<unk>  is traditionally diagnosed by characteristic clinical findings, which include progressive conductive hearing loss, a normal tympanic membrane, and no evidence of middle ear inflammation. The cochlear promontory may have a faint pink tinge reflecting the vascularity of the lesion, referred to as the Schwartz sign. Approximately 0.5% of the population will eventually be diagnosed with<unk> . Post-mortem studies show that as many as 10% of people may have otosclerotic lesions of their temporal bone, but apparently never had symptoms warranting a diagnosis. Caucasians are the most affected race, with the prevalence in the Black and Asian populations being much lower. In clinical practice<unk>  is encountered about twice as frequently in females as in males, but this does not reflect the true sex ratio. When families are investigated it is found that the condition is only slightly more common in women. Usually noticeable hearing loss begins at middle-age, but can start much sooner. The hearing loss was long believed to grow worse during pregnancy, but recent research does not support this belief. Differential testing Audiometry Fixation of the stapes within the oval window causes a conductive hearing loss. In pure-tone audiometry, this manifests as air-bone gaps on the audiogram (i.e. a difference of more than 10 dB between the air-conduction and bone-conduction thresholds at a given test frequency). However, medial fixation of the ossicular chain impairs both the inertial and osseotympanic modes of bone conduction, increasing the bone-conduction thresholds between 500 Hz and 4 kHz, and reducing the size of air-bone gaps. As 2 kHz is the resonant frequency of the ossicular chain, the largest increase in bone-conduction threshold (around 15 dB) occurs at this frequency – the resultant notch is called Carhart's notch and is a useful clinical marker for medial ossicular-chain fixation. Tympanometry measures the peak pressure (TPP) and peak-compensated static admittance (Ytm) of the middle ear at the eardrum. As the stapes is ankylosed in<unk> , the lateral end of the ossicular chain may still be quite mobile. Therefore,<unk>  may only slightly reduce the admittance, resulting in either a shallow tympanogram (type AS), or a normal tympanogram (type A).<unk>  increases in the stiffness of the middle-ear system, raising its resonant frequency. This can be quantified using multi-frequency tympanometry. Thus, a high resonant-frequency pathology such as<unk>  can be differentiated from low resonant-frequency pathologies such as ossicular discontinuity. In the absence of a pathology, a loud sound (generally greater than 70 dB above threshold) causes the stapedius muscle to contract, reducing the admittance of the middle ear and softening the perceived loudness of the sound. If the mobility of the stapes is reduced due to<unk> , then stapedius muscle contraction does not significantly decrease the admittance. When acoustic reflex testing is conducted, the acoustic reflex thresholds (ART) cannot be determined when attempting to measure on the affected side. Also, a conductive pathology will attenuate the test stimuli, resulting in either elevated reflex thresholds or absent reflexes when the stimulus is presented in the affected ear and measured in the other ear. CT imaging Imaging is usually not pursued in those with uncomplicated conductive hearing loss and characteristic clinical findings. Those with only conductive hearing loss are often treated medically or with surgery without imaging. The diagnosis may be unclear clinically in cases of sensorineural or mixed hearing loss and may become apparent only on imaging. Therefore, imaging is often performed when the hearing loss is sensorineural or mixed. A high-resolution CT shows very subtle bone findings. However, CT is usually not needed prior to surgery.<unk>  on CT can be graded using the grading system suggested by Symons and Fanning. * Grade 1, solely fenestral; * Grade 2, patchy localized cochlear disease (with or without fenestral involvement) to either the basal cochlear turn (grade 2A), or the middle/apical turns (grade 2B), or both the basal turn and the middle/apical turns (grade 2C); and * CT scan of otosclerotic focus in the anterior footplateGrade 3, diffuse confluent cochlear involvement (with or without fenestral involvement).
Otosclerosis
Band keratopathy
Corneal ulcer
Macular corneal dystrophy
Granular corneal dystrophy
Exposure keratopathy
Fundic gland polyposis
Bullous keratopathy