18. Sense Organs Pathologies Flashcards
Otitis Externa (‘Swimmer’s Ear’)
Inflammation of the outer ear: 90% associated with a bacterial infection and the remaining fungal or allergic.
• 5x more common in swimmers. Also more prevalent in humid climates, diabetes mellitus, HIV and persons with a narrow auditory canal.
• Ear wax (cerumen) contains lysozymes and oil that create an acidic, lubricating coat. This inhibits bacterial and fungal growth so insufficient wax can predispose to infection.
• Other causes include excess wax (obstruction), water in the ear, frequent use of earplugs / headphones / hearing aids, acne, eczema, fungal infections following antibiotic use.
Otitis Externa (‘Swimmer’s Ear’): Signs and Symptoms
- Pain (especially with movement of pinna).
- Discharge (often purulent), swelling, itchy, red, swollen auditory canal.
- Hearing deficit.
- Can cause itching, fever, lymphadenopathy.
Otitis Externa (‘Swimmer’s Ear’): Treatment
Hygiene, avoid water in ears, syringe ears with saline solution (by GP), topical antibiotics.
Otitis Media
Inflammation of the middle ear.
• Most common cause of earache in children. The eustachian tube is more horizontal (common route of spread). 75% < 10 years. Many have food or inhaled allergies ( e.g. cow’s milk, wheat, egg).
• Fluid puts pressure on tympanic membrane.
Otitis Media: Cause
• Infectious organisms typically spread from nasopharynx (bacterial, viral). Or due to allergy.
Otits Media: Signs and Symptoms
- Earache / pain.
- Malaise, fever, mild hearing loss, nausea.
- Can get bulging of tympanic membrane.
Otitis Media: Treatment
- Rupture of the tympanic membrane — results in discharge from the ear canal and relief of pain.
- Antibiotics (consider adverse effects).
Secretory Otitis Media
An effusion of the middle ear resulting from incomplete resolution of acute otitis media.
• Also known as ‘glue ear’.
• Gluey fluid dampens the tympanic membrane and ossicle vibrations, which leads to hearing impairment.
Secretory Otitis Media: Signs and Symptoms
- Hearing loss (difficult to determine in young children -> listening to TV very loudly).
- Pressure in ear and mild intermittent ear pain.
Secretory Otitis Media: Treatment
• Tympanostomy tube (‘grommet’):
- A tiny pipe inserted into eardrum under anaesthetic and fluid is drained, air circulates in middle ear and hearing improves. Typically fall out within 6–12 months.
- Hole usually heals when grommets fall out.
• Tonsils may be removed to improve eustachian drainage -> immune compromise!
Labyrinthitis (Otitis Interna)
balance disorder, associated with inflammation of the membranous labyrinth.
Labyrinthitis (Otitis Interna): Causes
- Often following upper respiratory infection.
* Following head injury, an allergy or reaction to medication.
Labyrinthitis (Otitis Interna): Signs and Symptoms
- Sudden and severe vertigo (not triggered by movement, unlike benign paroxysmal positional vertigo (BPPV).
- Sudden unilateral hearing loss (not in BPPV).
- Nausea and vomiting, tinnitus.
Labyrinthitis (Otitis Interna): Treatment
Anti-emetic drugs
Meniere’s Disease
A disorder of the inner ear, caused by a change in fluid volume in labyrinth, associated with progressive distention of the membranous labyrinth.
Meniere’s Disease: Causes
- Unknown: Genetics, viral, autoimmune links (RA, SLE).
* Links with food allergies.
Meniere’s Disease: Signs and Symptoms
- Vertigo, tinnitus and hearing loss.
- Nausea and vomiting. Ear pressure.
- Characterised by fluctuating patterns of symptoms (acute attacks typically last two–three hours every one–two months).
Meniere’s Disease: Treatment
•No cure — only symptom minimisation (managing acute attacks).
Tinnitus
The perception of sound originating from within the head rather than outside.
Tinnitus: Types
Objective
Subjective
Tinnitus: Objective
Pulsatile (carotid stenosis, valve disease), muscular (spasm of tympanic muscles).
Tinnitus: Subjective
No acoustic stimuli: Ear origin (Meniere’s, ear infection, wax), Neurological (head injury, MS, tumour), infections (meningitis), drug-related (NSAIDs, loop diuretics), TMJ (jaw) dysfunction.
Tinnitus: Treatment
- Treat any underlying causes.
- Very early stages: Ginkgo biloba.
- Avoiding loud noise and earwax build-up.
- Manual therapy to neck and jaw.
Hearing Impairment
- Measured in the degree of loudness, in decibels (dB):
- Mild hearing loss -> adults 25–40 dB.
- Moderate hearing loss -> 41–70 dB.
- Severe hearing loss -> 71–90 dB.
- Profound hearing loss -> 90 dB or greater.
- Long-term exposure to noises; e.g. living next to airport. 90 dB+ can cause temporary or permanent hearing loss.
Hearing Impairment: Catagorisation
Conducive
Sensory
Hearing Impairment: Conducive
Ear canal obstructions, ossicle abnormalities, ruptured tympanic membrane.
Hearing Impairment: Sensory
Poor hair cell function — can be due to a congenital condition, infection or noise trauma.
Hearing Impairment: Causes
- Diseases: Measles, meningitis, mumps (auditory nerve damage), rubella, chlamydia and syphilis (complete loss in foetus), premature birth (usually impaired, not lost).
- Head injuries can cause hearing loss through damage to the middle ear or auditory nerve.
- ‘Shaken baby syndrome’.
Hearing Impairment: Treatment
- Hearing aids (amplifier).
* Cochlear implant (sometimes called a bionic ear). This stimulates the auditory nerves by electrical impulses.
Blepharritis
Inflammation of the eyelid margin.
•Can be acute or chronic. Most commonly in adults.
•Often associated with Staphylococcus aureus infection or dermatitis.
Blepharitis: Signs and Symptoms
- Red eyelid margins.
- Sore, gritty eyes, scales and flakes.
- Eyelids may stick together, often worse in morning.
- Itching and burning.
- Loss of eyelashes.
- Can block sebaceous glands and cause recurrent styes.
Blepharitis: Treatment
- Eyelid hygiene. Clean with cotton bud.
- Warm compress (apply to closed eyes for 5–10 mins).
- Topical antibiotics.
- Avoid contact lens use until resolved.
Stye
Inflammation of sebaceous glands of eyelid.
• Usually a bacterial infection (Staphylococcus).
Stye: Risk Factors
• Diabetes mellitus, chronic blepharitis.
Stye: Symptoms
- Red, swollen and / or painful infection of sebaceous glands of eyelid.
- Usually affects the upper lid.
Stye: Complications
• Cyst formation can damage the cornea.
Stye: Treatment
- Usually none necessary.
- Typically will burst and the pus will drain, hot compresses used 3–4 x day eases pain and aids pus removal.
- Antibiotic ointment if the stye doesn’t resolve.
Conjuctivitis
A highly-contagious inflammation of the conjunctiva.
Conjunctivitis: Causes
•Viral, bacterial, often linked with allergies.
Conjuctivitis: Symptoms
- Red eye, irritated / uncomfortable, watery (viral/allergic) / purulent discharge (bacterial).
- Photophobia suggests corneal (deeper) involvement.
Conjunctivitis: Treatment
Eye bath with salt water or eye-cleansing solution. Antibiotic eye drops or oral antibiotics rarely.
Uveitis
Inflammation of any part of the uvea (iris, ciliary body, choroid).
Uveitis: Causes
- Autoimmune disease (increased with HLA-B27; e.g. AS).
- Trauma to the eye (includes contact lenses).
- Viral infection (e.g. herpes), fungal or parasitic.
Uveitis: Symptoms
- Progressive unilateral red eye with pain, blurred vision and photophobia.
- Visual acuity reduced in affected eye. Watery discharge.
Uveitis: Treatment
Antibiotics, cortisone depending on the cause
Corneal Ulcer
An ulcer (open sore) that develops in the cornea. •Rare due to extensive ocular defence mechanism.
Corneal Ulcer: Causes
- Bacterial (e.g. gonorrhoea), viral (e.g. herpes simplex), fungal infection.
- Trauma (e.g. contact lens), spread from blepharitis.
Corneal Ulcer: Symptoms
Pain, reduced vision, photophobia, discharge.
Corneal Ulcer: Treatment
- Medical emergency — possible loss of sight
* Antibiotics, antifungal or antiviral drugs, keratoplasty (corneal transplant).
Strabismus (squint)
Mis-alignment of the eyes, which means the retinal image is not in corresponding areas of both eyes.
• ‘Esotropia’ = inward squint
• ‘Exotropia’ = outward squint.
Strabismus (squint): Causes
- Genetic (family history of squint).
* Damage to nerves supplying extra-ocular muscles (e.g. stroke, brain tumour).
Strabismus (squint): Treatment
- Glasses to correct visual problems and patching the normal eye (forces the brain to use the affected eye).
- Surgery to tighten muscles around the eye.
Cataracts
Cataracts describe the opacity of the lens.
• Cataracts are the leading cause of blindness in the world.
• A healthy lens is transparent due to regular arrangement of lens fibres. In cataracts, new fibres are produced and become disorganised within cytoplasm.
• Treated with surgery to replace the lens.
Cataracts: Causes
- Age related deterioration of lens. Congenital.
* Diabetes mellitus, smoking, steroids.
Cataracts: Symptoms
Gradual painless loss of vision, diplopia
Age-Related Macular Degeneration
Age-related macular degeneration (AMD) describes the ageing changes that occur in the central areas of the retina (macula).
• Occurs in people aged 55 years and older.
• Advancing age is the most significant risk factor. Smoking, cardiovascular disease risk factors and family history are also thought to play a role.
• AMD is a progressive chronic disease that is also a leading cause of vision loss worldwide.
Age-Related Macular Degeneration: Symptoms
- Reduced visual acuity, particular difficulty with near vision.
- Gradual (and progressive) loss of central vision.
Age-Related Macular Degeneration: Diagnosis
- Diagnosis of AMD can be assisted with the use of an ‘Amsler grid’.
- Patients are asked to look into the grid (as shown on the left).
- Patients with AMD may describe observing an image similar to that displayed on the right
- Diagnosis can also be made using ophthalmoscopy.
Muscae Volitantes (‘Floaters’)
Opacities floating in the field of vision.
• Small, dark, shadowy shapes (can look like spots, thread-like strands, or squiggly lines).
• They move with eye movements and seemingly dart away when trying to look at them directly.
• Visible because of the shadows they create on the retina.
Muscae Volitantes (‘Floaters’): Causes
- Usually shrinkage of the vitreous humour causing collagen to become fibrils which present as a floater (age-related).
- Vitreous haemorrhage with haemorrhaging in diabetic retinopathy.
Retinal Detachement
Separation of the neurosensory layer of the retina from the pigmented epithelium.
• Results in accumulation of sub-retinal fluid in the potential space (vitreous seeps in).
• Presents as floaters in vision, flashing lights, curtains descending over vision.
• Ocular emergency — usually requires surgery. If minor retinal break can use laser.
• Can result in blindness or visual impairment.
• Most common in middle-aged and elderly.
Glaucoma
Increased intraocular pressure caused by inadequate drainage (IOP should be 10–21 mmHg. >40 = significant damage caused) .
• Glaucoma causes compression of the retina and optic nerve.
Glaucoma: Causes
- Can be congenital or acquired (uveitis, intraocular haemorrhage).
- Obstruction of the canal of Schlemm.
- Smoking will moderately increase pressure.
Glaucoma: Complications
• Damage to the optic nerve and retina leads to permanent blindness.
Glaucoma (Acute): Signs and Symtpoms
- Mild: Pain in the eyes and haloes around lights, relieved by sleep.
- Severe: Rapid deterioration of vision, intense eye pain, redness and watering of the eye, sensitivity to bright light, nausea and vomiting.
Glaucoma (Chronic): Signs and Symtpoms
- Often no symptoms until permanent damage has occurred.
* Late symptoms: Loss of peripheral vision, blurring of objects directly in front of the person. Loss of night vision.
Glaucoma: Treatment
- Eye drops / tablets to reduce fluid production (reduces eye pressure).
- Laser or surgical treatment if this is ineffective.
Diabetic Retinopathy
Diabetic retinopathy is a progressive, potentially sight-threatening disease of the retinal microvasculature.
• Diabetic retinophropathy occurs as a result of chronic hyperglycaemia.
• Microvascular damage occurs, which occludes branches of the retinal artery, causing neovascularisation (new vessel formation in an attempt to re-vascularise).
• The vessel walls become physically weak and leaky, leading to micro-aneurysms,
oedema and haemorrhaging.
• May retain normal sight, or present as a decline in vision and ‘floaters’ (if haemorrhages).
