Noninflammatory Diseases ofthe labyrinth Primary involvement of the cochlea, vestibular apparatus, or the eighth cranial nerve with spread to the contiguous structures is characteristic of this group of diseases. Unfortunately, the common involvement of the vestibular labyrinth and its widespread central nervous connections in systemic illness makes difficult the differentiation of symptoms due to this cause from those due to specific vestibular disease The principal subjective symptoms---vertigo(Hz ) deafness, and tinnitus--are all common to this group of disorders, again creating problems of diagnosis. Rap id progress in methods of examination of cochlear and vestibular function has greatly aided in the differentiation of these diseases and thus removed a great deal of the confusion which was present in the past Vertigo and dizziness Vertigo is defined as a hallucination of movement this may be a sensation of turning, sp inning, falling, rocking, etc. Dizziness, although commonly used by the patient as a term to describe the above sensations refers to less severe and distinct sensations of giddiness, faintness confusion, blankness, or unsteadiness. This differentiation is important since vertigo arises from disturbance of the vestibular end-organ vestibular nerve, or vestibular nucleus. Dizziness may arise from mild
Noninflammatory Diseases of the Labyrinth Primary involvement of the cochlea, vestibular apparatus, or the eighth cranial nerve with spread to the contiguous structures is characteristic of this group of diseases. Unfortunately, the common involvement of the vestibular labyrinth and its widespread central nervous connections in systemic illness makes difficult the differentiation of symptoms due to this cause from those due to specific vestibular disease. The principal subjective symptoms---vertigo(眩晕), deafness, and tinnitus--are all common to this group of disorders, again creating problems of diagnosis. Rapid progress in methods of examination of cochlear and vestibular function has greatly aided in the differentiation of these diseases and thus removed a great deal of the confusion which was present in the past. Vertigo and Dizziness Vertigo is defined as a hallucination of movement. This may be a sensation of turning, spinning, falling, rocking, etc. Dizziness, although commonly used by the patient as a term to describe the above sensations, refers to less severe and distinct sensations of giddiness, faintness, confusion, blankness, or unsteadiness. This differentiation is important, since vertigo arises from disturbance of the vestibular end-organ, vestibular nerve, or vestibular nucleus. Dizziness may arise from mild
disturbance of the vestibular apparatus but usually indicates distur bance in other regions An analogy given by Cawthoru helps to clarify the types of disturbance of the poripheral vestibular apparatus resulting in vertigo This mechanism may be likened to a twin-engined airplane. When both engines are running normally and the controls are properly operating, the airplane flies on a straight course. If one engine suddenly fails, the plane s violently diverted off its course by the unopposed action of the normally running engine. By readjusting the controls, after a short period the pilot is able to fly on a straight course again, though turning or a sudden gust of wind will have a more distur bing effect than when the two engines are working normally. In another situation the faulty engine may start up again, and even if it does not return to its normal speed, all is well provided it runs steadily. However, should the faulty engine repeatedly fail and recover, the result will be more disturbing than having a dead engine. In another situation one engine may fail to work properly only when the airplane is in a certain position, such as in a steep bank to the left, but will return to normal as soon as the airp lane straightens out Finally, if one engine loses power slowly, the pilot almost imperceptibly is able to readjust the controls without deviating from his course The airp lane engines may be directly compared to the set of vestibular end-organs in each labyrinth, Each of the types of failure may occur in
disturbance of the vestibular apparatus but usually indicates disturbance in other regions. An analogy given by Cawthoru helps to clarify the types of disturbance of the poripheral vestibular apparatus resulting in vertigo. This mechanism may be likened to a twin-engined airplane. When both engines are running normally and the controls are properly operating, the airplane flies on a straight course. If one engine suddenly fails, the plane is violently diverted off its course by the unopposed action of the normally running engine. By readjusting the controls, after a short period the pilot is able to fly on a straight course again, though turning or a sudden gust of wind will have a more disturbing effect than when the two engines are working normally. In another situation the faulty engine may start up again, and even if it does not return to its normal speed, all is well provided it runs steadily. However, should the faulty engine repeatedly fail and recover, the result will be more disturbing than having a dead engine. In another situation one engine may fail to work properly only when the airplane is in a certain position, such as in a steep bank to the left, but will return to normal as soon as the airplane straightens out. Finally, if one engine loses power slowly, the pilot almost imperceptibly is able to readjust the controls without deviating from his course. The airplane engines may be directly compared to the set of vestibular end-organs in each. labyrinth, Each of the types of failure may occur in
man, resulting in each case with loss of equilibrium and a type of vertigo evaluating vertigo, the history is of great importance. The following information should be elicited(引出) 1. Whether the symptom experienced is true vertigo. If the comp laint does consist of a sensation of motion or turning. the origin lies in the vestibular apparatus; otherwise, other regions must be subjected to examination and evaluation 2. The pattern of the vertigo. It is important to note whether the attacks are spontaneous or precip itated(突如其来的) by movement. The presence of paroxysmal attacks separated by periods of relative freedom from symptoms indicates a different pathologic condition than more or less continuous dizziness 3. The degree of vertigo. Vertigo arising in the labyrinth is usually accompanied by nausea and often vomiting. Less specific forms may be milder and may arise from any part ofthe body 4. The association of hearing loss or tinnitus with dizziness is a definite aid to localization. Complete audiometric evaluation is essential to the examination of the dizzy patient, since these diseases may affect the vestibular apparatus alone the cochlear apparatus alone, or both together Tinnitus This may be objective in rare instances(a sound which may be heard
man, resulting in each case with loss of equilibrium and a type of vertigo. In evaluating vertigo, the history is of great importance. The following information should be elicited (引出): 1. Whether the symptom experienced is true vertigo. If the complaint does consist of a sensation of motion or turning, the origin lies in the vestibular apparatus; otherwise, other regions must be subjected to examination and evaluation 2. The pattern of the vertigo. It is important to note whether the attacks are spontaneous or precipitated(突如其来的) by movement. The presence of paroxysmal attacks separated by periods of relative freedom from symptoms indicates a different pathologic condition than more or less continuous dizziness. 3. The degree of vertigo. Vertigo arising in the labyrinth is usually accompanied by nausea and often vomiting. Less specific forms may be milder and may arise from any part of the body. 4. The association of hearing loss or tinnitus with dizziness is a definite aid to localization. Complete audiometric evaluation is essential to the examination of the dizzy patient, since these diseases may affect the vestibular apparatus alone, the cochlear apparatus alone, or both together. Tinnitus This may be objective in rare instances (a sound which may be heard
by the examiner) but is usually a subjective sensation of sound arising from within the head. Tinnitus may vary in intens ity and may be continuous or intermittent. Subjectively loud and continuous tinnitus may produce a severe handicap(pal)to the individual Tinnitus is associated with hearing loss arising from disorders of the sound conduction system, the cochlea, or the neural pathways of the cochlear nerve. Patients describe the sound in various ways, but the examiner should attempt to obtain a description of the sound with which both the patient and the doctor is familiar. In general the sounds experienced will range from predominant!y(主要地) low frequencies (like a ventilating fan or sea shell sound) to wide-range white noise(a rushing sound commonly experienced in Meniere's disease) or high-p itched noise, whistles, or insect sounds(which frequently may be matched on the audiometer) Conductive hearing loss usually produces a low-pitched continuous sound which, if combined with inflammation, becomes pulsating High-pitched continuous or intermittent tinnitus is associated with high tone hearing loss and is an important and early sign of drug intoxication ( aspirin, digitalis洋地黄, quinine, dihydrostreptomycin,eec Pulsating low-pitched tinnitus without hearing loss is an important early symptom of glomus jugulare tumors of the middle ear. It is also associated with occlusive disease of the carotid artery which will at times
by the examiner) but is usually a subjective sensation of sound arising from within the head. Tinnitus may vary in intensity and may be continuous or intermittent. Subjectively loud and continuous tinnitus may produce a severe handicap(阻碍)to the individual. Tinnitus is associated with hearing loss arising from disorders of the sound conduction system, the cochlea, or the neural pathways of the cochlear nerve. Patients describe the sound in various ways, but the examiner should attempt to obtain a description of the sound with which both the patient and the doctor is familiar. In general the sounds experienced will range from predominantly（主要地） low frequencies (like a ventilating fan or sea shell sound) to wide-range white noise (a rushing sound commonly experienced in Meniere's disease) or high-pitched noise, whistles, or insect sounds (which frequently may be matched on the audiometer). Conductive hearing loss usually produces a low-pitched continuous sound which, if combined with inflammation, becomes pulsating. High-pitched continuous or intermittent tinnitus is associated with high tone hearing loss and is an important and early sign of drug intoxication (aspirin, digitalis 洋 地 黄 , quinine, dihyclrostreptomycin, etc.). Pulsating low-pitched tinnitus without hearing loss is an important early symptom of glomus jugulare tumors of the middle ear. It is also associated with occlusive disease of the carotid artery, which will at times
produce an audible bruit Other than relieving a conductive hearing loss there is no effective treatment of tinnitus. Even section of the eighth nerve in most cases does not result in cessation( IE)of tinnitus. Patients suffering from this symptom deserve a full and honest exp lanation of the nature of the disorder so that natural anxiety does not cause exaggeration of the severity of the symptoms. Barbiturates and tranquilizers are rarely indicated for use in this condition for in most instances patients are able to adapt to the presence of tinnitus and ignore it Examination and Differential Diagnosis The main causes of vertiginous labyrinthine distur bance are 1. Acute toxic labyrinthitis 2. Meniere's disease 3. Paroxysmal positional vertigo (postural verti 4. Vestibular neuronitis(前庭神经元炎) 5. Vertebral- basilar artery insufficiency(椎基底动脉供血不足) 6. Trauma 7. Tumor(Acoustic neurinoma The main types of distur bances to be differentiated from these diseases are the following 1. Disease of the cerebellum, especially vascular disease and tumors 2. Disease of the proprioceptive system
produce an audible bruit. Other than relieving a conductive hearing loss, there is no effective treatment of tinnitus. Even section of the eighth nerve in most cases does not result in cessation(停止) of tinnitus. Patients suffering from this symptom deserve a full and honest explanation of the nature of the disorder so that natural anxiety does not cause exaggeration of the severity of the symptoms. Barbiturates and tranquilizers are rarely indicated for use in this condition, for in most instances patients are able to adapt to the presence of tinnitus and ignore it. Examination and Differential Diagnosis The main causes of vertiginous labyrinthine disturbance are: 1. Acute toxic labyrinthitis 2. Meniere's disease 3. Paroxysmal positional vertigo (postural vertigo) 4. Vestibular neuronitis（前庭神经元炎） 5. Vertebral-basilar artery insufficiency(椎基底动脉供血不足) 6. Trauma 7. Tumor (Acoustic neurinoma) The main types of disturbances to be differentiated from these diseases are the following: 1. Disease of the cerebellum, especially vascular disease and tumors 2. Disease of the proprioceptive system