A. Symptoms
Hearing impairment, tinnitus, aural fullness, and vestibular symptoms are observed in cases who had preceding events, as listed below:
Coexisting or pre-existing middle and/or inner ear diseases (trauma, cholesteatoma, tumor, anomaly, SCCD, etc.) middle and/or inner ear surgeries Barotrauma caused by antecedent events or external origin (e.g., blasting, diving, or flying) Barotrauma caused by antecedent events of internal origin (e.g., nose-blowing, sneezing, straining, or carrying heavy objects) B. Laboratory findings
(1) Microscopic/endoscopic inspection
Visual identification of fistula(s) between the middle and inner ear by a microscope or endoscope. Fistulas can develop at the cochlear window, vestibular window, fracture site, microfissure, malformation, destruction in the bony labyrinth caused by inflammation, etc.
(2) Biochemical test
Perilymph-specific protein is detected in the middle ear
C. Reference
A perilymph-specific protein, e.g., Cochlin-tomoprotein (CTP) detection test. After myringotomy, the middle ear is rinsed with 0.3 mL of saline three times, the fluid recovered (middle ear lavage (MEL)) and tested by polyclonal antibody ELISA. The cutoff criteria are: 0.4 < CTP negative; 0.4 ≤ CTP <0.8 intermediate; 0.8 ≤ CTP positive Idiopathic cases may exist The following symptoms and/or test results may be observed: Streaming water-like tinnitus or feeling of running water in the middle ear Popping sound can be heard at the onset Nystagmus and/or vertigo induced by pressure application to the middle ear (Hennebert’s phenomenon, fistula sign) Imaging studies may show a fistula in the bony labyrinth or pneumolabyrinth Progression of hearing impairment, tinnitus, aural fullness may be acute, progressive, fluctuating, or recurrent The main complaints can be vestibular symptoms without hearing impairment D. Differential diagnosis
Inner ear diseases have known causes, such as viral infection, genetics, and vestibular schwannoma.
E. Diagnosis
Probable PLF: Only symptoms listed in A
Definite PLF: Symptoms and laboratory findings listed in B |
