Conjunctivitis laboratory findings
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Sara Mehrsefat, M.D. [2]
Overview
Laboratory tests are not often required in patients with mild conjunctivitis. Conjunctival cultures is generally reserved for cases of suspected infectious neonatal conjunctivitis, recurrent conjunctivitis, conjunctivitis recalcitrant to therapy, conjunctivitis presenting with severe purulent discharge, and cases suspicious for gonococcal or chlamydial infection.[1][2]
Laboratory Findings
Laboratory tests usually are not required in patients with mild conjunctivitis. However, specimens for bacterial cultures should be obtained in patients who have severe inflammation (hyperacute purulent conjunctivitis) or chronic or recurrent conjunctivitis. Cultures also should be obtained in patients who do not respond to treatment.[2]
Viral Conjunctivitis
In general, viral conjunctivitis is diagnosed based on clinical features alone. Laboratory studies for viral conjunctivitis should include the following:[3][4]
- Ocular swab samples for polymerase chain reaction (PCR) (gold standard)
- Rapid antigen testing for adenoviruses at the office (identify the viral causes of conjunctivitis and prevent unnecessary antibiotic use)
Bacterial Conjunctivitis
Acute bacterial conjunctivitis is usually self-limited and laboratory tests usually are not required. Swabs for bacterial culture is generally reserved for cases of suspected infectious neonatal conjunctivitis (ophthalmia neonatorum), recurrent conjunctivitis, conjunctivitis recalcitrant to therapy, conjunctivitis presenting with severe purulent discharge, and cases suspicious for gonococcal or chlamydial infection.[5][6]
Chlamydial Infection
Laboratory studies for chlamydial conjunctivitis should include the following:[7]
- Conjunctival scraping for polymerase chain reaction (PCR)
- Conjunctival scraping for gram staining or giemsa staining (help characterize the conjunctival inflammatory response and rarely done because of the cost and the general lack of laboratory staff experienced in handling ocular specimens)
- Conjunctival scraping for DNA hybridization assays
- Direct fluorescent monoclonal antibody staining of smears
- Enzyme immuno-assays for chlamydia organisms
Gonococcal Infection
Laboratory studies for chlamydial conjunctivitis should include the following:[8]
- Conjunctival scraping for gram staining of specimens for gram-negative intra-cellular diplococci
- Special cultures for neisseria species on chocolate agar or Thayer-Martin
Neonatal Conjunctivitis
Laboratory studies for neonatal conjunctivitis should include the following:[9]
- Conjunctival scraping for gram staining or giemsa staining
- Conjunctival scraping for Polymerase chain reaction (PCR) for chlamydia, gonorrhea, and HSV
- Special cultures for neisseria species on chocolate agar or Thayer-Martin
- Culture on blood agar
- Culture of corneal epithelial cells for HSV (cornea is involvement)
Allergic Conjunctivitis
Most cases are mild, and the patient just needs reassurance. Laboratory studies for allergic conjunctivitis should include the following:[10]
- Superficial conjunctival scrapings may reveal eosinophils (severe cases)
- Measurement of tear levels of various inflammatory mediators (such as IgE, histamine, and tryptase)
- Skin testing (may provide definitive diagnosis)
Keratoconjunctivitis Sicca
Keratoconjunctivitis sicca (dry eye syndrome), is essentially a clinical diagnosis, made by combining information obtained from the history, physical examination and performing one or more diagnostic tests to lend additional objectivity to the diagnosis. Laboratory studies for keratoconjunctivitis sicca should include the following:[11]
- Tear osmolarity (best single diagnostic test)
- Tear film interferometry (measure lipid layer thickness)
- Sjö test (Serology for circulating autoantibodies)
- Antinuclear antibody (ANA)
- Rheumatoid factor (RF)
- Anti Ro antibody (SS-A)
- Anti La antibody]] (SS-B)
- Salivary gland protein 1 antibody (SP-1)
- Carbonic anhydrase 6 antibody (CA6)
- Parotid secretory protein antibody (PSP)
Superior Limbic Keratoconjunctivitis
Superior limbic keratoconjunctivitis (SLK) has been associated with thyroid dysfunction, therefore, Laboratory studies for superior limbic keratoconjunctivitis should include the following:[12][13]
- Thyroid-stimulating hormone (TSH)
- Free thyroxine (T4)
- Thyroid stimulating immunoglobulin or TSH–binding inhibitory immunoglobulin
References
- ↑ Azari AA, Barney NP (2013). "Conjunctivitis: a systematic review of diagnosis and treatment". JAMA. 310 (16): 1721–9. doi:10.1001/jama.2013.280318. PMC 4049531. PMID 24150468.
- ↑ 2.0 2.1 Wood M (1999). "Conjunctivitis: diagnosis and management". Community Eye Health. 12 (30): 19–20. PMC 1706007. PMID 17491982.
- ↑ Pinto RD, Lira RP, Arieta CE, Castro RS, Bonon SH (2015). "The prevalence of adenoviral conjunctivitis at the Clinical Hospital of the State University of Campinas, Brazil". Clinics (Sao Paulo). 70 (11): 748–50. doi:10.6061/clinics/2015(11)06. PMC 4642493. PMID 26602522.
- ↑ Jhanji V, Chan TC, Li EY, Agarwal K, Vajpayee RB (2015). "Adenoviral keratoconjunctivitis". Surv Ophthalmol. 60 (5): 435–43. doi:10.1016/j.survophthal.2015.04.001. PMID 26077630.
- ↑ Leibowitz HM (2000). "The red eye". N Engl J Med. 343 (5): 345–51. doi:10.1056/NEJM200008033430507. PMID 10922425.
- ↑ Fransen L, Nsanze H, Klauss V, Van der Stuyft P, D'Costa L, Brunham RC; et al. (1986). "Ophthalmia neonatorum in Nairobi, Kenya: the roles of Neisseria gonorrhoeae and Chlamydia trachomatis". J Infect Dis. 153 (5): 862–9. PMID 3084664.
- ↑ Høvding G (2004). "[Acute bacterial conjunctivitis]". Tidsskr Nor Laegeforen. 124 (11): 1518–20. PMID 15195156.
- ↑ Høvding G (2008). "Acute bacterial conjunctivitis". Acta Ophthalmol. 86 (1): 5–17. doi:10.1111/j.1600-0420.2007.01006.x. PMID 17970823.
- ↑ Mallika P, Asok T, Faisal H, Aziz S, Tan A, Intan G (2008). "Neonatal conjunctivitis - a review". Malays Fam Physician. 3 (2): 77–81. PMC 4170304. PMID 25606121.
- ↑ La Rosa M, Lionetti E, Reibaldi M, Russo A, Longo A, Leonardi S; et al. (2013). "Allergic conjunctivitis: a comprehensive review of the literature". Ital J Pediatr. 39: 18. doi:10.1186/1824-7288-39-18. PMC 3640929. PMID 23497516.
- ↑ Savini G, Prabhawasat P, Kojima T, Grueterich M, Espana E, Goto E (2008). "The challenge of dry eye diagnosis". Clin Ophthalmol. 2 (1): 31–55. PMC 2698717. PMID 19668387.
- ↑ Nelson JD (1989). "Superior limbic keratoconjunctivitis (SLK)". Eye (Lond). 3 ( Pt 2): 180–9. doi:10.1038/eye.1989.26. PMID 2695351.
- ↑ Passons GA, Wood TO (1984). "Conjunctival resection for superior limbic keratoconjunctivitis". Ophthalmology. 91 (8): 966–8. PMID 6493706.