Acanthamoeba keratitis

ACANTHAMOEBA KERATITIS

Q. 1

A 17 year old girl with keratitis and severe pain in the eye came to the hospital and acanthamoeba keratitis was suspected. The patient gave the history of following 4 points. Out of these which is not a risk factor for acanthamoeba keratitis.

 A

Extended wear contact lens.

 B

Exposure to dirty water.

 C

Corneal trauma

 D

Squamous blepharitis

Q. 1

A 17 year old girl with keratitis and severe pain in the eye came to the hospital and acanthamoeba keratitis was suspected. The patient gave the history of following 4 points. Out of these which is not a risk factor for acanthamoeba keratitis.

 A

Extended wear contact lens.

 B

Exposure to dirty water.

 C

Corneal trauma

 D

Squamous blepharitis

Ans. D

Explanation:

D i.e. Squamous blepharitis


Q. 2

Acanthamoeba keratitis is:   

March 2012

 A

Allergic reaction to tuberculoprotein

 B

Seen in contact lenses users

 C

Lesion of herpes zoster

 D

Seen in congenital syphilis

Q. 2

Acanthamoeba keratitis is:   

March 2012

 A

Allergic reaction to tuberculoprotein

 B

Seen in contact lenses users

 C

Lesion of herpes zoster

 D

Seen in congenital syphilis

Ans. B

Explanation:

Ans: B i.e. Seen in contact lenses users

Keratitis

  • Phylctenular keratitis is an allergic reaction to an endogenous allergen, commonly tuberculoprotein
  • Acanthamoebic keratitis occurrence is frequently associated with wearing of soft contact lenses. It has also been seen to occur in non-contact lens wearers & may be related to swimming or bathing in contaminated water
  • Larger discoid lesions of herpes zoster are known as ‘nummular’ keratitis
  • Interstitial keratitis due to inherited syphilis most commonly affects children between the ages of 5 & 15 years

Q. 3

Which of the following statement is true regarding Acanthamoeba keratitis:   

September 2012

 A

For the isolation of the causative agent, corneal scraping should be cultured on a nutrient agar plate

 B

The causative agent, Acanthamoeba is a helminth whose normal habitat is soil

 C

Keratitis due to Acanthamoeba is NOT seen in the immunocompromised patient

 D

Acanthamoeba does NOT depend upon a human host for the completion of its life-cycle

Q. 3

Which of the following statement is true regarding Acanthamoeba keratitis:   

September 2012

 A

For the isolation of the causative agent, corneal scraping should be cultured on a nutrient agar plate

 B

The causative agent, Acanthamoeba is a helminth whose normal habitat is soil

 C

Keratitis due to Acanthamoeba is NOT seen in the immunocompromised patient

 D

Acanthamoeba does NOT depend upon a human host for the completion of its life-cycle

Ans. D

Explanation:

Ans. D i.e. Acanthamoeba does NOT depend upon a human host for the completion of its life-cycle


Q. 4

A regular contact lens user presents with complaints of severe pain, redness, photophobia & blurring of vision for more than two weeks not responding to standard treatment. on examination, a paracentral ring shaped lesion with stromal infiltrates & overlying epithelial defects is observed in the affected eye. Which of the following is the most likely diagnosis-

 A

Bacterial keratitis 

 B

Acanthamoeba keratitis

 C

Viral keratitis

 D

Fungal keratitis

Q. 4

A regular contact lens user presents with complaints of severe pain, redness, photophobia & blurring of vision for more than two weeks not responding to standard treatment. on examination, a paracentral ring shaped lesion with stromal infiltrates & overlying epithelial defects is observed in the affected eye. Which of the following is the most likely diagnosis-

 A

Bacterial keratitis 

 B

Acanthamoeba keratitis

 C

Viral keratitis

 D

Fungal keratitis

Ans. B

Explanation:

The presence of paracentral ring shaped corneal infiltrates in association with use of contact lenses & absence of response to standard treatment strongly suggests a diagnosis of Acanthamoeba keratitis (Protozoal keratitis)


Q. 5

A soft contact lens wearer developed pain & itching of the eye & showed a reticular pattern on the corneal epithelium the cause could be:

 A

Corneal dystrophy

 B

Acanthamoeba

 C

Pseudomonas

 D

Recurrent

Q. 5

A soft contact lens wearer developed pain & itching of the eye & showed a reticular pattern on the corneal epithelium the cause could be:

 A

Corneal dystrophy

 B

Acanthamoeba

 C

Pseudomonas

 D

Recurrent

Ans. B

Explanation:

  • Typical reticular pattern due to radial keratoneuritis (Radial perineuritis).
  • Due to this, the pain is very severe (neurological due to perineuritis) which is out of proportion to the degree of inflammation.
  • Later, reticular superficial keratitis advanced to ring-shaped lesion in central or paracentral region.

Q. 6

A patient using contact lens develops corneal infection. Laboratory diagnosis of acanthamoeba keratitis was established.The following is the best drug for treatment-

 A

Propamide

 B

Neosporine

 C

Ketoconazole

 D

Polyhexamethylene biguanide

Q. 6

A patient using contact lens develops corneal infection. Laboratory diagnosis of acanthamoeba keratitis was established.The following is the best drug for treatment-

 A

Propamide

 B

Neosporine

 C

Ketoconazole

 D

Polyhexamethylene biguanide

Ans. D

Explanation:

Polyhexamethylene biguanide PHMB (Drug of choice)

Chlorhexidine is an alternative



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