Eye disease in a child (conjunctivitis, hypermetropia, myopia, retinoblastoma, retinopathy of prematurity, strabismus) Flashcards
Define conjunctivitis.
Conjunctivitis is the inflammation of the lining of the eyelids and eyeball caused by bacteria, viruses, allergic or immunological reactions, mechanical irritation, or medicines
What are the types of conjunctivitis?
- Allergic
- Infective
- Mechanical stress
- Irritation by toxic chemicals or medication
What are the types of infective conjunctivitis and how do you distinguish between them?
Bacterial
- Purulent discharge
- Eyes ‘stuck together’ in the morninig
Viral
- Serous discharge
- Recent URTI
- Preauricular lymph nodes
How do you manage infective conjunctivitis?
- Normally self limiting - 1-2 weeks
- Topical antibitics (chloramphenicol) - drops given 2-3 hourly or oitment QDS OR topical fusidic acid BD for pregnant women
- Educate - highly contagious;do not wear contact lenses, do not share towels; but school exclusion not necessary*
Refer to consultant if persists >7-10 days
*BMJ best practice: Patients with bacterial conjunctivitis may return to work/school/daycare after 24 to 48 hours of antibiotic treatment, but viral conjunctivitis requires at least 1 week out of work/school/daycare
What are the features of allergic conjunctivitis?
- Bilateral symptoms conjunctival erythema, conjunctival swelling (chemosis)
- Itch
- Swollen eyelids
- Hx of atopy
- May be seasonal (due to pollen) or perennial (due to dust mite, washing powder or other allergens)
How do you manage allergic conjunctivitis?
- Topical or systemic antihistamines
- Topical mast-cell stabilisers, e.g. Sodium cromoglicate and nedocromil
What are the most common causes of bacterial and viral conjunctivitis? What is the pathophysiology of allergic conjunctivitis?
Bacterial:
- Pneumococcus
- Staph aureus
- Moraxella catarrhalis
- H influenzae
- Neusseria gonorrohoea (rare)
- Chlamydia (in persistent conjunctivitis)
Viral:
- Adenovirus
- HSV
- EBV
- VZV
- Molloscum
- Coxsackie
- Enterovirus
Allergic: type 1 hypersensitivity reaction to an allergen which binds to mast cell and cross-linking to IgE occurs, leading to mast cell degranulation and initiation of an inflammatory cascade.
What are the complications of conjunctivitis?
- Dry eyes/foreign body sensation
- Keratitis
- Subepitheial corneal infiltrates
- Lacrimal drainage problems
- Symplepharon (scarring)
What is ophthalmia neonatorum? Describe it.
Conjunctivitis in a newborn is common in day 3-4 of life.
Cleaning with saline may resolve condition
- Staphylococcal or streptococcal infection can be treated with topical antibiotic eye oitment e.g. chloramphenicol or neomycin
- Gonococcal infection presents with purulent discharge with conjunctival injection within the first 48 hours of life - discharge should be gram stained immediately (complication: permanent vision loss). Treat with 3rd generation cephalosporin.
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Chlamydia trachomatis presents with purulent discharge, swelling at 1-2 weeks of age or shortly after birth; identified with immunofluorescence staining; treated with oral erythromycin for 2 weeks (mother and partner should also be checked and treated)
4.
Which childhood infection which can be vaccinated against, also presents with conjunctivitis?
Measles - presents with maculopapular rash, Koplik spots, conjunctivitis and coryza, cough.
How common is conjunctivitis in children?
Incidence is highest in children aged <1 year old (80 cases in 1000 patient-years) and in children aged >4 years (12 cases in 1000 patient-years)
What is the most common refractive error in children?
Hypermetropia (long sight)
How is hypermetropia managed?
Mild - common in early childhood and may not need spectacle correction
More severe - overcome with accommodation (changing lens shape) but may need to be corrected with convex lenses which make the eye look bigger
When does myopia usually present? Who is most affected? How is it managed?
In adolescence and is relatively uncommon in childhood
Children born preterm are commonly affected and it may present at a younger age
Concave lenses - these make the eyes look smaller
When should you suspect abnormalities of vision in an infant or young child?
- Obvious ocular malformation e.g. anophthalmia, absent red reflex or white reflex (leukocoria)
- Not smiling responsively at 6 weeks post term
- Concerns about poor visual responses including eye contact
- Roving eye movements (constant movement)
- Nystagmus
- Squint (strabismus)
Describe visual testing at different ages from birth to 3years+.
When does visual acuity reach normal levels?
At birth visual acuity is very low but reaches normal at around 5 years -at birth only large targets can be detected and still appear fuzzy at 30cm (peripheral retina is well developed but fovea is immature)
Vision tests are performed at school or preschool entry
Define strabismus. Is it common in childhood?
Squint; common condition of misalignment of the visual axes.
Common until 3 months of age; but if persists >3 months of age then should be referred to a specialist ophthalmologist.
What are the causes of strabismus?
- Refractive error (most common)
- Cataracts
- Retinoblastoma
- Other intraocular causes
NB: marked epicanthic folds may give appearance of a squint
How are squints classified?
Concomitant (non-paralytic, common)
- Usually due to a refractive error in one or both eyes- correction of the refractive error with glasses often corrects the squint
- Squinting eye most often turns inwards (convergent), but there can be outward (divergent) or, rarely, vertical deviation
Paralytic (rare)
- Varies with gaze direction due to paralysis of the motor nerves
- Can be sinister because of the possibility of an underlying SOL such as a brain tumour
How does the corneal light reflex help detect squint?
Pen torch is held at a distance so that to produce reflection on both corneas simultaneously
Reflection is in a different position in the two eyes
But minor squint may be difficult to detect
How does the cover test help detect squint?
- Child looks at toy/light
- If fixing eye is covered the squinting eye will take up fixation
- Should be perfromed with near (33cm) and distant (6m) objects as certain squints only present at one distance
- Difficult to perform and reliable opinion given by orthoptist/ophthalmologist
What are some genetic, antenatal/perinatal and postnatal causes of visual impairment?
What is shown?
White pupillary reflex in retinoblastoma
What is retinoblastoma? What does it cause?
Malignant tumour of retinal cells which accounts for about 5% of severe visual impairment in children. It may affect one or both eyes.
How common is retinoblastoma?
3% of all childhood malignancies
1 in 18,000 births
No ethnic variation
What is true about all bilateral retinoblastomas?
They are all hereditary
20% of unilateral tumours are hereditary
What is the inheritance pattern of retinoblastoma? What is the gene?
- Germline mutation (i.e. present in all cells of the body) in the RB1 gene on Chr13
- Autosomal dominant pattern
- Incomplete penetrance
All children from families with the hereditary form of the disease should be screened regularly
30-40% of all cases are associated with this mutation
NB: most cases are sporadic
How does retinoblastoma present?
- Squint
- Red reflex replaced by white reflex (leukocoria)
- 90% diagnosed by age 3 years
- Can present with pain, glaucoma and buphthalmos and may cause metaststaic disease in CNS, bones and liver.
Only 10% have FH of disease
How is retinoblastoma managed?
Refer to specialist as soon as red reflex disappearance noted.
Aim to cure, but preserve vision. Treatment based on ophthalmological findings (no biopsy taken).
- Chemotherapy - used in bilateral disease to shrink tumour followed by laser treatment to the retina
- Radiotherapy - used in advanced disease but is reserved for treatment of recurrence
- Enucelation - may be necessary for more advanced disease
How is retinoblastoma diagnosed?
MRI and examination under anaesthetic
Tumours are commonly multifocal
What is the prognosis with retinoblastoma?
Significant risk of second malignancy (especially sarcoma) among survivors of hereditary retinoblastoma
Untreated tumours will metastasise and cause death within 2 years but ocassionally stop growing.
What other malignancies is herediatry retinoblastoma associated with?
Non-ocular cancers such as :
- Ewing’s sarcoma
- Olfactory neuroblastoma
- Osteosarcoma
What is the pathophysiology of retinopathy of prematurity?
- Affects blood vessels at the junction of the vascularised and non-vascularised retina. Vessels from optic disc only reach peripheries of eye 1 months after birth and so the retina is susceptible to oxygen damage. Normally retinal vessels grow in an environment of relatibe hypoxia.
- Vascular proliferation may occur which can progress to retinal detachment, fibrosis and blindness
- Caused by uncontrolled use of high concentrations of oxygen
Recognised in the 1950s following anecdotal reports of blindness when premature infants were nursed under additional ambient oxygen. It reduced mortality but increased blindness.
How common is retinopathy of prematurity?
Still identified in ~35% of all VLBW infants
How is retinopathy of prematurity diagnosed?
All infants at risk i.e.:
- <32 weeks’ gestation
- <1500g birthweight
…are screened by an ophthalmologist. This is quite an incomfortable examination for the baby and should be kept as brief as possible.
What is the management of retinopathy of prematurity?
Laser therapy reduces visual impairment
Intravitreal anti-VEGF therapy is being investigated
What are the complications of retinopathy of prematurity and what is the prognosis?
Severe visual impairment occurs in 1% of VLBW infants (mostly those <28 weeks’ gestation)
