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SYMPOSIUM
Year : 2008  |  Volume : 56  |  Issue : 3  |  Page : 221-222

First aid for complications of infectious keratitis


Clear Vision Eye Center, Santacruz (W), Mumbai - 400 054, Maharashtra, India

Date of Submission04-Sep-2007
Date of Acceptance14-Jan-2008
Date of Web Publication22-Apr-2008

Correspondence Address:
Vinaykumar Agrawal
Clear Vision Eye Center, 1A, Ashoka, 15, S.V.Road, Santacruz (W), Mumbai - 400 054, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0301-4738.40361

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  Abstract 

Infectious keratitis is a fairly common entity in India. However while paying attention to the primary entity, the associated events may be overlooked. Enhanced pain usually suggests a worsening of the condition or development of associated problems like secondary glaucoma. However, contrary to logic, a sudden decrease in pain is also liley to suggest a worsening, e.g. perforation of the corneal ulcer. Various such problems with their management are outlined.

Keywords: Complications, emergency, infectious keratitis


How to cite this article:
Agrawal V. First aid for complications of infectious keratitis. Indian J Ophthalmol 2008;56:221-2

How to cite this URL:
Agrawal V. First aid for complications of infectious keratitis. Indian J Ophthalmol [serial online] 2008 [cited 2020 Apr 7];56:221-2. Available from: http://www.ijo.in/text.asp?2008/56/3/221/40361

A patient with corneal ulcer will usually be monitored for his primary condition. However, there are certain signs that the clinician should be aware and watch out for. These are findings that would usually denote a change in the status, usually for the worse. The problems that we frequently encounter are:

  1. Pain - sudden increase and decrease
  2. Corneal thinning/melting
  3. Severe anterior chamber reaction
  4. Sudden increase in the ocular surface reaction despite medications



  Pain Top


This is a normal protective mechanism associated with any lesion anywhere in the body. The corneal ulcer is no exception. Usually the patients complain of a localized pain in the ocular area of the affected cornea. This is due to the ciliary spasm secondary to the corneal neuronal reflex arc. Ciliary spasm can be effectively relieved by use of cycloplegics such as homatropine eye drops. In addition, the pain is usually well controlled once the topical medication brings the corneal infiltrates under control.

Secondary glaucoma

However, if a patient complains of a sudden or severe increase in pain, one needs to consider secondary glaucoma. This is usually due to the secondary changes in the anterior chamber. They include hypopyon and exudates on the endothelial surfaces causing a block of the trabecular meshwork or secondary trabeculitis in some cases of viral keratitis.

Secondary glaucoma needs aggressive medical management in the form of topical beta blockers and carbonic anhydrase inhibitors (dorzolamide) with or without systemic carbonic anhydrase inhibitors (acetazolamide). We prefer systemic carbonic anhydrase inhibitors due to the potential toxicity of topical inhibitors to the damaged corneal endothelium. [1]

Perforation

Sudden reduction of pain in a patient with an active uncontrolled keratitis should be looked upon with suspicion rather than relief. Many a times due to the extensive exudation and/or accumulation of the medications (especially antifungal), the underlying wound is hidden. This can lead to a false sense of security and the underlying thinning may be missed. A micro-perforation in the area of the corneal ulcer can lead to natural drainage of the aqueous and relieve the intraocular pressure. This will relieve the pain induced by the secondary glaucoma. However, the collapse of the anterior chamber will lead to the formation of an adherent leukoma as well as closure of the angle of the anterior chamber. This will lead to irreversible secondary angle closure glaucoma with poor chances of visual rehabilitation. Perforations larger than 2 mm also have a significant risk of choroidal detachment. [2]


  Corneal Thinning Top


The most common effect of a microbial infection of the cornea is the necrotic changes of the stromal fibers. This is due to the various actions of the microbe. It can be the direct action of the microbe in breakdown of the stromal fibers. It can be indirect action due to the endotoxins released due to the destruction of the microbial cell wall by the antibiotics or the body defense mechanisms. It can also be due to autolysis induced by various human enzymes like matrix metalloproteinase's (MMPs) that are released due to an uncontrolled activation of the tissue destruction mechanisms. [3],[4]

The end result of all these mechanisms is the necrosis of the tissue in the infected area. If this is seen only due to the direct action of the microbes, then the control of the infection will limit the thinning. Thus, a regular watch on the corneal ulcer (we usually recommend a follow-up visit at least 48 h apart in ulcers < 3 mm and every 24 h in larger ulcers) is necessary to prevent such mishaps (V Agrawal, unpublished data).

In infections due to Gram-negative bacteria such as pseudomonas , the risk of rapid corneal melt is unusually high. These patients need to be seen as frequently as twice a day till the ulcer begins to heal.

The reason to watch for a corneal melt is that an early melt may respond to treatment and advanced melt is unlikely to respond well (V Agrawal, unpublished data).

In case of early melt, use of topical and systemic tetracycline is believed to help. [5],[6] In addition, the use of tissue glue and bandage contact lens can also be useful. If the perforation is larger than 2 mm, then the use of tissue glue is unlikely to be adequate. We have successfully used preserved amniotic membrane as a multilayered application with tissue glue at the wound edges to close such wounds. This is a modification of the method of Hick et al . [7] Amniotic membrane also has anti-collagenolytic properties and may help in stabilizing the ocular surface.

Perforations larger than 4 mm and up to 6 mm may need a corneal patch graft to close the fistula. The important point in these cases is to avoid undersizing the graft. The wound edges of a melting area are also likely to be weak. This can lead to cheese wiring of the sutures and wound leaks.

Total corneal melts have been managed with sclerokeratoplasty with guarded results. [8]

In summary, corneal melts are best avoided by rigorous observation and aggressive medical management.


  Severe Anterior Chamber Reaction Top


In severe fungal infection, the descemet's membrane can fail to limit the infection to the corneal stroma. Alternatively, the severe anterior chamber reaction secondary to the toxic effects of the microbe can lead to a complete organized hypopyon formation in the anterior chamber. The use of cycloplegics has been advocated but in our experience it may not be adequate. In such cases, we have used the concept of anterior chamber lavage to debulk the chamber and also reduce the infectious load to help the medications act better. Along with the lavage with Ringer's lactate, there may be a need to remove the organized fibrinoid material from the chamber. The use of a suitable antibiotic or antifungal agent in the lavage fluid is acceptable. [9]


  Ocular Surface Condition Top


Many a times one sees that the corneal ulcer is responding to the medications for first 24-48 h. After this period, the eye becomes significantly redder, there is lid edema and the conjunctival surface too starts to stain with fluorescein. This may be a sign of spreading infection. However, it is more likely to either be an allergic reaction to one of the medications being used or the occurrence due to keratitis medicamentosa. This is differentiated from spreading infection by the fact that the primary lesion size remains constant or shows improvement despite all the adnexal changes.

 
  References Top

1.
Konowal A, Morrison JC, Brown SV, Cooke DL, Maguire LJ, Verdier DV, et al . Irreversible corneal decompensation in patients treated with topical dorzolamide. Am J Ophthalmol 1999;127:403-6.  Back to cited text no. 1
[PUBMED]  [FULLTEXT]  
2.
Singh R, Umapathy T, Abedin A, Eatamadi H, Maharajan S, Dua HS. Choroidal detachment in perforated corneal ulcers. Br J Ophthalmol 2006;90:1111-4.  Back to cited text no. 2
[PUBMED]  [FULLTEXT]  
3.
Mitchell BM, Wu TG, Chong EM, Pate JC, Wilhelmus KR. Expression of matrix metalloproteinases 2 and 9 in experimental corneal injury and fungal keratitis. Cornea 2007;26:589-93.  Back to cited text no. 3
[PUBMED]  [FULLTEXT]  
4.
McChellan SA, Huang X, Burrett RP, Lighwani S, Zhang Y, Riechiert D, et al . Matrix mettaloproteinase 9 amplifies the immune response to pseudomonas aeruginosa corneal infection. Invest Ophthalmol Vis Sci 2006;47:256-64.  Back to cited text no. 4
    
5.
Smith VA, Cook SD. Doxycycline: A role in ocular surface repair. Br J Ophthlamol 2004;88:619-25.  Back to cited text no. 5
    
6.
McEvanney AM. Doxycycline in the management of pseudomonas corneal melting: Two cases and review of literature. Eye Contact Lens 2003;29:258-61.  Back to cited text no. 6
    
7.
Hick S, Demers PE, Brunette I, La C, Mabon M, Duchesne B. Amniotic membrane transplantation and fibrin glue in the management of corneal ulcers and perforations: A review of 33 cases. Cornea 2005;24:369-77.  Back to cited text no. 7
[PUBMED]  [FULLTEXT]  
8.
Jonas JB, Rant RM, Budde WM. Tectonic sclerokeratoplasty and tectonic penetrating keratoplasty as treatment for perforated or predescemetal corneal ulcers. Am J Ophthalmol 2001;132:14-8.  Back to cited text no. 8
    
9.
Yoon KC, Jeon IY, IM SK, Chae HJ, Yang SY. Therapeutic effect of intracameral amphotericin B in the treatment of fungal keratitis. Cornea 2007;26:814-8.  Back to cited text no. 9
    




 

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Pain
Corneal Thinning
Severe Anterior ...
Ocular Surface C...
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