Map of Vaccine-Preventable Outbreaks Over Time

Image by Council of Foreign Relations

The council of foreign relations have produced an interactive map the shows the concentration of vaccine-preventable outbreaks throughout the world over time. Such diseases include measles, mumps, rubella, polio, and whooping cough.

The take-home point of the map is that diseases that were once considered "eradicated" due to near-universal vaccinations have now made a tremendous comeback which is felt almost certainly due to the anti-vaccine movement.

Vaccinate!!!

Reference:
Vaccine Preventable Outbreaks. Council of Foreign Relations.

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Permanent Hearing Loss From Noise May Depend on Time of Day!

Research out of Sweden have discovered that noise-induced hearing loss sustained at night is more likely to become permanent than if it occurred during the day... at least in mice.

Apparently, there are certain genes found to cycle in the cochlea of mice in a pattern that followed the hours of the day. By measuring the auditory nerve activity, they found that mice exposed to moderate noise levels during the night suffered from permanent hearing loss while mice exposed to similar noise levels during the day did not. The ability to heal after noise-induced hearing loss (temporary threshold shift) was linked to the circadian rhythm due to levels of BDNF (brain derived neurotrophic factor).

Specifically, concentration of BDNF increases in the cochlea during the day which protected hearing from permanent damage whereas levels were absent at night. Furthermore, researchers were able to artificially increase BDNF levels at night when normally absent and confer hearing protection with noise exposure.

What does this mean for humans?

IF human ears also have a biologic clock similar to mice, than researchers MIGHT be able to develop a specific way to reverse (or prevent) noise-induced hearing loss. Currently, the only way to treat acute noise-induced hearing loss is high doses of steroids whether orally or by injection directly into the ear.

Also, humans should probably avoid listening to loud music at night (i.e. concerts, night-clubs, restaurants, etc) which elevates risk of permanent hearing loss (compared to during the day).

Reference:
TrkB-Mediated Protection against Circadian Sensitivity to Noise Trauma in the Murine Cochlea. Current Biology, 27 February 2014. 10.1016/j.cub.2014.01.047

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Vaccine to Prevent Throat Cancer

Spread through oral sex, it is well established that human papilloma virus (HPV) types 16 and 18 cause the vast majority of throat cancer especially in men... even more than smoking and drinking alcohol. What was not known, but suspected, was whether in BOTH men and women the HPV vaccine Cervarix (made by GSK) or Gardasil (made by Merck) would help prevent throat cancer as effectively as cervical cancer for which it is FDA approved for.

At least for the vaccine Cervarix, a randomized, control, double-blinded, prospective study has shown that it highly protects individuals from HPV 16 and 18 infection in the mouth/throat. The vaccine efficacy was calculated to be 93.3%. The big assumption being that reduced oral HPV 16/18 would lead to a decreased risk of throat cancer.

It is for these reasons that BOTH boys and girls are encouraged to get the HPV vaccine. We are talking about protecting our sons and daughters from getting throat and cervical CANCER later in life.

To be clear, more study is needed to really PROVE that such vaccines prevent throat cancer. For full disclosure, the weaknesses of this current study are as follows:

• It was performed only in women (the study would need to be replicated in males)
• The study lasted only 4 years... the question is whether life-long protection is present or will booster shots be needed?
• Does Gardasil also work for oral HPV 16/18?
• Does reduced HPV 16/18 presence in spit actually translate to decreased risk of throat cancer
• It is suspected that vaginal secretions carry a higher HPV viral load than the penis leading to a higher risk of throat cancer in men performing oral sex on infected women. As such, the other questions that need to be answered is whether such vaccines will:
     • Prevent a vaccinated woman from giving HPV to the man as well as
     • Prevent an infected woman to actually infect a vaccinated man?
     • Or, does BOTH partners need to be vaccinated to prevent HPV throat cancer?

It is truly an exciting time when vaccines can be given to prevent not only infections like mumps or shingles, but also cancer!

As a reminder, the HPV vaccines ONLY work when given to children before they become sexually active. It is too late to give the HPV vaccine for sexually active adults (ie, it won't work).

Source:
HPV Vaccine Found to Help With Cancers of Throat. NYT 7/18/13

Reference:
Reduced Prevalence of Oral Human Papillomavirus (HPV) 4 Years after Bivalent HPV Vaccination in a Randomized Clinical Trial in Costa Rica. PLOS One

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Why Would a Zenker's Diverticulum Recur After Surgical Treatment?

Zenker's diverticulum is an extremely rare disorder whereby a pouch develops in the throat leading to food and liquids getting caught causing symptoms of swallowing difficulties and food regurgitation. One of the best ways to address this rare condition is a procedure called endoscopic staple diverticulostomy (ESD).

Unfortunately, with any Zenker's treatment including ESD, there is a small percentage (~10%) that the Zenker's diverticulum recurs typically within one year of treatment (average 8.5 months).

Why might that be?

There are some known (and unknown) issues that may lead to recurrence including:

• Incomplete division of the cricopharyngeus muscle: If the pouch is small, the cricopharyngeus muscle may not be completely divided using the ESD method. It is a shortcoming inherent to the method itself and not a lapse on the surgeon's part. The only way to completely address the muscle when the pouch is small (less than 1 .5cm) is via external approach or use of a laser with its associated increased risk of complications.
• Unaddressed or persistent laryngopharyngeal reflux: Proton pump inhibitor medications are ALWAYS prescribed before and after surgery... even if heartburn symptoms are absent. However, even with such medications, there may be a certain sub-population that suffer from persistent throat-level reflux that may trigger the Zenker's diverticulum to reform. This factor is probably the single most important reason why recurrence may occur within months.
• Loose staples: After surgery is performed, all loose staples are removed to minimize recurrence from this factor.
• Idiopathic scarring of the common wall: Some unindentified inflammatory process leads to restenosis of the common wall.
• Unknown: Whatever factor lead to the Zenker's formation in the first place may cause it to happen again. Indeed, we actually don't precisely know what causes the Zenker's pouch to occur in the first place.

As such, if recurrence occurs years after treatment, it usually will suggest an incomplete cricopharyngeus muscle division. Repeat ESD can be performed with good results.

If recurrence occurs within one year of treatment, I typically will consider the possibility of persistent throat-level reflux (laryngopharyngeal reflux) that was not or incompletely addressed with reflux medications. Before performing ESD again after a recurrence, I will obtain a few studies to determine how significant throat-level reflux may be present.

That typically entails getting a 24 hour multi-channel pH and impedance testing with manometry. The most important result from this study is the frequency of proximal esophageal reflux events and as such, any other type of reflux study that does not include proximal esophageal or hypopharyngeal sensors would be considered inadequate. Ideally, it should be as close to zero as possible. If proximal esophageal reflux events are present, this needs to be thoroughly eliminated prior to revision Zenker's surgery... otherwise, the Zenker's pouch may yet again recur.

Manometry is performed to ensure the cricopharyngeus muscle (if present) is adequately "loose".

Of course, the barium swallow needs to be repeated as well.

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Allergies May Prevent Heart Attacks???

Research has been published suggesting an inverse relationship between serum IgE and heart attacks in the US population independent of coronary risk factors.

No kidding...

This conclusion was reached based analyzing 4002 participants between 2005-2006. They also detected that of the 7 "data-driven, prespecified allergen clusters," house dust mite was the only allergen cluster for which serum IgE is associated with reduced risk for heart attack.

For those wondering, serum IgE is a rough measure of how allergic a patient is generally speaking without any specification of what the patient may be allergic to. It is obtained by bloodwork (RAST or immunoCAP).

The higher the IgE levels, the more allergic a patient is generally speaking. However, one must keep in mind that it may still be possible to be allergic even if IgE is low or vice versa.

Also, although there appears to be a relationship between IgE and heart attacks, it is doubtful it reaches clinical significance for any given patient. Rather, such conclusions may apply to a general population. This study was also retrospective and as such, it would be nice if a new study now looked at a group of allergic patients and see how many suffer heart attacks in the future.

Such un-intuitive relationships just goes to show how complex the human body is where one thing doesn't cause one problem, but rather one thing may affect multiple different aspects of human health.

Now why would IgE and/or allergies in general influence heart attack risk?

Well heart attacks are due to vascular disease (blockage of the coronary artery). Vascular disease is thought to be influenced by how much inflammation is present in the body. The more inflammation present, the higher the risk of vascular disease which in turn increases heart attack rates.

One factor thought to influence the degree of inflammation present in the body is the immune system, and allergies is one part of the immune system.

As such, allergies could be a reflection of what the immune system is doing which in turn influences the degree of inflammation present in the body which in turn affects vascular disease which plays a role in heart attacks.

Reference:
Relation between objective measures of atopy and myocardial infarction in the United States. Journal of Allergy and Clinical Immunology. In Press Aug 27, 2012.

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