Talk:Obesity hypoventilation syndrome

Hi, the average man is not going to be able to understand this stuff! Perhaps someone should tone it down from it being a reference text for nuerologists, to something the average human being can understand?? --211.28.125.210 07:47, 23 April 2007 (UTC)


 * It also gives almost no information on the management of the condition. This is a 2001 review we could use to make it a more useful resource. With obesity becoming a major public health problem, we are already seeing a lot of this. JFW | T@lk  07:27, 13 January 2008 (UTC)


 * Sorry, the Chest paper is a research paper. Instead, I thought would be useful for an eventual update of this article. JFW |  T@lk  08:14, 13 January 2008 (UTC)


 * And there's, which isn't free yet. JFW | T@lk  08:16, 13 January 2008 (UTC)

More recent
is a very recent review. Unfortunately this is not available free, and I am therefore working from Olson et al in updating this article. JFW | T@lk  10:24, 20 January 2008 (UTC)


 * Bizarrely, PubMed doesn't list Burwell as the first author of the 1956 Am J Med paper, even though every citation of it and the 1994 reproduction do so. Anyone have an explanation? JFW | T@lk  11:31, 20 January 2008 (UTC)

Improvements
Having access to Mokhlesi's 2007 review, as well as another paper from his hand I am now expanding this article and will hopefully get it up to GA status.

My worklist for each section:
 * ✅ Signs and symptoms - update with Mokhlesi on physical features and comorbidities
 * ✅ Pathophysiology - update from Mokhlesi (may need substantial rewrite and diagram)
 * ✅ Criteria - update with list of conditions to be formally excluded (narcotics being just one)
 * ✅ Diagnosis - perhaps an image?
 * ✅ Treatment - more detail, especially using Mokhlesi's 2008 review with a useful flowchart
 * ✅ Prognosis - to be written
 * ✅ Epidemiology
 * ✅ History - when did the term OHS replace Pickwickian?
 * Question on nomenclature posted on WT:MED
 * Other - images would be nice

Anyone interested in helping is welcome, as usual. JFW | T@lk  09:24, 23 November 2008 (UTC)


 * The Mokhlesi 2008 review is not greatly different from the 2007 review, apart from being published in different journals. I'm sticking with the 2007 review for now, as it is more elaborate. The only important part of the 2008 review is the algorhythm for acutely decompensated OHS. JFW | T@lk  15:09, 23 November 2008 (UTC)

Stuff still to do
In "mechanism" I'm citing, but I've only seen the abstract of that review. I've requested the fulltext on WP:WRE to see if the article needs supplementing. Likewise, I need to review Harrison's to see if there is any discrepancy there with our current content.

Images would be nice, but apart from the CPAP machine I'd need to draw some sort of diagram to make this look pretty.

Once this is done, off to GAC it is. JFW | T@lk  16:43, 23 November 2008 (UTC)


 * Article reviewed. Not much more compared to the other sources. Off to GAC soon. JFW | T@lk  13:04, 25 November 2008 (UTC)

Treatment
Mokhlesi notes: "The optimal management of patients with OHS remains uncertain." However the Wikipedia article states (in the section "Positive airways pressure"): "Positive airway pressure ... is the treatment of choice for obesity hypoventilation syndrome". This is misleading. Weight loss is the initial strategy, in combination with a sleep study to assess the degree of OSA. The majority of patients with OHS also have some degree of OSA, hence a CPAP trial is performed. A proportion of patients do not respond adequately to weight loss and CPAP alone (CO2 remains high), so bilevel ventilation is trialled. Axl ¤  [Talk]  10:03, 1 December 2008 (UTC)


 * I chose this phrasing because weight loss is difficult, and by the time patients come under medical attention (in my limited experience anyway) they are already very symptomatic and need PAP in addition to their weight loss strategy of choice.
 * I'll rephrase the content in question. JFW | T@lk  18:26, 1 December 2008 (UTC)


 * Looks like I changed the wrong section.. Well done for spotting it and fixing it. JFW | T@lk  19:36, 1 December 2008 (UTC)

Morning headaches
There is some confusion about the significance of morning headaches in sleep-disordered breathing syndromes. Many texts and papers include morning headache as an unusual feature of OSA. This is because morning headache is actually a feature of carbon dioxide retention. McNicholas notes in "Breathing Disorders in Sleep" p. 80: "Carbon dioxide retention is uncommon in pure OSA without some accompanying problem that promotes CO2 retention, such as chronic obstructive pulmonary disease (COPD), morbid obesity, alcoholism, or chronic intoxication with benzodiazepines." (Emphasis mine.) However patients with OSA, CO2 retention and morbid obesity actually have the overlap with OHS. Strumpf in "The Management of Chronic Hypoventilation" notes: "Their earliest symptoms are related to the nocturnal exaggeration of CO2 retention that disrupts normal sleep patterns and causes fretful sleeping, nightmares, enuresis, and morning headaches." Axl ¤  [Talk]  11:17, 3 December 2008 (UTC)


 * At the moment we're listing morning headaches as symptoms of hypercapnia. It has been very hard to find a good source; it would be great if you could provide full citations for those two works.
 * I was taught that morning headaches may occur in OSA without OHS. JFW | T@lk  23:57, 3 December 2008 (UTC)


 * "At the moment we're listing morning headaches as symptoms of hypercapnia." That's because I changed the text to indicate that. Axl  ¤  [Talk]  03:54, 4 December 2008 (UTC)


 * "It has been very hard to find a good source" I agree; I struggled as well. Axl  ¤  [Talk]  03:54, 4 December 2008 (UTC)


 * "I was taught that morning headaches may occur in OSA without OHS." Were you explicitly taught that, or were you told that morning headaches can occur in OSA? Axl  ¤  [Talk]  03:54, 4 December 2008 (UTC)


 * "It would be great if you could provide full citations for those two works." Okay, I've added in-line citations here. Axl  ¤  [Talk]  04:10, 4 December 2008 (UTC)

Axl, I only realised later that you had changed the headache bit. Should teach me not to edit Wikipedia after a long day at work. Thanks for fixing all that. I was indeed taught that OSA was linked with morning headaches, by a general physician and subsequently by a respiratory physician running a sleep clinic. Oddly, Harrison's OSA chapter (16th ed, page 1574) doesn't mention headaches, but it is listed as a feature of hypoventilation. So I can only agree with you that I might have been misinformed. Does the McNicholas source make any mention of papilloedema, so we could replace the old BMJ source? JFW | T@lk  09:00, 4 December 2008 (UTC)
 * Unfortunately McNicholas doesn't mention papilloedema. I looked at a couple of ophthalmology texts, and they weren't helpful either. However Nunn's Applied Respiratory Physiology states "Cerebral blood flow increases with arterial pCO2.... Intracranial pressure tends to rise with increasing pCO2, probably as a result of cerebral vasodilation." Of course raised ICP causes papilloedema, but this isn't explicitly stated in Nunn's. Axl  ¤  [Talk]  10:05, 4 December 2008 (UTC)

Papilloedema
I have looked through a couple more respiratory physiology & sleep textbooks, and I didn't find any mention of papilloedema. The BMJ article is a case report, and references other case reports. Given the rarity of this clinical feature in this setting, I think that it is better to remove papilloedema from the Wikipedia article. Axl ¤  [Talk]  10:41, 4 December 2008 (UTC)


 * So much for Bob Ryder's classic PACES text marking it out as a classic feature of hypercapnia... I'll kill it. JFW | T@lk  12:03, 4 December 2008 (UTC)

Energy consumption
From "Mechanism", paragraph 1: "Firstly, people with obesity need to expend much more energy (about fivefold, or fifteen percent of overall energy consumption) to breathe effectively, as adipose tissue restricts the normal movement of the chest muscles, the diaphragm moves less effectively, the chest wall is less compliant, respiratory muscles are fatigued more easily, and airflow in and out of the lung is impaired." (Emphasis mine.) This long sentence should be simplified. Also, I am unsure where these figures come from. In the ironically named "Handbook of Obesity" (it stretches the meaning of the word "Handbook", all puns intended), p. 726 "Work of breathing can be increased two- to three-fold even in obese eucapnic patients." Axl ¤  [Talk]  09:45, 5 December 2008 (UTC)

From the unoriginally named textbook "Obesity", p. 569 "The mechanical work of breathing is increased by 30% in simple obesity and by three times normal in OHS." This is referenced to the Journal of Clinical Investigation: "Total respiratory work in kilogram-meters per 1 L breath (respiratory rate, 20) measured from tank respirator data averaged 0.073 in the normal subjects, 0.095 in the obese normal subjects, and 0.212 in the O.H. patients."

Axl ¤  [Talk]  10:02, 5 December 2008 (UTC)


 * I have rephrased the sentence in "mechanism". The figures on increased energy expenditure are actually oxygen expenditure. I took it from Mokhlesi, who cites it to . There are no figures comparing obese eucapnic people with OHS patients. I have no access to the sources you have provided. Please don't hesitate to add them to the article if you think they enhance the current content. JFW | T@lk  10:59, 5 December 2008 (UTC)


 * I saw that article in the AJRCCM and I considered including it above, but it didn't really add anything extra. The patients in the AJRCCM study had an average BMI of 53: some would classify this as "super obese", even higher than morbidly obese. It's unsurprising that this group of people have even higher VO2Resp than "regular" obesity. The third reference above has a free on-line link. Axl  ¤  [Talk]  10:22, 6 December 2008 (UTC)


 * The third reference looks interesting, but as a primary research study it doesn't really add much—unless you disagree. JFW | T@lk  20:41, 6 December 2008 (UTC)

Review in Thorax
Stop press! Just found another review in Thorax this year. It's actually part of a larger series on obesity and the lung (part 1 epidemiology, part 2 sleep disordered breathing , part 3 intensive care , part 4 asthma , part 5 COPD ). I will track down the paper and integrate any useful content into the article. JFW | T@lk  11:07, 5 December 2008 (UTC)


 * The Thorax paper is very good, but it makes roughly the same points and is shorter than Mokhlesi. At present I can't see any points we need to cite preferentially from this paper. JFW | T@lk  01:26, 9 December 2008 (UTC)

NEJM article
Dear all, My English is not good enough to write for the English version of wikipedia and I am already active on the Dutch version of wikipedia. I wanted to point out a new article from the New England Journal of Medicine that states that the CPAP doesn't prevent cardiovascular events. "CPAP for Prevention of Cardiovascular Events in Obstructive Sleep Apnea" I Hope someone can address this correctly in the article and in the article of sleep apnea. Yours Doctodoc (talk) 12:19, 23 September 2016 (UTC)

New review
10.1177/0885066616663179 - critically ill patients with OHS. JFW &#124; T@lk  10:58, 21 July 2017 (UTC)

ATS guideline
10.1164/rccm.201905-1071ST JFW &#124; T@lk  21:22, 22 August 2019 (UTC)


 * Also this in Eur Resp Rev 10.1183/16000617.0097-2018 JFW &#124; T@lk  21:22, 22 August 2019 (UTC)

NICE
https://www.nice.org.uk/guidance/ng202 JFW &#124; T@lk  20:31, 4 December 2021 (UTC)