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Questions and Answers
Which of the following is NOT a symptom of conjunctivitis?
Which of the following is NOT a symptom of conjunctivitis?
Which microorganism is associated with Gram-positive conjunctivitis?
Which microorganism is associated with Gram-positive conjunctivitis?
Conjunctival scrapings are NOT collected using which of the following?
Conjunctival scrapings are NOT collected using which of the following?
Which stain is commonly used in laboratory diagnosis of conjunctivitis?
Which stain is commonly used in laboratory diagnosis of conjunctivitis?
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Which of the following is a rare cause of conjunctivitis?
Which of the following is a rare cause of conjunctivitis?
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What percentage of office visits to ophthalmologists is constituted by red eye?
What percentage of office visits to ophthalmologists is constituted by red eye?
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Which type of conjunctivitis is usually unilateral?
Which type of conjunctivitis is usually unilateral?
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Which of the following is a Gram-negative bacterium that can cause conjunctivitis?
Which of the following is a Gram-negative bacterium that can cause conjunctivitis?
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Which of the following is a common bacterial isolate found in blepharitis?
Which of the following is a common bacterial isolate found in blepharitis?
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Which of the following bacteria are part of Enterobacteriaceae and can cause conjunctivitis?
Which of the following bacteria are part of Enterobacteriaceae and can cause conjunctivitis?
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What type of discharge is commonly associated with viral conjunctivitis?
What type of discharge is commonly associated with viral conjunctivitis?
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What is the preferred treatment for allergic conjunctivitis?
What is the preferred treatment for allergic conjunctivitis?
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Which microorganism is most frequently isolated from the lid margins in blepharitis?
Which microorganism is most frequently isolated from the lid margins in blepharitis?
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Which type of conjunctivitis typically presents bilaterally?
Which type of conjunctivitis typically presents bilaterally?
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Which microorganism is associated with viral blepharitis?
Which microorganism is associated with viral blepharitis?
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What is the main characteristic of discharge in bacterial conjunctivitis?
What is the main characteristic of discharge in bacterial conjunctivitis?
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Which type of agar is most appropriate for cultivating most bacterial and fungal ocular isolates?
Which type of agar is most appropriate for cultivating most bacterial and fungal ocular isolates?
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What is the preferred temperature range for incubating bacterial and fungal ocular isolates?
What is the preferred temperature range for incubating bacterial and fungal ocular isolates?
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Which molecular technique is ideal for detecting microbes in ocular samples that involve small volumes?
Which molecular technique is ideal for detecting microbes in ocular samples that involve small volumes?
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How long are thioglycollate tubes held if Actinomyces spp. or P. acnes is suspected?
How long are thioglycollate tubes held if Actinomyces spp. or P. acnes is suspected?
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Which staining technique is used for microexamination in cases of keratitis?
Which staining technique is used for microexamination in cases of keratitis?
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What transport media is recommended for transporting eye swab specimens?
What transport media is recommended for transporting eye swab specimens?
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What additional media is suggested if a fungus is suspected in ocular samples?
What additional media is suggested if a fungus is suspected in ocular samples?
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Which type of agar should be used for routine culture when Enterobacteriaceae is suspected?
Which type of agar should be used for routine culture when Enterobacteriaceae is suspected?
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What is microbial keratitis?
What is microbial keratitis?
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Which of the following is not a predisposing factor for microbial keratitis?
Which of the following is not a predisposing factor for microbial keratitis?
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Which of the following organisms is a common cause of microbial keratitis?
Which of the following organisms is a common cause of microbial keratitis?
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What is the risk if microbial keratitis is not promptly treated?
What is the risk if microbial keratitis is not promptly treated?
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Which condition can microbial keratitis progress to if inappropriately treated?
Which condition can microbial keratitis progress to if inappropriately treated?
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What organism is a common cause of canaliculitis?
What organism is a common cause of canaliculitis?
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What are the typical causes of canaliculitis?
What are the typical causes of canaliculitis?
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Which of the following is correct regarding the treatment of canaliculitis?
Which of the following is correct regarding the treatment of canaliculitis?
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What component in tears protects the eye from infection by removing bacteria and debris?
What component in tears protects the eye from infection by removing bacteria and debris?
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Which age group is more frequently affected by acute bacterial and viral conjunctivitis?
Which age group is more frequently affected by acute bacterial and viral conjunctivitis?
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Which of the following organisms can penetrate the intact epithelium of the conjunctiva or cornea?
Which of the following organisms can penetrate the intact epithelium of the conjunctiva or cornea?
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What is the role of lactoferrin in tears?
What is the role of lactoferrin in tears?
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What are the two main functions of the lacrimal apparatus?
What are the two main functions of the lacrimal apparatus?
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Which risk factor is NOT associated with ocular infections?
Which risk factor is NOT associated with ocular infections?
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Which of the following is NOT a common cause of disorders and infections of the lacrimal apparatus?
Which of the following is NOT a common cause of disorders and infections of the lacrimal apparatus?
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In what population does chronic conjunctivitis and varicella-zoster virus (VZV) conjunctivitis occur most frequently?
In what population does chronic conjunctivitis and varicella-zoster virus (VZV) conjunctivitis occur most frequently?
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Which microorganism is NOT commonly associated with lacrimal apparatus infections?
Which microorganism is NOT commonly associated with lacrimal apparatus infections?
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Which bacteria are part of the normal flora (NF) recovered from uninflamed eyes?
Which bacteria are part of the normal flora (NF) recovered from uninflamed eyes?
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Dacryoadenitis refers to inflammation of which part of the lacrimal apparatus?
Dacryoadenitis refers to inflammation of which part of the lacrimal apparatus?
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Women are more likely than men to be associated with which ocular disease?
Women are more likely than men to be associated with which ocular disease?
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Which of these viruses is associated with lacrimal apparatus infections?
Which of these viruses is associated with lacrimal apparatus infections?
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Which parasite is linked to infections of the lacrimal apparatus?
Which parasite is linked to infections of the lacrimal apparatus?
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Which organisms are primarily responsible for the majority of intraocular and corneal infections?
Which organisms are primarily responsible for the majority of intraocular and corneal infections?
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What is a common predisposing factor for ocular infections caused by indigenous flora?
What is a common predisposing factor for ocular infections caused by indigenous flora?
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Which microorganism has the highest variability in incidence as an ocular resident flora from non-inflamed eyes?
Which microorganism has the highest variability in incidence as an ocular resident flora from non-inflamed eyes?
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Which type of microorganism can persist in ocular tissue or biomaterials in a biofilm?
Which type of microorganism can persist in ocular tissue or biomaterials in a biofilm?
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What is one way that the intact epithelium of the eye can be breached, leading to an increased risk of infection?
What is one way that the intact epithelium of the eye can be breached, leading to an increased risk of infection?
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Which anatomical part of the eye is specifically mentioned as a common source of microbial organisms?
Which anatomical part of the eye is specifically mentioned as a common source of microbial organisms?
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Study Notes
Infections of the Conjunctiva (Conjunctivitis)
- Conjunctivitis is the most common ocular complaint, affecting all age groups worldwide.
- Symptoms include itching, tearing, foreign body sensation, discharge, and hyperemia (red or pink eye).
- Red eye constitutes more than 50% of office visits to ophthalmologists and is the most common ocular source for microbiologic evaluation.
Microorganisms Associated with Conjunctivitis
- Gram-negative bacteria:
- Acinetobacter spp., Borrelia burgdorferi, Enterobacteriaceae (e.g., Escherichia coli, Proteus mirabilis, Shigella spp.)
- Haemophilus influenza, Haemophilus ducreyi, Moraxella catarrhalis, Moraxella lacunata, Neisseria gonorrhoeae, Neisseria meningitides, Pseudomonas aeruginosa
- Gram-positive bacteria:
- β-Hemolytic streptococci (A, B, C, G), Corynebacterium diphtheriae, Corynebacterium spp., Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Viridans Streptococci
- Viruses:
- Human coronavirus, Herpesviruses (1 to 8), Chlamydia and related spp. (Chlamydophila pneumoniae, Chlamydia psittaci, Chlamydia trachomatis)
- Fungi (rare):
- Candida spp.
- Parasites (rare):
- Ascaris lumbricoides
Laboratory Diagnosis
- Laboratory tests help differentiate acute, allergic, and chronic conjunctivitis.
- Conjunctival scrapings are collected using a spatula, blade, or sterile swabs.
- Samples are plated directly onto slides and culture media.
- Routine stains (Gram, Giemsa) and culture should reveal the etiologic agent in most acute cases.
Infections of the Lids (Blepharitis)
- Blepharitis is the inflammation of the lid margins.
- It is not mutually exclusive with conjunctivitis, and any organism that causes conjunctivitis can affect the lids.
- The skin covering the lids is among the thinnest on the body, making it susceptible to skin infections.
- Staphylococcus aureus and coagulase-negative staphylococci are the most frequently isolated bacteria from the lid margins.
Microorganisms Associated with Blepharitis
- Bacteria:
- Common isolates: Staphylococcus aureus, Staphylococcus epidermidis, and other coagulase-negative staphylococci
- Less common isolates: Group A and other ß-streptococci, Moraxella lacunata, Moraxella spp.
- Fungi (rare):
- Candida spp., Cryptococcus neoformans
- Viruses:
- Herpes simplex virus types 1 and 2
Infections of the Cornea (Keratitis)
- Microbial keratitis is an infection of the cornea and is considered a true ocular emergency.
- Few organisms can invade the intact cornea, but if the cornea epithelium is breached, organisms can enter and cause infections.
- Predisposing factors include contact lens wear, pre-existing ocular disease, ocular trauma, ocular surgery, and laser refractive surgery.
Microorganisms Associated with Keratitis
- Bacteria:
- Staphylococci, Streptococci, Pseudomonads, Enterobacteriaceae, Corynebacterium species, Moraxella species, Serratia species, Haemophilus
- Fungi:
- Aspergillus species, Candida species
- Parasites:
- Propionbacterium species
Canaliculitis (TEHAB ALQNIAT ALDMUEIA)
- Canaliculitis is a rare infection of the lacrimal canaliculus.
- Infections are usually chronic and caused by anaerobic Actinomycetes such as Actinomyces israelii or by Propionibacterium propionicum.
- Swabs of samples of the canalicular pus are preferable.
Infections of the Lacrimal Apparatus
- The lacrimal glands, accessory glands, puncta, canaliculi, tear sac, and nasolacrimal duct together are known as the lacrimal apparatus.
- Disorders and infections of the lacrimal apparatus are caused by blockage, underproduction, or overproduction of tears.
- Organisms are seeded into the gland via the bloodstream.
Microorganisms Associated with Lacrimal Apparatus Infections
- Bacteria:
- Staphylococcus aureus, Streptococcus pneumonia, Streptococcus pyogenes, Haemophilus influenzae, Pseudomonas aeruginosa, Proteus mirabilis, Chlamydia trachomatis, Treponema pallidum
- Viruses:
- Coxsackie A virus, Cytomegalovirus, Echovirus, Epstein-Barr virus, Herpes simplex virus types 1 and 2
- Fungi:
- Aspergillus spp., Candida albicans, Rhizopus spp., Mucor
- Parasites:
- Cysticercus cellulosae, Onchocerca volvulus, Schistosoma haematobium
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Description
Learn about conjunctivitis, a common ocular complaint that can affect people of all ages worldwide, causing symptoms like itching, tearing, and redness. Test your knowledge of this eye infection and its causes.
