Week 1 - G - Microbiology of eye infections Flashcards

1
Q

Give an example of a gram negative cocci?

A

Neisseria meningitidis or gonorrhoeae

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2
Q

What is inflammation of the conjunctivae known as? What is inflammation of the cornea known as?

A

Conjunctivae - conjunctivitis

Cornea - keratitis

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3
Q

What is inflammation of the aqueous and vitreous humour known as?

A

Endopthalmitis

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4
Q

Bacterial conjunctivits presents with redness of the eye and pus usually What are bacterial causes of conjunctivitis in neonates? (remmeber can get STDs in neonates through mother to infant trasmisission)

A

Staph aureus

Neisseria gonorrhoeae

Chlamydia trachomatis

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5
Q

In all other ages, bacterial conjunctivits is usually caused by staph aureus or strep pneumonia or ? The third cause is especially common in chidlren

A

Haemophilus influenza

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6
Q

Child wakes up with eye glued shut The eye is red and itchy and there is a pus like substance leaking What is this?

A

Bacterial conjunctivits

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7
Q

What is the treatment of bacterial conjunctivits? (not including chlamydia trochamtis)

A

Bathe / clean the eyelids regularly to remove crusting

Second line - Treat with swab and then chloramphenical eye drops usually 4 times daily

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8
Q

Where should chloramphenical be stored after use? Chloramphenicol should be avoided in patients with allergy What should be suspected if patient complains of worsening symtpoms?

A

Should be stored in fridge

Worsening symptoms with worsening itchiness may be due to a chloramphenical allergy

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9
Q

What gram negative bacilli does chloramphenical not cover?

A

Does not cover pseudomonas arguinosa

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10
Q

Viral conjunctivitis usually follows a history of URTI – usually presents with bilateral eye watering What is the most common viral cause of viral conjunctivits?

A

Viral adenovirus - usually starts in one eye and then spreads but lasts around 2 weeks

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11
Q

What are the symptoms of a viral conjunctivirs?

A

Presents with a watery discharge and swelling of the conjunctivae

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12
Q

What is another viral cause of viral conjunctivits and can present with a sign on the tip of the nose? What is this sign known as?

A

Herpes zoster

Sign on tip of nose is the Hutchison sign which means the eye has been affected as the tip of the nose is supplied by the nasociliary nerve which is a branch of the opthalmic nerve

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13
Q

In a patient with herpes zoster - Herpes zoster is infection that results when varicella-zoster virus reactivates from its latent state in a posterior dorsal root ganglion. What should you start the patient on?

A

Start the patient on oral acyclovir

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14
Q

What can occur long after the shingles disappeared causing a burning pain ?

A

Post-herpetic neuralgia - there is no cure

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15
Q

What is suspect in bilateral conjunctivitis in young adults ?

A

CHlamydia trachomatis causing chlamydial conjunctivitis

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16
Q

In adults with chlamydial conjunctivits, where else can they complain of having a pain?

A

Burning sensation, stinging pain while urinating (observed in both men & women); watery discharge from vagina

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17
Q

What is keratitis?

A

Inflammation of the cornea of the eye

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18
Q

What is the small transparent canal running through the vitreous gel from the optic nerve to the lens? If infection in the cornea spreads in this it can infect the whole eye

A

Hyaloid canal - Cloquets canal

19
Q

Bacterial keratitis can cause the accumulation of inflammatory mediators in the anterior chamber of the eye, appears as a white exudate What is this known as?

A

Hypopyon

20
Q

People who wear contact lenses are more likely to get keratitis What bacteria is common in people who wear contact lens as they live in the solution the contact lens is stored in?

A

Pseudomonas aerguinosa

21
Q

What is the treatment of the psuedomonas aerguinosa bacteria causing keratitis?

A

Fluoroquinolone - eg oflaxacin, levoflaxacin

22
Q

When giving eye drops for bacterial keratitis, an eye scraping is taken and eye drops are then given Which eye drops are given t cover most organism before the scraping culture comes back?

A

Give flouroqinolone (eg oflaxacin) every one hour for 48 hours

23
Q

What is a dendritic ulcer the most common sign off? Dendritic meaning branch

A

Most common sign of herpetic keratitis - herpetic keratitis is due to HSV

24
Q

Herpetic keratitis is Very painful Can be recurrent recurrences eventually result in reduced corneal sensation What is it treated with? and what should be avoided in treatment?

A

Treated with topical acyclovir

Avoid treatment with steroids as can cause a corneal melt which can lead to perforation and more infection

25
Q

Orbital cellulitis can have pain on eye movements What does the orbital septum lie in front? What is orbital cellulitis often associated with?

A

Orbital septum lies in front of the tarsal plates of the eye

Is associated with paranasal sinusitis

26
Q

What colour is the eyelid in orbital cellulits? What can happen if left untreated? What is the common bacterial cause of orbital cellulitis in children?

A

Eyelid is left red/purple

Can cause blindness, compartment syndrome due to swelling

Common cause in children is H.influenza

27
Q

Orbital cellulitis as said is usually due to Hinfluenza, what other organsims can cause it?

A

Can be caused by staph aureus and strep pneumoniae

28
Q

What is a coliform? Give an example?

A

Gram negative bacilli

Example is Ecoli or klebsiella pneumoniae

29
Q

Devastating infection inside of the eye Very very painful with decreasing sight Usually due to surgery of the eye eg cataracts What is this known as?

A

Endopthalmitiis - treat with injection antibiotics into the eye

30
Q

What commensal is the most common cause of endopthalmitis?

A

Staph epidermis

31
Q

What is the treatment of antibiotics for endopthalmitis?

A

Intravitreal Vancomycin + Amikacin or

Intraviteral Vancomycin + Ceftazidime

32
Q

What type of antibiotic is amikacin? What type of antibiotic is ceftazidime?

A

It is an aminoglycoside

It is a cephalosporin

33
Q

Chorioretinitis is an inflammation of the choroid (thin pigmented vascular coat of the eye) and retina of the eye. Can be caused in AIDS due to cytomegalovrius What is the treatment of CMV?

A

Ganciclovir

34
Q

How are eye infections dianosed? (eg bacterial, viral, chlamydial and corneal)

A

Use swabs for all eye infections apart from keratitis in which you use corneal scrapings

35
Q

What eye infection can acanthomoeba cause? What should you tell the patient to bring with if this is the case of the scraping?

A

Seen in fungal causing keratitis

Tell patient to bring their contact lenses with them

36
Q

Chloramphenical is the most commonly used topical antibiotic for eye infection (ointment or drops) as it treats most bacteria except Pseudomonas aeruginosa For which bacteria is it bacteriostatic or bacteriocidal Staph aureus? H.Influenza? Strep?

A

Strep and Hinfluenza - is bacteriocidal

Staph aureus is bacteriostatic

37
Q

What are the three main side effects of chloramphenicol? One is in babies

A

Can cause allergy

Aplastic anaemia

And grey baby syndrome

38
Q

Aplastic anemia is a rare disease in which the bone marrow and the hematopoietic stem cells that reside there are damaged. This causes a deficiency of all three blood cell types (pancytopenia) What are the three blood cell losses then?

A

Red blood cell - anaemia

White blood cell - leukopaenia

Platelets - thrombocytopaenia

39
Q

Gray baby syndrome (also termed Gray or Grey syndrome) is a rare but serious side effect that occurs in newborn infants (especially premature babies) following the accumulation of antibiotic chloramphenicol.

A

https://s3.amazonaws.com/classconnection/403/flashcards/11907403/jpg/picture1-15A488E734E59594EAB.jpg

40
Q

What is used for dendritic ulcer treatment? What is the different in strength between this treatment and the one for skin?

A

Acyclovir is used 3% strength for eye 5% strength for skin

41
Q

Due to chloramphenicol bein bacteriostatic in staph aureus, what is used to treat this if staph aureus causes bacterial conjunctivits?

A

Fusidic acid is given

42
Q

What treatmen can be given to cover most gram negative organsism incuding coliforms?

A

Gentamicin

43
Q

What drug is given to treat Chlamydial conjunctivitis? What may adults also need in conjucntion with this for genital chlamydial infection?

A

Give topical oxytetracylcine for Chlamydial conjunctivitis

Give oral doxycycline in adults for the genital chlamydial infection

44
Q

A fluoroquinolone will cover most gram negative bacteria including pseudomonas and is used in treating bacterial keratitis What is the alternative treatment option used to treat bacterial keratitis and covers most gram positive and negative bacteria?

A

Gentamicin + cefuroxime