Conjunctivitis pathophysiology
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2]
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Overview
Pathophysiology
Infective Conjunctivitis is an infection of the conjunctiva either cause by Viruses or Bacteria . Both the palpebral and the bulbar ocular conjunctival surfaces are usually affected and typically become red and inflamed. Bacterial and viral Conjunctivitis is spread from: [1]
- Direct contact with the infected person’s eye drainage or drainage from the person’s cough, sneeze, or runny nose
- Contact with the infected person’s fingers, hands or objects that may have the infected person’s drainage on them (e.g. eye makeup applicators, towels, shared eye medications)
- Adjacent infectious sites (rubbing of the eyes)
Any change in the host defense or in the species of normal flora of the eye (such as streptococci, staphylococci, and corynebacteria) can lead to clinical infection and Conjunctivitis.[2] Change in the flora can occur by:
- External contamination
- Contact lens wear
- Swimming
Neonatal conjunctivitis is often known as ophthalmia neonatorum. [Newborns]] can be infected by bacteria in the birth canal. It is a disease characterized by conjunctivitis occurring in a newborn during the first month of life with clinical signs of erythema and edema of the eyelids and the palpebral conjunctivae, purulent eye discharge with one or more polymorph nuclear per oil immersion field on a Gram stained conjunctival smear. Additionally, neonatal conjunctivitis is a pink eye in a newborn caused by irritation (Chemical Conjunctivitis) , a blocked tear duct, or infection.[3]
Development of Allergic Conjunctivitis is result of type I hypersensitivity reactions involving the conjunctiva. [4]
- IgE and Mast cell play an important role in these allergic inflammations
- There is a strong association with atopic dermatitis and Allergic Conjunctivitis
In Giant papillary conjunctivitis combination of type I and type IV hypersensitivity reactions may be responsible. Also prolonged mechanical irritation to the superior tarsal conjunctiva, of the upper lid, from any of a variety of foreign bodies may also be a contributing factor in Giant papillary conjunctivitis.[5][6] Airborne antigens may be involved in the pathogenesis of Allergic Conjunctivitis. Common airborne antigens, include:[7][8]
- Pollen,
- Grass,
- Weeds,
Keratoconjunctivitis sicca or dry eye syndrome is multifactorial disease and associated with different medical conditions such as:[9][10]
- Sjögren's syndrome
- Ocular surface disease
- Ocular allergy
- Dysfunction of the lacrimal gland with reduced tear production and Mucin deficiency
Keratoconjunctivitis sicca-associated Sjögren's syndrome may be is the result of an auto immunological sequelae which can lead to chronic inflammatory state with production of auto antibodies, such as: antinuclear antibody (ANA), rheumatoid factor (RF), fodrin (a cytoskeletal protein), the muscarinic M3 receptor, or Sjögren's syndrome-specific antibodies (anti-RO and anti-LA. Focal CD4+ T cells and B cells infiltration of the lacrimal gland can induce apoptosis in the conjunctiva and lacrimal glands and this results in dysfunction of the lacrimal gland with reduced tear production.
Superior limbic keratoconjunctivitis (SLK) is a disease characterised by inflammation of the upper palpebral and superior bulbar conjunctiva, keratinisation of the superior limbus and corneal and conjunctival filaments. The exact pathogenesis of Superior limbic keratoconjunctivitis is not fully understood, however association between thyroid abnormalities (Graves ophthalmopathy) and Superior limbic keratoconjunctivitis has been reported.[11][12]
Gross Pathology
Microscopic Pathology
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.
- ↑ Everitt H, Kumar S, Little P (2003). "A qualitative study of patients' perceptions of acute infective conjunctivitis". Br J Gen Pract. 53 (486): 36–41. PMC 1314490. PMID 12564275.
- ↑ 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.
- ↑ Kyei S, Koffuor GA, Ramkissoon P, Abokyi S, Owusu-Afriyie O, Wiredu EA (2015). "Possible Mechanism of Action of the Antiallergic Effect of an Aqueous Extract of Heliotropium indicum L. in Ovalbumin-Induced Allergic Conjunctivitis". J Allergy (Cairo). 2015: 245370. doi:10.1155/2015/245370. PMC 4657065. PMID 26681960.
- ↑ Donshik PC (1994). "Giant papillary conjunctivitis". Trans Am Ophthalmol Soc. 92: 687–744. PMC 1298525. PMID 7886881.
- ↑ Donshik PC, Porazinski AD (1999). "Giant papillary conjunctivitis in frequent-replacement contact lens wearers: a retrospective study". Trans Am Ophthalmol Soc. 97: 205–16, discussion 216-20. PMC 1298261. PMID 10703125.
- ↑ Malling HJ, Montagut A, Melac M, Patriarca G, Panzner P, Seberova E; et al. (2009). "Efficacy and safety of 5-grass pollen sublingual immunotherapy tablets in patients with different clinical profiles of allergic rhinoconjunctivitis". Clin Exp Allergy. 39 (3): 387–93. doi:10.1111/j.1365-2222.2008.03152.x. PMC 4233960. PMID 19134019.
- ↑ Kämpe M, Stålenheim G, Janson C, Stolt I, Carlson M (2007). "Systemic and local eosinophil inflammation during the birch pollen season in allergic patients with predominant rhinitis or asthma". Clin Mol Allergy. 5: 4. doi:10.1186/1476-7961-5-4. PMC 2174506. PMID 17967188.
- ↑ Zhang X, Zhao L, Deng S, Sun X, Wang N (2016). "Dry Eye Syndrome in Patients with Diabetes Mellitus: Prevalence, Etiology, and Clinical Characteristics". J Ophthalmol. 2016: 8201053. doi:10.1155/2016/8201053. PMC 4861815. PMID 27213053.
- ↑ Sivaraman KR, Jivrajka RV, Soin K, Bouchard CS, Movahedan A, Shorter E; et al. (2016). "Superior Limbic Keratoconjunctivitis-like Inflammation in Patients with Chronic Graft-Versus-Host Disease". Ocul Surf. doi:10.1016/j.jtos.2016.04.003. PMID 27179980.
- ↑ Nelson JD (1989). "Superior limbic keratoconjunctivitis (SLK)". Eye (Lond). 3 ( Pt 2): 180–9. doi:10.1038/eye.1989.26. PMID 2695351.
- ↑ Chelala E, El Rami H, Dirani A, Fakhoury H, Fadlallah A (2015). "Extensive superior limbic keratoconjunctivitis in Graves' disease: case report and mini-review of the literature". Clin Ophthalmol. 9: 467–8. doi:10.2147/OPTH.S79561. PMC 4362972. PMID 25792798.
- ↑ Image Courtesy of Joyhil09 [1]
- ↑ http://picasaweb.google.com/mcmumbi/USMLEIIImages
![[1]](https://commons.wikimedia.org/wiki/File:An_eye_with_viral_conjunctivitis.jpg){kind=link}