Timothy C. Hain, MD • Page last modified: August 20, 2020
Hydrops means that the pressure in the inner ear is elevated. Dogma states that all persons with Meniere's disease have hydrops, but that some people can have hydrops without meeting the committee criteria for Meniere's.
Delayed endolymphatic hydrops consists of new ear symptoms that occur many years after onset of profound deafness. It can be ipsilateral, contralateral or bilateral. This is very broad. DEH resembles the common situation where Meniere's on one side starts to affect the other side.
While the early literature states that DEH is different than Meniere's disease, practically we find it hard to tell them apart. "Walks like a duck, quacks like a duck ... " In our view, the Meniere's committee criteria are simply not flexible enough to cover DEH, but Meniere's disease and DEH they seem to be variants of the same process.
Harold Schuknecht (1978), an otopathologist at the Mass Eye and Ear Infirmary in Boston, was the first to introduce the term "DEH". Schuknecht's colleagues at Mass Eye/Ear were the first to recognize the entity, but this paper was published under the name of "unilateral deafness with subsequent vertigo", by Wolfson and Lieberman (1975), and Vertigo of delayed onset after sudden deafness" (Nadol, 1975) . However, most subsequent discussion quote Schuknecht, who appeared to have coined the term, and who also discussed the entity in his influential text on the pathology of the ear. Schuknecht wrote in 1978:
"Delayed endolymphatic hydrops is a disease entity that can be differentiated from Meniere's disease. Typically it occurs in patients who have sustained a profound hearing loss in one ear, usually from infection or trauma, and then after a prolonged period of time develop either episodic vertigo from the same ear (ipsilateral delayed endolymphatic hydrops) or fluctuating hearing loss, also sometimes with episodic vertigo, in the opposite ear (contralateral delayed endolymphatic hydrops). The ipsilateral form of the disease may be treated by labyrinthectomy but no satisfactory therapy is available for the contralateral form of the disease."
This definition is tricky. When he says -- "can be differentiated" -- presumably he meant at autopsy, as Dr. Schuknecht was a pathologist. Thus a little hard to be sure by this definition -- unless you are already dead. A cynical take on the definition of "differentiated" is that without a claim of distinction from Meniere's, this paper would not be published. The definition is wonderfully broad - either hearing loss or dizziness or both, on either side, in someone who had a previous "profound hearing loss", after a "prolonged period of time". So essentially, almost any type of ear symptom, occurring after a long delay from a severe hearing loss.
Two years later, LeLiever and Barber (1980) reported DEH in 18 patients, of whom 8 were "thought" to have hearing loss due to either measles or mumps. The average delay between hearing loss and vertigo was 22.6 years.
Futaki et al (1984) proposed that the furosemide test was positive in a subset of 11 cases at the University of Tokyo.
The broad brush with which DEH was defined might easily apply to almost any ear disorder, including noise damage, such as military gunfire. Supporting this idea, Ylikoshi (1988) reported DEH in 18 senior army officers. It is presently not thought that DEH is noise induced.
Hicks and Wright (1988) provided their definition of DEH as "a profound sensorineural hearing loss in one ear, with the onset of episodic vertigo from that ear after a prolonged period of time (ipsilateral delayed endolymphatic hydrops) or the development of fluctuating hearing loss and/or episodic vertigo in the opposite ear after a prolonged period of time (contralateral delayed endolymphatic hydrops) ". Here there is again the idea that there can be symptoms on the other side, many years after profound hearing loss. Hicks and Wright, who are surgeons, suggested that surgical treatment provided the best results.
Yaku and Komatsuzaki (1989)examined the inner ear of two women, aged 27 and 16, carrying the diagnosis of DEH from tissue obtained in the course of surgery, and found very little abnormal. One wonders if these patients had another source of dizziness such as migraine.
Schuknecht clarified in 1990 that there were "ipsilateral and contralateral types". Makes sense, but what about bilateral ?. Based on 2 patients where autopsy was done, he proposed that "These observations support the proposition that Meniere's disease may occur as a delayed sequela of inner ear damage sustained during an attack of subclinical viral labyrinthitis occurring in childhood." This seems to us to be somewhat of a "stretch" based on 2 autopsy specimens.
Kobayashi et al (1993) reported a single case of DEH after acoustic surgery, in the same ear. One would wonder if this was really DEH.
Aso and Watanabe (1994) reported ECOG may be helpful for diagnosis of DEH. The numbers were not very convincing.
Harris and Aframian (1994) proposed that contralateral DEH may be autoimmune.
Harcourt and Brookes (1995) reported on 24 patients with ipsilateral DEH, and also that this group responded well to destructive surgery.
Takeda (1998) reported that among 23 patients with DEH, 15 were ipsilateral and 8 were contralateral.
Casani et al (1993) reported on a similar series of 12 cases, and added that in their patients the average delay was only 12 years.
Huang and Lin (2001) reported on 160 patients with ipsilateral, contralateral, or bilateral DEH. Thus they added another category (bilateral). They suggested that "DEH and Meniere's disease are related disorders caused predominantly by cases of viral labyrinthitis with unknown etiology. "
Kamei published a review of DEH in the International Tinnitus Journal (2004). This is a lightly reviewed academic journal, and his statements we think are properly viewed as his opinions (much the same as many of my statements on this web site). Kamei suggested that the delay can be as short as 1 year, or as long as 74 years. This makes the definition broader yet ! According to Kamei, surgical treatment is not available for the contralateral type of DEH. We would think that low dose gentamicin might still be reasonable, and see no reason why shunt surgery might not also be offered.
Shojaku et al (2010) presented data on 198 DEH cases collected by national surveys in Japan. Japan seems to have a lot less Meniere's disease than the USA, and perhaps the same is true concerning DEH - -in other words, this prevalence figure may be low. They stated "The incidence of the ipsilateral type of DEH was 47.5%, which was almost equal to that of the contralateral type. In both types of DEH, the most common diagnosis of precedent deafness was deafness of unknown cause with onset in early childhood: 43.9% in both types of DEH. Sudden deafness and mumps deafness were the subsequent diagnoses of precedent deafness." Oddly, the criteria put forth by Shojaku, do not include documentation of hydrops. For this reason, it would seem plausible that they are talking about a more varied population.
Iwasa et al (2018), again developed the idea of bilateral DEH, diagnosed by intratympanic injection of gadolinium. To us, this diagnostic process seems unreasonably invasive.
One might think that DEH might occur due to:
- Collateral damage
- Scarring of plumbing in the ear
- Mistaken attribution of causality
Starting with chance alone, the criteria for DEH are very broad, and one might think that there could easily be a chance occurrence of Meniere's disease (1/2000 population), and profound deafness. Similarly, one might have Meniere's disease that initially "took out" the ear on one side, and then 20 years later, started to act up again (i.e. mistaken causality). For either of these situations, DEH is just another name for Meniere's disease. Supporting this idea, Kitahara et al (2009) found no difference in the huge over expression of V2 mRNA in the endolymphatic sac between DEH and Meniere's patients.
The collateral damage idea is more prevalent. Schuknecht appeared to believe that an early life viral labyrinthitis might eventually result in DEH. Huygen and Admiraal (1976) presented 3 cases of congenital CMV, with delayed onset of symptoms. This is a reasonable thought, although not necessarily the source for all DEH presentations.
There is also very reasonable data for the "sympathetic ear" autoimmune mechanism. Damage to one ear, releases antigen, resulting in symptoms in the opposite ear. (Harris and Aframian, 1994). This idea is also somewhat applicable to Meniere's disease, which commonly generalizes to involve both ears over time (about 50% by 10 years). It might also apply to the situation where there are symptoms in the contralateral ear after a cochlear implant.
With respect to trauma and subsequent development of DEH, little has been written. It is a subject of potential importance due to the high prevalance of litigation concerning trauma. Our opinion is that it would seem reasonable that severe ear trauma, such as a temporal bone fracture, could result in DEH as in the case presented here. However, it would not seem reasonable that minor trauma, such as from a "concussion" lacking strong objective evidence of damage to the ear, should be a subsequent cause of DEH. We are also dubious that impact noise such as due to gunfire during military service or air bag deployment is a cause of DEH or Meniere's.
Albernaz (2007), based on 4 cases, proposed that "this condition probably occurs in patients with congenitally sensitive ears that make them prone to the development of the late hydrops." This idea seems a little vague.
We would think DEH is a Meniere's variant with a mixture of the first three causes, and the "DEH" entity would better be relabeled according to causality. I.e. post-viral Meniere's, or perhaps just Meniere's by itself.
Related conditions ?
Cooper et al A(2020) invented a new word -- "metachronous" sudden sensorineural hearing loss, which they defined as hearing loss occuring first in one ear, and then the other. They said "Unilateral ISSNHL, occurring first in 1 ear and then the contralateral ear at a separate and discrete time, is a rare presentation that we refer to as metachronous ISSNHL." The timing aspect seems somewhat simlar with DHL, as well as bilateral Meniere's disease. We are not entirely sure if this is an "entity" or just a different way of slicing up data.
As DEH is presumably a variant of Meniere's disease, with either viral or autoimmune cause, one would expect that treatment should be identical to Meniere's disease. This is generally supported by literature about this -- diet, medication, and surgery. Papers written by surgeons commonly suggest that surgery is the best treatment (e.g. Gionnoni et al, 1998) . Our position is that one should invoke the same algorithm as for Meniere's, and start with conservative (i.e. medical) treatment.
Shojaku et al (2011) reported good results from use of the Meniett device in DEH. As the Meniett has been reasonably well established to be a placebo treatment in other studies, we are very dubious that it has some special utility in DEH. The Meniett device, being invasive, is impossible to use in a blinded way, making placebo effects difficult to avoid. Watanabe et al (2011) reported good results from a similar device, again without blinding. Again, the risk of a placebo effect is high and we are very dubious.
Low dose gentamicin treatment would seem to be well suited for treatment of vertigo from DEH, as it has very low risk to hearing.
While autopsy was in the past the only reliable method of establishing hydrops beyond a shadow of a doubt, recent advances in MRI technology has provided emerging results allowing diagnosis of hydrops using MRI. This is a very logical development that will likely change the definition of the DEH diagnosis to make it require MRI hydrops.
Kasai et al (2009) reported hydrops using intratympanic injection of gadolinium and 3T MRI in 7 patients. This method of inserting gadolinium is not favored as it is invasive.
Using IV contrast and 3T MRI, Noyoyama et al (2014) reported finding bilateral hydrops in 4/5 patients with unilateral DEH. Gu et al (2014) evaluated 25 patients, and found that 84% had EH on MRI. They reported using a MRI scoring system, which may be an advance. In the study of Fukushima et al (2016), 10 patients meeting the criteria for DEH were imaged to evaluate hydrops. Here intravenous injection was used. Blinding was not mentioned in the abstract. They reported that "DEH patients, however, showed significant EH in either the cochlea or vestibule, suggesting that EH development and DEH onset were strongly correlated." More study is needed here.
There are also a number of papers suggesting that VEMP may be useful in diagnosing DEH (eg. Lin and Young, 2012). We think that this methodology is far inferior to the method outlined above using MRI.
Patients who are diagnosed with DEH are unfortunate persons with severe hearing loss, and new development of either dizziness or hearing loss, attributed to either side. It has been used in the past to suggest that an ear injury 50 years ago (think an auto accident or a whack on the head), is responsible for new inner ear symptoms.
In our opinion, the criteria for DEH are extremely broad, and the inference of cause is often difficult to follow. We are most enthused about the narrow situation where there is an injury to one ear (such as surgery), followed by a Meniere's picture on the other ear. Perhaps there is causal connection due to inner ear autoimmunity. We think the criteria for DEH need to be tightened up -- and include some time limits (maybe 5 years max), and proof of hydrops (perhaps one of the MRI protocols for hydrops).