Bacterial Keratitis and Treatment Quiz

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Questions and Answers

Which type of bacteria is most commonly associated with contact lens-related keratitis?

Streptococcus species

Atypical Mycobacterium

Serratia Marcescens (correct)

Methicillin resistant Staph. aureus

What phenomenon helps a bacterial species protect itself and increase resistance to treatments?

Enhanced flagellar movement

Rapid cell division

Biofilm formation (correct)

Increased metabolic rate

What is the recommended dosage of Azithromycin for the treatment mentioned?

20 mg/kg/d for 2 days

15 mg/kg/d for 7 days

10 mg/kg/d for 3 days (correct)

5 mg/kg/d for 5 days

Which type of exposure is commonly associated with the development of keratitis from Gram-negative bacilli?

Trauma with contaminated water, soil, and vegetation Signup and view all the answers

Which of the following treatments is suggested for lid hygiene and maintenance?

Warm compress, PF AT’s, and MG expression Signup and view all the answers

Which generation of fluoroquinolones is noted for expanding the antimicrobial spectrum to combat resistant strains?

4th generation Signup and view all the answers

What combination is noted to be effective in treating inflammatory reactions from staph antigens?

Steroid and antibiotic eye drops Signup and view all the answers

In cases of mild blepharitis, what regimen is prescribed?

Steroid every 4 hours and antibiotic every 4 hours Signup and view all the answers

How does Serratia Marcescens typically develop antibiotic resistance?

Via both intrinsic and acquired mechanisms Signup and view all the answers

Which of these is an example of a lid scrub or spray with antimicrobial activity?

Ocusoft Plus or Hypochlorous Acid Signup and view all the answers

What is a common result of prolonged ulceration in terms of vascularization?

Vascularization can occur Signup and view all the answers

Which of the following best describes cicatricization?

Replacement with fibrotic/scarred tissue Signup and view all the answers

Which bacterial species is associated with the formation of round, well-circumscribed infiltrates in keratitis?

Staphylococcus aureus Signup and view all the answers

What does regression in the context of keratitis typically indicate?

Improvement in signs and symptoms Signup and view all the answers

Which of the following pathogens is NOT typically associated with acute keratitis?

Staphylococcus epidermidis Signup and view all the answers

What is the primary role of bacterial exotoxins and proteases in the context of keratitis?

To facilitate stromal destruction Signup and view all the answers

What do decreasing numbers of colonies on consecutive C streaks suggest in culture analysis?

Improvement in the infection Signup and view all the answers

Which of the following is NOT commonly noted during improvement of ulceration?

Persistence of cloudy discharge Signup and view all the answers

What is the main characteristic of keratitis caused by Mycobacterium species?

It shows margins that have a spoke-like or frosted glass appearance. Signup and view all the answers

Which method is primarily used to diagnose Nocardia keratitis?

Acid-fast stain. Signup and view all the answers

Why should a laboratory be notified before submitting a lone CTA for mycobacteria testing?

To prevent a delay in processing and potential false negatives. Signup and view all the answers

What is the standard treatment for Nocardia keratitis?

Topical Amikacin. Signup and view all the answers

Which condition is considered a major risk factor for Nocardia infection in South Florida?

Exposure to contaminated soil. Signup and view all the answers

What type of bacteria is primarily responsible for infections associated with slow progressive keratitis?

Mycobacterium species. Signup and view all the answers

What appearance do the infiltrates of Nocardia keratitis typically have?

Wreath-like configuration. Signup and view all the answers

What is a typical characteristic of the progression of Nocardia infections?

Indolent and waxes and wanes course. Signup and view all the answers

What type of immunity is decreased in atopic patients?

Systemic cell-mediated immunity Signup and view all the answers

What is a common consequence of atopic dermatitis related to eye health?

Increased susceptibility to herpes simplex keratitis Signup and view all the answers

Which treatment is used for managing blepharitis?

Topical antihistamine-mast cell stabilizer Signup and view all the answers

What is the male to female ratio associated with atopic dermatitis?

2:1 Signup and view all the answers

What are perennial triggers associated with atopic dermatitis likely to worsen?

Winter weather Signup and view all the answers

What is the expected outcome for patients with atopic dermatitis regarding resolution?

Low expectation of resolution Signup and view all the answers

Which condition is most likely associated with cicatricial ectropion?

Atopic dermatitis Signup and view all the answers

Which component is part of the treatment for presenile cataracts?

Cataract Surgery (CE/IOL) Signup and view all the answers

What is the recommended approach for treating keratoconus without using topical steroids?

Topical steroid sparing options Signup and view all the answers

What is a common ocular condition associated with atopic dermatitis specifically?

Blepharitis Signup and view all the answers

What is the primary treatment option mentioned for severe dry eye disease (DED)?

All-trans retinoic acid ung from a compounding pharmacy Signup and view all the answers

What components are found in 20-50% Autologous Serum Tears (AST)?

Epidermal growth factors, Vitamin A, and Albumin Signup and view all the answers

What is the recommended dosing schedule for platelet-rich plasma eye drops?

4-6 times a day for 3 months Signup and view all the answers

Which cell type is primarily associated with Steven Johnson Syndrome (SJS)?

CD8 T cells Signup and view all the answers

What is a significant characteristic of Steven Johnson Syndrome?

Affects at least 2 mucus membranes Signup and view all the answers

What distinguishes platelet-rich plasma eye drops from serum tears?

Higher concentration of growth factors Signup and view all the answers

Which type of tubes are specified for blood draw to prepare autologous serum tears?

Red cap tubes Signup and view all the answers

What is the role of albumin in autologous serum tears?

Acts as a carrier protein Signup and view all the answers

Study Notes

Allergic Eye Disease

Affects up to 30% of the population
Seasonal and perennial
Bilateral
Conjunctival injection and chemosis, tearing, itching, eyelid swelling
Papillary reaction
Many patients self-medicate
Allergic shiners are caused by blood pooling
Atopy (eczema, hayfever, and asthma starting early in life)
Chronic with seasonal exacerbations and remissions
Improves around puberty
Itching, photophobia, blurred vision, copious mucoid discharge, ptosis, shield ulcer
Two main subtypes: palpebral, limbal, and mixed
Vernal Keratoconjunctivitis (VKC)
- Younger
- Males > females
- Limited duration; resolves at puberty
- Spring
- Upper tarsus
- Rare conjunctival cicatrization
- Shield ulcer, corneal scar, and rare corneal vascularization
Atopic Keratoconjunctivitis (AKC)
- Older
- No predilection
- Chronic
- Perennial
- Lower tarsus
- Common conjunctival cicatrization
- Persistent epithelial defects, common corneal scar, common corneal vascularization

Treatment Algorithm for Allergic Conjunctivitis

Mild: Symptoms without photophobia; Occasional topical antiallergic drop
Moderate: Symptoms with photophobia; Daily topical antiallergic drop + cold compress
Severe: Diffuse SPK and/or shield ulcer; Pulsed high-dose steroids
- Oral steroids 1 mg/kg/day x 3 days if severe
First-line:
- Oral antihistamine
- Nasal steroid
- Immunotherapy
- Other immunomodulator
- Topical ophthalmic steroids
- Topical ophthalmic dual-activity agents
Topical cyclosporine
Topical calcineurin inhibitor (tacrolimus)
Consider allergen avoidance and supportive measures.

Allergic Conjunctivitis Management

Avoid/eliminate allergens
Shower and change clothes after exposure
Identify contributing factors: contact lenses, dry eye, blepharitis
Supportive measures:
- Cold compresses
- Artificial tears
- Topical vasoconstrictors
- Topical antihistamines and mast-cell stabilizers
- NSAIDs
- Judicious use of corticosteroids

Clinical Grading of Vernal and Atopic Keratoconjunctivitis and Treatment

Grade 1 to 4: Signs/Symptoms range from mild to severe
Grade 1: Mild symptoms
Grade 2: Moderate symptoms
Grade 3: Severe, diffuse symptoms
Grade 4: Severe symptoms with complications
Treatment: depends on grade
- Mild to moderate: daily topical antiallergic drop, cold compress, cromolyn sodium QID, olopatadine QD-BID ,Tx1 +FML0.1% QD-BID
- Severe: pulsed high-dose steroids, oral corticosteroids

Vitamin A Deficiency

Partial night blindness is the 1st symptom
Xerophthalmia: corneal and conjunctival dryness
Can progress to corneal ulceration, perforation, and keratomalacia (severe wrinkling/opacification esp in children)
Vitamin A is required for goblet cell development
Deficiency leads to a thick mucin layer, keratin buildup (Bitot's spots), usually in temporal area

Infectious Conjunctivitis

Viral
- Adenovirus: most common cause of acute viral conjunctivitis (90%). Very contagious (respiratory and ocular secretions). Symptoms include: watery discharge, conjunctival hyperemia, irritation, itching, mild photophobia, contralateral involvement. 10-minute rapid test for Adeno hexon protein.
- Pharyngo-Conjunctival Fever: Adenovirus (serotypes 3, 4, & 7). Symptoms include: pharyngitis (sore throat, difficulty swallowing), follicular conjunctivitis, fever, mild epithelial keratitis (rarely subepithelial infiltrates), and preauricular lymphadenopathy (+PAN sometimes).
- Epidemic Keratoconjunctivitis (EKC): Adenovirus (serotypes 8, 19, and 37). Symptoms include: tearing, may be preceded by URI, FB sensation, bilateral follicular conjunctivitis, and punctate epithelial keratitis. Long-term complications are possible
- Acute Hemorrhagic Conjunctivitis: Picornavirus (enterovirus type 70, coxsackievirus A24). Common in densely populated tropical areas and in younger patients. Symptoms include sudden-onset pain, tearing, FB sensation, conjunctival injection, subconjunctival hemorrhage (SCH) which may be petechial.
Bacterial
- Causes: often infectious (duration < 3 weeks), immunologic, traumatic, or toxic
- Discharge subtypes: watery, mucoid, purulent/mucopurulent, hyperpurulent
- Papillae: allergies, topicals, irritation, bacteria
- Follicles: viruses, chlamydia, drugs, lymphoid disease
Chlamydial Conjunctivitis (Adult)
- Transmission: Auto-inoculation from genital secretions or eye-eye spread
- Can cause systemic complications like urethritis and dysuria, especially in females.
- Symptoms include watery mucopurulent discharge, preauricular lymphadenopathy, large follicles, perilimbal subepithelial K infiltrates, and pannus
Neonatal Conjunctivitis -Causes: bacterial, reflecting maternal vaginal flora. Gram-positive and gram-negative bacteria are common. -Risk factors: Maternal STIs, ruptured membranes, prolonged labor, prematurity
Gonococcal Conjunctivitis (Neonatal) -Transmission: sexual contact or vertical transmission -Symptoms are acute. Common symptoms include: thick, purulent discharge (often serosanguineous initially), lid edema, conjunctival chemosis, and small conjunctival hemorrhages -Gonococcal keratoconjunctivitis= Can lead to significant corneal involvement
Corynebacterium Conjunctivitis
- Bacteria, rare in developed countries -Causes systemic symptoms such as pseudomembranes (throat, nose) -May cause other systemic issues like cardiac arrhythmias and myocarditis -Treatment: Frequently resistant to FQs and emycin, so sensitivity testing is imperative. Possible treatment is cephalosporins or aminoglycosides.
Other
- Viral (mumps, herpes simplex): rare in the neonatal population; typically manifests within 1 or 2 weeks of birth.
- Bacterial (staphylococcal, streptococcal): rare in newborns but can develop with poor hygiene or if there are breaks in skin or mucus membranes
- Viral: (measles, haemorrhagic conjunctivitis)

Phlyctenulosis

Focal elevated nodule
Accompanied by engorged blood vessels
Type IV hypersensitivity reaction to microbial antigens (e.g., staphylococcal cell wall components)
Associated with tuberculosis
Primarily occurs in the perilimbal conjunctiva (near the limbus). It's mostly seen in children, but can appear elsewhere.
Initial appearance: small, subepithelial, often asymptomatic. Central portion can turn yellow or ulcerate.
Treatment: Topical steroids, often starting with low concentrations and gradually tapering down to a daily application. TB testing is important if TB is suspected. Maintenance therapy may involve topical cyclosporine or tacrolimus.

Pediatric Blepharokeratoconjunctivitis (BKC)

Average onset age: approximately 6 years old
More severe in Asian/Middle Eastern populations
Typically recurrent episodes of blepharitis, hordeola (styes), or chalazia (granulomas).
Usually unilateral or bilateral, involving one or more localized peripheral stromal infiltrates, separated from the limbus.
Conjunctival changes: phlyctens (small, elevated lesions), follicles or papillary hyperplasia
Corneal involvement: phlyctenulosis, punctate epithelial erosions/superficial punctate keratitis, and pannus.
Treatment: Topical steroids (short-term), cyclosporine, tacrolimus (compounded for use). Important to assess and treat any associated blepharitis with lid hygiene including warm compresses and cleaning as needed.

Phlyctenular Conjunctivitis (and Tuberculosis)

Recurrent fever and cough every 2 weeks for 3 months, possibly associated with abdominal TB; (+) PPD skin test (22 mm after 48 hrs)
Confirmation of active or latent TB necessary: sputum test for acid-fast bacilli (-) and chest radiograph (-).
Treatment: Rifampin, isoniazid, ethambutol, pyrazinamide for 2+ months and subsequently rifampin + isoniazid for another 4 months or until disease is resolved.

Infectious Infiltrates (Sterile vs. Infectious)

Infiltrates: large, central >2mm, and/or associated with stromal involvement/melting suggest infection.
Signs suggesting infection: pain, anterior chamber reaction (AC), mucopurulent discharge, epithelial defect.
Hypopyon: whitish-yellowish layer of WBCs, often associated with corneal ulceration and iritis. May be helpful for judging severity/effectiveness of therapy.

Corneal Ulcer (Culture & Collection)

When to Culture: central, large, or deep stromal involvement, chronic or unresponsive infection, history of corneal surgery, atypical features
Culture Techniques: Kimura spatula, blade, culturette swab, calcium alginate swab. Sterilize scraping tools.
Culture media: blood agar, chocolate agar, Sabouraud dextrose agar (for fungi), thioglycollate broth
Microscopy stains: Gram stain, Giemsa stain, Calcofluor white, acid-fast stain, Grocott-Gömöri methenamine silver, Periodic acid-Schiff (PAS)

Bacterial Keratitis (Subtypes & Treatment)

Common organisms: Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pneumoniae
Gram negative bacilli
- Pseudomonas aeruginosa—most common cause of contact-lens related corneal infections, with a tendency to form biofilms. Can create a “ground glass” appearance to the surrounding stroma. Antibiotic resistance common.
Gram positive cocci: Staphylococcus aureus, Streptococcus pneumoniae and Streptococcus viridians
Treatment: -4th gen FQs, topical antibiotics -If unresponsive, systemic agents such as oral antibiotics (doses vary per agent) and fortified antibiotic combos (Cefazolin 50 mg/mL + [Gentamycin OR Tobramcyin 14 mg/mL] q1h each, alternate every 30 minutes)

Atypical Mycobacterium (Non-TB)

Often slower to develop, may present as a lack of response to conventional antibiotic therapies
Diagnosis: acid-fast stain, culture on Löwenstein-Jensen medium
Treatment: empiric, broad-spectrum topical antibiotics (frequently using FQs, or aminoglycosides)

Fungal Keratitis

Clinical presentation: nonspecific to specific. Specific signs suggest fungal infection: feathery or filamentous margins, gray/white non-suppurative infiltrate, elevated infiltrate, multifocal or satellite lesions, or hypopyon.
Diagnosis: KOH wet mount; in vivo confocal microscopy (IVCM)
Common risk factors: CL wear, chronic ocular surface disease, chronic keratitis (HSV, HZ), corneal trauma, immunosuppression, topical corticosteroid use.
Treatment: early use of topical and systemic antifungals. (Amphotericin B 0.15%, Natamycin 5%, Topical Voriconazole 1%, Ketoconazole, Fluconazole or Itraconazole) Systemic antifungal agents for severe/recalcitrant infections: Voriconazole (200-400 mg/day), Posaconazole (800 mg/day)

Anterior Chamber Tap (Paracentesis)

Procedure: document VA & IOP first, administer anesthetic and antiseptic, insert 1/2 inch, 30-guage needle to the anterior chamber. Aspirate 0.1-0.2 mL. Allow culture time.
Used for endophthalmitis diagnosis.

Acanthamoeba Keratitis

Risk factors: soft contact lens wear, contaminated water or soil, trauma, immunosuppression.
Pathophysiology: Trophozoite form feeds on corneal cells.
Clinical findings: varies depending on stage: epithelial, subepithelial/anterior stromal, radial keratoneuritis, or hypopyon.
Treatment:
Biguanides (polyhexamethylene biguanide 0.02% and chlorhexidine 0.02%) every 1 to 2 hours for milder forms or when drug is available.
Diamidines (propamidine-isethionate) 0.1% every 1 to 2 hours. Taper down to every 4 hours as inflammation resolves.
Miltefosine (50 mg twice to three times per day), Voriconazole (systemic and 1% topical), systemic and topical antifungal agents (Natamycin, Miconazole, Ketoconazole, Itraconazole)
Mechanical debridement (for epithelial level) is sometimes needed.

Corneal Dystrophies

Overview: group of disorders that affect the cornea, often resulting in corneal opacity or visual problems. (EBMD):
- Symptoms: mild irritation to acute pain; on awakening, epiphora and redness occur. Can cause irregular astigmatism.
- Treatment: symptomatic relief, epithelial debridement, and diamond burr polish, or PTK.
Other dystrophies:
- Spheroidal degeneration
- Salzmann's nodular degeneration
- Crocodile shagreen
- White Limbal Girdle of Vogt
Treatment is variable, and dependent on individual needs. This may include topical lubrication in earlier stages. Consider topical steroids in inflammatory episodes, but avoid in cases of risk of recurrence.

Keratoplasty (General)

Indications: vision improvement, restoration of corneal integrity, therapeutic treatment of infection, or cosmetic needs
Donor tissue: evaluated and screened for potential viability.
Recipient factors: should be evaluated to assess health of ocular surface (eyelid, conjunctiva, tear film), inflammation, glaucoma, and other systemic factors.

Keratoplasty (Specific Subtypes)

Penetrating keratoplasty (PK): comprehensive replacement of the corneal tissue
Partial-thickness keratoplasty: anterior lamellar keratoplasty (ALK), deep anterior lamellar keratoplasty (DALK), Descemet stripping endothelial keratoplasty (DSEK), Descemet membrane endothelial keratoplasty (DMEK)

Neurotrophic Keratitis/Keratopathy

Reduced corneal sensation — associated with reduced or absent corneal innervation, commonly seen with HSV keratitis, HZ keratitis, or other neurological diseases or surgical ablation.
Treatment: taping of lids (nighttime), lubricative eye drops, amniotic membrane patching, or in some cases, tarsorraphies (suturing the eyelids).

Mooren's Ulcer

Progressive stromal ulceration and thinning of the peripheral cornea associated with significant inflammation (benign type vs. aggressive type).
Treatment: Topical steroids, topical antibiotics, and/or systemic immunosuppressants as indicated

Peripheral Ulcerative Keratitis (PUK)

Progressive stromal ulceration and thinning of the peripheral cornea linked to systemic autoimmune conditions like Rheumatoid Arthritis, Granulomatosis with polyangiitis, or Systemic lupus erythematosus
Treatment: Topical and sometimes systemic steroids and/or immunosuppressants.

Corneal Verticillata (and Fabry Disease)

Golden-brown, whorled epithelial opacities.
Can be associated with Fabry disease, a systemic disorder.
Treat by discontinuing potentially causative pharmaceutical agents (e.g., quinolones, amiodarone).

Miscellaneous Conditions of the Cornea

Arcus senilis: bilateral, white ring in peripheral cornea due to lipid deposition in elderly individuals. No treatment necessary unless cholesterol or other lipid issues need managing.
Band keratopathy: chalky or band-like, calcified deposits in the anterior stroma associated with diverse systemic disorders or ocular conditions. Treatment is dependent on underlying cause
Cornea verticillata: fine, golden-brown, irregular, horizontal lines/opacities in the inferior and paracentral cornea Treatment required only if attributed to systemic medications/diseases. If corneal verticillata is secondary to Fabry disease, a multidisciplinary approach including genetic testing, cardiac evaluation, and kidney function evaluation is required.

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Test your knowledge on the types of bacteria linked to contact lens-related keratitis, the recommended dosage of Azithromycin for treatment, and the mechanisms that enhance bacterial resistance. This quiz will challenge your understanding of bacterial infections and their management.