Trachoma Workup

  • Author: Anthony W Solomon, MBBS, DTM&H, PhD, MRCP; Chief Editor: Hampton Roy Sr, MD   more...
 
Updated: May 19, 2011
 

Laboratory Studies

  • In endemic areas, the diagnosis is almost always based on the clinical appearance.
  • Laboratory assays are principally used in research.
    • To confirm that the clinical diagnosis of active trachoma is the result of ocular C trachomatis infection, the best laboratory techniques are the nucleic acid amplification tests (NAATs), of which the polymerase chain reaction (PCR) is one example.
    • The NAATs have high sensitivity and specificity but are too expensive and too technically complex to be widely available in most settings where trachoma is endemic.
    • On any assay, apparent false-positive and false-negative results (compared with the clinical signs of active trachoma) may be related to the natural history of infection and disease. Individuals become infected several weeks before specific clinical signs appear, and evidence of conjunctival inflammation persists for weeks to months after the infection resolves.
    • Other useful techniques are direct fluorescein-labeled monoclonal antibody (direct fluorescent antibody [DFA]) assay and enzyme immunoassay (EIA) of conjunctival smears. These tests are less sensitive than the NAATs. However, to determine whether antibiotics are needed by a community, the prevalence of infection may be an important parameter, so a test with high specificity may be useful even if it has lower sensitivity. A dipstick-based EIA for infection that can be deployed in remote trachoma-endemic villages has now been developed and has shown good performance characteristics in early trials.
    • Newer diagnostic methods have superseded cell culture, which was the criterion standard for laboratory diagnosis. Cell culture requires a highly specialized laboratory and is expensive and technically demanding. Cell culture has virtually 100% specificity but only moderate sensitivity.
    • Giemsa cytology is microscopic examination of stained conjunctival scrapings for intracytoplasmic inclusions. Giemsa cytology is technically demanding. This test has high specificity but low sensitivity.
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Contributor Information and Disclosures
Author

Anthony W Solomon, MBBS, DTM&H, PhD, MRCP  Specialist Registrar in Infectious Diseases and Tropical Medicine, The Hospital for Tropical Diseases, London; Lecturer, International Centre for Eye Health, Clinical Research Unit, London School of Hygiene and Tropical Medicine, London

Anthony W Solomon, MBBS, DTM&H, PhD, MRCP is a member of the following medical societies: Royal College of Physicians of the United Kingdom and Royal Society of Tropical Medicine and Hygiene

Disclosure: Pfizer Inc Grant/research funds Researcher; International Trachoma Initiative Grant/research funds Researcher; Pfizer Inc Support to attend the Trachoma Scientific Exchange in Phoenix, 2006 Speaking and teaching; International Trachoma Initiative Member of Trachoma Expert Committee None

Coauthor(s)

Hugh Ringland Taylor AC, MD, MBBS, BMedSc (Melb), DO (Melb), FRACO, FRACS, FAAO, FACS, FAICD  Harold Mitchell Professor of Indigenous Eye Health, Melbourne School of Population Health, University of Melbourne

Hugh Ringland Taylor AC, MD, MBBS, BMedSc (Melb), DO (Melb), FRACO, FRACS, FAAO, FACS, FAICD is a member of the following medical societies: American Academy of Ophthalmology, American Ophthalmological Society, and Association for Research in Vision and Ophthalmology

Disclosure: Nothing to disclose.

Specialty Editor Board

Anastasios J Kanellopoulos, MD  Assistant Program Director, Clinical Associate Professor, Department of Ophthalmology, Manhattan Eye, Ear, and Throat Hospital, New York University

Anastasios J Kanellopoulos, MD is a member of the following medical societies: American Academy of Ophthalmology, Association for Research in Vision and Ophthalmology, Eye Bank Association of America, and International Society of Refractive Surgery

Disclosure: Nothing to disclose.

Simon K Law, MD, PharmD  Associate Professor of Ophthalmology, Jules Stein Eye Institute, University of California, Los Angeles, David Geffen School of Medicine

Simon K Law, MD, PharmD is a member of the following medical societies: American Academy of Ophthalmology, American Glaucoma Society, and Association for Research in Vision and Ophthalmology

Disclosure: Nothing to disclose.

Christopher J Rapuano, MD  Professor, Department of Ophthalmology, Jefferson Medical College of Thomas Jefferson University; Director of the Cornea Service, Co-Director of Refractive Surgery Department, Wills Eye Institute

Christopher J Rapuano, MD is a member of the following medical societies: American Academy of Ophthalmology, American Society of Cataract and Refractive Surgery, Contact Lens Association of Ophthalmologists, Cornea Society, Eye Bank Association of America, International Society of Refractive Surgery, and Pan-American Association of Ophthalmology

Disclosure: Allergan Honoraria Speaking and teaching; Allergan Consulting fee Consulting; Alcon Honoraria Speaking and teaching; Inspire Honoraria Speaking and teaching; RPS Ownership interest Other; Vistakon Honoraria Speaking and teaching; EyeGate Pharma Consulting; Inspire Consulting fee Consulting; Bausch & Lomb Honoraria Speaking and teaching; Bausch & Lomb Consulting fee Consulting

Lance L Brown, OD, MD  Ophthalmologist, Affiliated With Freeman Hospital and St John's Hospital, Regional Eye Center, Joplin, Missouri

Disclosure: Nothing to disclose.

Chief Editor

Hampton Roy Sr, MD  Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences

Hampton Roy Sr, MD is a member of the following medical societies: American Academy of Ophthalmology, American College of Surgeons, and Pan-American Association of Ophthalmology

Disclosure: Nothing to disclose.

References

  1. Bobo LD, Novak N, Munoz B, Hsieh YH, Quinn TC, West S. Severe disease in children with trachoma is associated with persistent Chlamydia trachomatis infection. J Infect Dis. Dec 1997;176(6):1524-30. [Medline].

  2. Thylefors B, Dawson CR, Jones BR, West SK, Taylor HR. A simple system for the assessment of trachoma and its complications. Bull World Health Organ. 1987;65(4):477-83. [Medline].

  3. Kalua K, Chirwa T, Kalilani L, Abbenyi S, Mukaka M, Bailey R. Prevalence and risk factors for trachoma in central and southern Malawi. PLoS One. Feb 5 2010;5(2):e9067. [Medline].

  4. Baker MC, Mathieu E, Fleming FM, et al. Mapping, monitoring, and surveillance of neglected tropical diseases: towards a policy framework. Lancet. Jan 16 2010;375(9710):231-8. [Medline].

  5. Evans JR, Solomon AW. Antibiotics for trachoma. Cochrane Database Syst Rev. Mar 16 2011;3:CD001860. [Medline].

  6. West S, Munoz B, Lynch M, Kayongoya A, Chilangwa Z, Mmbaga BB, et al. Impact of face-washing on trachoma in Kongwa, Tanzania. Lancet. Jan 21 1995;345(8943):155-8. [Medline].

  7. Reacher M, Foster A, Huber J. Trichiasis surgery for trachoma: the bilamellar tarsal rotation procedure. WHO/PBL 93.29. Geneva: World Health Organization;. 1993.

  8. Dawson CR, Schachter J, Sallam S, Sheta A, Rubinstein RA, Washton H. A comparison of oral azithromycin with topical oxytetracycline/polymyxin for the treatment of trachoma in children. Clin Infect Dis. Mar 1997;24(3):363-8. [Medline].

  9. Grayston JT, Wang SP, Yeh LJ, Kuo CC. Importance of reinfection in the pathogenesis of trachoma. Rev Infect Dis. Nov-Dec 1985;7(6):717-25. [Medline].

  10. Mabey DC, Solomon AW, Foster A. Trachoma. Lancet. Jul 19 2003;362(9379):223-9. [Medline].

  11. Solomon A, Burton M. What's new in azithromyin?. Community Eye Health. Dec 2004;17(52):54-6. [Medline].

  12. Taylor HR, Johnson SL, Schachter J, Caldwell HD, Prendergast RA. Pathogenesis of trachoma: the stimulus for inflammation. J Immunol. May 1 1987;138(9):3023-7. [Medline].

 
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Trachomatous inflammation, follicular (TF), is the presence of 5 or more follicles (each at least 0.5 mm in diameter) on the central part of the upper tarsal conjunctiva. Images from the Slides/Text Teaching Series, No. 7, Trachoma, published by The International Centre for Eye Health, Institute of Ophthalmology, 11-43 Bath St, London EC1V 9EL, United Kingdom. Photograph courtesy of John D. C. Anderson, MD.
Trachomatous inflammation, intense (TI) is pronounced inflammatory thickening of the upper tarsal conjunctiva that obscures more than one half the normal deep tarsal vessels. Photograph courtesy of Allen Foster, MD.
Trachomatous conjunctival scarring (TS) is the presence of easily visible scars in the tarsal conjunctiva.
Trachomatous trichiasis (TT) is defined as the presence of at least 1 eyelash rubbing on the eyeball or evidence of recent removal of in-turned lashes. Photograph courtesy of John D. C. Anderson, MD.
Easily visible corneal opacity over the pupil; it is so dense that at least part of the pupil margin is blurred when viewed through the opacity. Photograph courtesy of John D. C. Anderson, MD.
The image on the left shows intense inflammatory trachoma, and the image on the right shows allergic conjunctivitis with the typical cobblestone papillae. Courtesy of John D. C. Anderson, MD, and Murray McGavin, MD.
 
 
 
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