Ask The Doctor

Ask The Doctor

Dear IBIA, I have often dealt with post-TBI patients who complain of dizziness.  A patient of mine was recently given a diagnosis of "post traumatic perilymphatic fistula".  I have never heard of this condition and cannot find much information on it, although I may be looking in the wrong places.  Please inform me, as well as, other readers, about this condition.  Also any information on dizziness in our clients with TBI would be appreciated.   

D.L., British Columbia, Canada

IBIA Responds

It is all too common that clinicians make a diagnosis of "post-traumatic dizziness" without looking much further than that in an attempt to identify the underlying etiology of the subjective complaint of dizziness.  All dizziness has a cause.  Elucidating the cause allows for appropriate and timely treatment to be rendered and, certainly, for more optimal functional outcome, if the diagnosis is indeed correct.

There are various etiologies of post traumatic dizziness.  Perilymphatic fistulas (PLFs), which can occur following trauma of various types is only one potential etiology and its frequency following trauma has been highly debated (e.g. some clinicians feel it is very common, whereas others feel it is quite uncommon.  Readers should note that brain injury is not necessary for development of a PLF.

Perilymphatic Fistula

Post-traumatic PLFs may present following trauma as a result of rupture of the oval and less commonly the round window with subsequent dehiscence between the inner ear and middle ear resulting in inappropriate stimulation of labyrinthine receptors.  Symptoms may include vertigo, fluctuating hearing loss (usually a late complication), tinnitus (ringing in the ears) and chronic low grade nausea.

Other associated conditions include endolymphatic hydrops (Meniere's disease), cervical myodystonia (abnormal muscle tone) and persistent or exertional headache.  These types of patients, as with other patients with vestibular disorders may often complain of non-specific imbalance problems, worse than by sudden turning, as well as disequilibrium with perceptually complex external stimuli.  Specifically, these individuals report feeling uncomfortable in crowds, when driving down tree-lined streets and when traveling on an escalator. 

It is quite interesting that patients with perilymphatic fistula, as well as, vestibular disorders, in general, often become agoraphobic (develop a fear of being among crowds) and have a relatively high incidence of anxiety related disorders, including panic attacks. 

The aforementioned phenomena has been studied to some extent and makes sense, if one thinks about it, relative to the fact that visual stimulation associated with a perceptually stimulating environment has the propensity to make one become avoidant of such stimuli if one has a vestibular disorder of any magnitude.  Given that such stimuli cause the patient to feel uncomfortable, it is not unexpected that such secondary psychological disorders may develop. 

Some clinicians have speculated that post-traumatic perilymphatic fistula symptoms stimulate visual compensation for labyrinthine dysfunction subsequently causing disorientation in visually complex situations. Additionally, some have noted problems with higher level cognition and language. All these aforementioned problems are presumed to have a perceptual basis, related not to brain injury per se, but attempted sensory accommodation to aberrant sensory input as a result of the perilymphatic fistula.

I think this point is quite important in that I have seen many cases, both clinically, as well as, forensically where patients are labeled as brain injured who, in fact, only have a vestibular disorder which has caused an array of somatic, cognitive and behavioral symptoms that were incorrectly apportioned to brain injury.  The diagnoses of traumatic brain injury and perilymphatic fistula are not mutually exclusive and patients not uncommonly have both conditions concurrently and must be treated for each accordingly.

The definitive diagnostic test for perilymphatic fistulas remains somewhat controversial.  There has been recent literature, looking at the use of the fistula test which questions it utility as a definitive measure of PLF presence.  Bedside clinical findings are generally not particularly sensitive to this condition including the Hallpike or Nylen-Barany maneuver, Tragus test and/or Hennebert's test, among others. 

Certain software programs have been designed to provide a "fistula test" during posturographic assessment; again, this literature and the efficacy of the test has been debated in the field of neuro-otology and vestibular rehabilitation relative to it's level of specificity and sensitivity. 

New techniques including transtympanic electrocochleography have been used, pre-operatively, as well as, post-operatively to evaluate for perilymphatic fistulas. Many clinicians believe that the definitive diagnosis can only be made at the time of surgery based on inspection, however, many clinicians will tell you, even at that point, it is still sometimes difficult to make a definitive diagnosis. Another promising technique involves analysis of fluid harvested at the time of surgical inspection with analysis for beta II transferrin via immunoblotting assay to assist in making a more definitive diagnosis. Beta II transferrin is only found in cerebrospinal fluid and inner ear perilymph and is absent from serum and other body fluids.

Generally, post-traumatic PLFs heal spontaneously.  Treatment of non-resolving PLFs involves surgical patching of the leak if bed rest is ineffective.  Surgery is also indicated if there is a sudden hearing loss without improvement and/or continued symptoms beyond one month from a presumptive PLF. 

Causes of Dizziness

Other causes of dizziness following trauma include inner ear dysfunction due to a variety of different conditions aside from perilymphatic fistula including post traumatic endolymphatic hydrops (so-called Meniere's disease), benign paroxysmal positional vertigo (also referred to BPPV) and labyrinthine concussion.  Vestibular nerve damage with disruption of 8th cranial nerve function, not uncommonly associated with temporal bone fractures, is another etiology of post traumatic dizziness.  

Direct injury of the brain stem or vestibulocerebellar connections can also result in so-called central vertigo.  This is a very challenging problem with a very guarded prognosis for improvement. In my own clinical experience, a common, yet still controversial etiology of dizziness is so-called cervical vertigo associated with whiplash injuries. 

This type of dizziness is related to perturbations in information received from joint position receptors (i.e. proprioceptors) in the neck that feed into the vestibular system.  A relatively uncommon cause of dizziness following trauma can also been seen with what has been termed ictal vertigo, associated with post-traumatic epilepsy.  This has also been referred to as "tornado" epilepsy.  This primarily occurs in simple partial seizures which usually evolve into complex partial seizures or generalized seizures with loss of consciousness.

Psychological conditions, in and of themselves, can also result in complaints of dizziness including anxiety disorders, depression, panic disorders, and certain somatoform disorders.  Certainly, dizziness can also be embellished and/or malingered.  One should not forget dizziness due to such things as over medication or medication related side effects. 

Bottom line is that if we just treat symptoms without trying to delineate the cause of a specific impairment then we will only have limited efficacy in ameliorating the condition in question.

REFERENCES

Conroy NE, Erogul M, Logan JR, et al: Perilymph fistula. E-medicine. 3/17/2007.

Delaroche O, Bodoure P, Lippert E, Sagniez M:  Perilymph Detection by Beta II - Transferrin Immunoblotting Assay.  Application to the Diagnosis of Perilymphatic Fistula.  Clin Chim Acta.  254:1, 93-104, 1996

Fitzgerald DC:  Head Trauma:  Hearing Loss and Dizziness.  J Trauma 40:3, 488-96, 1996

Granier M, Renaud-Picard L, Chobaut JC, et al: Mild head trauma: complications and acousticovestibular sequelae. Rev Stomatol Chir Maxillofac. 107(4):253—263, 2006.

Iverson, GL, Zasler, ND, Lange, RT: Post-Concussive Disorder. In: Brain Injury Medicine: Principles and Practice. N. Zasler, D. Katz, R. Zafonte (Eds.). New York. Demos Publishers. 2007.

Maitland CG: Perilymphatic fistula. Curr Neurol Neurosci Rep. 1(5):486-491, 2001.

Michel O, Petereit H, Klemm E, et al: First clinical experience with beta-trace protein (prostaglandin D synthase) as a marker for perilymphatic fistula. J Laryngol Otol. 119(10):765-769, 2005.

Sass K, Densert B, Magnusson M, Transtympanic Electrocochleography in the Assessment of Perilymphatic Fistulas.  Audiol Neuro-Otol 2: 6, 391-402 1997

Tusa RJ, Brown SB, Neuro-Otologic Trauma and Dizziness.  N Mathew Rizzo and Daniel Tranel:  Head Injury and Post Concussive Syndrome.  Vertual Livingston, New York.  Pgs 177-200, 1996

Zasler, N.D.:  Neuromedical diagnosis and management of post-concussive disorders.  In:  L. Horn and N.D. Zasler (Eds.):  Medical Rehabilitation of Traumatic Brain Injury.  Philadelphia.  Hanley & Belfus, Inc.  1996.