Ординатура / Офтальмология / Английские материалы / Ophthalmology A Short Textbook_Lang_2000

15.5 Orbital Inflammation 413

CT image of a patient with Graves’ disease.

Fig. 15.4 The image shows obvious thickening of the extraocular muscles in the right orbit, primarily the rectus medialis (1) and rectus lateralis (2), and of the rectus medialis (3) in the left orbit.

Differential diagnosis: Rarer clinical syndromes such as orbital tumors and orbital pseudotumors must be excluded.

Treatment: The main principles in treating the disease in its acute stage include management of the thyroid dysfunction, systemic cortisone (initially 60–100 mg of prednisone) and radiation therapy of the orbital cavity. Surgical decompression of the orbital cavity is indicated in recurrent cases that do not respond to treatment to avoid compressive optic neuropathy. Exposure keratitis (keratitis due to inability to close the eye) should be treated with artificial tears or tarsorrhaphy (partial or complete suture closure of the upper and lower eyelid to shorten or close the palpebral fissure). In the postinflammatory stage of the disease, eye muscle surgery may be performed to correct strabismus.

Clinical course and prognosis: Visual acuity will remain good if treatment is initiated promptly. In the postinflammatory phase, exophthalmos often persists despite the fact that the underlying disorder is well controlled.

15.5Orbital Inflammation

Because of the close proximity of the orbital cavity to the paranasal sinuses, which are particularly susceptible to inflammation, orbital inflammation represents the second most frequent group of orbital disorders after Graves’ disease. Orbital cellulitis is the most severe of these.

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15.5.1Orbital Cellulitis

Definition

Acute inflammation of the contents of the orbital cavity with the cardinal symptoms of limited motility and general malaise.

Orbital cellulitis is the most frequent cause of exophthalmos in children.

Etiology: Acute orbital inflammation posterior to the orbital septum is usually an inflammation that has spread from surrounding tissue. Over 60% of all cases (as high as 84% in children) may be classified as originating in the sinuses, especially the ethmoidal air cells and the frontal sinus. In infants, tooth germ inflammations may be the cause. Less frequently, this clinical picture occurs in association with facial furuncles, erysipelas, hordeolum, panophthalmitis, orbital injuries, and sepsis.

Symptoms: Patients report severe malaise, occasionally accompanied by fever and pain exacerbated by eye movement.

Diagnostic considerations: Typical symptoms include exophthalmos with severe chemosis (conjunctival swelling), eyelid swelling, and significantly limited ocular motility (“cemented” globe; see Fig. 15.5). Patients may exhibit leukocytosis and an increased erythrocyte sedimentation rate. Where there is clinical evidence of suspected involvement of the paranasal sinuses, an ENT specialist should be consulted to evaluate the sinuses and initiate any necessary treatment.

Patient with orbital cellulitis.

Fig. 15.5 Typical symptoms include chemosis (conjunctival swelling), exophthalmos, and significantly limited ocular motility (the right eye does not move with the left eye).

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Differential diagnosis: Preseptal cellulitis, which is more frequently encountered, should be excluded. The inflammation in preseptal cellulitis is anterior to the orbital septum; chemosis and limited motility are absent. Rarer clinical syndromes that should also be considered in a differential diagnosis include an orbital pseudotumor, orbital periostitis which may be accompanied by a subperiosteal abscess, and an orbital abscess.

The crucial characteristic feature of orbital cellulitis for differential diagnosis is the significantly limited ocular motility (“cemented” globe). A rhabdomyosarcoma should also be considered in children.

Treatment: This consists of high-dose intravenous antibiotic therapy with 1.5 g of oxacillin every four hours combined with one million units of penicillin G every four hours. Infants are treated with ceftriaxone and school-age children with oxacillin combined with cefuroxime in the appropriate doses.

Treatment of underlying sinusitis is indicated in applicable cases.

Clinical course and complications: Orbital inflammation can lead to optic neuritis with subsequent atrophy and loss of vision. Purulent thrombophlebitis of the orbital veins can result in cavernous sinus thrombosis with meningitis, cerebral abscess, or sepsis.

Orbital cellulitis can progress to a life-threatening situation (cavernous sinus thrombosis).

15.5.2Cavernous Sinus Thrombosis

Definition

Rare but severe acute clinical syndrome in which the spaces of the cavernous sinus posterior to the orbital cavity become thrombosed, usually in the presence of adjacent purulent processes. This is not an orbital disorder in the strict sense.

Etiology: These are purulent inflammations that have spread from the middle ear, petrous bone, orbital cavities, or from the facial skin via the angular vein.

Symptoms: Patients present with an acute clinical picture with headache, stupor, fever, and vomiting.

Clinical findings: The ophthalmologist will usually diagnose bilateral exophthalmos and episcleral and conjunctival venous stasis in combination with multiple pareses of the cranial nerves. Neurogenic paralysis of all ocular muscles is referred to as total ophthalmoplegia. Where the optic nerve is also involved, the condition is referred to as orbital apex syndrome.

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The limited motility of the globe is primarily neurogenic and due to damage to the nerves in the cavernous sinus as opposed to the mechanical limitation of motility due to the orbital inflammation in orbital cellulitis.

Diagnostic considerations and treatment: This lies primarily in the hands of ENT specialists, neurosurgeons, and internists. High-dose systemic antibiotic therapy and anticoagulation are indicated.

15.5.3Orbital Pseudotumor

Definition

Lymphocytic orbital tumor of unknown origin.

Symptoms and findings: Painful, moderately severe inflammatory reaction with eyelid swelling, chemosis, and unilateral or bilateral exophthalmos. Involvement of the ocular muscles results in limited motility with diplopia.

Diagnostic considerations: The CT and MR images will show diffuse softtissue swelling. A biopsy is required to confirm the diagnosis.

Occasionally the CT image will simulate an infiltrative tumor.

Differential diagnosis: Various disorders should be excluded. These include

Graves’ disease and orbital cellulitis, which is usually bacterial. Special forms of orbital pseudotumor include myositis and Tolosa–Hunt syndrome (painful total ophthalmoplegia produced by an idiopathic granuloma at the apex of the orbit).

Treatment: High-dose systemic cortisone (initially 100 mg of prednisone) usually leads to remission. Orbital radiation therapy or surgical intervention may be indicated in cases that fail to respond to treatment.

15.5.4Myositis

This a special form of orbital pseudotumor in which the lymphatic infiltration primarily involves one or more ocular muscles. Aside from significant pain during motion, symptoms include limited ocular motility with double vision

(diplopia). Depending on the extent of the myositic changes, exophthalmos with chemosis and eyelid swelling may also be present. Ultrasound studies

(Fig. 15.6) will reveal thickening of the ocular muscles with tenonitis (inflammation of Tenon’s capsule).

In Graves’ disease, only the muscle belly is thickened. In myositis, the entire muscle is thickened.

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Diagnosis of myositis.

Fig. 15.6 The ultrasound image (B-mode scan) shows thickening of the entire hypoechoic rectus medialis (arrow).

15.5.5Orbital Periostitis

This is an inflammation of the periosteum lining the orbital cavity, usually due to bacterial infection such as actinomycosis, tuberculosis, or syphilis. Less frequently, the disorder is due to osteomyelitis or, in infants, tooth germ inflammations. The clinical symptoms are similar to orbital cellulitis although significantly less severe and without limitation of ocular motility. Liquefaction of the process creates an orbital abscess; large abscesses may progress to orbital cellulitis.

15.5.6Mucocele

These mucus-filled cysts may invade the orbital cavity in chronic sinusitis. They displace orbital tissue and cause exophthalmos.

Treatment is required in the following cases:

Displacement of the globe causes cosmetic or functional problems, such as lagophthalmos or limited motility.

Compression neuropathy of the optic nerve results.

The mucocele becomes infected (pyocele).

15.5.7Mycoses (Mucormycosis and Aspergillomycosis)

These rare disorders occur primarily in immunocompromised patients, such as those with diabetes mellitus or AIDS. The disorder often spreads from infected paranasal sinuses. The clinical picture is similar to those of inflammatory orbital disorders.

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15.6Vascular Disorders

These changes are rare. The most important and most frequently encountered disorder in this group is pulsating exophthalmos.

15.6.1Pulsating Exophthalmos

Definition

Acute exophthalmos with palpable and audible pulsations synchronous with the pulse in the presence of a cavernous sinus fistula or arteriovenous aneurysm.

Etiology: An abnormal communication between the cavernous sinus and the internal carotid artery (a direct shunt) or its branches (indirect shunt) results in distention of the orbital venous network. Eighty per cent of all cases are attributable to trauma; less frequently the disorder is due to syphilis or arteriosclerosis.

Symptoms: Patients report an unpleasant sound in the head that is reminiscent of a machine and synchronous with their pulse.

Diagnostic considerations: The increased venous pressure leads to dilation of the episcleral and conjunctival vessels (Fig. 15.7), retinal signs of venous stasis with bleeding, exudation, and papilledema. Intraocular pressure is also increased. The increased pressure in the cavernous sinus can also result in oculomotor and abducent nerve palsy.

Sounds near the direct fistula are clearly audible with a stethoscope.

Fistula between the carotid artery and cavernous sinus.

Fig. 15.7 The episcleral and conjunctival vessels are significantly dilated and describe tortuous corkscrew courses.

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Doppler ultrasound studies can confirm a clinical suspicion. However, only angiography can determine the exact location of the shunt.

Treatment: Selective embolization may be performed in cooperation with a neuroradiologist once the shunt has been located.

Small shunts may close spontaneously in response to pressure fluctuations such as can occur in air travel.

15.6.2Intermittent Exophthalmos

This rare clinical picture characterized by intermittent unilateral or bilateral exophthalmos is caused by varicose dilation of the orbital veins, such as can occur following trauma or in Osler’s disease (polycythemia vera). Patients report protrusion of the eyeball of varying severity. Exophthalmos is usually unilateral and is especially prone to occur when the resistance to venous drainage is increased, as can occur when the patient presses, bends over, screams, or compresses the vessels of the neck. Occasionally the exophthalmos will be associated with increased filling of the episcleral and/or conjunctival vessels. The disorder can be diagnosed in ultrasound studies using the Valsalva maneuver. A differential diagnosis should exclude a fistula between the carotid artery and cavernous sinus or an arteriovenous aneurysm, which is usually accompanied by a dramatic clinical picture with pulsation and increased intraocular pressure. In these clinical pictures, the ultrasound examination will reveal generalized dilation of the orbital veins. Surgical removal of orbital varices entails a high risk of damaging crucial delicate neurovascular structures in the orbital cavity. However, it may be indicated in rare cases such as cosmetically unacceptable exophthalmos or where symptoms of keratoconjunctivitis sicca occur due to exposure that fails to respond to treatment.

15.6.3Orbital Hematoma

Orbital bleeding is usually post-traumatic but may occur less frequently due to coagulopathy resulting from vitamin C deficiency, anticoagulants, or leukemia. Retrobulbar injections prior to eye surgery and acute venous stasis such as may occur in coughing fits, asphyxia, or childbirth can also cause orbital hematomas. Exophthalmos may be accompanied by monocle or eyeglass hematoma, eyelid swelling, and subconjunctival hemorrhage; limited motility is rare. Surgical decompression of the orbital cavity (transfornix orbital decompression or orbitotomy) is indicated where damage to the optic nerve or blockage of the central retinal artery is imminent.

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15.7Tumors

15.7.1Orbital Tumors

All orbital tumors displace the globe and cause exophthalmos that is frequently associated with limited ocular motility. Some tumors also cause specific additional symptoms and findings. These are discussed separately for each of the tumors presented in the following section.

Tumors of the lacrimal gland are discussed in Chapter 3, Lacrimal System.

15.7.1.1 Hemangioma

Hemangiomas are the most common benign orbital tumors in both children and adults. They usually occur in a nasal superior location. Capillary hemangiomas are more common in children (they swell when the child screams), and cavernous hemangiomas are more common in adults. Treatment is only indicated where the tumor threatens to occlude the visual axis with resulting amblyopia or where there is a risk of compressive optic neuropathy. Capillary hemangiomas in children may be treated with cortisone or low-dose radiation therapy.

15.7.1.2 Dermoid and Epidermoid Cyst

These lesions are the most common orbital tumors in children. Etiologically, they are choristomas, i.e., dermal or epidermal structures that have been displaced into deeper layers. However, they usually are located anterior to the orbital septum (and therefore are not in the actual orbit itself). Lesions located posterior to the orbital septum usually become clinically significant only in adults. Treatment consists of complete removal.

15.7.1.3 Neurinoma and Neurofibroma

These tumors are often associated with Recklinghausen’s disease (neurofibromatosis). If they occur in the optic canal, they must be removed before they cause compressive optic neuropathy.

15.7.1.4 Meningioma

A meningioma can proceed from the optic nerve (meningioma of the optic nerve sheath) or from within the cranium (sphenoid meningioma). Symptoms vary depending on the location of the tumor. Exophthalmos, limited motility, and compressive optic neuropathy can result. Hyperostoses are frequent findings in radiographic studies. Treatment consists of neurosurgical removal of the tumor. Like neurinomas, 16% of all meningiomas are

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associated with neurofibromatosis (Recklinghausen’s disease). Meningiomas of the optic nerve sheath are usually histologically benign but can recur if not completely removed. Interestingly, the average age of patients is 32; 20% are younger than 20.

15.7.1.5 Histiocytosis X

This is a generic term for the proliferation of Langerhans’ cells of undetermined etiology; all three of the following types can cause exophthalmos where there is orbital involvement:

Letterer-Siwe disease (malignant).

Hand-Schüller-Christian disease (benign).

Eosinophilic granuloma (rare and benign).

15.7.1.6 Leukemic Infiltrations

Leukemic infiltrations occur especially in acute lymphoblastic leukemia and in a special form of myeloid leukemia (granulocytic sarcoma or chloroma). Inflammation is present in addition to exophthalmos.

15.7.1.7 Lymphoma

Lymphomas can occur in isolation or in systemic disease. Cooperation with an oncologist is required. The disorder may be treated by radiation therapy or chemotherapy. Usually these tumors are only slightly malignant. The highly malignant Burkitt’s lymphoma, which has a high affinity for the orbital cavity, is a notable exception.

15.7.1.8 Rhabdomyosarcoma

This is the commonest primary malignant tumor in children. The tumor often grows very rapidly. Because of the accompanying inflammation, a differential diagnosis should exclude orbital cellulitis. Other indicated diagnostic studies include a CT scan and possibly a biopsy. With modern therapeutic regimes such as chemotherapy and radiation therapy, curative treatment is possible in many cases.

15.7.2Metastases

In children, the incidence of metastasis is higher in the orbital cavity than in the choroid. In adults, it is exactly the opposite. The most common orbital metastases in children originate from neuroblastomas. Malignant tumors from adjacent tissue can also invade the orbital cavity.

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15.7.3Optic Nerve Glioma

In children, this is the second most common potentially malignant orbital tumor. In 25% of all patients, the optic nerve glioma is associated with neurofibromatosis (Recklinghausen’s disease). Fifteen percent of all patients with neurofibromatosis develop optic nerve gliomas. The prognosis is good only where the tumor is completely resected.

Injuries

See Chapter 18.

15.8Orbital Surgery

Access to the orbital cavity is gained primarily through an anterior approach (transconjunctival or transpalpebral approaches yield good cosmetic results) or through a lateral approach. The lateral Krönlein approach provides better intraoperative exposure. Transantral, transfrontal, transcranial, and transnasal orbitotomies are used less frequently.

Orbital exenteration is indicated with advanced malignant tumors. This involves removal of the entire contents of the orbital cavity including the eyelids.