THE RISE OF AN OBLIVION MONSTER: NON TUBERCULAR MYCOBACTERIAL KERATITIS

NON TUBERCULAR MYCOBACTERIAL KERATITIS : A BRIEF NOTE

• Aerobic, acid fast bacilli.
• Causes delayed onset keratitis with indolent course.
• Increased incidence after LASIK.
• Other causes include trauma, cataract surgery, penetrating keratoplasty or contact lens use.

• Fast growing Non Tubercular Mycobacteria : M. chelonae, M. abscessus, M. fortuitum, M. mucogenicum. Onset after 3-4 weeks of procedure. 

• Slow growing Non Tubercular Mycobacteria : M. szulgai. Onset after 6-24 weeks of procedure.

• Symptoms & Signs :  * mild foreign body sensation, pain, photophobia, reduced visual acuity.                                      * Non suppurative corneal involvement.                                                                                        * Multifocal lesions.                                                                                                                        * CRACKED WIND SHIELD APPEARANCE. 

• Diagnostic Stains and Culture media : STAINS- Gram stain, Giemsa stain, Ziehl Neilson stain.
• CULTURE MEDIA- Lowenstein-Jensen Media, Middlebrook 7H9 or 7H12.                         Fast growing NTMB are culture positive within 7 days while slow growing NTMB takes few weeks to be culture positive.
• Flap elevation in post LASIK cases for corneal swabs facilitates easy microbial recovery.

• Treatment : Fortified Amikacin (6-7 mg/ml) + 1% azithromycin or Clarithromycin eye drops half hourly are antibacterials of choice along with adjuvent therapy. Flap amputation in post LASIK cases facilitates drug penetration and early response.