Ординатура / Офтальмология / Английские материалы / Moorfields Manual of Ophthalmology_Jackson_2007

Avoid precipitating factors such as red wine or cheese if any can be identified.

Follow–up Refer to the GP or a neurologist, particularly if the headache is disabling and frequent (more than twice per month), needing prophylactic treatment to prevent headache (e.g. propranolol, pizotifen, or amitryptiline), or atypical features are present requiring investigation. Specific antimigraine agents are available for acute attacks but are best prescribed in neurology or general practice.

OPHTHALMOLOGY-NEURO 14 Chapter

Ischaemic optic neuropathy

Ischaemic Optic Neuropathy

Anterior ischaemic optic neuropathy (AION) is caused by infarction of the optic nerve head. It may be nonarteritic, or arteritic (giant cell arteritis, GCA).

Nonarteritic anterior ischaemic optic neuropathy

Background Increased risk if male, systemic arteriopathy, aged 40–60 years, or disc vessel crowding (small hypermetropic discs, disc drusen). Occasionally precipitated by severe hypovolaemia or anaemia, e.g. cardiac surgery. Excluding an arteritic cause is key but GCA is rare under 65 years; other types of vasculitis may occur in younger age groups but this and thrombophilia are rare causes of AION.

Symptoms Typically sudden, painless, nonprogressive partial monocular vision loss. Sometimes asymptomatic.

Signs Optic disc swelling that may be sectoral, with flame haemorrhages and occasionally a macular star. Longstanding cases show sectoral disc atrophy corresponding to the field defect.

History and examination Ask about the speed of visual loss and any recovery. Importantly, exclude symptoms of GCA (see below). Record: refractive error; VA (typically 6/12–6/60); Ishihara plates (reduced); RAPD (expected); confrontation fields (typically, unilateral altitudinal hemianopia); dilated peripheral fundoscopy (exclude peripheral haemorrhage, vitritis, periphlebitis). Draw or photograph the optic disc. Confirm pulsatile, nontender, temporal arteries, full eye movements, and no lid-lag or proptosis.

Differential diagnosis

(see below).

Consider posterior ischaemic optic neuropathy following facedown spinal surgery, radiotherapy, and hypotension/hypovolaemia/ haemodialysis. This produces no disc swelling, is often bilateral, with worse VA, and a poor prognosis. There is no proven treatment.

Investigations Check ESR and CRP (mandatory) ± temporal artery biopsy; FBC; fasting blood glucose; lipids; BP; and Goldmann or 24–2 Humphrey field test. If disc drusen are suspected, consider USS or disc photos for autofluorescence.

Treatment

■Casualty : start aspirin 75 mg o.d. if there are no contraindications. Review all vascular risk factors. Exclude GCA and if in doubt discuss with a senior colleague. Request review at 6 weeks.

■Clinic : recheck clinical findings, particularly fields. Early stepwise progression occurs but is unusual. Neuroimaging is not required unless findings are atypical. Expect three lines of VA improvement in 30%. AION is unlikely (5%) to recur in the same eye after nerve fibre atrophy relieves disc vessel congestion. Studies suggest a 15–50% risk of fellow eye involvement. Review in 6 months then discharge if stable.

Giant cell arteritis (temporal arteritis)

Background Occlusive arterial inflammation causes optic disc ischaemia and sudden, usually total, unilateral visual loss. It is an ophthalmic emergency, as the second eye may develop irreversible visual loss within hours. Patients are usually elderly and never

<50 years. Associated with polymyalgia rheumatica.

Symptoms These include new headache, scalp tenderness, loss of appetite, weight loss, limb girdle pain (worse in the morning, relieved by movement), and ischaemic jaw pain on chewing. Prodromal episodic transient visual loss, often on standing due to poor perfusion, occurs in 10%. Ophthalmoplegia may occur.

Signs Common features include thickened temporal arteries which may be nonpulsatile and tender, RAPD, and pale disc swelling ± flame haemorrhages. VA is usually ≤ count fingers. Central retinal artery occlusion and retinal cotton-wool spots may occur. Optic nerve ischaemia may be retrobulbar.

History and examination Ask about polymyalgia rheumatica and steroid contraindications or recent withdrawal. Record: temporal artery findings, VA, Ishihara plates, confrontation fields, eye movements, proptosis, RAPD, dilated fundoscopy, disc appearance, and any vitritis. Measure BP and BM before starting steroids.

Differential diagnosis Disc infarction is sectoral in nonarteritic AION but total in GCA. Disc infarction makes the diagnosis of GCA relatively easy, but it can be more difficult in those presenting with headache only, or ophthalmoplegia, postural transient monocular visual loss, or posterior nerve ischaemia (and no disc swelling).

Investigations ESR >47 and CRP >25 = 97% probability of GCA if the clinical features fit. Normal ESR is ≤ age/2 in men;

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Ischaemic optic neuropathy

(age +10)/2 in women. Thrombocythaemia is common. Numerous other causes of raised ESR include infections that may worsen with steroids. Temporal artery biopsy (see Box 14.1) should be arranged but should not delay treatment. Choroidal hypoperfusion on fluorescein angiography suggests GCA.

Treatment Give stat methylprednisolone 1 g in 500 mL normal saline over 30 minutes and oral ranitidine 150 mg b.d. Substitute oral prednisolone 100 mg if arranging i.v. treatment will cause delay. Admit if elderly or cardiac disease. Expect a dramatic improvement in systemic symptoms in 24 hours. Continue i.v. steroids for 3 days then switch to oral prednisolone 100 mg daily. Osteoporosis prophylaxis is mandatory as treatment will be required for many months. For this and other aspects of long term steroid use, see p. 342.

Follow–up Review at 1 week then monthly with repeat ESR. Taper steroids only when the patient is asymptomatic and the ESR has fallen substantially.

Box 14.1: Temporal artery biopsy (Fig. 14.15)

May be positive after months of steroids, but aim to do within a week. If negative it does not exclude GCA, as skip lesions occur.

1.Consent

Benefit : confirm diagnosis (in approximately 35%).

Risk : bleeding, infection, scar. Scalp necrosis is very rare. Repeat biopsy is sometimes required. Damage to the facial nerve is theoretically possible but very rare in practice. Stroke has been reported but is extremely rare.

2.Mark tender areas of artery to biopsy with a surgical pen. If not obvious, mark the frontal branch.

3.Infiltrate with lidocaine 2% with adrenaline (≤10 mL).

4.Open skin with a No. 15 blade directly over the artery. Control bleeding with cautery.

5.Blunt dissect with blunt-nosed scissors, down to temporal fascia.

6.Identify and bluntly dissect around the artery. Before removing, tie two pairs of 4/0 Vicryl suture around either end, at least 3 cm apart. Avoiding crush artefact. Ensure haemostasis.

7.Close with Vicryl (4/0 subcutaneous tissues; 7/0 skin). Let skin sutures dissolve or remove at 1 week.

8.Apply a compression bandage for 24 hours. Avoid excessive

A

Parietal branch Frontal branch

Superficial temporal branch

Fig. 14.15: Temporal artery anatomy and biopsy.

OPHTHALMOLOGY-NEURO 14 Chapter

Demyelinating (MS-associated) optic neuritis

Demyelinating (MS-associated)

Optic Neuritis

Background Typically occurs in young women (average age 31) who have spent childhood in temperate latitudes. Associated with multiple sclerosis (MSAON).

Symptoms Headache and/or pain on eye movements (92%) then progressive, uniocular loss of vision over days. Photopsia may occur.

Signs These include optic disc swelling (50%) or retrobulbar neuritis, reduced Ishihara plates and VA (≤6/60 in 35%), diffuse field loss in 48% (though classically a central scotoma) and uveitis in 3%.

History and examination Ask about symptoms of demyelination: episodes of paraesthesia or sensory loss; transient weakness with onset over days and resolution over weeks; bladder dysfunction; vertigo; diplopia; Lhermitte’s symptom (electric sensation down the spine and into the limbs on neck flexion). Ask about Uhthoff’s symptom (see below). Record: BP, cranial nerves, saccades, cerebellar signs, proptosis, ocular inflammation, VA, Ishihara plates, confrontation fields and dilated fundoscopy.

Differential diagnosis Question the diagnosis if any of the following are present: age >60 years or born and raised in tropical latitudes; severe pain interrupting sleep; very rapid and severe visual loss (<48 hours, <CF vision); simultaneous bilateral involvement; pain for >2 weeks; optic disc haemorrhage; family history of Leber’s hereditary optic neuropathy (LHON); known sarcoidosis, collagen vascular disease or cancer. Consider the following alternative diagnoses:

■Orbital : thyroid eye disease (not usually painful) and myositis (painful but causes ophthalmoplegia; visual loss is rare).

■Ocular: posterior uveitis, neuroretinitis, central serous retinopathy, and scleritis.

■Optic neuropathy : compressive (optic nerve, orbital, or intracranial tumours are rarely painful), paranasal mucocele (usually painful and subacute onset; mucocele may closely mimic MSAON), inflammatory (sarcoid, autoimmune disease), ischaemic (arteritic or nonarteritic: do not usually produce

■Systemic disease : severe hypertension, raised intracranial pressure (occasionally causes unilateral disc swelling), acute disseminated encephalomyelitis, and Devic’s disease (bilateral optic neuritis is the rule).

Investigations If the clinical picture is typical of MSAON and if spontaneous recovery has occurred, no investigations are mandatory. Refer the patient to a neurologist for discussion. In atypical cases investigation is mandatory : In the acute-phase MRI, STIR orbital sequences show high signal/swelling of the optic nerve. T1 orbital scan with fat suppression shows gadolinium enhancement of the optic nerve. In the chronic phase there is no enhancement but T2 high signal is seen. Also in the chronic phase, with good recovery of acuity, the typical VEP finding is a substantial delay with preserved amplitude; this is unusual in any other cause of optic neuropathy. Consider: FBC, syphilis serology, sACE, ANA, ESR, ANCA, B12, folate, CXR, lumbar puncture.

Key study Optic Neuritis Treatment Trial1 Intravenous steroids hastened visual recovery and reduced the risk of MS at 2, but not 5 years. Neither oral nor intravenous treatment offered any longterm visual benefit. Note that some inflammatory optic neuropathies (e.g. sarcoid and autoimmune disorders) may require steroids to prevent severe visual loss.

Treatment

■Casualty : refer to clinic within 1 week. Offer analgesia but if pain is severe (e.g. through the night) reconsider the diagnosis.

■Clinic : expect 93% to improve by 5 weeks; 70% recover nearnormal vision, but this may take 1 year. May recur (19% at 5 years), or affect the other eye within months (17%).

Mention the association with MS but emphasise that it tends to be a relatively benign form. If the patient wants to know the risk, refer to a neurologist who may order an MRI scan. If there are no white-matter lesions, the incidence of a second episode is 22% within 10 years. One lesion gives a 51% risk that rises with more lesions.

No treatment is required after a single episode. In relapsing remitting MS, beta-interferon reduces the number of relapses by one-third. A beneficial effect on long-term disability has not been proven.

In children, bilateral optic neuritis may follow viral infection or immunizations. The risk of MS is low. Treat with i.v. methylprednisolone 15 mg/kg for 3 days if there is significant visual loss.

OPHTHALMOLOGY-NEURO 14 Chapter

Demyelinating (MS-associated) optic neuritis

Follow–up Review every few months initially. Discharge if stable at 1 year. Refer to a neurologist if symptoms of MS occur.

Other ocular features of MS

■Uhthoff’s phenomenon : transiently decreased vision with exertion or in hot conditions.

■Intermediate uveitis : sheathing of retinal venules may be seen.

■Cranial nerve palsy : commonly 6th, but any may be affected.

■Internuclear ophthalmoplegia : the ipsilateral eye fails to adduct or adducts slowly, whilst the contralateral eye has horizontal nystagmus on abduction.

■Wall-eyed bilateral internuclear ophthalmoplegia (WEBINO): both eyes have no adduction. Prisms may reduce diplopia.

■One-and-a-half syndrome : one eye has no voluntary horizontal movements and the other can only abduct. If supranuclear, the palsy is overcome by dolls-head movements. Other supranuclear gaze palsies may occur.

■Cerebellar disease : dysmetric saccades and gaze-evoked nystagmus.

■Acquired pendular nystagmus : associated with reduced acuity; the amplitude may differ greatly in the two eyes.

Traumatic Optic Neuropathy

Background Caused by direct head, face, or orbital trauma. Rarely surgically induced. May be unilateral or bilateral. So-called ‘indirect’ injury to the optic nerve occurs following a blow to the brow which can be relatively minor with no other injuries, no fractures, and no loss of consciousness.

Symptoms Sudden loss of vision at the time of injury. May progress initially as soft tissue swelling compresses the nerve or if there is a haematoma.

Signs RAPD, VA decreased (6/6 to NPL), variable field loss, and decreased colour vision. The optic nerve may initially appear swollen or avulsed but is usually normal, with later atrophy.

History and examination Record Glasgow coma scale and ensure extraocular injuries are treated. Exclude orbital, anterior, and posterior segment injuries (pp. 101, 205, and 551, respectively). Check VA, RAPD, Ishihara colour vision, confrontation fields, eye movements, IOP, and dilated fundoscopy, noting disc, or retinal abnormalities. Avoid dilating if the patient requires neuro-observations for other injuries.

Differential diagnosis Visual loss is usually maximal at the instant of injury; any delay in loss may indicate a haematoma in the orbit or in the optic nerve sheath. Consider occipital infarct, vitreous haemorrhage, retinal detachment, retinal commotio, globe rupture, traumatic cataract, and lens dislocation.

Investigations Arrange an urgent CT scan of the brain and orbits looking for displaced orbital fracture, and orbital or intracranial haemorrhage, particularly if the patient has a decreased Glasgow coma scale. Liaise with other specialties as required. Arrange field testing if general health permits.

Treatment About 30% improve spontaneously. High-dose steroids have been advocated but there is no evidence that treatment will influence the outcome. Consider immediate lateral cantholysis if the orbit is tense and retrobulbar haemorrhage is suspected. Surgical decompression is rarely indicated unless there is evidence of optic nerve compression by a haematoma or bone fragment.

Follow–up Review with regular field tests for the first year. Check eligibility to drive.

OPHTHALMOLOGY-NEURO 14 Chapter

Compressive, infiltrative, and inflammatory optic neuropathy

Compressive, Infiltrative, and

Inflammatory Optic Neuropathy

Background A wide range of orbital and systemic conditions may rarely involve the optic nerve.

Symptoms Visual loss over hours to weeks, severe periocular pain, pain on eye movements, or headache may occur. May be unilateral or bilateral. Compressive lesions usually cause gradual, painless, monocular loss of visual field or VA that may go unnoticed for months.

Signs Findings include reduced VA and colour vision, RAPD (if unilateral or asymmetric), visual field loss, optic nerve swelling, or atrophy. Examination may be normal.

History and examination Record the duration of symptoms and speed of visual loss. Ask about any obscurations on sustained eccentric gaze. Take a complete history and systems review. Look for typical features of demyelinating optic neuropathy (p. 658). Record VA, colour vision, RAPD, IOP, eye movements, and dilated fundus exam. Exclude vitritis and thyroid eye disease. Check orbital signs (p. 72), cranial nerves, and confrontation visual fields. Look for optic disc venous collaterals suggesting optic nerve sheath meningioma. Physician review is advisable.

Differential diagnosis Consider: neoplasm (leukaemia, lymphoma, secondaries); syphilis; sarcoid; TB; autoimmune disease; collagen vascular disease; vasculitides; sinus disease/ mucocele; HIV; thyroid eye disease; pituitary tumour; craniopharyngioma; fibrous dysplasia; Paget’s disease; sphenoid wing meningioma; frontal lobe tumour; optic nerve glioma or meningioma; nasopharyngeal carcinoma; ophthalmic or carotid artery aneurysm; other optic neuropathies (demyelinating, traumatic, nutritional, toxic, radiation).

Investigations Initially, send for FBC and film, ESR, CRP, U&E, LFT, glucose, ANA, sACE, TPHA, ANCA, protein electrophoresis, and CXR. Request MRI of brain and orbits and formal perimetry (Goldmann or Humphrey). Consider Mantoux and HIV testing if the history is suggestive, and Lyme serology in endemic areas. Consider lumbar puncture.