Ophthalmology

Question 1

What symptom distinguishes scleritis from episcleritis?

Answer 1

Pain

Question 2

Treatment for infectious conjunctivitis?

Answer 2

Topical chloramphenicol (antibiotic)

Question 3

Features of bacterial conjunctivitis vs viral conjunctivitis

Answer 3

Bacterial: purulent discharge, eyes stuck together in morning

Viral: serous discharge, recent URTI, preauricular lymph nodes

Question 4

What is orbital cellulitis?

Answer 4

Orbital cellulitis is the result of an infection affecting the fat and muscles posterior to the orbital septum, within the orbit but not involving the globe.
It is usually caused by a spreading upper respiratory tract infection from the sinuses and carries a high mortality rate.
It is a medical emergency requiring hospital admission and urgent senior review.

Question 5

What is periorbital cellulitis?

Answer 5

Periorbital cellulitis/ preseptal cellulitis is an infection of the soft tissues anterior to the orbital septum- this includes the eyelids, skin and subcutaneous tissue of the face, but not the contents of the orbit.

Question 6

Risk factors for orbital cellulitis

Answer 6

-childhood
-previous sinus infection
-lack of Haemophilus influenzae type b (Hib) vaccination
-recent eyelid infection/insect bite on eyelid (peri-orbital cellulitis)
-ear or facial infection

Question 7

Clinical features of orbital cellulitis

Answer 7

5 P’s :

Pain
Proptosis (exophthalmos)
Periocular oedema/swelling
Pupil involvement and visual changes- blurred vision, decreased visual acuity, diplopia….
Palsy (ophthalmoplegia)

Question 8

What are the most common bacterial causes of orbital cellulitis?

Answer 8

Streptococcus, staphylococcus aureus, haemophilus influenzae B

Question 9

Investigations for orbital cellulitis

Answer 9

Full blood count – WBC elevated, raised inflammatory markers.
Clinical examination involving complete ophthalmological assessment – Decreased vision, afferent pupillary defect, proptosis, dysmotility, oedema, erythema.
CT with contrast – Inflammation of the orbital tissues deep to the septum, sinusitis.
Blood culture and microbiological swab to determine the organism. Most common bacterial causes – Streptococcus, Staphylococcus aureus, Haemophilus influenzae B.

Question 10

Management of orbital cellulitis

Answer 10

Admission to hospital for IV antibiotics

Question 11

Pathophysiology of preseptal/periorbital cellulitis

Answer 11

Infection usually spreads to the structures surrounding the orbit from other nearby sites, most commonly from breaks in the skin or local infections such as sinusitis or other respiratory tract infections

Question 12

What are the most frequent causative organisms of preseptal cellulitis?

Answer 12

Staph. aureus, staph. epidermidis, streptococci and anaerobic bacteria

Question 13

clinical features of cellulitis

Answer 13

-red, swollen, painful eye of acute onset
-symptoms associated with fever

-erythema and oedema of the eyelids, which can spread onto the surrounding skin
-partial or complete ptosis of the eye due to swelling

Question 14

investigations of preseptal cellulitis

Answer 14

Bloods - raised inflammatory markers
Swab of any discharge present
Contrast CT of the orbit may help to differentiate between preseptal and orbital cellulitis. It should be performed in all patients suspected to have orbital cellulitis

Question 15

management of preseptal cellulitis

Answer 15

All cases should be referred to secondary care for assessment
Oral antibiotics are frequently sufficient - usually co-amoxiclav
Children may require admission for observation

Question 16

What are the features of Horner’s syndrome?

Answer 16

Basics: Miosis, ptosis, enophthamos, andhidrosis

Clinical features:

Anisocoria: -miosis on affected side
-relative pupillary dilation lag in darkness (2-8 seconds)

Pitosis: - partial ptosis due to a weakness of Muller’s muscle
-involvement of levator palpebrae superioris may lead to more pronounced ptosis

-Ipsilateral loss of sweating (anhidrosis) over forehead, face and neck regions.
-Facial vasodilation due to loss of sympathetic tone

Heterochromia Iridum (in congenital cases):
-lighter iris colour in the affected eye
-due to a lack of melanin deposition during development

Enophthalmos (rare)
-slight posterior displacement of the eyeball within the orbit
-attributed to loss of sympathetic innervation to orbital smooth muscles

Question 17

Describe Horner’s syndrome

Answer 17

Horner’s syndrome is a rare condition that affects the sympathetic nervous system.

AKA oculosympathetic paresis

Classic triad of ptosis, miosis and anhidrosis

It results from a lesion to the sympathetic pathway that supplies the head and neck, including the oculosympathetic fibers.
The cause of Horner’s syndrome varies with the site of the lesion.

Question 18

What does anisocoria mean?

Answer 18

Difference in pupil sizes

Question 19

How do central lesions in Horner’s syndrome present and what are the causes?

Answer 19

-Anhidrosis of the face, arm and trunk

-Stroke, syringomyelia (cyst in spinal cord), multiple sclerosis, tumour, encephalitis

Question 20

How do pre-ganglionic lesions present in Horner’s syndrome and what are the causes?

Answer 20

Anhidrosis of the face

-Pancoast’s tumour, thyroidectomy, trauma, cervical rib

Question 21

How do post-ganglionic lesions present in Horner’s syndrome and what are the causes

Answer 21

No anhidrosis

-Carotid artery dissection, carotid aneurysm, cavernous sinus thrombosis, cluster headache