Hearing Loss and Tinnitus Flashcards
What is tinnitus?
Perception of a sound in the absence of an environmental acoustic stimulus.
What is objective v subjective tinnitus? Which is more common?
Objective can also be heard by the observer.
Subjective is by far the most common.
What is implied by pulsatile and organic tinnitus?
An underlying organic cause.
What are the causes of tinnitus?
All causes of hearing loss
It is possible to experience with normal, no or intermittent hearing.
What are the causes of pulsatile tinnitus?
Hypervascularity: physiological or pathological
Arterial: arteriosclerosis, aneurysms, dissection, aberrant vessels
Venous: benign intracranial hypertension, dehiscent jugular bulb
Both: AVMs
Other: myoclonus, stapedius, tensor tympani, tensor veli, palatini.
What are the physiological causes of hypervacsularity?
Pregnancy
Children
Athletes
What are the pathological causes of hypervascularity?
Infection
Malignancy
Cardiac shunts etc
How can pulsatile tinnitus be investigated?
Augiogram
Imaging: anatomy (CT temporal bones for tumours, dehiscent jugular bulbs) and blood vessels (carotid doppler, MRI/MRA/MRV)
-CT (to image bony windows etc)
-MRI (acoustic neuromas, tumours etc, BIHTN)
What are the types of hearing loss?
Sensorineural (inner ear)
Conductive (outer/middle ear)
Mixed
Central (relating to auditory cortex)
What is the basic difference in sensorineural vs conductive audiogram?
Condctive will have two separate lines (for each ear) however sensorineural will have generally the same hearing in both ears declining at a point.
What is the appearance of mixed hearing loss?
Bone conduction and air conduction in one ear the same BUT
the bone conduction on the other side will be different to the sensorineural line.
What are the causes of conductive hearing loss?
Obstruction: wax, water, bone
Tympanic membrane: perforation, thickening/scarring
Middle ear: infection, serous effusion, discontinuity of bones, otosclerosis (bones lay down excess bone and fuse).
What are the causes of sensorineural hearing loss?
Age: presbycusis Noise induced HL Trauma Neoplasm Infection
What are the causes of asymmetrical SNHL?
Trauma
Neoplasm
Infection
What is sudden sensorineural hearing loss?
Acute sensorineural hearing loss of at least 30dB across at least 3 frequencies, occurring within 3 days.
