Meniere disease Flashcards
General findings
Unfortunately, there is no known way to prevent the natural progression of hearing loss. Most patients sustain moderate to severe sensorineural hearing loss in the affected ear within 10 to 15 years.
Meniere disease is an inner ear disorder that causes vertigo, fluctuating sensorineural hearing loss, and tinnitus. There is no reliable diagnostic test. Vertigo and nausea are treated symptomatically with anticholinergics or benzodiazepines during acute attacks. Diuretics and a low-salt diet, the first line of treatment, often decrease the frequency and severity of episodes. For severe or refractory cases, the vestibular system can be ablated with topical gentamicin or surgery.
In Meniere disease, pressure and volume changes of the labyrinthine endolymph affect inner ear function. The etiology of endolymphatic fluid buildup is unknown. Risk factors include a family history of Meniere disease, preexisting autoimmune disorders, allergies, trauma to the head or ear, and, very rarely, syphilis. Peak incidence is between ages 20 and 50.
Attacks of hydrops probably are caused by an increase in endolymphatic pressure, which, in turn, causes a break in the membrane that separates the perilymph (potassium-poor extracellular fluid) from the endolymph (potassium-rich intracellular fluid). The resultant chemical mixture bathes the vestibular nerve receptors, leading to a depolarization blockade and transient loss of function. The sudden change in the rate of vestibular nerve firing creates an acute vestibular imbalance (ie, vertigo).
Clinica
- vertigo (da 1 ora a 6 ore) (di tipo periferico)
- nausea, vomito
- tinnitus
- Fluctuating hearing impairment, typically affecting low frequencies (nei traumi acustici tipicamente sono colpite le alte frequenze). Before and during an episode, most patients sense fullness or pressure in the affected ear. In a majority of patients, only one ear is affected.
Evoluzione
Unfortunately, there is no known way to prevent the natural progression of hearing loss. Most patients sustain moderate to severe sensorineural hearing loss in the affected ear within 10 to 15 years.
🧨Chronic progressive hearing loss!
During the early stages, symptoms remit between episodes; symptom-free periods may last > 1 year. As the disease progresses, however, hearing impairment persists and gradually worsens, and tinnitus may be constant.
Diagnosi,CLINICA
- Clinical evaluation
- Audiogram and gadolinium-enhanced MRI to rule out other causes
- Romberg positivo, con oscillazione del paziente verso il lato affetto, con nistagmo di tipo orizzontale verso il lato sano, e vertigine periferica o oggettiva (è la stanza che gira) 💥
The diagnosis of Meniere disease is made clinically. The simultaneous combination of fluctuating low-frequency sensorineural hearing loss, episodic vertigo, ipsilateral fluctuating aural fullness, and tinnitus is characteristic.
DDx
Similar symptoms can result from vestibular migraine, viral labyrinthitis or neuronitis, a cerebellopontine angle tumor (eg, acoustic neuroma), or a brain stem stroke. Although bilateral Meniere disease can occur, bilateral symptoms increase the likelihood of an alternate diagnosis (eg, vestibular migraine). Vestibular migraine (also known as migrainous vertigo) is characterized by episodes of vertigo in patients who have a history of migraines or with other features of migraines, such as headache, photophobia and phonophobia, or visual aura; there is no loss of hearing.
Treatment
- Symptom relief with antiemetics, antihistamines, or benzodiazepines
- Diuretics and low-salt diet
- Rarely vestibular ablation by drugs or surgery (gentamicina)
- Anticholinergic antiemetics (eg, prochlorperazine can minimize vagal-mediated gastrointestinal symptoms) ondansetron is a 2nd-line antiemetic.
- Antihistamines (eg, diphenhydramine, meclizine, or cyclizine or benzodiazepines (eg, diazepam 5 mg orally every 6 to 8 hours) are used to sedate the vestibular system.
💥Neither antihistamines nor benzodiazepines are effective as prophylactic treatment.
- A low-salt (< 1.5 g/day) diet, avoidance of alcohol and caffeine, and a diuretic (eg, hydrochlorothiazide 25 mg orally once/day or acetazolamide 250 mg orally 2 times a day) may help prevent or reduce the incidence of vertigo attacks and are commonly used first steps👓.
- Although more invasive, endolymphatic sac decompression relieves vertigo in a majority of patients, spares vestibular function, and poses minimal risk of hearing loss. Thus this procedure is still classified as a vestibular-sparing treatment.
- When vestibular-sparing treatments fail, an ablative procedure is considered. Intratympanic gentamicin is injected through the tympanic membrane. Follow-up with serial audiometry is recommended to monitor for hearing loss. The injection can be repeated in 4 weeks if vertigo persists without hearing loss.
- Ablative surgery is reserved for patients with frequent, severely debilitating episodes who are unresponsive to less invasive modalities. Vestibular neurectomy (an intracranial procedure) relieves vertigo in about 95% of patients and usually preserves hearing. A surgical labyrinthectomy is done only if preexisting hearing loss is profound.
SCENARIO Durante uno studio clinico si analizza la concentrazione ionica dell’endolinfa DOMANDA La speciale concentrazione ionica dell’endolinfa si deve all’azione secretoria dell’epitelio di:
Membrana timpanica Acquedotto cocleare. Membrana di Reissner Sacco endolinfatico. ✔Stria vascolare
La stria vascolare si trova nella faccia interna del condotto cocleare ed è dove si produce l’endolinfa, a partire da un filtrato attivo derivato dalla perilinfa. Nel sacco endolinfatico si verifica il riassorbimento di endolinfa. La composizione dell’endolinfa sembra quella dei liquidi intracellulari, con elevato contenuto di potassio, mentre la perilinfa è più simile al liquido cefalorachidiano, con maggiore quantità di sodio. Ricorda che le alterazioni nella regolazione degli elettroliti tra endolinfa e perilinfa danno luogo ad idrope endolinfatica (vedi patogenesi della malattia di Meniere).
