Autoimmune and Systemic Disorders Flashcards
What is autoimmunity?
When the body goes awry and attacks the body itself
Produces autoantibodies or T lymphocytes reacting with the host’s antigens
What is the cause of autoimmunity?
Not well understood
Seen as possibly an interaction of various immunologic, hormonal, genetic, and viral factors
What is the incidence of autoimmune diseases?
5-8% of the population
Higher in women (have to be due to some hormonal influence or x-inactivation)
Are autoimmune diseases the 3rd most common category of diseases in the US?
Yes
After cancer and cardiovascular disease
Can damage done by some autoimmune responses be limited to a single organ?
Yes
Thyroid in Hashimoto’s disease
Can some autoimmune diseases cause systemic damage?
Yes
Lupus, rheumatoid arthritis, and MS
Does the inner ear have a blood-labyrinth barrier?
Yes, it is very important for the immune response of the inner ear
What was originally believed about the blood-labyrinth barrier?
That it protected the inner ear from systemic immune responses like the blood brain barrier
What is known now about the blood-labyrinth barrier?
Immune responses can occur in the inner ear activated by several immunologic mechanisms, making the inner ear susceptible to autoimmune conditions
Is little known about the inner ear vasculature and its role in inner ear disorders and treatment?
Yes
Does the blood-labyrinth barrier allow for the endolymph to maintain a high potassium level?
Yes
Required for production and maintenance of the EP
Disruption of the blood-labyrinth barrier due to vascular leakage can lead to an immediate hearing loss
Can normal vascular reactions to inflammatory factors be harmful to the inner ear?
Yes
Can cause breakdown of strial integrity, decreased endolymph production, and reduced EP levels
Is vasculature the connection between the body and the ear?
Yes
What tends to be the first vascular reaction to inflammation?
Breakdown of the blood-labyrinth barrier
Can steroids cause blood-labyrinth barrier restoration?
Yes by un-regulating tight junction genes
Are steroids the first line of treatment in autoimmune, inflammatory, and infectious conditions of the inner ear?
Yes because they suppress the immune system
What else do steroids do?
They suppress the production of inflammatory cells that produce cell death
Suppress the production of cytokines resulting in reduced inflammatory reaction
Suppress production of antibodies against foreign antigens and body’s own proteins
Stimulate the production of inhibitory factors that can inhibit the inflammatory cascade
Increase production of junctional proteins to seal the capillary lining restoring the blood-labyrinth barrier
What are some autoimmune disorders that affect the auditory system?
Systemic demyelinating conditions (MS)
Sudden-onset SNHL
What is a vascular disorder than affects the auditory system?
Vasculitis such as Wegener granulomatosis
What are metabolic disorders?
Diabetes
Thyroid disorders
What is autoimmune inner ear disease (AIED)?
Progressive bilateral SNHL occurring over a period of weeks to months
Responsive to immunosuppressive agents
Is it important to determine the underlying immune pathology for AIED?
Yes
Because AIED is one of the few cases of SNHL that is reversible
What are the two types of AIED?
Primary AIED and secondary AIED
What is primary AIED?
Diseases that are restricted to the ear
What is secondary AIED?
Coming from the rest of the body
Multisystemic
Cogan syndrome and Wegener granulomatosis
What is the incidence of AIED?
Rare disorder
1% of reported HL or dizziness
More common in females
Symptoms appear between 20 and 50 years of age
What is the clinical presentation of AIED?
Bilaterally SNHL progressive over weeks to months (although some present with unilateral fluctuating SNHL)
Aural fullness and/or tinnitus
Vestibular symptoms (imbalance, ataxia, vertigo)
How is AIED diagnosed?
Normal physical examination
May have manifestation of systemic autoimmune disease (effusion of the ME, EAC, and cough (Wegener), skin lesions, and vision loss (cogan’s)
Lab tests and imaging may be helpful in diagnosis
What is the treatment for AIED?
Corticosteroids (standard of care for 4 weeks)
Must begin as soon as possible, irreversible damage occurs within 3 months of onset
Steroids can be given longer than 4 weeks or repeated
What is the differential diagnosis for AIED?
Sudden SNHL (typically unilateral and not progressive)
Meniere’s disease (fluctuating SNHL, tinnitus, aural fullness, and vertigo)
Vestibular schwannoma, MS, and otosyphilis (need to rule out)
What is sudden SNHL?
Greater or equal to 30 dB HL SNHL occurring in at least 3 contiguous frequencies within 3 days
Is sudden SNHL typically unilateral?
Yes
If bilateral, probably not sudden SNHL (could be AIED)
If one ear is affected by sudden SNHL, what is the risk of the other ear being affected during a patient’s lifetime?
Rises by 4 to 17%
What is the incidence of sudden SNHL?
4000 new cases in the US and 15000 in the world (annually)
No gender difference
Increased incidence with age (most common during 5th and 6th decade of life)
Patient may report a cold or viral infection one to three weeks prior to symptoms
Can sudden SNHL happen if they already have a preexisting SNHL?
Yes
What are some possible causes of sudden SNHL?
Idiopathic
Viral infections
Ototoxic drugs
Trauma
Tumor
Autoimmune diseases
Meniere’s diseases
Perilymphatic fistula
Non-organic HL
Vascular pathology (diabetes, renal disease, leukemia, strokes, surgery causing embolus, etc.)
What are some histopathologic findings of sudden SNHL?
Atrophy of the organ of corti
Atrophy of the stria vascularis
Atrophy of the tectorial membrane
Most of the damage is observed at the cochlear basal turn but can occur anywhere along the cochlea
Degeneration of neural structures is significantly less than the cochlear structures
Vascular channels normal unless vascular etiology
Closely resemble those with viral hearing loss (mumps, rubella, measles, CMV)
What are the audiologic findings for sudden SNHL?
Unilateral sudden SNHL of any severity
Typically high frequency or flat mild to profound SNHL
WRS is much worse than predicted by pure tone thresholds
Vestibular system may be affected too (dizziness or severe vertigo in early stages, long symptom-free periods, long term oscillopsia and ataxia)
Normal tymps
ARTs consistent with degree of loss
What is needed to evaluate sudden SNHL?
A good case history and an audiologic evaluation
How can MRIs be helpful in sudden SNHL?
Useful in ruling out trauma, tumors, or MS
Can lab tests be useful in diagnosing sudden SNHL?
If the etiology is related to hormone levels, a autoimmune condition, or diabetes
When should treatment for sudden SNHL begin?
Within one week of onset
Steroids
What are some consequences of long-term steroid therapy?
Increased appetite and weight gain
Increased susceptibility to infection
Organ damage (blurred vision, upset stomach, gastric ulcers)
Bone loss
Increased hyperglycemia, a major concern for diabetic patients
Fluid retention and increased blood pressure
Can intratympanic steroids be used?
Yes, such as dexamethasone
Can be given in higher concentration with less of the side effects of systemic administration
Injection
What is the prognosis for sudden SNHL?
Variable
30-60% of patients improve without treatment
The SNHL will be permanent in about half the patients even with treatment
What are some indications of a good prognosis for sudden SNHL?
Mild low frequency SNHL
Symptoms persisting for a shorter time
Even with recovery of thresholds, WRS may not fully recover
What are some indications for a poor prognosis for sudden SNHL?
Age; the very old and very young
High frequency or flat SNHL
Greater severity of the SNHL
Accompanying vertigo
Diabetes
What are demyelinating diseases?
Diseases that results in damage (demyelination) of the myelin sheath that surrounds nerve fibers in the brain and spinal cord