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RETINOBLASTOMA

KEY POINTS
NOTES
DEFINITION
  • Malignant tumor of the retina that arises from the embryonic retinal cells

PHYSIOLOGY
  • Retina
    • Thin layer of nerve cells at back of the eye
    • Blood vessels
    • Photoreceptors
    • Impulses translated into images

CAUSES AND RISK FACTORS
  • Cause
    • Genetic mutation
      • Inherited or spontaneous 
  • Risk factors
    • Advanced paternal age
    • Family history or retinoblastoma or RB1 gene mutation in one parent
    • Paternal exposure to radiation
    • Maternal exposure to diesel or gasoline exhaust during pregnancy

PATHOPHYSIOLOGY
  • Mutation to the RB1 gene
  • Unregulated growth of retinal cells
  • Tumor grows in retina
  • Metastasis
    • Brain
    • Opposite eye
    • Lymph nodes
    • Bone
    • Bone marrow
    • Liver
  • Complications
    • Blindness
    • Retinal detachment
    • Secondary tumors

SIGNS AND SYMPTOMS
  • Leukocoria
  • Strabismus
  • Ocular inflammation
  • Extraocular growth
  • Decreased vision
  • Restricted eye movements
  • Proptosis

DIAGNOSIS
  • History
  • Physical assessment
  • Red reflex
  • Ophthalmoscopic examination
  • Slit lamp examination
  • Ocular ultrasound
  • MRI of the orbits and brain
  • Genetic testing
  • Eye examinations
  • Genetic screening 

TREATMENT
  • Local or systemic chemotherapy
  • Radiotherapy
  • Laser surgery
  • Cryotherapy
  • Enucleation
  • Prosthesis implantation

MANAGEMENT OF CARE
  • Goals of care
    • Managing symptoms
    • Providing supportive care
  • Assess pain, nausea, and vomiting
  • Administer prescribed analgesic and antiemetic
  • Comfort measures
  • Baseline height and weight
  • Confirm informed consent is obtained
  • Monitor for adverse effects after procedures
  • Routine postoperative care
  • Monitor for side effects of chemotherapy
  • Monitor for signs of infection
  • Implement neutropenic precautions
  • Assess psychosocial needs
  • Collaborate with child-life specialist
  • Provide needed referrals 

PATIENT AND FAMILY TEACHING
  • Explain condition, plan of care, and how to safely self-administer medications

  • Administer medications as directed
  • Small, frequent meals
  • Frequent rest
  • For enucleation
    • Care of surgical dressing
    • Keep head out of water
    • Maintain regular eye appointments and check--ups
  • Report to HCP
    • New symptoms
    • Appearance of eye or around eye changes
    • Change in vision

Transcript

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With retinoblastoma, retino- refers to the retina of the eye and -blastoma means arising from embryonic tissue. So, retinoblastoma describes a malignant tumor of the retina that arises from embryonic retinal cells; and it typically affects children younger than 5 years of age.

Now, let’s quickly review the physiology of the retina, which is a thin layer of nerve cells that lie at the back of the eye. This layer houses blood vessels, as well as nerve cells called photoreceptors, which receive light and convert it into neural impulses. These impulses are then directed to the visual cortex of the brain, where they get translated into images.

Now, the cause of retinoblastoma is rooted in genetics, specifically, inactivation mutations of a tumor suppressor gene called RB1, which can be the result of an inherited germline mutation or a spontaneous mutation. Spontaneous mutations means that both RB1 mutations occur spontaneously in the somatic cells of the individual, and typically cause retinoblastoma in only one eye. On the other hand, inherited mutations usually cause multiple tumors in both eyes.

Lastly, risk factors for retinoblastoma include advanced paternal age, family history of retinoblastoma or a known RB1 gene mutation in one parent, paternal exposure to radiation, in addition to maternal exposure to diesel or gasoline exhaust during pregnancy.

Now, the pathology of retinoblastoma starts with mutations to the RB1 gene, which cause unregulated growth of retinal cells. Over time, these cancerous cells form a tumor in the retina, which can then invade nearby structures. Left untreated, retinoblastoma can metastasize to the brain, opposite eye, lymph nodes, bone, bone marrow, and to the liver. Other complications of retinoblastoma include blindness, retinal detachment, and secondary tumors, which are typically sarcomas.

Typically, the clinical manifestations of retinoblastoma start by the age of one year in cases of bilateral involvement, and by the age of three years in cases of unilateral involvement. The first symptom of retinoblastoma noticed by the parents is leukocoria, also called the cat’s eye reflex, meaning the pupil appears white instead of red as the light reflects off the tumor white surface. Other signs and symptoms of retinoblastoma include strabismus, ocular inflammation, which can cause pain and a red eye, in addition to visible extraocular growth, decreased vision, restricted eye movements, and protrusion of the eyeball, called proptosis.

The diagnosis of retinoblastoma starts with the client's history and physical assessment, followed by diagnostic tests. These tests include red reflex examination using an ophthalmoscope, which will show leukocoria; direct ophthalmoscopic examination, which will show a retinal mass;

as well as slit lamp examination may identify blood or tumor debris in the anterior chamber.

An ocular ultrasound can also be done to evaluate the size of the tumor; an MRI of the orbits and brain can reveal if there is tumor extension outside the eye;

and genetic testing can also be done.

Finally, eye examinations for all newborns and children should be done at routine child care for early detection; and clients with a family history of retinoblastoma should undergo genetic screening to determine if frequent clinical monitoring for retinoblastoma is needed.