optic nerve and GCA: it is important to assess the appearance of the swollen optic nerve, the prodromal symptoms prior to the loss of vision, the current visual functions and the status of the other optic nerve (crowded, disc-at-risk or not). This can usually help differentiate non arteritic anterior ischaemic optic neuropathy (NAION) from AAION.

CRAO and GCA: if a thrombus is seen in the context of CRAO then it is not GCA related. It is extremely rare for GCA to cause branch RAO as such arteries are not middle size muscular arteries.


Case studies

Case 1:

A 70-year-old patient was referred to the eye emergency clinic with sudden onset loss of vision in his left eye. He did not have any headaches or temporal tenderness. His vision in the affected eye was reduced to hand movements only. Fundus examination showed CRAO with mildly swollen optic nerve. His inflammatory markers were mildly raised (ESR: 26, CRP 25) so colleagues at the eye emergency clinic suspected that he has GCA and he was started on steroids.

If you look carefully to his fundus photo below, it clearly shows multiple emboli suggesting that his CRAO is not GCA related and his raised ESR and CRP are due to a different cause.

Case 2:

A 55-year-old man was seen in eye emergency clinic having been transferred from another hospital complaining of two weeks blurred vision in both eyes (left > right). His vision was 0.0 LogMAR (6/6 Snellen) in the right and 0.4 LogMAR (6/15 Snellen) in the left. He had reduced colour vision both eyes and constricted field defect left eye on confrontation. There was no relative afferent pupillary defect (RAPD) reported. Aside from small crowded discs, the rest of the ocular examination was unremarkable.

His past medical history was significant and complex, with known metastatic renal cell carcinoma (on long-term oral dexamethasone) with known metastatic lesions in his bones. An MRI scan was requested and was reported by the neuroradiologist as normal.

His inflammatory markers were raised on admission CRP 114, ESR 47, however, he had a normal white cells blood count and platelets but no obvious source of infection. These inflammatory markers have significantly reduced following a dose of Tazocin. He denies any GCA symptoms and no tenderness on palpation of temporal arteries.

His ophthalmic history includes a left-sided NAION in 2012 with a residual visual field loss. The main concern in this patient was whether there is an arteritic element to his complaint that was masked by his chronic steroid use.


This is a complex situation, however, there is no obvious optic nerve swelling and no transient visual obscurations. The reduced vision in the left eye could be explained by the previous NAION. There are no signs of GCA at the moment and the raised inflammatory markers are likely to be malignancy related with possible underlying infection process as they responded well to Tazocin.

Conclusion

GCA is a serious and potentially blinding condition. It is important to suspect and treat in all relevant circumstances but it equally important to remember that all the above signs and symptoms are nonspecific and can happen in a multitude of conditions. This is important to avoid over treatment with high doses of steroids with all the possible side-effects and complications that come with such treatment. Good, detailed history and attention to detail is key, and assessing the level of suspicion before committing to treatment is very important in order to avoid over treatment or missing a diagnosis with subsequent loss of vision.

Close relationship with rheumatology colleagues with a clear and urgent referral pathway is very important in managing these complex cases safely.

Eye Test Glasses

Traumatic Optic Neuropathy

October 2021

In neuro-ophthalmology we get asked a lot about management of patients who suffered significant trauma and presented with loss of vision secondary to presumed traumatic optic neuropathy (TON).

TON happens usually in the context of significant craniofacial trauma. The incidence is around 2-5%, with several mechanisms suggested to explain the pathophysiology of TON. These include mechanical injury, which could be direct or indirect, orbital compartment syndrome and vascular ischaemic injury [1].

Assessment [2]

It is important to make every effort to take a full history and details of the incident, as this will help understand the mechanism of suspected TON. Assessment of visual functions, including visual acuity, colour vision, confrontation field tests, pupils assessment (for relative afferent pupillary defect – RAPD) and optic nerve and macular optical coherence tomography (OCT), if possible, is very helpful in establishing a baseline. Neuro-imaging should be done, ideally a computed tomography (CT) scan looking for bone fractures or acute haemorrhages and an magnetic resonance imaging (MRI) scan, if possible, to assess the visual pathways. It is also very important to perform a full ocular and adnexal examination looking for signs of ocular trauma. In the context of indirect mechanical or ischaemic damage, the most important objective test is the presence or absence of an RAPD. In these patients, the optic disc will often be normal in appearance and only develop disc pallor over the next few weeks.

Types of injury [3]

  1. Evulsion (avulsion: tearing of the optic nerve from the globe): this could be partial or complete. Fundus examination could reveal a vitreous haemorrhage and absent optic nerve disc, partially or totally.

  2. Direct injury: this could be due to sharp or blunt trauma. If the injury is anterior, the fundus exam could reveal a picture similar to central retinal artery occlusion, but if posterior then fundus exam might be normal in the acute setting.

  3. Indirect injury: this is the most common type of TON. It happens usually due to blunt trauma to the craniofacial area with forces transmitted to the orbital apex causing damage to the canalicular optic nerve. In these cases, fundus examination will reveal normal optic nerve, but optic atrophy will happen a few (six to eight) weeks later.

Treatment options [2]

It is difficult to draw any evidence-based, clinically-proven conclusions on TON treatment. Many patients improve spontaneously (20-35%). Treatment options include observation, medical treatment with high dose of steroids, surgical treatment to decompress the optic nerve or a combination of both.

There is significant controversy around best evidence-based treatment as there is no clear benefit from steroids, with some toxicity in animal models and increased mortality in patients with concomitant head trauma. Surgical intervention to remove any bony fragments or to decompress the optic nerve might be beneficial but very difficult, with considerable morbidity.



Figure 1: Algorithm for best evidence-based management of traumatic optic neuropathy.


Literature review

Most studies suggested that there was slight or no benefit to treatment over observation but did not find a significant difference between treatment modalities or steroid dose. There was no agreement on the dose needed for treatment of TON, with suggestions of IV methylprednisolone as an option. Surgical intervention to decompress the optic nerve was suggested if there was no improvement on medical treatment. This could be done using various surgical approaches [2].

Steinsapir and Goldberg in 2011 reviewed treatment options for traumatic optic neuropathy and found that most studies were small and lacking any control arm [4]. The Corticosteroid Randomization for Acute Head Trauma (CRASH) trial found increased death rates in patients who were treated with steroids compared to the placebo group. Other studies also suggested toxicity of steroids to the injured optic nerve in animal studies. They concluded, given that most TON patients will have concomitant brain trauma, these patients should not be treated routinely with steroids due to lack of demonstrated benefit and increased mortality. They also concluded that the benefits of surgery are also unclear.

In 2013, Yu-Wai-Man and Griffiths reviewed all major medical databases for evidence on surgical treatment for traumatic optic neuropathy [5]. They did not find any randomised controlled trials (RCTs). They concluded there is a lack of RCTs and a high rate of spontaneous recovery, without clear evidence that surgical decompression provides any benefit, although these surgical interventions can carry significant risk of complications such as cerebrospinal fluid leak and meningitis.

The same authors also reviewed all major medical databases for evidence on the benefits of steroids treatment for TON [6]. They found one RCT on the use of high dose intravenous steroids in patients with indirect TON. This study looked at 31 patients (16 treated with steroids and 15 with placebo) followed for three months and found that although vision was slightly better in the steroid group, this was not statistically significant. They concluded that there is a lack of clear evidence on benefit of steroid treatment compared to observation, with high rates of spontaneous recovery in TON.

Chaon and Lee in 2015 looked again at available treatment options for TON [7]. They also noted the lack of randomised trials and current literature consisted of small retrospective observational studies. Findings suggested lack of clear benefit of treatment with either steroids or surgery or combination of both over observation only. Novel neuro-protective approaches such as erythropoietin were still under investigation.

Very recently, in 2021, Naguib et al. looked at intravitreal injections in animal models of TON and found that these injections might be harmful to the optic nerve with increased number of the degenerative nerve fibres and increased levels of the pro-inflammatory cytokines, IL-1α and IL-1β [8].

Suggested protocol for treatment of TON (evidence class II-IV, level C):

  1. Diagnose TON (exclude alternative causes including open globe) (class III, level B).

  2. Perform CT scan of the optic canal and orbit.

  3. Perform canthotomy or cantholysis if the orbit is tense.

  4. Drain subperiosteal haematoma if present (class III–IV, level C).

  5. Consider starting IV corticosteroids (Methylprednisolone 30mg/kg IV, then 15mg/kg every six hours for 48 hours) even in patients with no light perception (NLP) vision (class III, level C).

  6. Consider optic nerve decompression if bony fragments impinging on the optic nerve present (class III, level U).

  7. If vision improves on IV methylprednisolone after 48 hours, then start rapid oral taper of prednisone (class III, level C).

  8. If there is no clinical response after 48 hours or if vision deteriorates during the steroid taper, then surgical decompression of the optic canal is offered, especially for patients with severe visual loss (class III, level C).

Conclusion

There is a lack randomised controlled trials on the treatment of TON and treatment remains controversial. Options should be tailored to each patient and these include observation, medical treatment with steroids or surgical treatment to decompress the optic nerve. The options should be discussed with individual patients to gain informed consent as benefits are not clear with high risk of morbidity or mortality.


References

1. Schiefer U, Wilhelm H, Hart W: Clinical Neuro-Ophthalmology. A Practical Guide. Springer: New York, USA; 2007: 124.
2. Lee AG, Brazis PW: Pathways in Neuro-Ophthalmology: An Evidence-Based Approach. Thieme: New York, USA; 2003: 119-28.
3. Kline LB, Foroozan R: Neuro ophthalmology review manual. (7th ed). SLACK Incorporated: New Jersey, USA; 2013: 167-8.
4. Steinsapir KD, Goldberg RA. Traumatic optic neuropathy: an evolving understanding. Am J Ophthalmol 2011;151(6):928-33.e2.
5. Yu-Wai-Man P, Griffiths PG. Surgery for traumatic optic neuropathy. Cochrane Database Syst Rev 2013;6(6):CD005024.
6. Yu-Wai-Man P, Griffiths PG. Steroids for traumatic optic neuropathy. Cochrane Database Syst Rev 2013;2013(6):CD006032.
7. Chaon BC, Lee MS. Is there treatment for traumatic optic neuropathy? Curr Opin Ophthalmol 2015;26(6):445-9.
8. Naguib S, Bernardo-Colon A, Rex TS. Intravitreal injection worsens outcomes in a mouse model of indirect traumatic optic neuropathy from closed globe injury. Eye Res 2021;202:108369.

Fig 2.jpg

Idiopathic Intracranial Hypertension

June 2021

IIH is a medical condition where the intracranial pressure (ICP) is raised without an obvious cause. The cerebrospinal fluid (CSF) is produced in by the choroid plexus in the lateral ventricles and the roof of the third and fourth ventricles, it then circulates around the brain, spinal cord and optic nerves sheaths then gets absorbed by the arachnoid villi into the cerebral sinus veins system. The CSF is produced at a rate of 500ml daily and the normal intracranial pressure is up to 20cm of water.

Mechanism, signs and symptoms

The mechanism of IIH is still unknown but thought to be related to reduced drainage through the venous system. In fact, many patients with IIH have transverse sinus stenosis, although there still debate on whether this is the cause of IIH or a result from the raised intracranial pressure. There is a very strong link between IIH and weight; in fact, most patients are young women with increased BMI (typical IIH). IIH usually presents with headaches, pulse synchronised tinnitus and visual symptoms.

The headaches are usually more intense in the morning or following any activity that raises the intracranial pressure such as bending down, coughing or sneezing. They are usually generalised but throbbing in nature.

Ophthalmologically, IIH can cause optic nerve swelling (papilloedema = swollen optic nerve due to raised intracranial pressure) which is usually bilateral but could be very asymmetric or even unilateral in rare cases. It can also cause ocular motility abnormalities, most commonly VI cranial nerve palsy.

Papilloedema can be classified on Frisen grading system from grade 0 (no swelling) to grade 5 (Table 1). Patients should be assessed by examining their visual functions (visual acuity, colour vision, peripheral vision and pupil reactions). The central visual acuity tends to be preserved unless the swelling is severe and hyperacute (fulminant IIH) while visual field defects are more common and can happen earlier (enlarged blind spot and inferior nasal defect).


Differential diagnosis

It is important to rule out other causes of raised intracranial pressure such as brain tumours, medical conditions or medications that raise intracranial pressure (Table 2). It is also important to assess optic nerves and confirm the optic nerve swelling (rather than pseudo swelling such as optic disc drusen, peripapillary hyperreflective ovoid mass-like objects – phoms, crowded or tilted discs) and rule out other causes of optic nerve swelling such as vascular or inflammatory optic neuropathies.

Diagnosis and investigations

Modified Dandy criteria (1985, 2001) suggest a set of criteria to diagnose IIH and eliminating other causes of raised intracranial pressure (Table 3).

Investigations for IIH include optic nerve ultrasound to assess the optic nerve sheath width, which helps rule out pseudo swelling. Optical coherence tomography (OCT) scan, especially enhanced depth imaging (EDI) helps in the assessment of optic nerve swelling and picking up disc drusen and phoms. Neuro-imaging (CT or MRI scans) and venogram (CTv or MRv) are necessary to rule out any space occupying lesion and cerebral venous sinus thrombosis (CVST). The MRI scan in IIH should be normal, but there are several non-specific findings that fit with the possibility of raised intracranial pressure. These include: flattening of the posterior sclera, empty sella, extended optic nerve sheaths, vertical tortuosity of the optic nerves, slit ventricles and narrowing of the transvers sinuses.

Once neuro-imaging has been done patients undergo a lumbar puncture (LP) to assess CSF constituents (should be normal in IIH) and check the opening pressure in the left lateral recumbent position (normal is up to 20cm of water, up to 25cm is borderline and >25cm is raised, compatible with IIH).

Classification

IIH can be classified into typical IIH which affects the typical phenotype of young overweight women, atypical which can affect other phenotypes (men or children or women who are not overweight) and fulminant IIH which has a very severe and aggressive clinical pathway.

It is important in atypical cases to investigate all other possible causes of raised intracranial pressure and to take swift action in fulminant cases.

Treatment

Treatment options depend on the severity of the symptoms (headaches or visual symptoms) as well as the severity of optic nerve swelling.

In cases with very mild optic nerve swelling (grade 1) and minimal general symptoms, observation might be a good option.

Medical treatment is usually the first line of treatment for the majority of patients. This includes acetazolamide where doses can go up to 2000mg daily if patients tolerate, especially when there is significant optic nerve swelling. Later in the course of the disease when headaches persist, in the absence of significant swelling, topiramate could be used as it has effects against the raised intracranial pressure as well as effects against chronic migraines. It is also important to discuss and encourage weight loss in patients as there is a very strong body of evidence to support that as a long-term treatment option that modifies the course of the disease.

In cases of IIH refractory to treatment or fulminant IIH where there is imminent risk to vision, surgical intervention might be warranted. Surgical options include optic nerve fenestration, transverse sinus stenting and ventriculoperitoneal (VP) shunting. The choice depends largely on local expertise and availability. Repetitive LPs don’t usually work as a treatment option as the CSF gets replaced within 24 hours but can be used as a temporary measure while awaiting surgical intervention or in special cases such as pregnancy.

Figure 1: OCT scan of papilloedema patient with bilateral optic nerve swelling grade 3.


Case study 1:

A 22-year-old female saw her local optician complaining of mild blurring of vision and generalised headaches. On assessment her visual acuity was slightly reduced at 6/7.5 in both eyes (0.1 on logMAR). Colour vision was full and visual fields testing showed enlarged blind spots. An OCT scan of her optic nerve showed bilateral optic nerve swelling (Figure 1). She was referred to the eye emergency clinic where her optic nerve swelling was confirmed. She was referred to the medical team where she had CT/CTv followed by an LP which showed raised opening pressure of 35cm of water (raised intracranial pressure). As there were no other causes, she was diagnosed with IIH. She was put on acetazolamide (250mg QDS) and followed up in the neuro-ophthalmology clinic until her papilloedema resolved. Weight loss advice was given and side- effects of treatment were explained and her acetazolamide was reduced gradually and she continues to be on regular follow-up until full remission.

Figure 2: OCT scan of patient with fulminant IIH and bilateral grade 5 optic nerve swelling.


Case study 2:

A 35-year-old female presented to the eye emergency clinic with severe headaches, tinnitus and bilateral reduction of vision. Her visual acuity was 6/24 in her right eye and 6/18 in the left. Fundus examination showed severe bilateral optic nerve swelling (Figure 2). She was referred urgently for neuro-imaging (CT / CTv), both were normal, then had an LP which showed opening pressure of more than 40cm of water. She was put on high dose of acetazolamide (500mg TDS), but on follow-up in the neuro-ophthalmology clinic a few days later there was no significant response and her visual functions remained compromised so she was referred for urgent surgical intervention and she had a VP shunt inserted. On follow-up a few weeks later her optic nerve swelling started to reduce (Figure 3) with improvement of her visual acuity, although she developed a nasal field defect in her right eye.

Figure 3: OCT scan of the same patient following VP shunt insertion.


Conclusions

IIH is a relatively common condition with increasing prevalence in young overweight women. It is important to recognise features of optic nerve swelling and differentiate pseudo swelling from true optic nerve swelling. It is also important to differentiate IIH from other causes of optic nerve swelling such as inflammatory vascular causes, as well as other causes of raised intracranial pressure such as brain tumours or medication related. Early intervention is very important in fulminant IIH, while it is important to fully investigate all atypical cases. In typical IIH, monitoring or medical treatment is usually the first line of treatment but weight loss advice is always important and encouraged.


References

1. Mollan SP, Davies B, Silver NC, et al. Idiopathic intracranial hypertension: consensus guidelines on management. J Neurol Neurosurg Psychiatry 2018;89:1088-100.
2. Mollan SP, Hornby S, Mitchell J, Sinclair AJ. Evaluation and management of adult idiopathic intracranial hypertension. Pract Neurol 2018;18:485-8.
3. Idiopathic intracranial hypertension UK: www.iih.org.uk Last accessed April 2021.
4. Mollan SP, Markey KA, Benzimra JD, et al. A practical approach to, diagnosis, assessment and management of idiopathic intracranial hypertension. Pract Neurol 2014;14:380-90.
5. Thurtell MJ, Wall M. Idiopathic Intracranial Hypertension (Pseudotumor Cerebri): Recognition, Treatment, and Ongoing Management. Curr Treat Options Neurol 2013;15(1):1-12.
6. Wall M. Idiopathic intracranial hypertension. Neurol Clin 2010;28(3):593-617.
7. Lee AG, Brazis PW: Clinical Pathways in Neuro Ophthalmology. An Evidence Based Approach (2nd Edition). Thieme; 2003:129-65.