Pathology Revision PDF

### Otitis #### Inflammation of ear **Otitis Media** **Definition:** - Inflammation of middle ear - (commonest type of otitis) **Causes:** 1. S. pneumoniae 30-35% 2. *H. influenza* 3. *M. Catarrhalis* 4. Others: Group A Strep, STB,... **Routes:** 1. via eustachian tube - most common route...

### Otitis #### Inflammation of ear **Otitis Media** **Definition:** - Inflammation of middle ear - (commonest type of otitis) **Causes:** 1. S. pneumoniae 30-35% 2. *H. influenza* 3. *M. Catarrhalis* 4. Others: Group A Strep, STB,... **Routes:** 1. via eustachian tube - most common route 2. via External ear - Perforated tympanic membrane 3. Direct Spread - mastoiditis 4. Blood-born - uncommon **Risk factors:** * **Age:** - 6-24 months - 4.5 years - ET Short - wide - horizontal * **Sex:** * **Anatomical abnormalities:** - Cleft lip - Cleft palate - Narrow ET - Breastfeeding - Supine position * **Seasons:** - Autumn & winter * **Over Crowded:** - Close contact * **Smoking** * **Air pollution** **Types:** - **Acute otitis media:** Bacterial infection - Symptoms: - Severe earache - Fever - **Examination:** - Erythema - Bulging tympanic membrane - Loss of light - **Otitis media effusion (Serous/Secretory):** - Fluid in middle ear - No signs of acute infection - Cause: follow acute otitis media - **Pathogenesis:** (Glue Ear) - Fluid in middle ear - Pressure on tympanic membrane - Prevent vibration - ↓ Sound conduction - **Chronic Suppurative otitis media:** - Chronic inflammation of middle ear & mastoid - Recurrent ear discharge through tympanic perforation - **Cause:** 1. Spontaneous perforation of ACM 2. After Secretory OM - **Clinically:** - Ear discharge from 6 weeks to 3 months - More incidence of hearing loss *** #### Otitis externa **Definition:** - Infection of cutis and subcutis of external auditory canal (EAC) - Possibly involving tympanic membrane. - Pinna as well **Types:** 1. **Acute diffuse otitis.** - Most common - **Externa** 2. **Acute localized otitis media.** - (Frundosis) - **Externa** 3. **Chronic otitis media.** - (≥6 weeks). - **Externa** 4. **Malignant necrotizing otitis media.** - & extend in deeper tissue - **Externa** *** #### Otitis interna **Definition:** - Inflammation in inner ear - Known as labyrinthitis - Affects hearing and balance. **Stages:** 1. Serous 2. Purulent 3. Fibrous 4. Asseous *** #### Eye **(Keratitis)** **Definition:** Inflammation of cornea. **Types:** I. Infectious - Bacterial: Contact lens - Viral: Herpes simplex - Parasitic: Acanthamoeba - Fungal II. Non infectious - Injury - Exposure to intense light - Dry eye syndrome - Eye lid disorders **Symptoms:** - Pain - Redness - Discharge - Difficulty in opening eyelid - Decrease vision - Sensitivity to light/ photophobia **(Conjunctivitis)** **Definition:** Inflammation of conjunctiva (membrane over eyelid and eyeball) **Causes:** - Viral infection: Adenovirus, Herpes simplex, herpes zoster, - Bacterial infection. - Allergic reaction. **Symptoms:** - Redness. - Discharge. - Gritty sensation - Itching - Tearing - Photophobia **(Blepharitis)** **Definition:** Inflammation of eye lid **Causes:** Acne rosacea - Allergies - Dandruff - Dry eyes - Mites. - Meibomain gland dysfunction **(Stye (Hordeolum))** **Definition:** Painful infected lesion on edge of eyelid (eye lash follicles). - Come quickly, drain at or near eyelash **Cause:** Bacterial infection. **Symptom:** -Tender - Swelling **(Chalazion)** **Definition:** Less painful small swelling on inside edge of eyelid. - Cause by block of tiny oil glad above eyelash on upper eyelid. - Block oil gland. **Symptom:** - Pain less, firm. **Treatment:** - Spontaneous drainage - Warm compresses - Steroid injection - Surgery