Symptoms

Symptoms of orbital disease include eyelid and conjunctival swelling, redness, watering, pain (sometimes on, or exacerbated by, eye movement), increasing ocular prominence, displacement or a sunken impression of the eye, double vision and blurring, and sometimes a pulsing sensation or audible bruit.

Soft tissue involvement

Eyelid and periocular oedema, skin discoloration, ptosis, chemosis (oedema of the conjunctiva, which may involve the plica and caruncle) and epibulbar injection ( Fig. 3.2 ) may be seen; causes include thyroid eye disease, orbital inflammatory diseases and obstruction to venous drainage.

Chemosis and injection in orbital disease

Proptosis

Proptosis ( Fig. 3.3 ) describes an abnormal protrusion of an organ, but is generally applied to the eyeball; exophthalmos refers specifically to the eyeball only. Proptosis may be caused by retrobulbar lesions or, less frequently, a shallow orbit. The intraorbital portion of the optic nerve is longer (25 mm) than the distance between the back of the globe and the optic canal (18 mm). This allows for significant forward displacement of the globe (proptosis) without excessive stretching of the nerve.

• •
  

  Asymmetrical proptosis is readily detected by looking down at the patient from above and behind ( Fig. 3.4A ).

  
  

  
  

  
  

  

  
  

  
  

  General signs of orbital disease. (A) Left proptosis visualized from above; (B) right inferior dystopia; (C) measurement of proptosis with an exophthalmometer

  
  

  
  

  

  
  

  
  

  

  
  
  
  
• •
  

  The direction of proptosis may indicate the likely pathology. For example, space-occupying lesions within the muscle cone such as a cavernous haemangioma or optic nerve tumours cause axial proptosis, whereas extraconal lesions usually give rise to combined proptosis and dystopia (see next).

  
  
• •
  

  Dystopia implies displacement of the globe in the coronal plane, usually due to an extraconal orbital mass such as a lacrimal gland tumour ( Fig. 3.4B ). Horizontal displacement is measured from the midline (nose) to the centre of the pupil while vertical dystopia is read on a vertical scale perpendicular to a horizontal rule placed over the bridge of the nose. The measured eye should fixate straight ahead, if necessary facilitating this by occluding the fellow eye.

  
  
• •
  

  The severity of proptosis can be measured with a plastic rule resting on the lateral orbital margin, or with the Luedde™ exophthalmometer using a similar principle. Commonly, a binocular exophthalmometer (e.g. Hertel) is employed, using visualization of the corneal apices to determine the degree of ocular protrusion from a scale ( Fig. 3.4C ). Measurements can be taken both relaxed and with the Valsalva manoeuvre. Readings greater than 20 mm are indicative of proptosis and a difference of 2–3 mm or more between the two eyes is suspicious regardless of the absolute values. The dimensions of the palpebral apertures and any lagophthalmos should also be noted.

  
  
• •
  

  Pseudoproptosis (the false impression of proptosis) may be due to facial asymmetry, enlargement of the globe (e.g. high myopia or buphthalmos), lid retraction or contralateral enophthalmos.

Bilateral proptosis

(Courtesy of C Barry)

Enophthalmos

Enophthalmos implies recession of the globe within the orbit. Causes include congenital and traumatic orbital wall abnormalities, atrophy of the orbital contents (e.g. radiotherapy, scleroderma, chronic eye poking in blind infants – the ‘oculodigital’ sign) or sclerosis (e.g. metastatic scirrhous carcinoma, sclerosing orbital inflammatory disease). Pseudoenophthalmos may be caused by a small or shrunken eye (microphthalmos or phthisis bulbi), by ptosis, or by contralateral proptosis or pseudoproptosis.

Ophthalmoplegia

Defective ocular motility is very common in orbital disease. Causes include an orbital mass, restrictive myopathy (e.g. thyroid eye disease – Fig. 3.5 , orbital myositis, tethering of muscles or tissue after orbital wall fracture), ocular motor nerve involvement associated with lesions in the cavernous sinus, orbital fissures or posterior orbit (e.g. carotid–cavernous fistula, Tolosa–Hunt syndrome, malignant lacrimal gland tumours). The following tests may be used to differentiate a restrictive from a neurological motility defect:

• •
  

  Forced duction test. Under topical anaesthesia, the insertion of the muscle in an involved eye is grasped with forceps and the globe rotated in the direction of reduced mobility; checked movement of the globe indicates a restrictive problem; no resistance will be encountered with a neurological lesion.

  
  
• •
  

  Differential intraocular pressure (IOP) test involves less discomfort than forced duction and an objective rather than subjective endpoint. The IOP is measured in the primary position of gaze and then with the patient attempting to look in the direction of limited mobility; an increase of 6 mmHg or more denotes resistance transmitted to the globe by muscle restriction (the Braley sign).

  
  
• •
  

  Saccadic eye movements in neurological lesions are reduced in velocity, while restrictive defects manifest normal saccadic velocity with sudden halting of ocular movement.

Restrictive myopathy and bilateral lid retraction and proptosis in thyroid eye disease – nine positions of gaze

(Courtesy of C Barry)

Dynamic properties

• •
  

  Increasing venous pressure by dependent head position, the Valsalva manoeuvre or jugular compression may induce or exacerbate proptosis in patients with orbital venous anomalies or infants with orbital capillary haemangioma.

  
  
• •
  

  Pulsation is caused either by an arteriovenous communication or a defect in the orbital roof. In the former, pulsation may be associated with a bruit depending on the size of the communication. In the latter the pulsation is transmitted from the brain by the cerebrospinal fluid and there is no associated bruit. Mild pulsation is best detected on the slit lamp, particularly by applanation tonometry.

  
  
• •
  

  A bruit is a sign found with a larger carotid–cavernous fistula. It is best heard with the bell of the stethoscope and is lessened or abolished by gently compressing the ipsilateral carotid artery in the neck.

Fundus changes

• •
  

  Optic disc swelling may be the initial feature of compressive optic neuropathy ( Fig. 3.6A ).

  
  

  
  

  
  

  

  
  

  
  

  Fundus changes in orbital disease. (A) Disc swelling; (B) optic atrophy; (C) opticociliary vessels on a chronically swollen disc; (D) choroidal folds

  
  

  (Courtesy of S Chen – fig. D)

  
  

  
  

  

  
  

  
  

  

  
  

  
  

  

  
  
  
  
• •
  

  Optic atrophy ( Fig. 3.6B ), which may be preceded by swelling, is a feature of severe compressive optic neuropathy. Important causes include thyroid eye disease and optic nerve tumours.

  
  
• •
  

  Opticociliary collaterals consist of enlarged pre-existing peripapillary capillaries that divert blood from the central retinal venous circulation to the peripapillary choroidal circulation when there is obstruction of the normal drainage channels. On ophthalmoscopy the vessels appear as large tortuous channels most frequently sited temporally, which disappear at the disc margin ( Fig. 3.6C ). The collaterals may be associated with any orbital or optic nerve tumour that compresses the intraorbital optic nerve and impairs blood flow through the central retinal vein. The most common tumour associated with shunts is an optic nerve sheath meningioma but they may also occur with optic nerve glioma, central retinal vein occlusion, idiopathic intracranial hypertension and glaucoma.

  
  
• •
  

  Choroidal folds ( Fig. 3.6D ) are discussed in detail in Ch. 14 ; they may occur in a wide variety of orbital lesions. Although tending to be more common with greater amounts of proptosis and anteriorly located tumours, in some cases their presence can precede the onset of proptosis.

Thyrotoxicosis

Thyrotoxicosis (hyperthyroidism) is a condition involving excessive secretion of thyroid hormones. Graves disease, the most common form of hyperthyroidism, is an autoimmune disorder in which IgG antibodies bind to thyroid stimulating hormone (TSH) receptors in the thyroid gland and stimulate secretion of thyroid hormones. It is more common in females and may be associated with other autoimmune disorders. Presentation is often in the fourth or fifth decades with symptoms including weight loss despite good appetite, increased bowel frequency, sweating, heat intolerance, nervousness, irritability, palpitations, weakness and fatigue. There may be enlargement of the thyroid gland, tremor, palmar erythema, and warm and sweaty skin. Thyroid acropachy is a phenomenon similar to clubbing of the fingers, occurring in 1%; pretibial myxoedema (1–5%) is indurated thickening of the skin of the shins. Cardiac manifestations may include sinus tachycardia and other arrhythmias. Other autoimmune disorders can be associated. Thyroid function is commonly tested initially with a TSH level; if this is low, or normal but thyroid disease is still suspected, a range of additional investigations can be carried out. Treatment options include carbimazole, propylthiouracil, propranolol, thyroid ablation with radioactive iodine, and partial thyroidectomy.

Risk factors for ophthalmopathy

Once a patient has Graves disease, the major clinical risk factor for developing TED is smoking. The greater the number of cigarettes smoked per day, the greater the risk, and giving up smoking seems to reduce the risk. Women are five times more likely to be affected by TED than men, but this largely reflects the increased incidence of Graves disease in women. Radioactive iodine used to treat hyperthyroidism can worsen TED. TED can also, though less commonly, occur in euthyroid and hypothyroid (including treated hyperthyroid) patients. It can sometimes be the presenting manifestation of thyroid-related disease.

Pathogenesis of ophthalmopathy

Thyroid ophthalmopathy involves an organ-specific autoimmune reaction in which an antibody that reacts against thyroid gland cells and orbital fibroblasts leads to inflammation of extraocular muscles, interstitial tissues, orbital fat and lacrimal glands characterized by pleomorphic cellular infiltration, associated with increased secretion of glycosaminoglycans and osmotic imbibition of water. There is an increase in the volume of the orbital contents, particularly the muscles, which can swell to eight times their normal size. There may be a secondary elevation of intraorbital pressure, and the optic nerve may be compressed. Subsequent degeneration of muscle fibres eventually leads to fibrosis, which exerts a tethering effect on the involved muscle, resulting in restrictive myopathy and diplopia.

Introduction

TED typically proceeds through a congestive (inflammatory) stage in which the eyes are red and painful; this tends to remit within 1–3 years and only about 10% of patients develop serious long-term ocular problems. A fibrotic (quiescent) stage follows in which the eyes are white, although a painless motility defect may be present. Clinical features broadly can be categorized into (i) soft tissue involvement, (ii) lid retraction, (iii) proptosis, (iv) optic neuropathy and (v) restrictive myopathy. A commonly used classification for the severity of TED has been issued by the European Group on Graves Orbitopathy (EUGOGO): (i) sight-threatening due to optic neuropathy or corneal breakdown; (ii) moderate–severe, with one of moderate–severe soft tissue involvement, lid retraction of 2 mm or more, diplopia and proptosis of 3 mm or more; (iii) mild, with only a minor impact on daily life.

Soft tissue involvement

• •
  

  Symptoms. Grittiness, red eyes, lacrimation, photophobia, puffy lids and retrobulbar discomfort.

  
  
• •
  

  Signs may include:

  
  
  
  
  • ○
    

    Epibulbar hyperaemia. This is a sensitive sign of inflammatory activity. Intense focal hyperaemia may outline the insertions of the horizontal recti ( Fig. 3.7A ).

    
    

    
    

    
    

    

    
    

    
    

    Soft tissue involvement in thyroid eye disease. (A) Epibulbar hyperaemia overlying a horizontal rectus muscle; (B) periorbital oedema, chemosis and prolapse of fat into the eyelids; (C) superior limbic keratoconjunctivitis

    
    
    
    
  • ○
    

    Periorbital swelling is caused by oedema and infiltration behind the orbital septum; this may be associated with chemosis and prolapse of retroseptal fat into the eyelids ( Fig. 3.7B ).

    
    
  • ○
    

    Tear insufficiency and instability is common.

    
    
  • ○
    

    Corneal signs are exacerbated by lid retraction (see next) and can include punctate epithelial erosions, superior limbic keratoconjunctivitis ( Fig. 3.7C and see Ch. 5 ), and occasionally bacterial keratitis, thinning and scarring.

  
  

Lid retraction

Retraction of upper and lower lids occurs in about 50% of patients with Graves disease. Humorally induced overaction of Müller muscle is postulated to occur as a result of sympathetic overstimulation secondary to high levels of thyroid hormones. Fibrotic contracture of the levator palpebrae and inferior rectus muscles associated with adhesion to overlying orbital tissues is another probable mechanism, together with secondary overaction in response to hypo- or hypertropia produced by fibrosis.

• •
  

  Symptoms. Patients may complain of a staring or bulging-eyed appearance, difficulty closing the eyes and ocular surface symptoms.

  
  
• •
  

  Signs

  
  
  
  
  • ○
    

    The upper lid margin normally rests 2 mm below the limbus ( Fig. 3.8A , right eye). Lid retraction is suspected when the margin is either level with or above the superior limbus, allowing sclera to be visible (‘scleral show’; Fig. 3.8A , left eye).

    
    

    
    

    
    

    

    
    

    
    

    Lid signs in thyroid eye disease. (A) Mild left lid retraction; (B) moderate bilateral symmetrical lid retraction – Dalrymple sign; (C) severe bilateral lid retraction – Kocher sign; (D) right lid lag on downgaze – von Graefe sign

    
    

    (Courtesy of G Rose – fig. B; S Chen – fig. C)

    
    

    
    

    

    
    

    
    

    

    
    

    
    

    

    
    
    
    
  • ○
    

    The lower eyelid margin normally rests at the inferior limbus; retraction is suspected when sclera shows below the limbus. Lid retraction may occur in isolation or in association with proptosis, which exaggerates its severity.

    
    
  • ○
    

    The Dalrymple sign is lid retraction in primary gaze ( Fig. 3.8B ).

    
    
  • ○
    

    The Kocher sign describes a staring and frightened appearance of the eyes which is particularly marked on attentive fixation ( Fig. 3.8C ).

    
    
  • ○
    

    The von Graefe sign signifies retarded descent of the upper lid on downgaze (lid lag – Fig. 3.8D ).

  
  

Proptosis

• •
  

  Symptoms are similar to those of lid retraction.

  
  
• •
  

  Signs. Proptosis is axial, unilateral or bilateral, symmetrical ( Fig. 3.9A ) or asymmetrical ( Fig. 3.9B ), and frequently permanent. Severe proptosis may compromise lid closure and along with lid retraction and tear dysfunction can lead to exposure keratopathy, corneal ulceration and infection ( Fig. 3.9C ).

  
  

  
  

  
  

  

  
  

  
  

  Proptosis in thyroid eye disease. (A) Symmetrical; (B) asymmetrical; (C) bacterial keratitis due to severe exposure

  
  

  (Courtesy of A Pearson – figs A and B; S Kumar Puri – fig. C)

  
  

Restrictive myopathy

Between 30% and 50% of patients with TED develop ophthalmoplegia and this may be permanent. Ocular motility is restricted initially by inflammatory oedema, and later by fibrosis.

• •
  

  Symptoms. Double vision, and often discomfort in some positions of gaze.

  
  
• •
  

  Signs, in approximate order of frequency:

  
  
  
  
  • ○
    

    Elevation defect ( Fig. 3.10A ) caused by fibrotic contracture of the inferior rectus, may mimic superior rectus palsy and is the most common motility deficit.

    
    

    
    

    
    

    

    
    

    
    

    Restrictive thyroid myopathy. (A) Defective elevation of the left eye; (B) defective depression of the right eye

    
    

    
    

    

    
    
    
    
  • ○
    

    Abduction defect due to fibrosis of the medial rectus, which may simulate sixth nerve palsy.

    
    
  • ○
    

    Depression defect ( Fig. 3.10B ) secondary to fibrosis of the superior rectus.

    
    
  • ○
    

    Adduction defect caused by fibrosis of the lateral rectus.

  
  

Optic neuropathy

Optic neuropathy is a fairly common (up to 6%) serious complication caused by compression of the optic nerve or its blood supply at the orbital apex by the congested and enlarged recti ( Fig. 3.11 ) and swollen orbital tissue. Such compression, which may occur in the absence of significant proptosis, may lead to severe visual impairment if adequate and timely treatment is not instituted.

• •
  

  Symptoms. Impairment of central vision occurs in conjunction with other symptoms of TED. In order to detect early involvement, patients should be advised to monitor their own visual function by alternately occluding each eye, reading small print and assessing the intensity of colours, for example on a television screen.

  
  
• •
  

  Signs. A high index of suspicion should be maintained for optic neuropathy, and it is important not to mistakenly attribute disproportionate visual loss to minor disease.

  
  
  
  
  • ○
    

    Visual acuity (VA) is usually reduced, but not invariably.

    
    
  • ○
    

    Colour desaturation is a sensitive feature.

    
    
  • ○
    

    There may be diminished light brightness appreciation.

    
    
  • ○
    

    A relative afferent pupillary defect, if present, should give cause for marked concern.

    
    
  • ○
    

    Visual field defects can be central or paracentral and may be combined with nerve fibre bundle defects. These findings, in concert with elevated IOP, may be confused with primary open-angle glaucoma.

    
    
  • ○
    

    The optic disc may be normal, swollen or, rarely, atrophic.

  
  

CT shows muscle enlargement in thyroid eye disease. (A) Axial view; (B) coronal view – note sparing of the right lateral rectus muscle; (C) coronal view shows crowding at the orbital apex

(Courtesy of N Sibtain – figs A and B; J Nerad, K Carter and M Alford, from ‘Oculoplastic and Reconstructive Surgery’, in Rapid Diagnosis in Ophthalmology, Mosby 2008 – fig. C)

Introduction

Preseptal cellulitis is an infection of the subcutaneous tissues anterior to the orbital septum. It is considerably more common than orbital cellulitis, and though regarded as less serious, can still be associated with severe complications such as abscess formation, meningitis and cavernous sinus thrombosis. Rapid progression to orbital cellulitis may occasionally occur. Organisms typically responsible are Staphylococcus aureus and Streptococcus pyogenes , with causes including skin trauma such as laceration or insect bites, spread from focal ocular or periocular infection such as an acute hordeolum, dacryocystitis, conjunctivitis or sinusitis, and haematogenous spread from remote infection such as the upper respiratory tract or middle ear.

Diagnosis

The condition manifests with a swollen, often firm, tender red eyelid that may be very severe ( Fig. 3.13A ); however, in contrast to orbital cellulitis, proptosis and chemosis are absent, and visual acuity, pupillary reactions and ocular motility are unimpaired. The patient is often pyrexial. Imaging with MRI or CT ( Fig. 3.13B ) is not indicated unless orbital cellulitis or a lid abscess is suspected, or there is a failure to respond to therapy.

Preseptal cellulitis. (A) Left preseptal cellulitis resulting from an infected eyelid abrasion; (B) axial CT shows opacification anterior to the orbital septum

(Courtesy of C Barry – fig. A)

Treatment

Treatment is with oral antibiotics such as co-amoxiclav 250–500 mg/125 mg 2–3 times daily or 875/125 mg twice daily, depending on severity. Severe infection may require intravenous antibiotics. The patient’s tetanus status should be ascertained in cases following trauma.

Introduction

Bacterial orbital cellulitis is a serious infection of the soft tissues behind the orbital septum, which can be sight- and life-threatening. It can occur at any age but is more common in children. Streptococcus pneumoniae , Staphylococcus aureus , Streptococcus pyogenes and Haemophilus influenzae are common causative organisms, with infection originating typically from the paranasal (especially ethmoid) sinuses. Infection can also spread from preseptal cellulitis, dacryocystitis, midfacial skin or dental infection, and can follow trauma, including any form of ocular surgery. Blood-borne spread from infection elsewhere in the body may occur.

Clinical features

• •
  

  Symptoms consist of the rapid onset of pain exacerbated by eye movement, swelling of the eye, malaise, and frequently visual impairment and double vision. There is commonly a recent history of nasal, sinus or respiratory symptoms.

  
  
• •
  

  Signs

  
  
  
  
  • ○
    

    Pyrexia, often marked.

    
    
  • ○
    

    VA may be reduced and colour vision impaired, raising the possibility of optic nerve compression; the presence of a relative afferent pupillary defect in a previously normal eye makes this almost certain.

    
    
  • ○
    

    Tender, firm, erythematous and warm eyelids, with periocular and conjunctival (chemosis) oedema, conjunctival injection and sometimes subconjunctival haemorrhage; the signs are usually unilateral, though oedema may spread to the contralateral eyelids.

    
    
  • ○
    

    Proptosis is common in established infection, but is often obscured by lid swelling; it may be non-axial (dystopia), particularly if an abscess is present.

    
    
  • ○
    

    Painful ophthalmoplegia ( Fig. 3.14A ).

    
    

    
    

    
    

    

    
    

    
    

    (A) Right orbital cellulitis with ophthalmoplegia; (B) axial CT shows both preseptal and orbital opacification

    
    
    
    
  • ○
    

    Choroidal folds and optic disc swelling may be present on fundus examination.

  
  
  
  
• •
  

  Differential diagnosis. Major diagnostic alternatives are listed in Table 3.1 .

  
  
  
  

  Table 3.1

  
  

  Differential diagnosis of an acutely inflamed orbit

  
  

  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

  Infection

  • Bacterial orbital cellulitis • Fungal orbital infection • Dacryocystitis • Infective dacryoadenitis

  Vascular lesions

  • Acute orbital haemorrhage • Cavernous sinus thrombosis • Carotid–cavernous fistula

  Neoplasia

  • Rapidly progressive retinoblastoma • Lacrimal gland tumour • Other neoplasm, e.g. metastatic lesion with inflammation, lymphoma, Waldenström macroglobulinaemia • Rhabdomyosarcoma, leukaemia, lymphangioma or neuroblastoma in children

  Endocrine

  • Thyroid eye disease of rapid onset

  Non-neoplastic inflammation

  • Idiopathic orbital inflammatory disease • Tolosa–Hunt syndrome • Orbital myositis • Acute allergic conjunctivitis with lid swelling • Herpes zoster ophthalmicus • Herpes simplex skin rash • Sarcoidosis • Vasculitides: Wegener granulomatosis, polyarteritis nodosa • Scleritis, including posterior scleritis • Ruptured dermoid cyst

   
  
  
  
  
• •
  

  Complications

  
  
  
  
  • ○
    

    Ocular complications include optic neuropathy, exposure keratopathy, raised IOP, endophthalmitis and occlusion of the central retinal artery or vein.

    
    
  • ○
    

    Subperiosteal abscess, most frequently located along the medial orbital wall.

    
    
  • ○
    

    Intracranial complications, which are uncommon (3–4%) but extremely serious, include meningitis, brain abscess and cavernous sinus thrombosis.

  
  

Investigation

Investigations may include:

• •
  

  Ascertainment of tetanus immunization status in cases of trauma.

  
  
• •
  

  White cell count.

  
  
• •
  

  Blood cultures.

  
  
• •
  

  Culture of nasal discharge.

  
  
• •
  

  High-resolution CT of the orbit, sinuses and brain ( Fig. 3.14B ) is vital to confirm the diagnosis and exclude a subperiosteal or intracranial abscess. MRI is also sometimes performed.

  
  
• •
  

  Lumbar puncture if meningeal or cerebral signs develop.

Treatment

• •
  

  Hospital admission is mandatory, with urgent otolaryngological assessment and frequent ophthalmic review. Paediatric specialist advice should be sought in the management of a child, and a low threshold should be adopted for infectious disease specialist consultation.

  
  
• •
  

  Delineation of the extent of erythema on the skin using a surgical marker may help in judging progress.

  
  
• •
  

  Antibiotics are given intravenously, with the specific drug depending on local sensitivities; ceftazidime is a typical choice, supplemented by oral metronidazole to cover anaerobes. Intravenous antibiotics should be continued until the patient has been apyrexial for 4 days, followed by 1–3 weeks of oral treatment.

  
  
• •
  

  Monitoring of optic nerve function is performed at least every 4 hours initially by testing VA, colour vision, light brightness appreciation and pupillary reactions. Deterioration should prompt the consideration of surgical intervention.

  
  
• •
  

  Surgery. Drainage of an orbital abscess should be considered at an early stage; drainage of infected sinuses should be considered if there is a lack of response to antibiotics, or if there is very severe sinus disease. Biopsy of inflammatory tissue may be performed for an atypical clinical picture. Severe optic nerve compression may warrant an emergency canthotomy/cantholysis (see Ch. 21 ).

Introduction

Mucormycosis is a rare aggressive and often fatal infection caused by fungi of the family Mucoraceae. It typically affects patients with diabetic ketoacidosis or immunosuppression and is extremely rare in the immunocompetent. Infection is acquired by the inhalation of spores, which give rise to an upper respiratory infection. Spread then occurs to the contiguous sinuses and subsequently to the orbit and brain. Invasion of blood vessels by the hyphae results in occlusive vasculitis with infarction of orbital tissues.

Diagnosis

• •
  

  Symptoms. Gradual onset facial and periorbital swelling, diplopia and visual loss.

  
  
• •
  

  Signs are similar to bacterial orbital cellulitis, but tend to be less acute and with slower progression. Infarction superimposed on septic necrosis is responsible for the classic black eschar that may develop on the palate, turbinates, nasal septum, skin and eyelids ( Fig. 3.15 ).

  
  

  
  

  
  

  

  
  

  
  

  Necrosis of the eyelid in rhino-orbital mucormycosis

  
  
  
  
• •
  

  Complications include retinal vascular occlusion, multiple cranial nerve palsies and cerebrovascular occlusion.

  
  
• •
  

  Differential diagnosis is listed in Table 3.1 .

  
  
• •
  

  Investigation is much the same as for bacterial orbital cellulitis.

Treatment

• •
  

  Correction of the underlying metabolic defect should be instituted if possible.

  
  
• •
  

  Intravenous antifungal treatment.

  
  
• •
  

  Daily packing and irrigation of the involved areas with antifungal agent.

  
  
• •
  

  Wide excision of devitalized and necrotic tissues; exenteration may be required in unresponsive cases in order to reduce the risk of death.

  
  
• •
  

  Adjunctive hyperbaric oxygen may be helpful.