Ординатура / Офтальмология / Английские материалы / Pediatric Ophthalmology for Primary Care 3rd edition_Wright, Farzavandi_2008

axis is clear, treatment is often deferred, as the lesions will regress sponta neously. If amblyopia is present, treatment includes systemic interferon, systemic corticosteroids, or intralesional corticosteroid injection. In this author’s experience, corticosteroid injection is the most effective treat ment for large hemangiomas that block the visual axis. There have been a few isolated reports of visual loss secondary to retrograde embolization of the central retinal artery during intralesional corticosteroid injection. This complication can be reduced and perhaps avoided if the volume of injection is 2 mL or less and minimal pressure is used during the injection. Corti costeroid injections are most effective when done early in infants younger than 8 months. Repeat corticosteroid injections can be given; however, long term local corticosteroid injections can cause adrenal axis depression and decrease growth. Some advocate systemic corticosteroids; however, this author has found that systemic corticosteroids can cause significant side effects and do not deliver a large enough dose to significantly shrink most tumors. Surgical excision is reserved for small, localized lesions. It usu

ally is avoided in larger lesions because of the risk of considerable bleeding and because the infiltrative nature of the lesion requires removal of large amounts of skin.

Lymphangiomas

Lymphangiomas are benign, vascular hamartomas that usually appear in childhood. Lymphangiomas may appear superficially, involving the conjunc tiva, or may be located deep in the orbit. They tend to increase in size when the child has a viral cold or flu. These tumors have a tendency to spontane ously hemorrhage and develop spontaneous hematomas. Most often, the first sign of a lymphangioma is the rapid onset of proptosis secondary to acute bleeding within the tumor (Figure 16 4). The hemorrhage can form

a hematoma or chocolate cyst, which is the accumulation of clotted blood. With very large hemorrhages, compression of the optic nerve may necessi tate urgent surgical decompression.

There is no good treatment for lymphangiomas. Surgical excision of the lymphangioma is difficult because of the diffuse infiltrative nature of the tumor and its tendency to hemorrhage. Conservative management consists of preventing inadvertent trauma and limiting the child’s activity.

A

B

Figure 16 6.

A, Thirteen-year-old boy with downward displacement of the left eye secondary to a deep orbital dermoid cyst. B, Coronal computed tomography scan of the same patient, showing the superior orbital dermoid cyst and expansion of the left orbit.

Because of this, most ophthalmologists suggest early removal, shortly after 6 months of age. Complete excision of the dermoid cyst results in an excel lent prognosis.

Dermolipoma

Dermolipoma is a gelatinous mass located in the lateral canthal area (Figure

16 7). These masses are choristomas that contain fatty tissues with dermal appendages. Generally, no treatment is needed. Surgical excision is indi cated only when the mass presents a significant cosmetic problem. Surgical removal can cause local scarring and limited ocular motility.

Figure 16 7.

Dermolipoma of the right eye. Note the fatty mass in the lateral canthal area.

Optic Nerve Tumors

Optic nerve gliomas are relatively rare in children. Seventy percent of chil dren with optic nerve gliomas will have neurofibromatosis type 1. Most cases are unilateral; however, bilateral cases occur and are almost always patho gnomonic of neurofibromatosis. The tumors may occur anywhere along the course of the optic nerve, chiasm, or optic tracts. Unfortunately, there is no good treatment at this time, and the management remains controversial. Patients with good vision and lesions isolated to the optic nerve (not threat ening the chiasm) are usually observed. Tumors that show rapid growth or involve the optic chiasm may require neurosurgical intervention. Radiation therapy has also been used for non resectable tumors.

Fibro osseous Tumors

Tumors involving fibrous connective tissue from bone and cartilage can occur in the orbit. Patients present with proptosis, and computed tomogra phy (CT) is critical to making the appropriate diagnosis. Of these lesions, fibrous dysplasia is one of the most common. This is a hamartoma that involves the bony structure of the orbit. Children present with facial asym metry, proptosis, and globe displacement. The frontal bone is most com monly affected and results in downward ocular displacement. Malignant transformation is uncommon; however, it has been reported. Computed

granulomas are most common in children and result in a solitary osseous lesion in the orbit. The lesion causes bony erosion and soft tissue expansion, with the frontal and zygomatic bones most frequently involved. Hand Schüller Christian disease has the classic triad of diabetes insipidus, bilateral proptosis, and bony punched out lesions of the cranial bones (Figure 16 1). This disease almost always affects infants and young children and may have a cutaneous component, with orbital involvement rarely being present. Letterer Siwe disease carries the worst prognosis and is associated with hepatosplenomegaly, lymphadenopathy, jaundice, anemia, respiratory insufficiency, osseous defects, and thrombocytopenia. This disease has a very high mortality rate.

Rhabdomyosarcomas

Rhabdomyosarcoma is a malignant tumor that arises from undifferenti ated mesenchymal tissues of the orbit that are precursors to striated muscle. This is the most common malignant orbital neoplasm in children. Most children present with a rapid onset of painless proptosis or an acquired lid mass. Tumors most commonly occur between the ages of 6 and 10 years; however, these tumors can present at virtually any age, even infancy. This is a potentially lethal tumor but if it is confined to the orbit at the time of presentation, there is a 90% survival rate at 3 years. Once the tumor spreads beyond the orbit, the survival rate diminishes significantly. Therefore, it is

important to obtain an urgent ophthalmic consultation for any child with an acquired proptosis to rule out rhabdomyosarcoma. At one time, the treat ment of this tumor was surgical exenteration of the orbit, which resulted in a poor survival rate. Recently, with the use of radiation therapy combined with chemotherapy, survival rates have improved dramatically. A biopsy may be necessary if orbital imaging does not make the definitive diagnosis.

Of the 3 types of rhabdomyosarcoma tumors (embryonal, alveolar, and pleomorphic), the embryonal tumors most commonly occur within the orbit. Histopathology reveals fascicles of spindle cells with small hyperchro matic nuclei. Electron microscopy often shows cross striations consistent with striated muscle.

Figure 16 9.

Abdominal computed tomography scan demonstrates primary abdominal neuroblastoma originating in the adrenal gland.

posterior orbit. Preseptal cellulitis, therefore, involves the tissues of the eyelids (Figure 16 10), but does not involve the posterior orbit. It is often associated with upper respiratory tract infections, local trauma, bacteremia, or sinusitis. Signs include erythema of the upper or lower lid, swelling of the lid, and tenderness. Because the infection only involves the anterior tissue, the eye motility is normal, there is no proptosis, and vision is good. The most common bacterial pathogens include Haemophilus influenzae, Staphylococ­ cus aureus, group A streptococcus, and Streptococcus pneumoniae. Children younger than 4 years are particularly susceptible to H influenzae infection; however, the incidence has decreased significantly since the advent of vac cination for H influenzae. The treatment for infants with preseptal cellulitis may require admission to the hospital for intravenous antibiotics, but most pediatricians first prescribe cephalexin or amoxicillin/clavulanate as outpa tient treatment to cover S aureus and group A streptococcus. If admitted

to the hospital, cefuroxime, a cephalosporin effective against H influenzae, S aureus, and streptococci, is commonly used. For older children with

Figure 16 10.

Left preseptal cellulitis with swelling and erythema of the upper lid. The eye has full range of movements, no proptosis, and excellent vision.

milder preseptal cellulitis, oral cephalosporin can be given on an outpatient basis as long as there is close follow up.

Orbital Cellulitis

Orbital cellulitis is an extremely dangerous condition and may be vision or life threatening. Orbital cellulitis can result in severe complications such as vision loss, meningitis, cavernous sinus thrombosis, brain abscess, and even death. The clinical characteristics of orbital cellulitis include erythema and swelling of the eyelids, proptosis, limitation of eye movement, and in advanced cases, decreased vision (Figure 16 11). Orbital cellulitis is most commonly associated with sinusitis, but it can also occur secondary to

an orbital fracture, infection of the skin, or lacrimal sac infection (Figure 16 12). Systemic effects of orbital cellulitis may be minimal, or patients may only have a mild increase in peripheral white counts and no fever. If orbital cellulitis is suspected, an immediate ophthalmic consultation along with a CT scan of the orbits is advised.

Other causes of orbital inflammation include pseudotumor of the orbit (discussed later in this chapter), ruptured dermoid cyst, and orbital neoplasms such as rhabdomyosarcoma. The most common organisms responsible for orbital cellulitis are similar to those of preseptal cellulitis, with the addition of anaerobes and Gram negative organisms. Often, more than a single organism may be present. Blood cultures and cultures of

the conjunctiva may identify the bacterial cause. Initial therapy is always