Eye infections Notes


Osmosis High-Yield Notes

This Osmosis High-Yield Note provides an overview of Eye infections essentials. All Osmosis Notes are clearly laid-out and contain striking images, tables, and diagrams to help visual learners understand complex topics quickly and efficiently. Find more information about Eye infections:

Periorbital cellulitis

Hordeolum (stye)




Orbital cellulitis

NOTES NOTES EYE INFECTIONS GENERALLY, WHAT ARE THEY? PATHOLOGY & CAUSES ▪ Ocular disorders with infectious, noninfectious etiologies → inflammation, damage to eye structures RISK FACTORS DIAGNOSIS DIAGNOSTIC IMAGING ▪ Fundoscopy CT scan/MRI ▪ Orbits, sinuses ▪ Immunocompromised state, contact with infectious agent, ocular trauma, certain systemic diseases LAB RESULTS COMPLICATIONS OTHER DIAGNOSTICS ▪ Range from benign, self-limiting to visionthreatening infections SIGNS & SYMPTOMS ▪ Structural damage, functional impairment ▪ Giemsa/Gram stains; cultures ▪ Snellen chart TREATMENT MEDICATIONS ▪ Antimicrobials OTHER INTERVENTIONS ▪ Address comorbidities OSMOSIS.ORG 585
CHALAZION osms.it/chalazion PATHOLOGY & CAUSES ▪ Firm, painless lipogranulomatous inflammatory lump in eyelid; caused by blockage of ocular sebaceous glands ▫ Deep chalazion: inflammation of meibomian sebaceous glands ▫ Superficial chalazion: inflammation of Zeis sebaceous glands ▪ Gland obstruction → impissation (decreased flow of secretions) → granulomatous inflammatory response → lipogranuloma inflammation → lesion forms on upper (most common)/lower eyelid ▪ Slow growing; may persist for weeks/ months; deeper within eyelid than hordeolum (stye) RISK FACTORS ▪ Rosacea, seborrhea, blepharitis, inflamed hordeolum may demonstrate diffuse inspissation of yellowish contents from eyelid margin orifices Figure 76.1 A chalazion of the left upper eyelid. COMPLICATIONS ▪ If large chalazion presses on cornea → visual changes ▪ Recurring chalazion: may signal carcinoma (rare) SIGNS & SYMPTOMS ▪ Eyelid erythema; swelling; firm, nodular, rubbery consistency DIAGNOSIS OTHER DIAGNOSTICS ▪ Clinical history, physical examination ▪ Histological examination: chalazia may indicate eyelid carcinoma Slit-lamp ▪ Determine status of meibomian glands; 586 OSMOSIS.ORG Figure 76.2 The histological appearance of a chalazion. There is granulomatous inflammation with giant cells, numerous macrophages as well as neutrophils and eosinophils surrounding a nidus of lipid.
Chapter 76 Eye Infections TREATMENT MEDICATIONS ▪ Recalcitrant chalazia: intralesional steroid injection SURGERY ▪ Recalcitrant chalazia: incision, curettage OTHER INTERVENTIONS ▪ Warm, wet compresses encourage drainage ▪ Ocular cleansing pads applied to eyelid margin ▪ Treat comorbidities (e.g. blepharitis, rosacea) ▪ Small chalazion may resolve on own CHORIORETINITIS osms.it/chorioretinitis PATHOLOGY & CAUSES ▪ Inflammation of choroid, retina; AKA posterior uveitis CAUSES Infectious ▪ Bacterial: tuberculosis, syphilis ▪ Viral: cytomegalovirus, West Nile virus, herpes simplex virus (HSV) 1 ▪ Parasitic: toxoplasmosis, onchocerciasis ▪ Fungal: Candida albicans Noninfectious ▪ Sarcoidosis, Behçet’s disease, traumatic chorioretinitis RISK FACTORS ▪ Immunodeficiency, contact with infectious agent, traumatic eye injury, systemic disease associated with chorioretinitis COMPLICATIONS ▪ Retinal hemorrhage/detachment, visual impairment with macular involvement SIGNS & SYMPTOMS ▪ Floaters (vitritis), blurred vision, impaired color/night vision, ocular pain, photophobia, excessive lacrimation DIAGNOSIS DIAGNOSTIC IMAGING Fluorescein angiography ▪ Irregularities Fundoscopy ▪ Creamy white/yellow/gray lesions; keratic precipitates; retinal edema, necrosis; chorioretinal atrophy, neovascularization; cotton-wool infiltrates (Candida-associated chorioretinitis); polymorphic retinochoroidal scars (toxoplasmosis-associated chorioretinitis) OTHER DIAGNOSTICS ▪ Clinical history, physical examination TREATMENT MEDICATIONS ▪ Corticosteroids/antimicrobials OSMOSIS.ORG 587
Figure 76.3 A retinal photograph displaying the features of chorioretinitis. There are numerous, patchy, cream-colored lesions and retinal edema. CONJUNCTIVITIS osms.it/conjunctivitis PATHOLOGY & CAUSES ▪ Inflammation of conjunctiva, transparent mucous membrane covering inside of eyelids (tarsal conjunctiva), globe (bulbar conjunctiva) ▫ Non-keratinized epithelium containing goblet cells, highly vascularized substantia propria ▫ Turns pink/red when inflamed: diffuse conjunctival injection ▪ Infection, inflammation → dilatation of conjunctival vessels → conjunctival hyperemia, edema → inflammatory discharge TYPES Infectious (bacterial) ▪ Highly contagious; spread by direct contact 588 OSMOSIS.ORG ▪ Common causes: Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae ▪ Hyperacute bacterial conjunctivitis ▫ Causes: Neisseria gonorrhoeae (most common)/Neisseria meningitidis ▫ Oculogenital disease: usually transmitted from genitals to eyes via hands ▫ Vision-threatening ▪ Chlamydial ▫ Caused by Chlamydia trachomatis ▫ Adult inclusion conjunctivitis: chronic, indolent ▫ Trachoma: infectious blindness cause worldwide; active trachoma caused by serotypes A, B, Ba, C (low-income country-endemic, mostly in children); initial follicular inflammation progresses in severity → cicatricial disease, vision loss
Chapter 76 Eye Infections Infectious (viral) ▪ Highly contagious; spread by direct contact ▪ Causes: adenovirus (most common), HSV (in children), varicella zoster virus (VZV) ▫ Ocular manifestation of systemic infection ▫ Epidemic keratoconjunctivitis (EKC): caused by adenovirus 8, 19, 37; fulminant conjunctivitis, keratitis (epithelium of conjunctiva, cornea); corneal inclusions degrade visual acuity Noninfectious (allergic) ▪ Caused by airborne allergens (seasonal, perennial) ▪ Immunoglobulin E (IgE)-mediated → local mast cell degranulation Noninfectious (nonallergic) ▪ Caused by mechanical/chemical insult RISK FACTORS ▪ Exposure to causative agent, immunocompromised state, atopy (allergic conjunctivitis) ▪ Contact lens wear: common source of mechanical injury, nonallergic, infectious conjunctivitis COMPLICATIONS ▪ Cornea: keratitis (inflammation), ulcer, perforation, scarring ▪ Dacryocystitis (bacterial infection of lacrimal sac) ▪ Vision loss SIGNS & SYMPTOMS ▪ Appearance: unilateral/bilateral inflammation; pinkish-red eye; eyelid edema; chemosis (conjunctival edema); excessive lacrimation ▪ Discharge ▫ Bacterial: purulent/mucopurulent; white/ yellow/green ▫ Gonococcal: hyper-purulent, profuse ▫ Viral: watery; stringy ▫ Allergic: watery, mucoid ▫ Nonallergic: mucoid ▪ Infected eye “stuck” shut from morning crusting; gritty, burning sensation (viral); itching (allergic); photophobia (corneal involvement); transient visual impairment ▪ Preauricular lymphadenopathy Figure 76.4 The clinical appearance of conjunctivitis. DIAGNOSIS LAB RESULTS ▪ Adenoviral conjunctivitis: rapid point-ofcare adenovirus antigen test ▪ Recalcitrant conjunctivitis: conjunctival biopsy (rule out neoplasm) Giemsa/gram stains ▪ Confirm identity of organism in suspected infectious cause OTHER DIAGNOSTICS ▪ Clinical history, physical examination TREATMENT MEDICATIONS ▪ Ocular lubricant drops/ophthalmic ointment ▪ Allergic conjunctivitis: antihistamine drops ▪ Adult inclusion conjunctivitis: systemic therapy to eradicate Chlamydia infection (antibiotics) ▪ Bacterial conjunctivitis: Topical antibiotic drops/ointment ▪ Epidemic keratoconjunctivitis (EKC): topical glucocorticoids OSMOSIS.ORG 589
OTHER INTERVENTIONS ▪ Warm, wet compresses encourages drainage ▪ Hyperacute conjunctivitis, EKC: immediate specialized ophthalmologist referral ▪ Viral conjunctivitis: self-limiting; usually resolves in 2–3 weeks KERATITIS osms.it/keratitis PATHOLOGY & CAUSES ▪ Cornea inflammation → corneal tissue destruction ▪ Inflammatory response → stromal damage from infection, host response → edema, infiltrates, necrotic ulceration, focal thinning, perforation CAUSES Infectious ▪ Bacteria: Staphylococcus aureus, Pseudomonas aeruginosa, coagulasenegative Staphylococcus, diphtheroids, Streptococcus pneumoniae ▪ Viruses: HSV, herpes zoster ▪ Fungi: Candida supp., Aspergillus supp., Fusarium supp. ▪ Parasites: Acanthamoeba Noninfectious ▪ Corneal inflammation with no known infectious etiology RISK FACTORS ▪ Corneal epithelium disruption ▫ Contact lenses (contact lens-related keratitis); esp. improper use (e.g. overnight wear, poor hygiene) ▫ Recent keratoplasty, trauma, corneal exposure (e.g. Graves’ ophthalmopathy, Bell’s palsy) 590 OSMOSIS.ORG ▪ Immunocompromised state ▪ Topical (ocular) corticosteroid use ▪ Contributing disorders: rosacea; keratoconjunctivitis sicca (dry eye syndrome); neurotrophic keratitis (lesion on cranial nerve V); autoimmune diseases (e.g. rheumatoid arthritis, cicatricial pemphigoid) COMPLICATIONS ▪ Endophthalmitis (interior eye inflammation), intraocular damage, vision loss, keratolysis (corneal melting) SIGNS & SYMPTOMS ▪ Erythema ▪ Preauricular lymphadenopathy ▪ Discharge: mucopurulent (bacterial), watery (viral) ▪ Corneal opacity, stromal infiltrate (immune complex deposits), ulcer ▫ Bacterial keratitis: yellow infiltrates ▫ Fungal keratitis: white infiltrates, feathery borders ▫ Acanthamoeba: Wessely ring infiltrate ▪ Hypopyon (layer of white cells in anterior chamber): fulminant bacteria ▪ Foreign body sensation; difficulty keeping eye open; photophobia; pain; decreased visual acuity, blurred vision; blepharospasm
Chapter 76 Eye Infections Penlight ▪ Visualizes infiltrate/ulcer (> 0.5mm); round, white spot (bacterial keratitis) Figure 76.5 An individual with sterile keratitis of the left eye. DIAGNOSIS DIAGNOSTIC IMAGING Fundoscopy ▪ Slit beam; examine contour abnormalities of cornea, lens, retina; small corneal infiltrates; faint branching grey opacity (viral keratitis) Fluorescein dye ▪ Corneal uptake of dye ▫ Visualize loss of epithelial cells, ulceration ▫ Green glow under cobalt blue light ▫ Diffuse white opacity/dull corneal light reflex ▫ Seidel sign (leaking aqueous humor → fluorescein streaming): penetrating trauma Snellen chart ▪ ↓ visual acuity TREATMENT MEDICATIONS ▪ Topical antimicrobials for infectious etiology LAB RESULTS ▪ Corneal scrapings, cultures: suspected infectious etiology OTHER DIAGNOSTICS ▪ Clinical history, physical examination OTHER INTERVENTIONS ▪ Control of associated comorbidities ▪ Temporary discontinuation of wearing contact lenses ORBITAL CELLULITIS osms.it/orbital-cellulitis PATHOLOGY & CAUSES ▪ Serious infection involving contents of orbit (ocular muscles, surrounding fat; not globe) CAUSES ▪ Entry of microorganisms into orbital space ▫ Via anatomical perforations of nerves, blood vessels in paranasal sinuses (e.g. ethmoid) ▫ Migration from surrounding tissues (e.g. face, eyelids) after local trauma/surgery ▫ Inflammatory response → tissue destruction RISK FACTORS ▪ More common in children ▪ Migration from other infections ▫ Bacterial rhinosinusitis: Staphylococcus aureus, streptococci (common); fungal rhinosinusitis (rare) ▫ Dacryocystitis: lacrimal sac infection ▫ Infected mucocele: mucus-containing cystic lesion of salivary gland ▫ Infections involving teeth, middle ear, face ▪ Direct inoculation: ophthalmic surgical procedures; orbital trauma with fracture/ foreign body OSMOSIS.ORG 591
COMPLICATIONS ▪ Extraorbital extension: epidural/subdural empyema; brain abscess; meningitis; cavernous sinus thrombosis; dural sinus thrombosis; involvement of cranial nerves III, IV, V, VI; optic neuritis ▪ Endophthalmitis: interior eye inflammation ▪ Vision loss ▪ Potentially fatal if sepsis develops SIGNS & SYMPTOMS Systemic ▪ Fever; severe headache, vomiting, mental status changes (intracranial complications) Ocular ▪ Red, swollen eyelids; chemosis (conjunctival edema); pain (esp. with eye movement); ophthalmoplegia (paralysis of eye muscles); proptosis (abnormal displacement of eye); impaired visual acuity, color vision; abnormal pupillary light reflex DIAGNOSIS DIAGNOSTIC IMAGING CT scan/MRI ▪ Orbits, sinuses; detects abscess, intracranial changes Dilated fundoscopy ▪ Determines optic neuropathy/retinal vascular occlusion 592 OSMOSIS.ORG LAB RESULTS Complete blood count (CBC) ▪ Leukocytosis; ↑ absolute neutrophil count (ANC) Blood/orbital/subperiosteal aspirates cultures ▪ Identify causative organism OTHER DIAGNOSTICS ▪ Clinical history, physical examination ▪ Ocular motility: pain with movement ▪ Pupillary light reflex: sluggish/absent reflex → optic nerve involvement ▪ Exophthalmometry: measures degree of proptosis ▪ Asses color vision acuity: determines optic nerve involvement ▪ Intraocular pressure measurement (↑) TREATMENT MEDICATIONS ▪ Antimicrobials SURGERY ▪ External (through orbit)/endoscopic transcaruncular approach
Chapter 76 Eye Infections OSMOSIS.ORG 593
PERIORBITAL (PRESEPTAL) CELLULITIS osms.it/periorbital-cellulitis PATHOLOGY & CAUSES ▪ Mild infection of superficial tissues of anterior eyelid (tissues anterior to orbital septum); more common than orbital cellulitis CAUSES ▪ Introduction/migration of microorganisms into preseptal space: Staphylococcus aureus, Streptococcus pneumoniae, other streptococci, anaerobes RISK FACTORS ▪ More common in children ▪ Migration from other infections: sinusitis; upper respiratory tract infection; dacryocystitis; bacteremia (rare) ▪ Direct inoculation: trauma (e.g. insect bites, animal bites, introduction of foreign bodies); ophthalmic surgical procedures COMPLICATIONS ▪ Orbital cellulitis SIGNS & SYMPTOMS ▪ Ocular pain, eyelid swelling, erythema, fever, lymphadenopathy DIAGNOSIS DIAGNOSTIC IMAGING Contrast-enhanced CT scan (orbits, sinuses) ▪ Distinguishes between preseptal, orbital cellulitis; associated sinusitis LAB RESULTS CBC ▪ Leukocytosis Cultures (abscess contents, paranasal sinus secretions) ▪ Identify causative agent OTHER DIAGNOSTICS ▪ Clinical history, physical examination TREATMENT MEDICATIONS ▪ Oral antibiotics Figure 76.6 An individual with left-sided periorbital cellulitis. 594 OSMOSIS.ORG
Chapter 76 Eye Infections STYE (HORDEOLUM) osms.it/stye PATHOLOGY & CAUSES ▪ Blockage, purulent inflammation of upper/ lower eyelid SIGNS & SYMPTOMS ▪ Tenderness; fluctuant pustule; localized swelling, erythema; excessive lacrimation; photophobia CAUSES DIAGNOSIS ▪ Sterile/bacterial (e.g. Staphylococcus aureus, Staphylococcus epidermidis) Internal ▪ Meibomian sebaceous gland; points toward conjunctival side of lid → conjunctival inflammation External ▪ Zeiss/Moll sebaceous glands; points toward skin surface of eyelid RISK FACTORS ▪ Touching eyes with contaminated hands, chronic blepharitis, seborrhea, improper contact lens hygiene, sleeping with eye makeup, immunocompromised state COMPLICATIONS ▪ Hardens → chalazion DIAGNOSTIC IMAGING Slit lamp, fundoscopy ▪ Determine infection extension to other tissues OTHER DIAGNOSTICS ▪ Clinical history, physical examination ▪ Visual acuity assessment TREATMENT MEDICATIONS ▪ Topical antibiotic ointment SURGERY ▪ Incision, curettage: if progresses to chalazion OTHER INTERVENTIONS ▪ Warm compresses encourage drainage ▪ Usually self-limiting with spontaneous resolution Figure 76.7 A stye on the right lower eye lid. OSMOSIS.ORG 595
UVEITIS osms.it/uveitis PATHOLOGY & CAUSES ▪ Inflammation of uveal tract (choroid, ciliary body, iris); unilateral/bilateral ▪ Onset: rapid/insidious ▪ Course: acute/recurrent/chronic ▪ Duration: persistent (> three months)/ limited (≤ three months) TYPES Anterior (most common) ▪ Anterior uveal tract; iritis, iridocyclitis (inflammation of ciliary body) Panuveitis ▪ Anterior chamber, vitreous body, retina/ choroid Posterior uveitis ▪ Retina/choroid 596 OSMOSIS.ORG
Chapter 76 Eye Infections Intermediate uveitis ▪ Vitreous body; chorioretinal inflammation CAUSES Bacterial: tuberculosis, syphilis Viral: cytomegalovirus, HSV Fungal: candidiasis, Pneumocystis jirovecii Parasitic: Acanthamoeba, toxoplasmosis Noninfectious systemic: Crohn’s disease, ankylosing spondylitis ▪ Conditions confined to eye: trauma, acute retinal necrosis ▪ ▪ ▪ ▪ ▪ RISK FACTORS ▪ Systemic infectious, inflammatory conditions COMPLICATIONS ▪ Intraocular hypertension, glaucoma; increased intraocular pressure; posterior synechiae (iris adheres to lens); band keratopathy (corneal calcium deposits); cataract; vision loss SIGNS & SYMPTOMS ▪ Ocular erythema ▪ Impaired vision ▪ Pain, photophobia, vision distortion, floaters (vitritis), photopsia (flashing lights) DIAGNOSIS LAB RESULTS Microscopy, cytology, culture, polymerase chain reaction (PCR) ▪ Fluid sampling/biopsy; identify presence of infectious agent OTHER DIAGNOSTICS ▪ Clinical history, physical examination Snellen chart ▪ ↓ visual acuity Pupillary light reflex ▪ Sluggish pupillary reaction to light → synechiae Intraocular pressure ▪ No change if uncomplicated uveitis; ↑ in acute uveitis-induced glaucoma TREATMENT MEDICATIONS ▪ Corticosteroids: topical, local injection, implantable, systemic ▪ Recalcitrant uveitis: immunomodulatory agents (if corticosteroid response inadequate) ▪ Recalcitrant uveitis: tumor necrosis factor (TNF) inhibitor (if resistant to treatment) ▪ Posterior synechiae prevention: mydriatic/ cycloplegic medications ▪ Viral-associated uveitis: antivirals DIAGNOSTIC IMAGING Fluorescein/indocyanine green angiography (posterior uveitis) ▪ Evaluate status of retinal vascular circulation; identify choroidal disease Fundoscopy ▪ Ciliary flush: perilimbal redness ▪ Keratic precipitates: inflammatory deposits on cornea ▪ Hypopyon: white blood cells settle on bottom of anterior chamber ▪ Haziness of aqueous humor: protein accumulation Figure 76.8 An individual with a hypopyon of the left eye as a result of severe anterior uveitis. OSMOSIS.ORG 597

Osmosis High-Yield Notes

This Osmosis High-Yield Note provides an overview of Eye infections essentials. All Osmosis Notes are clearly laid-out and contain striking images, tables, and diagrams to help visual learners understand complex topics quickly and efficiently. Find more information about Eye infections by visiting the associated Learn Page.