Cheratite

Question 1

General findings

🧨DOLORE!

Answer 1

Keratitis is inflammation of the cornea, a clear and transparent covering over the iris and pupil. Important forms of keratitis include bacterial, herpes zoster, herpes simplex, and Acanthamoeba keratitis. Most corneal injuries and infections are associated with severe pain, although sometimes pain is absent. Other findings include irritation, eye redness, watery or purulent secretion, and impaired vision. Diagnosis is usually based on clinical findings and slit-lamp examination. Keratitis is an emergent disorder that can lead to irreversible vision loss left untreated.

Question 2

Bacterial keratitis

Answer 2

• Most common form of keratitis (90%)
• ↑ Risk with wearing contact lenses e stenosi del dotto lacrimale
• Purulent discharge and/or HYPOPION🧨 (A sedimentation of leukocytes at the bottom of the anterior chamber of the eye secondary to an inflammatory process (e.g., bacterial/fungal keratitis, uveitis, endophthalmitis). Indicates a potentially sight-threatening condition that requires prompt assessment and treatment.) In contrast to viral infections, which produce a watery discharge!!!
• Round corneal infiltrate or ulcer

✔Etiology
Mainly: staphylococci (Staphylococcus aureus), streptococci (Streptococcus pneumoniae), Pseudomonas aeruginosa
Syphilis👓: la sifilide comporta una cheratite interstiziale, con coinvolgimento stromale. Risulta pertanto essere fluorescina negativa.Usa ciclopegici e corticosteroidi.
Enterobacteriaceae (including Klebsiella)

✔Clinical features
Progressive pain
Foreign body sensation
Purulent discharge 
Photophobia
Excessive tearing
Blurry vision
Eye redness
Conjunctival injection

✔Diagnostics
Slit lamp examination
-Hypopyon: collection of leukocytes at the bottom of the anterior chamber; occurs in severe cases of keratitis
-Fluorescein staining: round corneal infiltrate or ulcer

🧨Cultures are indicated when the corneal infiltrate is large, central, and extends to the deep stroma, for refractory cases, or those with atypical features.

✔Topical broad-spectrum antibiotics
-Cefazolin with tobramycin/gentamicin or Ofloxacin or
Ciprofloxacin
-ciclopegia mediante somministrazione di parasimpaticolitici 👓(bisogna favorire la midriasi: aim is to reduce pain and prevent synechiae formation between the cornea and iris when a significant amount of inflammatory cells (e.g., leukocytes) are in the anterior chamber of the eye.)

✔Complications
Irreversible vision loss
Corneal destruction (potentially leading up to perforation)
Leukoma: a dense, white opacity of the cornea caused by scarring
Caused by inflammation, injuries, or congenital corneal conditions.
Vascularization into the cornea
↑ Intraocular pressure; if necessary, reduce intraocular pressure during the acute phase
Endophthalmitis

Question 3

Special form: Pseudomonas keratitis

Answer 3

!Most common cause of bacterial keratitis in contact lens users
Characterized by a fulminant course with severe ulceration and corneal destruction/perforation within 2–5 days

Question 4

Herpes simplex keratitis (type 1)
Occhio rosso! L’ulcera dendritica comporta assenza di dolore per anestesia corneale

Glucocorticoids should not be used in initial treatment of dendritic epithelial keratitis!

Reactivated herpes zoster virus (involvement of the ophthalmic nerve, primo ramo del trigemino). Vesicles typically develop on the ipsilateral forehead, eyelid, and nose. Can cause conjunctivitis, decreased corneal sensitivity, keratitis, and iritis and is potentially sight-threatening.

Answer 4

✔Clinical features
Similar to viral conjunctivitis, but usually UNILATERAL (invece la congiundivite virale è tipicamente bilaterale)
Eye redness🧨
± Eye pain
Foreign body sensation
Photophobia
Blurry vision; can lead to vision loss if untreated
Watery disharge!!!!!🧨

✔Diagnostics
-Fluorescein staining: superficial corneal erosions (dendritic ulcers) that resemble the branches of a tree (geographic ulcers may be seen when dendritic ulcers widen in shape)
Direct fluorescein antibody test (HSV antigen detection) or polymerase chain reaction (PCR) test

✔Treatment for epithelial HSV keratitis
Topical trifluridine or ganciclovir
Oral antiviral (e.g., acyclovir) when topical treatment cannot be administered by the patient, prophylactic treatment after surgery, or refractory cases despite topical treatment
Corneal transplantation for patients with severe corneal scarring

Question 5

Acanthamoeba keratitis

Answer 5

Primarily occurs in immunocompetent contact lens wearers!

Corneal ring infiltrate (late-stage)

Treatment
Topical antiseptic (e.g., chlorhexidine) with propamidine

Question 6

Cheratite stromale-interstiziale

Answer 6

Unico caso in cui è permesso l’utilizzo di corticosteroidi, può essere secondaria ad una cheratite erpetica oppure la ritroviamo nella triade du Hutchinson della sifilide congenita:

• cheratite interstiziale (corticosteroidi)
• lesioni dentarie
• sordità congenita neurosensoriale

Question 7

Cheratite da esposizione

Answer 7

Lubrificanti e occlusione oculare