Eyes: Conjunctivitis, Orbital & Periorbital Cellulitis Flashcards

1
Q

What is conjunctivitis?

A

Inflammation of the conjunctiva (thin membrane that covers the sclera and lines the inner surface of the eye).

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2
Q

Conjunctivitis may be bacterial, viral or allergic.

What are the 4 most common bacterial causative organisms?

A

1) Staph. aureus
2) Strep. pneumoniae
3) H. influenzae
4) Moraxella catarrhalis

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3
Q

What are the 4 most common viral causes of conjunctivitis?

A

1) Adenovirus (most common)
2) HSV
3) VZV
4) Enterovirus

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4
Q

What is the most common virus causing infective conjuctivitis?

A

Adenovirus

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5
Q

Features of bacterial vs viral conjunctivitis?

A

Bacterial:
- purulent discharge
- eyes may be ‘stuck together’ in morning

Viral:
- serous discharge
- recent URTI e.g. dry cough, sore throat
- preauricular lymph nodes

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6
Q

Are bacterial & viral conjunctivitis contagious?

A

yes - both are

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7
Q

Onset of symptoms in conjunctivitis?

A

Acute onset of symptoms, typically unilateral but may become bilateral within 24-48 hours.

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8
Q

What may be present in history in conjunctivitis?

A
  • Recent exposure to an infected individual, swimming in contaminated water, or contact lens use.
  • Presence of comorbidities e.g. URTI or atopy.
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9
Q

Clinical symptoms of conjunctivitis?

A

-Red, bloodshot eye

  • Ocular discomfort, itching, burning sensation.
  • Foreign body sensation or grittiness in the affected eye(s).
  • Photophobia may be present in cases of viral conjunctivitis.
  • Discharge: watery in viral, purulent in bacterial
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10
Q

What symptoms does conjunctivitis NOT cause?

A

Does NOT cause pain, photophobia or reduced visual acuity.

Discharge covering the eye may cause blurry vision, but this should return to normal when the discharge is cleared.

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11
Q

Potential clinical signs in conjunctivitis?

A
  • Conjunctival injection and chemosis.
  • Eyelid swelling and erythema.
  • Palpable preauricular lymphadenopathy (viral)
  • Subconjunctival haemorrhage may be present in cases of adenoviral conjunctivitis
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12
Q

what are some causes of an acute PAINFUL red eye? (7)

A

1) Acute angle-closure glaucoma

2) Anterior uveitis

3) Scleritis

4) Corneal abrasions or ulceration

5) Keratitis

6) Foreign body

7) Traumatic or chemical injury

Note - Conditions that require emergency same-day referral to ophthalmology tend to cause pain or reduced visual acuity.

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13
Q

what are some causes of an acute PAINLESS red eye? (3)

A

1) Conjunctivitis

2) Episcleritis

3) Subconjunctival haemorrhage

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14
Q

Typical management of infective conjunctivitis?

A

Normally a self-limiting condition that usually settles without treatment within 1-2 weeks.

Hygiene measures to reduce spreading e.g. avoiding towel sharing and close contact.

Clean eyes with cooled boiled water and cotton wool can help clear the discharge.

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15
Q

What are 2 pharmacological options for bacterial conjunctivitis if necessary?

A

1) Chloramphenicol (eye drops)

2) Fusidic acid (eye drops)

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16
Q

What medical management is indicated for conjunctivitis in pregnant women?

A

Fusidic acid

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17
Q

Indications for chloramphenicol? (2)

A

1) Superficial bacterial eye infections

2) Bacterial infection in otitis externa

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18
Q

Key contraindications of chloramphenicol?

A

Acute porphyrias

Pregnacy & breastfeeding

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19
Q

Is chloramphenicol safe in pregnancy & breast feeding?

A

No

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20
Q

What is risk of using Chloramphenicol in pregnancy?

A

‘Grey baby’ syndrome

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21
Q

What age children with conjunctivitis need urgent ophthalmology assessment?

A

Neonates <1 month old

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22
Q

Why do neonates with conjunctivitis need urgent ophthalmology assessment?

A

Neonatal conjunctivitis may be caused by gonococcal infection, which can cause serious complications (e.g., permanent vision loss).

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23
Q

Is school exclusion necessary in infective conjunctivitis?

A

No

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24
Q

What is allergic conjunctivitis?

A

An ocular inflammatory condition triggered by an immune response to various environmental allergens e.g. pollen, animal dander, and dust mites.

25
Q

What type of reaction is involved in allergic conjunctivitis?

A

Type 1 hypersensitivity

26
Q

Pathophysiology of allergic conjunctivitis?

A

The initial exposure to an allergen leads to sensitization of mast cells, which, upon re-exposure, release inflammatory mediators, including histamine, prostaglandins, and leukotrienes.

These mediators cause vasodilation, increased vascular permeability, and recruitment of eosinophils, resulting in the clinical manifestations of allergic conjunctivitis.

27
Q

Clinical features of allergic conjunctivitis?

A
  • Bilateral ocular itching and redness
  • Watery or stringy, mucoid discharge
  • Conjunctival chemosis and hyperemia
  • Eyelid oedema and erythema
  • Tearing and photophobia
28
Q

Management of allergic conjunctivitis?

A

1) Allergen avoidance

2) Basic eye care e.g. avoid rubbing eyes as this may cause mast cell degranulation, cool compresses

3) Pharmacotherapy:
- topical antihistamines e.g. olopatadine, ketotifen
- topical mast cell stabilisers e.g. sodium cromoglicate, nedocromil
- topical corticsteroids

29
Q

how do topical mast cell stabilisers work in allergic conjunctivitis?

A

Preventing mast cells from releasing histamine.

These require several weeks of use before they show any benefit.

30
Q

Give 2 examples of topical antihistamines used in allergic conjunctivitis

A

1) Olopatadine
2) Ketotifen

31
Q

Give 2 examples of topical cell stabilisers used in allergic conjunctivitis

A

1) Sodium cromoglicate

2) Nedocromil

32
Q

What is periorbital/preseptal cellulitis?

A

Infection of the soft tissues ANTERIOR to the orbital septum –> eyelids, skin & subcutaneous tissue of the face (but not the contents of the orbit).

33
Q

What is a key differential for periorbital cellulitis?

A

Orbital cellulitis (medical emergency)

34
Q

Where does infection in preseptal cellulitis usually spread from?

A

From nearby sites e.g. breaks in the skin, local infections (e.g. sinusitis), other RTIs.

35
Q

What are the 2 most common bacteria implicated in periorbital cellulitis?

A

1) Staph. aureus
2) Staph. epidermis

36
Q

Clinical features of periorbital cellulitis?

A
  • Red, swollen, painful eye of ACUTE onset
  • Fever
  • Partial or complete ptosis of the eye due to swelling
37
Q

What investigation can help distinguish orbital & periorbital cellulitis?

A

Contrast CT

38
Q

Are there orbital signs in periorbital cellulitis?

A

E.g. pain on movement of the eye, restriction of eye movements, proptosis, visual disturbance, chemosis, RAPD.

NO –> this indicates orbital cellulitis

39
Q

Does pain & restriction of movement of eye indicate orbital or periorbital cellulitis?

A

orbital

40
Q

Investigations in periorbital cellulitis?

A

1) Bloods: raised inflammatory markers

2) Swab of any discharge present

3) Contrast CT of the orbit –> differentiate between preseptal and orbital cellulitis

41
Q

What investigation should be performed in ALL patients suspected to have orbital cellulitis?

A

Contrast CT of the orbit

42
Q

Typical management of preseptal cellulitis?

A

Systemic Abx (oral or IV) e.g. co-amoxiclav

Note - can develop into orbital cellulitis, so vulnerable patients (e.g., children) or severe cases may require admission for monitoring.

43
Q

What is orbital cellulitis?

A

Infection involving the fat and muscles POSTERIOR to the orbital septum.

Medical emergency –> hospital admission and urgent senior review

44
Q

What is orbital cellulitis usually caused by?

A

Spreading URTI from the sinuses

45
Q

Risk factors for orbital cellulitis?

A

1) Childhood

2) Previous sinus infection

3) Lack of Haemophilus influenzae type b (Hib) vaccination

4) Recent eyelid infection/ insect bite on eyelid (Peri-orbital cellulitis)

5) Ear or facial infection

46
Q

A lack of which vaccine can predispose to orbital cellulitis?

A

Haemophilus influenzae type b (Hib)

47
Q

Clinical features of orbital cellulitis? (5 P’s)

A

1) Pain

2) Proptosis

3) Periocular swelling (oedema): swollen eyelids, chemosis, erythema

4) Pupil involvement and visual changes

5) Palsy (opthalmoplegia)

Additional features: fever, malaise, 1ary infection e.g. sinusitis

48
Q

Describe pain in orbital cellulitis

A
  • throbbing or deep ache
  • intensifies with eye movements
  • can radiate to the forehead, cheek, or teeth
49
Q

What causes proptosis in orbital cellultiis?

A

Inflammation and oedema of the orbital contents, or in severe cases, formation of an abscess.

This causes forward displacement or protrusion of the eyeball.

50
Q

What is chemosis?

A

Swelling of the conjunctiva

51
Q

What visual changes can orbital cellulitis cause?

A
  • blurred vision
  • decreased visual acuity
  • diplopia
  • loss of vision (severe)
  • RAPD
52
Q

what does a RAPD indicate in orbtial cellulitis?

A

Optic nerve involvement –> risk of permanent vision loss

53
Q

What causes palsy/opthalmoplegia in orbital cellulitis?

A

Inflammation and swelling in the orbit can cause restriction or paralysis of the extraocular muscles, leading to impaired eye movements (ophthalmoplegia)

54
Q

Investigations in orbital cellulitis?

A

1) FBC: raised WCC
2) Inflammatory markers: raised
3) CT with contrast
4) Blood culture & swab

55
Q

What can CT with contrast show in orbital cellulitis?

A

Inflammation of the orbital tissues deep to the septum, sinusitis.

56
Q

What are the 3 most common organisms implicated in orbital cellulitis?

A

1) Streptococcus
2) Staph. aureus
3) H. influenzae B

57
Q

management of orbital cellulitis?

A

Admit for IV Abx

58
Q
A