Ophthalmology
Question 16 of 180
A 32 year old woman presents to the Emergency Department with a 3 day history of right eye redness associated with a purulent discharge. You suspect bacterial conjunctivitis and feel that antibiotic treatment is indicated. Which antibiotic would you prescribe?
Answer:
Treat with topical antibiotics if severe or circumstances require rapid resolution. A delayed treatment strategy may be appropriate; advise the person to initiate topical antibiotics if symptoms have not resolved within 3 days. Options for topical antibiotics include:- Chloramphenicol 0.5% drops — apply 1 drop 2 hourly for 2 days, then reduce frequency depending on the severity of infection (3-4 times daily is usually sufficient for less severe infection). Continue use until 48 hours after infection has cleared.
- Chloramphenicol 1% ointment — apply 3-4 times daily. Continue use until 48 hours after infection has cleared.
- Fusidic acid 1% eye drops — apply 1 drop twice daily. Continue use until 48 hours after infection has cleared.
Conjunctivitis
Ophthalmology
Last Updated: 17th March 2023
Conjunctivitis is inflammation of the conjunctiva due to allergic or immunological reactions, infection (viral, bacterial or parasitic), mechanical irritation, neoplasia, or contact with toxic substances. Inflammation or infection of the conjunctiva causes dilation of conjunctival vessels leading to hyperaemia and oedema of the conjunctiva (chemosis) which may be associated with discharge.
Aetiology
- Infective
- Bacterial infection
- Most common causes are Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae
- Other bacterial causes include Moraxella catarrhalis, Chlamydia trachomatis, and Neisseria gonorrhoea
- Viral infection (up to 80% of all cases of acute conjunctivitis)
- Most common cause is adenovirus
- Other viral causes include Herpes simplex, Epstein-Barr, Varicella zoster, Molluscum contagiosum, coxsackie, and enteroviruses
- Bacterial infection
- Allergic
- Irritant
- Mechanical
- Toxic/chemical
- Contact-lens related
- Immune-mediated
- Neoplastic
Clinical features
- Non-specific
- Acute onset conjunctival erythema
- Discomfort which may be described as ‘grittiness’, ‘foreign body’ or ‘burning’ sensation
- Watering and discharge which may cause transient blurring of vision
- No significant pain, light sensitivity or visual loss
- Allergic conjunctivitis
- Usually bilateral
- Itching is prominent feature
- Most commonly seasonal and often associated with atopy
- May be associated with watery or mucoid discharge, conjunctival redness, chemosis, conjunctival papillary reaction and eyelid oedema
- Bacterial conjunctivitis
- Associated with purulent or mucopurulent discharge with eyelid matting
- Itching is uncommon
- Chlamydial conjunctivitis often presents with a chronic (longer than 2 weeks) unilateral low-grade irritation and mucus discharge in a sexually active person
- Gonococcal conjunctivitis usually develops rapidly (over 12 – 24 hours) with copious mucopurulent discharge, eyelid swelling, and tender preauricular lymphadenopathy
- Viral conjunctivitis
- Associated with mild to moderate erythema of the palpebral or bulbar conjunctiva, follicles on eyelid eversion and lid oedema
- Mild to moderate itching
- Less discharge (usually watery) than bacterial conjunctivitis
- Associated with upper respiratory tract infection and preauricular lymphadenopathy
- Pseudomembranes may form on tarsal conjunctival surfaces in severe cases
Red flags
Red flags which indicate need for urgent ophthalmological assessment include:
- Reduced visual acuity
- Marked eye pain, headache or photophobia
- Red sticky eye in a neonate (within 30 days of birth)
- History of trauma (mechanical, chemical or ultraviolet) or possible foreign body
- Copious rapidly progressive discharge (may indicate gonococcal infection)
- Infection with a herpes virus (Herpes simplex typically presents as unilateral red eye with vesicular lesions visible on eyelid and watery discharge; ocular involvement in Herpes zoster infection should be assumed if lesions are present at the tip of the nose (Hutchinson's sign))
- Soft contact lens use with corneal symptoms (such as photophobia and watering)
- Suspected periorbital or orbital cellulitis
- Severe disease, for example, corneal ulceration, significant keratitis or presence of pseudomembrane
- Recent intraocular surgery
- Conjunctivitis associated with a severe systemic condition e.g. rheumatoid arthritis, or immunocompromise
Investigations
- Do not routinely take swabs (swabs may be appropriate if the person fails to respond to initial treatment)
- Swabs for severe purulent discharge (which may indicate gonococcal infection) or conjunctivitis in neonates, should be carried out urgently
Management
- Allergic conjunctivitis
- Avoidance of allergens, artificial tears, cool compresses
- Topical antihistamines +/- topical mast cell stabilisers
- Bacterial conjunctivitis
- Advise the person that most cases of bacterial conjunctivitis are self-limiting and resolve within 5 – 7 days without treatment
- Treat with topical antibiotics if severe or circumstances require rapid resolution. A delayed treatment strategy may be appropriate; advise the person to initiate topical antibiotics if symptoms have not resolved within 3 days. Options for topical antibiotics include:
- Chloramphenicol 0.5% drops — apply 1 drop 2 hourly for 2 days, then reduce frequency depending on the severity of infection (3-4 times daily is usually sufficient for less severe infection). Continue use until 48 hours after infection has cleared.
- Chloramphenicol 1% ointment — apply 3-4 times daily. Continue use until 48 hours after infection has cleared.
- Fusidic acid 1% eye drops — apply 1 drop twice daily. Continue use until 48 hours after infection has cleared.
- Viral conjunctivitis (non-herpetic)
- Reassure the person that most cases of acute infectious conjunctivitis are self-limiting and do not require antimicrobial treatment
- Advise the person that symptoms may be eased with self-care measures such as:
- Bathing/cleaning the eyelids with cotton wool soaked in sterile saline or boiled and cooled water to remove any discharge
- Cool compresses applied gently around the eye area
- Use of lubricating drops or artificial tears
- Inform the person that infective conjunctivitis is contagious and they should try to prevent spread of infection to their other eye and other people by:
- Washing hands frequently with soap and water
- Using separate towels and flannels
- Avoiding close contact with others especially if they are a healthcare professional or child care provider (they may be infectious for up to 14 days from onset)
Follow-up
Public Health England does not recommend an exclusion period from school, nursery or childminders except if an outbreak or cluster of cases occurs. Give written information, explain red flags for urgent review and advise the person to return/seek further help if symptoms persist.
If the person reattends with ongoing symptoms of conjunctivitis, consider sending swabs for viral PCR (for adenovirus and herpes simplex) and bacterial culture (for Chlamydia trachomatis and Neisseria gonorrhoeae) and start empirical topical antibiotics (if not already prescribed).
Consider referral to ophthalmology if symptoms persist for more than 7 to 10 days after initiating treatment.
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
