Conjunctiva PDF

Dr.Zubaida lec.1 Conjunctiva Anatomy: The conjunctiva is a transparent mucous membrane that lines the inner surface of the eyelids and the anterior surface of the globe, terminating at the corneoscleral limbus. There is...

Dr.Zubaida lec.1 Conjunctiva Anatomy: The conjunctiva is a transparent mucous membrane that lines the inner surface of the eyelids and the anterior surface of the globe, terminating at the corneoscleral limbus. There is a dense lymphatic network, with drainage to the preauricular and submandibular nodes and It has a key protective role, mediating both passive and active immunity. It can be divided anatomically into; bulbar (covers the eyeball), forniceal (covers the superior and inferior fornices), and palpebral, or tarsal (starts at the mucocutaneous junction of the eyelid and covers the inner eyelid). The plica semilunaris is a crescent-shaped vertical fold at the medial angle of the eye. The caruncle—a fleshy, ovoid modified mass that bears goblet cells and lacrimal tissue, as well as hairs, sebaceous glands, and sweat glands. Histologically; it it’s composed of 1-non- keratinising surface epithelium with mucus-secreting goblet cells are located within the epithelium, being most dense inferonasally and in the fornices. 2-The stroma (substantia propria) consists of richly vascularized loose connective tissue. Conjunctiva-associated lymphoid tissue (CALT) is critical in the initiation and regulation of ocular surface immune responses. 1 Conjunctival diseases: can be divided into infectious & non- infectious Infectious : bacterial, viral Non- infectious: allergic, associated with systemic diseases, neoplastic, degenerative, traumatic. Clinical features of conjunctival inflammation Symptoms: Non-specific symptoms include lacrimation, grittiness, and burning. Itching is the hallmark of allergic disease. The visual acuity is not usually affected. Significant pain, photophobia or a marked foreign body sensation suggest corneal involvement. Signs: Lids: edema, vesicles. Discharge: Watery discharge;can be seen in acute allergy & viral conjunctivitis Mucoid discharge is typical of chronic allergic conjunctivitis and dry eye. Mucopurulent discharge typically occurs in chlamydial or acute bacterial infection. Severe purulent discharge is suggestive of gonococcal infection. Other signs; redness, haemorrhage, lymphandenopathy. Infectious conjunctivitis can be bacterial & viral. Bacterial conjunctivitis: Acute bacterial conjunctivitis is a common and usually self-limiting condition that is caused either by direct contact with an infected individual’s secretions (usually through eye–hand contact) or the spread of infection from the organisms colonizing the patient’s own nasal and sinus mucosa. The most common isolates are; S pneumoniae, Streptococcus viridans, H influenzae, and S aureus. 2 Occasionally be severe and sight-threatening when caused by virulent bacterial species such as N gonorrhoeae or Streptococcus pyogenes. In rare cases, it may presage life-threatening systemic disease, as with conjunctivitis caused by N meningitidis. Clinical features: Symptoms: acute onset of redness, discharge, and grittiness. Involvement is usually bilateral although one eye may become affected 1–2 days before the other. On waking, the eyelids are frequently stuck together and may be difficult to open. In children, the possibility of progression to systemic involvement should always be borne in mind. Systemic symptoms may occur in patients with severe conjunctivitis associated with gonococcus, meningococcus, Chlamydia and H. influenzae. Signs : VA: usually normal Lids : edema & erythema can be seen in severe infection like gonococcal infection. Discharge….mucopurulent or purulent. Conjunctival injection : diffuse, beefy-red and more intense away from the limbus. Peripheral corneal ulceration may occur in gonococcal and meningococcal infection and may rapidly progress to perforation. Lymphadenopathy is usually absent except in severe gono- coccal and meningococcal infection. Rx: Risk of transmission should be reduced by hand-washing and the avoidance of towel sharing. 3 Most cases of acute bacterial conjunctivitis resolve in 2–7 days without treatment. Contact lens wear should be discontinued until at least 48 hours after complete resolution of symptoms. Contact lenses should not be worn whilst topical antibiotic treatment continues. Topical antibiotics are given 4-6 times daily for 5-7 days quinolones like ciprofoxacin or ofloxacin, aminoglycosides like to tobramycin and bacitracin or erythromycin ointment can be used. Systemic antibiotics are indicated for : 1-H. influenzae conjunctivitis should be treated with oral amoxicillin/clavulanate because of occasional extraocular involvement (e.g., otitis media, pneumonia, and meningitis). 2- Gonococcal conjunctivitis ( STD) Ceftriaxone, a third-generation cephalosporin, is highly effective it is advisable to give patients supplemental oral antibiotics for treatment of chlamydial infection because of their associations. Viral conjunctivitis Overall, 80% of cases of infectious conjunctivitis in adults are viral in origin. Viral conjunctivitis is most commonly due to adenoviral infection but it can be caused by herpes viruses, mulluscum contagious and other viruses. Adenoviral conjunctivitis: It is caused by adenovirus; a double stranded DNA virus and is transmitted by close contact with ocular or respiratory secretions, contaminated fomites, or contaminated swimming pools. Transmission 4 occurs more readily in populations living in close quarters, such as schools, nursing homes, & military housing. Symptoms: Itching,tearing, and foreign body sensation; historyof recent upper respiratory tract infection or contact with someone with viral conjunctivitis. Often starts in one eye and involves the fellow eye a few days later. Signs Watery discharge, red & edematous lids, conjunctival injection, follicles, pinpoint subconjunctival haemorrhage, with variable degrees of keratopathy. Pharyngoconjunctival fever is characterized by fever, headache, pharyngitis, follicular conjunctivitis, and preauricular adenopathy. Epidemic keratoconjunctivitis is the only adenoviral syndrome with significant cornealinvolvement and may be preceded by an upper respiratory tract infection. Treatment 1. Counsel the patient that viral conjunctivitis is a self-limited condition that typically gets worse for the first 4 to 7 days after the onset and may not resolve for 2 to 3 weeks (potentially longer with corneal involvement). 2. Viral conjunctivitis is highly contagious (usually for 10 to 12 days from the onset).Patients should avoid touching their eyes, shaking hands, sharing towels or pillows, etc. Restrict work and school for patients with significant exposure to others while the eyes are red and weeping. 3. Frequent hand washing. 4.Cool compresses several times per day. 5. Application of preservative-free artificial tears or tear ointment four times per day for 1 to 3 weeks. 5 6.Application of antihistamine drops if itching is severe. Ophthalmia neonatorum (Newborn Conjunctivitis) It is defined as conjunctival inflammation developing within the first month of life. Causes: The causative organism usually infects the infant through direct contact during passagethrough the birth canal. Infection can ascend to the uterus, especially if there is prolonged rupture of membranes, so even with cesarean delivery, infants can be infected. Chemical: Seen within a few hours of instilling a prophylactic agent (e.g., silver nitrate). Lasts no more than 24 to 36 hours. Neisseria gonorrhoeae: Usually seen within 3 to 4 days after birth. Chlamydia trachomatis: Usually presents within first week or two of birth. Bacteria: Staphylococci & streptococci at the end of the first week. Herpes simplex virus: within 2nd week of life. Signs: Lids: swelling & erythema in gonococcal infection, Eyelid and periocular vesicles when present in HSV infection and can critically aid early diagnosis and treatment. Discharge Diffuse conjunctival injection. Corneal examination is mandatory ….looking for dendrites, corneal ulceration in case of gonococcal infection. Features of systemic illness in the child: pneumonitis, rhinitis and otitis in chlamydial infection, skin vesicles and features of encephalitis in HSV. 6 DDx congenital glaucoma, congenital nasolacrimal duct obstruction. Investigations Conjunctival scrapings for two slides: Gram and Giemsa stain Conjunctival cultures with blood and chocolate agars. Scrape the conjunctiva for the chlamydial immunofluorescent antibody test or PCR, if available. Treatment: If No information from stains, no particular organism suspected….oral erythromycin & erythromycin ointment for 3 ws. If chlamydia infection is suspected, oral erythromycin or azithromycin with Rex if the mother & her partner. If N.gonorrhoeal infection is suspected, hospital admission with systemic ceftriaxone or cefotaxime. Mild sticky eyes with no suspicion of gonococcal or chlamydial infection…. erythromycin or fusidic acid ointment can be given. Suspicion of herpes simplex virus regardless of the presenting ocular findings, should be treated with acyclovir intravenously & topical antiviral. Follow up Initially examine daily as an inpatient or outpatient then accordingly. 7