Infectious Diseases in Special Senses Organs (L8) PDF

Special sense infections By pathology team presented by Dr.Dina Abdallah Elnady 1  ILOs Understanding different types of otitis. Identify different types of otitis media. Clarify pathological aspects of keratitis and conjunctivitis....

Special sense infections By pathology team presented by Dr.Dina Abdallah Elnady 1  ILOs Understanding different types of otitis. Identify different types of otitis media. Clarify pathological aspects of keratitis and conjunctivitis. Differentiation between Blepharitis, chalazion ad stye.  Otitis Otitis media Otitis externa. Otitis interna. Otitis  1- Otitis media Def: inflammation of the middle ear (commenest type of otitis) Causes of otitis media 1- S. pneumoniae: 30-35% 2- H. influenzae 3- M. catarrhalis 4- Others: group A strep.,Mycobacterium Tuberculosis, Rhinovirus, Parainfluenza virus, Influenza virus  Routes of Infection of otitis media 1. Via eustachian tube: It is the most common route. 2. Via external ear: Traumatic perforations of tympanic membrane due to any cause open a route to middle ear infection. 3. Direct spread: from mastoiditis. 4. Blood-born: uncommon route.  Risk factors of otitis media: 1- Age: First peak in children aged between 6 – 24 months Again, between ages four and five years. Eustachian tube in infants and young children is shorter, wider and more horizontal. 2- Sex: More common in males.  Risk factors of otitis media: 3- Anatomical abnormalities : Abnormalities such as cleft palate, cleft lip and narrow Eustachian tubes 4- Breastfeeding: Breastfeeding for at least six months may protect against otitis media. Breast and bottle feeding in supine position increases risk of OM.  Risk factors of otitis media: 5- Seasons : Upper respiratory tract infections are more common in autumn and winter which can lead to acute otitis media 6- Overcrowded homes and/or a large number of siblings: Due to close contact. 5- Passive exposure to smoking 8- Air pollutants  Types: 1- Acute otitis media (AOM; most common): Acute inflammation and effusion of the middle ear In younger children 2- Otitis media with effusion (OME): Middle ear effusion Without symptoms and signs of an acute ear infection 3- Chronic suppurative otitis media (CSOM): Chronic inflammation of the middle ear and mastoid cavity Otorrhea through a perforated tympanic membrane  A- Acute otitis media - Mostly caused by bacterial infection and rarely viral infection. - Severe earache with fever. - Erythema, bulging tympanic membrane, loss of light reflex  B- Otitis media with effusion (Serous or secretory otitis media) Def: a condition in which there is fluid in the middle ear but no signs of acute infection Cause: Can follow acute otitis media. Pathogenesis: - As fluid builds up in the middle ear and Eustachian tube, it places pressure on the tympanic membrane. - The pressure prevents the tympanic membrane from vibrating properly, decreases sound conduction, and therefore results in decreased hearing. - Over weeks or months, fluid becomes very thick and glue like (Glue ear)  C- Chronic suppurative otitis media Def: a chronic inflammation of the middle ear and mastoid cavity, which presents with recurrent ear discharges or otorrhoea through a tympanic perforation. Causes: 1. a spontaneous tympanic perforation due to AOM 2. a sequel of less severe forms of otitis media (e.g. secretory OM) Clinically: patients with tympanic perforations which continue to discharge mucoid material for periods of from 6 weeks to 3 months, despite medical treatment. - More incidence for hearing impairment.  Otitis media A- Acute otitis media B- Serous or secretory otitis media C- Chronic suppurative otitis media ü Mostly caused by ü Mostly due to spread of URTI. ü Involved active bacteria infection bacterial infection ü Can follow acute otitis media. ü Perforation of ear drum ü rarely viral infection. ü Fluid in middle ear & pus drainage. ü Erythema, bulging tympanic membrane, ü Glue ear (Over weeks or months) loss of light reflex  2- Otitis externa Def: Infection of the cutis and subcutis of the external auditory canal (EAC), possibly involving the tympanic membrane and the pinna as well Has four types: 1- Acute diffuse otitis externa (most common form, typically seen in swimmer 2- Acute localized otitis externa (furinclosis) infection to hair follicle. 3- Chronic otitis externa (longer duration more than 6 weeks) 4- Malignant (Necrotizing) otitis externa infection extend to deeper tissue adjecent to EAC & occur primary in immunocomprimized adults.  3- Otitis interna Def:Inflammation that is located in inner ear. More commonly known as labyrinthitis that affect hearining & balance. Has four stages: 1-Serous stage 2-Purulent stage 3-Fibrous stage 4-Osseous stage Keratitis and conjunctivitis  Keratitis Def: inflammation of the cornea Types: Infectious keratitis ü Bacterial:common contact lenses wearer. from contaminated eye drops or contact lens solution ü Viral:The repeated infections are triggered by stress, an impaired immune system. Mainly causes bt herpes simplex virus ü Parasitic (Acanthamoeba):Poor contact lens hygiene Exposure to water (like swimming pools and hot tubs) while wearing contact lenses. üFungal Non infectious keratitis üInjury üExposure to intense ultraviolet (UV) light (photokeratitis) üDry eye syndrome ü Eyelid disorders that prevent proper eyelid function  Symptoms of Keratitis Eye pain Eye redness Excess tears or other discharge Difficulty opening eyelid because of pain or irritation Decreased vision Sensitivity to light (also called photophobia)  Conjunctivitis (Pink eye) Def: the inflammation or infection of the transparent membrane that lines your eyelid and eyeball. Causes: Viral infection (Adenovirus, Herpes simples and herpes zoster) Bacterial infection Allergic reaction. Symptoms: - Redness - A discharge that forms a crust during the night that may prevent eyes from opening in the morning. - A gritty feeling - Itchiness. - Tearing. - Photophobia.  Inflammation of eye lid Blepharitis Def: Inflammation of eye lid Causes Acne rosacea Allergies Dandruff Dry eyes Lice or mites in eyelashes Meibomian gland (oil gland) dysfunction (MGD)  Stye & chalazion Stye (Hordeolum) : It is a painful infected lesions on the edge of the eyelid (eyelash follicles) that come on quickly and eventually break open and drain Chalazion: Is a less painful small swelling on the inside edge of the eyelid (conjunctival side) caused by a blockage of a tiny oil gland.  RECOMMENDED REFERENCES 1. Robbins & Cotran Pathologic Basis of Disease, (Robbins Pathology), 2018 ISBN: 978-0-323-35317-5, Edition: 10th 2. Pathmax: http://www.pathmax.com/ 3. Webpath: http://library.med.utah.edu/webpath/webpath.html