Ординатура / Офтальмология / Английские материалы / Pediatric Opthalmology_Mukherjee_2005

Differential diagnosis consists of orbital cellulitis, orbital neuroblastoma and retinoblastoma, leukaemic deposits, infected dermoids, Burkitt’s sarcoma, pseudo tumour.

As the tumour is relatively fast growing and fatal, it should be treated early. Diagnosis is confirmed by X-ray that may or may not show boney erosion and enlargement of the orbit. CT and MRI are more definitive to assess the location, size of the tumour and plan treatment. Presence of bone erosion carries less favourable prognosis. Excisional biopsy is better avoided. Fine needle biopsy is not always reliable.

Management consists of :

1.Treatment directed towards the local growth.

2.Treatment of distant metastasis

3.Handling of local complications—Once upon a time debulking and excentration were only treatment available. At present exentration has been given up. Sometime debulking is used to be followed by chemotherapy and radiotherapy. The tumour responds very well to combined chemotherapy and radiotherapy in which the survival rate is as high as 90% when the tumour is confined to orbit. With extra orbital extension this drops to 65%. The tumour is fatal within 18 months if not treated. Death is due to multiple organ failure following distant mertastasis. Many chemotherapeutic drugs have been used from time to time with variable results. They are—andriamycin, vincristine, cyclo phosphamide and actinomycin D (dactinomycin). A combination of vincristine, actinomycin D and cyclophosphamide (VAC) is most commonly used as adjunct to radiotherapy.

Radiotherapy consists of external beam radiation directed to the orbit. Total dose ranges between 4000 cGy to 6000 cGY given over four to six weeks protecting the cornea and lens. Side effects of radiation are—madarosis, dry eye, cataract, retinopathy of radiation. In children with diminished orbital volume, the size of the orbit may stop growing.51

Common secondaries that involve orbit in children are :

—Neuroblastoma

—Leukaemia

—Retinoblastoma

—Ewing’s sarcoma

—Wilm’s tumour

—Burkitt’s lymphoma

Out of the above retinoblastoma and Burkitts lymphoma are not true metastatic tumour of orbit. They invade the orbit from primary source i.e. from the eyeball in case of retinoblastoma and from the maxilla in case of Burkits lymphoma.

Neuroblastoma

Neuroblastoma is a common malignancy of infants and children. It develops from embryonal neuroblast generally from adrenaline gland and sympathetic chain. However in 3% cases it develops from sympathetic plexus in orbit. Most of the neuroblastomas develop under seven years of age. The primary develops either in abdominal or thoracic segment of

the sympathetic chain. It may develop in the cervical sympathetic as well. Fifty percent of children who develop neuroblastoma are under two years of age.54 The metastatic neuroblastoma rarely show rossette formation which is seen mostly in primary site. There are two types of neuroblastoma i.e. (1) that has predilection for orbits known as Hutchinson type; (2) that metastasise in liver known as Pepper type. The metastasis is mostly blood borne, which develop in the orbital bones and from which it spreads to the orbital54 contents.

Metastatic neuroblastoma is generally bilateral, which is detected few months after the primary has been discovered. However proptosis may be the first sign of neuroblastoma and generally attributed to a doubtful trauma because of one of the clinical feature is ecchymosis of the lid. Commonest presentation is fast growing proptosis in a child with a lump in abdomen or a para vertebral shadow on X-ray. The lids are swollen and ecchymotic. Forty percent of children with neuroblastoma develop orbital metastasis.53 The mass not only invades the orbit but may form a lump in the cheek, temple. Zygomatic bone is the commonest bone to be involved.

Neuroblastoma should be differentiated from orbital cellulitis, infected dermoid, black eye, retrobulbar haemorrhage, rhabdomyosarcoma, Burkitts lymphoma and leukaemia. orbital retinoblastoma is diagnosed with ease due to presence of white reflex in pupillary area.

Diagnosis is confirmed by CT, MRI, X-ray chest, ultrasonography of abdomen. A body scan may be required to locate the primary, fine needle biopsy may be helpful.

Treatment consist of radiation and systemic chemotherapy. In radiation external beam photon is directed to the orbit. Total dose may vary 1500 to 3000 cGy in divided doses. Chemotherapy in neuroblastoma gives long term regression in about one third cases. However it should be remembered that radiation and chemotherapy are only paliative.

Ewing’s sarcoma55,56,57

This is less common metastatic tumour of the orbit in children than neuroblastoma. Common age is first and second decade. The tumour has been observed more frequently in second decade. In contrast to neuroblastoma this tumour has para sympathetic origin. It generally develops in bones and from there it spreads to orbit. It may develop as second tumour following radiation in children who have undergone treatment for retinoblastoma. It presents as proptosis with or without visual loss. It must be differentiated from rhabdomyosarcoma, neuroblastoma and other metastatic tumours of the orbit in children.

Treatment consists of chemotherapy and radiotherapy.

Burkitt’s lymphoma (Lympho sarcoma) is a relatively uncommon tumour, no race or gender is immune to it. However, it is more common among coloured Africans. Common age is three to seven years with affinity for orbit. It has been postulated that this tumour has a viral etiology. The tumour starts in maxilla and erodes the floor of the orbit. It does not invade the eyeball. It starts as a painless swelling over the maxilla, spread into the lower lid and conjunctiva. The proptosis is rapid in progress. It may be bilateral. There may be involvement of central nervous system and invariably leads to death of the child. Some of the children58,59 may have abdominal mass. Proptosis may cause exposure keratitis with sloughing of cornea and perforation. The lymphoma responds to chemotherapy and radiation. Commonly used cytotoxic drugs are cyclophosphamide, methotrexate and vincristine. Relapse are common and fatal.

Optic nerve glioma61,62

Glioma of the orbital part of optic nerve is a manifestation of congenital hamartoma of the anterior visual path.

It is a benign slow growing tumour of ectodermal origin. Commonly associated with neurofibreomatosis.45 Topographically gliomas of visual path are divided into two parts :

1.Glioma of the orbital part is again divided into two groups according to its potential malignancy :

(i) Benign glioma of childhod and

(ii) Malignant glioblastoma of adult.

The benign glioma of childhood arises from the supportive tissue of the optic nerve i.e. astrocytes and oligodocytes. The tumour is generally formed predominantly by one type of these cells and has been divided into astrocytomas and oligodendro glioma according to predominance of type of cells. Commonly found cells are pilocytic astrocytes.

The incidence of glioma of optic nerve falls gradually with age. Though the growth is designated as congenital hamartoma, its common age is around seven years. The incidence falls sharply from first to second decade, however, when found in adults it is malignant in nature.

The optic nerve glioma is an unilateral slow growing tumour that starts near the optic canal and spreads towards the globe in a fusiform shape. It is an intrinsic tumour of optic nerve and does not involve the sheath of the nerve. The growth is generally not palpable. Optic nerve glioma itself is painless swelling but the eye may become painful due to severe proptosis. The proptosis is axial and slowly progressive over years. It is non pulsative, irreducible, is not influenced by change in the position of the eye or straining. After years the lids may fail to protect the cornea, resulting in exposure keratitis, corneal ulcer and perforation. Reduction of vision is common but some vision may be retained for years, which is eventually lost due to optic atrophy. In later stages the growth presses on the posterior pole of the globe and results in axial hypermetropia. Unilateral diminished vision in childhood leads to strabismus and amblyopia. The squint is always non paralytic.

Other clinical findings are presence of frank neurofibromatosis in about 25% of cases or presence of neurofibroma in close relatives. Suspicion of neurofibromatosis amy be aroused by presence of café au lait in absence of obvious neurofibroma.

A child with :

1.Unilateral painless diminished vision

2.Slow proptosis

3.With café au lait anywhere in the body is a case of optic glioma that can be confirmed by X-ray, CT and MRI.

Biopsy of the growth is seldom indicated. Sometimes the iris may show neurofibromatosis nodule (Lisch nodule). otherwise anterior segment has no findings that can be attributed to glioma except afferent pupillary reaction. Fundus may show papilledema, post papilledematous optic atrophy and even primary atrophy. The posterior pole shows retinal striation.

X-ray of orbit and optic foramen are most important diagnostic investigation. On plain X-ray orbit :

(1)There may be uniform enlargement of the orbit on the side of the growth.

(2)Most characteristic finding is seen on X-ray examination of optic foramen by Rhese view.

(i) Both the optic foramena should be examined at the same time.

(ii) The diameter of normal optic foramen is almost constant i.e. 6.5 mm.

(iii) Any foramen larger than 7 mm is sure evidence of enlargement.

(iv) When both foramena are compared, a difference of more than 1 mm between the two is also diagnostic.

(v) The enlargement is uniform without erosion showing slow expansion of the growth.

(vi) The edge gives a polished sclerosed appearance.

(vii) The optic canal is generally not enlarged as the tumour rarely invades the canal, which is more common in retinoblastoma.

(viii) The sella may also show some changes in the form of J. shaped sella instead of usual round sella. Changes in sella are more common in glioma of optic chiasma. Ultrasonography and MRI show a well circumscribed, well delineated, fusiform growth.

Chiasma glioma63 does not differ in histopathology. However it may extend in to the third ventricle or hypothalamus or may spread backwards in the optic tract. Involvement of chiasma does not produce typical bitemporal field changes. The field changes are generally stable as the growth is slow in expansion. The field changes are bizarre.64 They are more like optic nerve field changes than chiasma. Invasion of third ventricle leads to hypothalamic syndrome consisting of obesity, diabetic insipidus, precociuspuberty, dwarfism, pan hypopituitarism.

Management

As the growth is slow progressive, unilateral, non malignant and non fatal, there is no urgency in instituting definite treatment unless the cornea is at risk. Corneal involvement should be managed by - antibiotic and cycloplegic. If necessary the eye should be patched. In case of poor response to patching a median tarsorrhaphy is advised.

Surgery is indicated for cosmetic reason and protection of cornea. In the past, the eye was enucleated with as much part of glioma as possible. This procedure is seldom practised. The surgical procedure is to remove as much of tumour tissue as possible either through an orbital or transcranial route leaving the eyeball intact.

Radiation is indicated only when there is a tendency towards malignancy.

Leukaemia deposit in orbit in children

Lymphoblastic leukaemia is the commonest type of leukaemia that involves eye. It has both intra ocular as well as orbital manifestation. Myeogenous and monocytic leukaemia has less common ocular presentation. Orbital deposits are less common than intra ocular lesion.

The child is generally anaemic and has thrombocytopenia that may result in bleeding form gums and cause epistaxis. The deposits are bilateral. The optic nerve may be infiltrated leading to loss of vision. The lymphoblastic leukaemia have good prognosis with modern chemotherapy. The proptosis regresses with chemotherapy combined with radiation.

Capillary haemangioma of orbit

Capillary haemangiomas are non neoplastic growths. They are hamartomas. Capillary haemangioma may be present in orbit, in the lid, on the skin of the face. There may be a combination of orbital and lid tumour. Some of the orbital tumours may be mistaken for lid tumours due to purple blue coloration of the skin of the lid. Histopathologically, they are blood filled endothelial channels without a true capsule. The growth is general diffuse but may be well localised. Most of the capillary haemangiomas are congenital but not recognised at birth. The presence of tumour becomes evident within first few months of birth when the growth increases in size while the child strains. The growth is compressible without bruit. The proptosis is unilateral and non tender. The growth is generally situated in the anterior orbit in the superio nasal quadrant. The tumour has a very predictable mode of evolution that is—(1) Stage of rapid growth, (2) Stage of stability and (3) Stage of regression. The stage of growth is generally limited to the first year, stage of stability lasts for one to two or three years followed by regression by five years.

The tumours situated deep in orbit are less common and difficult to diagnose. Capillary haemangioma may be associated with strawberry patches on the lid or skin. Sometimes dilated vessels may be visible in the fornices. Besides cosmetic blemish the common complications are associated myopia, astigmatism and amblyopia.

Diagnosis is straight forward in case of growth in anterior orbit by :

1.Careful history

2.Examination of earlier photographs that may reveal proptosis not noticed by parents.

3.Presence of strawberry growth elsewhere.

4.X-ray orbit may show diffuse enlargement of orbit.

5.B scans show diffuse irregular mass.

6.CT and MRI give an ill defined appearance.

7.Contrast CT delineates the endothelial lined channel along with its feeding vessels.

Differential diagnosis consist of—orbital dermoid, orbital cellulitis, rhabdomyosarcoma, lymphangioma. Rhabdomyosarcoma has rapid progress without stage of stabilisation and commonly seen at about seven years of age while lymphangioma which is also a hamartoma is seen in teens with sudden enlargement due to haemorrhage in the growth that causes chocolate cyst formation.

Management is divided into two groups -

1.Management of error of refraction and amblyopia. Amblyopia may be due to uncorrected error of refraction or deprivation due to edema of lid or a growth in the lid.

2.Management of the tumour—As the growth is self-limiting regresses without interference. Most of them do not require any treatment however if there is evidence of corneal exposure or compression of the optic nerve medial treatment with steroids and interferon is indicated, both of them are always associated with possible side effects, that should be monitored regularly in consultation with pediatrician.

Steroid can be given either (1) orally or (2) intra lesional injection. Oral steroid is generally given in the form of prednisolone 1 to 2 mg/kg/day or 2 to 4 mg /kg/alternate day. Shrinkage of tumour starts within two weeks but there is high incidence of rebound growth.

Intra lesional injection consist of 40 mg of triamcinolone with 6 mg of betathethasone given in the growth under general anaesthesia and repeated after 8 weeks.

Orbital varices

Orbital varices are commonest cause of intermittent unilateral proptosis. The orbital varices are part of vascular malformation of the orbit, which can be arterial, venous or arterio venous42. The venous formation are known as orbital varices. They are pathological dilatation of pre-existing venous channel. The commonest form is simple or primary varix that causes unilateral, intermittent, non pulsatile proptosis in a child. Proptosis may be present at birth and may be overlooked. The proptosis may disappear when the child is lying flat only to appear when the venous pressure is increased as in crying, sneezing, straining or pressure on the jugular vein. The proptosis becomes more when the child lowers the head. It may be associated with prominent vessels on the conjunctiva, lid or scalp on the same side.65 Besides congenital malformation orbital varices can be seen following orbital trauma where the superior orbital veins is torn. Some people presume that congenital varices are a variation of capillary haemangioma and lymphangioma, which is slow progressive, non intermittent and stationary. There may be dilatation of orbital veins secondary to intracranial AV malformation, generally in adults. The primary varices keep on growing at slow pace till the child is in teens when the progress stops.

The plain X-ray picture is characteristic which shows (1) Enlargement the orbit, (2) Presence of round pheboliths, (3) There is a prominent vascular markings in the frontal bone. Venography may show either localised dilatation or a system of diffuse abnormal channels throughout the orbit.

Ultrasonography shows dilatation of superior ophthalmic vein that may increase in size if venous pressure is raised. MRI gives better result as compared to CT.

Orbital varices rarely cause visual disturbance or strabismus. Only complain is cosmetic. No specific treatment is required.

Histocytosis

Histocytosis is a systemic disease that affect children predominantly in various combinations of ocular and non ocular clinical presentation. Previously they were known by various names i.e. Histocytosis, Lettercrswie disease, Hand Shuller Christian disease and eosinophilic granuloma67. Since 1987, they have been brought under only one name that is Langerhan’s cell cytosis.66

The Langerhans cells do not have any definite function. They are derived from bone marrow. They are basically monocytes and present in various tissues in the body. The disorder

histocytosis seems to be an auto immune disease that responds to systemic steroid as well as anti cancer drugs and radiation. The disease may start in infancy or early childhood. Common orbital manifestations can be unifocal, eosinophilic granuloma of the bones of the orbit. However bones involvement sometimes can be at more than one site. Multi focal involvement have multiple organ involvement, with bilateral proptosis, involvement of orbital bone and diabetes insipidus. Involvement of posterior pituitary is the cause of diabetes insipidus. There may be multiple intra ocular and periocular involvement. X-ray of the orbit shows lytic lesion of bone.

Treatment consists of systemic steroid, vincristine, vinblastin, antibiotic and radiation.

Some probable features and probable cause of proptosis in children

Orbital compartment syndrome67

This consist of a group of condition that cause acute rise of intra orbital pressure that result in elevation of intra ocular pressure, obliteration of central retinal artery and diminished ocular perfusion. The causes could be—Haemorrhage, emphysema, profound edema of retro

ocular structure due to trauma infection or inflammation like orbital cellulitis or expanding orbital abscess and namely pseudo tumours.

The clinical features are—Diminished vision, restricted movement of globe, afferent pupil, proptosis and raised IOP tight lids.

Management

This should be treated as emergency and treatment consist of lateral canthotomy and cantholysis. Reduction of IOP by IV Mannitol oral glycerine, broad spectrum systemic antibiotic and systemic steroids.

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