Conjunctiva Flashcards
Conjunctival Segments (3)
Palpebral conjunctiva - lines the posterior surface of the eyelids
Bulbar conjunctiva - lines the anterior surface of the sclera
Forniceal conjunctiva - a folded layer between the palpebral and bulbar conjunctiva. It allows movement of the eyelids.
Where does the conjunctiva fuse with the sclera?
At the limbus
Innervation to conjunctiva
Main - CNV1 (ophthalmic division of the trigeminal nerve)
Inferior conjunctiva - infraorbital nerve
Limbus - long ciliary nerve (branch of the nasociliary nerve)
Lymphatics of the conjunctiva
Medial conjunctiva - submandibular nodes
Lateral conjunctiva - preauricular nodes
List 4 signs of conjunctival disease?
What is Hyperaemia (conjunctival injection)
Enlargement of conjunctival vessels
What is Chemosis (conjunctival oedema)
Transparent swelling of the conjunctiva
What are conjunctival membranes
Exudative adherences of the conjunctiva
What is Cicatrization?
Scarring of the conjunctiva
What are Follicles?
Discrete lesions which appear like transparent grains of rice. No vessels inside the lesion
What are Papillae?
Lesions confined to the palpebral conjunctiva with a vascular center.
What are the 2 distinct clinical appearances of conjunctivitis
Follicles vs papillae
(help you differentiate the potential causes)
Compare follicles vs papillae conjunctivitis
Papillae
* Papillae have a red (blood vessel) center and fat top
* More common on the upper lid
* Associated with: viral, chlamydial & toxic conjunctivitis
Follicles
* Dome-shaped discrete transparent lesions
* More common on the lower lid
* Associated with: bacterial & allergic conjunctivitis
Compare broad presentations of microbial conjunctivitis
Investigations for conjunctivitis
- Diagnosis is clinical
- Conjunctival swabs for microbiology are only required in unresolving cases or severe infections.
Any involvement of the cornea (keratitis) can be sight-threatening and warrants admission for further workup
When to suspect bacterial conjunctivits
Bacterial infection of the conjunctiva is common, often self-limiting, and frequently encountered in primary care.
It should be suspected in patients with red gritty sticky eyes and purulent discharge.
Pathology of Bacterial Conjunctivitis
Cool climates → Streptococcus Pneumoniae and Haemophilus influenzae
Warm climates → Haemophilus aegyptius
Children → Haemophilus influenzae
Chronic and relapsing conjunctivitis
Typically indicates the presence of a nearby reservoir colony.
This should be suspected in the case of chronic dacryocystitis, staph blepharitis and giant fornix syndrome
What is Giant fornix syndrome?
Giant fornix syndrome is characterised by the sequestration of bacteria in the upper fornix of the conjunctiva and is typically seen in the elderly.
Presentation of bacterial conjunctivits
- Acute/hyperacute red sticky eyes with purulent discharge
- Typically bilateral but often starts unilaterally
- Patients complain of their eyes being stuck together in the morning
A patient with bacterial conjunctivitis. The eye is red and there is a purulent green discharge.
Management of bacterial conjunctivitis
Initial
* Practice good hand and eye hygiene
* Advise the patient to return if the infection doesn’t self-resolve within a week or gets worse
* Switch to spectacles from contact lenses during the episode
Medications
* Topical chloramphenicol drops
* Systemic antibiotics are reserved for gonococcal conjunctivitis in adults or H.influenzae/Meningococcal conjunctivitis in children
* H.influenzae → PO Co-amoxiclav
Important side effect of Chloramphenicol
Aplastic anaemia
What are the two types of conjunctivitis caused by Chlamydia trachomatis
- Trachoma
- Adult Inclusion Body Chlamydial Conjunctivitis
Pathology of Adult Inclusion Body Chlamydial Conjunctivitis
Caused by Chlamydia trachomatis, a gram-negative intracellular obligate organism
Associated with serotypes D-K of Chlamydia trachomatis
What Immunotypes of Chlamydia cause Lymphogranuloma Venereum
L1, L2, L3
Presentation of adult inclusion body Chlamydia
- Subacute (2-3wks) unilateral conjunctivitis in young people
- Associated with STI symptoms such as urethritis
- Inferior follicular conjunctivitis with persisting mucopurulent discharge and lymphadenopathy
Investigations for adult inclusion body chlamydia
Conjunctival swab for PCR provides prompt diagnosis
Giemsa stain shows basophilic intracytoplasmic inclusion bodies
Management of Adult Inclusion Body Chlamydial Conjunctivitis
1g oral azithromycin STAT or 100mg doxycycline BD for 14 days
A patient with Chlamydial conjunctivitis. Note the inferior follicular conjunctivitis.
What is the leading cause of preventable blindness worldwide.
Trachoma
Pathology of Trachoma
- Caused by Chlamydia trachomatis serotypes A-C
- Acute conjunctivitis is caused by the pore-like infectious particle (elementary body) of chlamydia
- A type 4 hypersensitivity reaction occurs after initial infection → scarring → trichiasis and entropion → corneal damage → blindness
How does Trachoma cause entropion?
The conjunctival scarring leads to entropion, where the lids roll inwards. This causes the lashes to rub against the cornea when blinking.
Presentation of Trachoma
- Seen in poverty and crowded places
- Chronic superior follicular conjunctivitis
- Herbert pits (depressions of superior limbus)
- Arlt’s line (a thick band of scar tissue in the conjunctiva)
- Trichiasis and entropion
Management of Trachoma
“WHO SAFE strategy”
Surgery for trichiasis (bilamellar rotation)
Azithromycin 1g PO
Facial hygiene
Environmental improvement
Pathology of adult gonococcal conjunctivitis
Caused by infection with Neisseria gonorrhoeae, a gram -ve diplococcus.
These patients can be severely unwell.
Presentation of adult gonococcal conjunctivitis
Hyperacute and with severe pain, tearing and red-eye.
Conjunctival membranes and preauricular lymphadenopathy
Investigations for adult gonococcal conjunctivitis
Conjunctival swab for microbiology and referral to GUM clinic for sexual health follow up
Management of adult gonococcal conjunctivitis
- Treat all with topical ofloxacin drops
- Ceftriaxone IM 1g STAT to treat gonorrhoea
- If keratitis → admit for IV ceftriaxone
What is Ophthalmia Neonatorum?
Conjunctivitis within the first 30 days of life
Compare the causes and treatment of Ophthalmia Neonatorum
Gonococcal ophthalmia neonatorum
What is the most common microbial cause of conjunctivitis
Adenovirus
highly contagious
How to diagnosis Viral Conjunctivitis
PCR
Management of viral conjunctivitis
Conservative with cold compress and artificial tears.
What are the 3 clinical syndromes of viral conjunctivitis
A patient with epidemic keratoconjunctivitis. Note the clear discharge and follicular conjunctivitis.
Pathology of allergic conjunctivitis
Allergic conjunctivitis is a Type 1 (immediate IgE) reaction involving mast cell degranulation. It is characterised by bilateral itchy papillary conjunctivitis.
A patient with allergic conjunctivitis.
4 types of allergic conjunctivitis
Perennial and seasonal are common subacute conditions mediated by a type 1 hypersensitivity reaction with mast cell degranulation.
Vernal Keratoconjunctivitis (VKC) and Atopic Keratoconjunctivitis (AKC) are clinically serious with a chronic/recurrent component mediated by a type 4 hypersensitivity component in addition to the acute type 1 reaction.
Management of allergic conjunctivitis
- Artificial tears to dilute allergen and restore surface integrity
- Mast cell stabilizers and/or antihistamines
- Topical steroids
- Systemic immunosuppression with steroids or steroid-sparing agents such as cyclosporine
- Surgical debridement and/or keratectomy to address corneal ulcers in vision-threatening disease
What must we be aware of when using When using immunosuppressive medications
HSV reactivation - patients should receive antiviral therapy.
What is Seasonal Conjunctivitis?
A common subacute conjunctivitis seen in hay fever.
Pathology of seasonal conjunctivitis
Type 1 hypersensitivity reaction with mast cell degranulation
Typically triggered by pollen in the summer period
Presentation of seasonal conjunctivitis
Subacute bilateral itchy conjunctivitis
Characteristic seasonal pattern of onset and prior episodes
Management of Seasonal Conjunctivitis
Often benign and self-limiting. Treatment options include:
* Artificial tears to dilute allergen and restore surface integrity
* Mast cell stabilizers and/or antihistamines
What is Perennial Conjunctivitis
A similar disease to seasonal conjunctivitis, except it can occur at any point and does not necessarily follow a seasonal pattern.
Pathology of Perennial Conjunctivitis
Type 1 hypersensitivity reaction with mast cell degranulation.
Thought to be caused by allergy to moulds and dust mites
Presentation of Perennial Conjunctivitis
Subacute bilateral itchy conjunctivitis
No specific seasonal variation
Management of Perennial Conjunctivitis
Often benign and self-limiting. Treatment options include:
Artificial tears to dilute allergen and restore surface integrity
Mast cell stabilizers and/or antihistamines
What is Vernal Keratoconjunctivitis
A recurrent conjunctivitis that characteristically effects teenage boys
Pathology of VKC
An acute type 1 hypersensitivity reaction with mast cell degranulation followed by a chronic type 4 hypersensitivity mediated by T cells.
The additional type 4 component makes this disease chronic
Subtypes are categorised based on which part of the conjunctiva is affected: palpebral, limbal or mixed
Presentation of VKC
Manifests in adolescent boys in dry climates
Initial onset is often in the summer
Also involves the cornea
Effects the upper conjunctiva with characteristic cobblestone appearance
Management of VKC
Clinically serious and likely to require steroids during acute attacks and steroid-sparing agents long term to reduce attack frequency
- Artificial tears to dilute allergen and restore surface integrity
- Mast cell stabilizers AND/OR Antihistamines
- Topical steroids
- Systemic immunosuppression with steroids or steroid-sparing agents such as cyclosporine
- Surgical debridement AND/OR keratectomy to address corneal ulcers in vision-threatening disease
What is Atopic Keratoconjunctivitis
This is the most severe disease of the group and is characteristically associated with other atopic conditions.
Pathology of AKC
An acute type 1 hypersensitivity reaction with mast cell degranulation followed by a chronic/recurrent type 4 hypersensitivity mediated by T cells.
The additional type 4 component makes this disease chronic
Presentation of AKC
Affects the lower conjunctiva
More associated with lid diseases such as: blepharitis and eczema
Management of AKC
Clinically serious and likely to require steroids during acute attacks and steroid-sparing agents long term to reduce attack frequency
- Artificial tears to dilute allergen and restore surface integrity
- Mast cell stabilizers AND/OR Antihistamines
- Topical steroids
- Systemic immunosuppression with steroids or steroid-sparing agents such as cyclosporine
- Surgical debridement AND/OR keratectomy to address corneal ulcers in vision-threatening disease
What medicication is highly effective in exacerbations of AKC
Calcineurin inhibitors
What is Cicatricial conjunctivitis?
Refers to inflammation of the conjunctiva which has led to scarring.
It can be used to describe a wide number of conditions from chemical burns to infections such as trachoma, and systemic diseases such as sarcoidosis and Stevens-Johnson syndrome.
The presence of a cicatrix (conjunctival scar) should be suspected in trichiasis, entropion, symblepharon and keratinisation.
Pathology of Cicatricial Conjunctivitis
These diseases are typically bilateral and progressive.
The essential pathology is inflammation which leads to loss of goblet cells → failure of ocular surface integrity → limbitis and limbal stem cell failure → keratopathy and scarring
Symblepharon of the lower conjunctiva
What is Ocular Mucous Membrane Pemphigoid?
A chronic blistering type 2 hypersensitivity reaction of the mucosal surfaces. Suspect in severe bilateral cases of papillary conjunctivitis with evidence of cicatrisation and systemic cutaneous involvement.
Pathology of Ocular Mucous Membrane Pemphigoid
Linear deposits of IgA, IgG and complement in the basement membranes of mucosal surfaces. This can be seen on conjunctival autofluorescence.
The antibodies target hemidesmosomes and components of the basement membranes.
Management of Ocular Mucous Membrane Pemphigoid
In general, topical steroids and doxycycline are administered. Disease-modifying treatment is stepwise:
Mild → dapsone
Moderate → mycophenolate, methotrexate or azathioprine
Severe → IV methylprednisolone and/or cyclophosphamide or rituximab long term (se. pulmonary toxicity)
What are Erythema Multiforme, SJS and TEN
These conditions can be thought of as a spectrum of diseases where TEN is the most severe.
Pathology of Erythema Multiforme, SJS and TEN
Inflammation of the vessels of the mucous membranes and skin, driven by type 4 hypersensitivity to a variety of triggers.
Triggers include: drugs (sulfonamides, allopurinol and AEDs) and infections such as HSV
Presentation of Erythema Multiforme, SJS and TEN
Acutely unwell with target lesions, bullae and mucous membrane inflammation.
Nikolsky sign - sloughing sheets of skin
Management of Erythema Multiforme, SJS and TEN
Management in the acute phase is with steroids and expert help with a burns unit should be sought, particularly in cases of TEN.
In the chronic phase, management is stepwise and follows the same structure as for ocular mucous membrane pemphigoid (above).
What are Pterygium and Pinguecula
- Both are conjunctival surface degenerations.
- They start nasally and invade laterally.
- UV light and age are important risk factors.
- The key difference is that pterygium invades into the cornea, pinguecula does not.
- Surgery is only needed in cases of pterygium where vision is obscured.
A patient with Pterygium. Note how the lesion invades the cornea.
A patient with pinguecula. Note how the lesion does not invade the cornea
Superior Limbic Keratoconjunctivitis
A chronic disease of the superior limbus and conjunctiva.
It is believed to be secondary to superior bulbar conjunctival laxity which can be induced by thyroid eye disease.
Ligneous Conjunctivitis
An idiopathic chronic conjunctivitis of children, with associated systemic disease. It is characterised by recurrent ‘wood’ like pseudomembranes of the conjunctiva and other mucous membranes.
Parinaud Oculoglandular syndrome
It is a triad of:
* Unilateral granulomatous conjunctivitis
* Ipsilateral preauricular lymphadenopathy
* Fever
It is caused by infection with Bartonella henselae
