Breathing Easier: How New Guidance Helps Manage Sleep Issues in Achondroplasia

Hey there! I want to share something really important with you today about managing sleep-disordered breathing (SDB) in people with achondroplasia. It’s a topic that can be a bit complex, but getting it right makes a huge difference in quality of life. You see, because of the unique way the head and face are shaped in achondroplasia, breathing issues during sleep, like obstructive sleep apnoea (OSA), are way more common than in folks of average height. Sometimes, though less often, we also see central sleep apnoea (CSA) or nocturnal alveolar hypoventilation (NH).

These sleep troubles aren’t just about snoring; untreated SDB can lead to some serious stuff down the line, affecting how the brain works, and potentially causing heart and metabolism problems in both kids and adults. For a while, there’s been a bit of back-and-forth in the medical community about the best way to check for and manage SDB in achondroplasia.

That’s where the European Achondroplasia Forum (EAF) comes in! It’s this fantastic group of doctors, researchers, and patient advocates who really know their stuff about achondroplasia. They got together in October 2023 for a virtual workshop. Their mission? To hash out, vote on, and agree upon five key guiding principles for tackling SDB in achondroplasia. Forty healthcare pros from all sorts of fields – geneticists, surgeons, paediatricians, sleep specialists, you name it – plus two patient group reps, joined the chat.

These five principles are all about making sure SDB is looked at and managed proactively throughout a person’s entire life. They cover everything from using tailored sleep studies and regular screening to having a step-by-step plan for treatment. And guess what? The EAF team was totally on board with all of them! Every single principle got 100% consensus, with super high levels of agreement (scoring between 8.9 and 9.7 out of 10). By putting these principles out there, the EAF is really hoping to make sure babies, kids, and adults with achondroplasia get the best possible care for SDB.

Understanding Why SDB is a Big Deal in Achondroplasia

Achondroplasia is the most common type of skeletal dysplasia, basically meaning it affects bone growth. It’s known for causing disproportionate short stature and those specific craniofacial features we talked about [1,2]. It happens because of a change in the FGFR3 gene and affects about 3.72–4.6 out of every 100,000 births worldwide [2,3,4]. It’s a complex condition that can involve lots of different body systems, bringing potential issues with bones, nerves, heart and lungs, and ear, nose, and throat throughout life [1,2,5].

SDB isn’t just one thing; it includes OSA, and less often, CSA and NH [6,7,8,9,10,11]. While OSA affects about 4-6% of average adults, it can be as high as 60% in adults with achondroplasia [12,13,14]. The text mentions SDB might be common in other skeletal dysplasias too, like osteogenesis imperfecta or craniosynostosis [15,16], but achondroplasia is particularly high-risk for OSA. Why? Those anatomical differences, like the mid-face hypoplasia and narrower airway passages [17].

Babies with achondroplasia face extra risks, including CSA, sometimes due to pressure on the brain stem from the base of the skull [18]. Sadly, there’s also a higher chance of sudden unexpected deaths in childhood in this group [2,7,18,19,20,21,22,23]. As people get older, the craniofacial features stick around and can even get more pronounced, keeping the risk of OSA high [17]. SDB can also get worse, sometimes with NH, because of a smaller chest size, curved spine (scoliosis), and higher rates of increased weight or obesity, which are common in achondroplasia [24,25,26].

Untreated OSA is linked to problems with thinking and learning, behaviour issues, metabolic syndrome, and stress on the heart [27,28,29]. So, catching and treating SDB early is super, super important. The tricky part is that just looking at symptoms, doing a physical exam, or using questionnaires isn’t enough to reliably diagnose OSA, CSA, or NH. This is why systematic screening with sleep studies is needed and should be available for everyone with achondroplasia.

Managing and following up should really be done by a multidisciplinary team (MDT) – a group of different specialists working together. This helps make sure SDB is diagnosed and treated quickly, avoiding those nasty long-term problems.

The European Achondroplasia Forum Steps Up

The EAF is a network of experts dedicated to improving care for individuals with achondroplasia. They work with healthcare pros and patient groups to share best practices across countries and develop recommendations. The steering committee is a mix of specialists from 10 countries, covering everything from genetics and hormones to surgery, neurology, sleep, and patient advocacy [30].

Spotting and treating SDB early is absolutely vital to avoid neurocognitive, heart, and metabolic issues [7]. But even with these known risks, there’s still been debate on the best way to assess and manage SDB [24]. Untreated SDB can seriously impact development in kids with achondroplasia [1]. So, making sure it’s found early and managed correctly is essential.

To tackle this lack of clear guidance, the EAF aimed to build consensus on screening and managing SDB. They searched the literature, developed five draft principles, and held that workshop in October 2023. Attendees from 17 countries, including 40 healthcare professionals and two patient advocates, discussed the principles, looking at the evidence and their own experiences. They voted anonymously, needing 75% agreement to pass a principle. If it passed, they rated their agreement level from 1 (don’t agree) to 10 (strongly agree).

All five principles were agreed upon [Table1 in the source]. They cover:

• A: Lifelong assessment and proactive management.
• B: Individualized assessment tailored to needs, age, and symptoms.
• C: Routine screening throughout life.
• D: Sleep studies and management within a multidisciplinary team (MDT).
• E: Individualized therapeutic management based on age, type, and severity.

After some tweaks to the wording of principle D, all five principles hit that 100% consensus mark, with high agreement scores (8.9–9.7). Let’s dive a little deeper into what these principles mean.

Principle A: Lifelong Vigilance is Key

Because SDB is so common in achondroplasia at all ages, and the risks are significant, the first principle is all about needing lifelong assessment and proactive management. The summary points really hammer this home:

• The unique anatomy (face, airways) plus higher rates of increased weight contribute to high OSA frequency.
• OSA is often more frequent and severe than in the general population.
• CSA is less common in infants with achondroplasia.
• NH might be more likely than in the general population.
• Due to serious consequences in infants and children, close monitoring and systematic sleep studies are vital early on.
• Since untreated OSA can cause metabolic and heart stress, lifelong assessment is crucial, especially for adults.

Let’s look at the anatomy bit again. People with achondroplasia often have a mid-face hypoplasia, meaning the middle part of the face is less developed, and the upper jaw is set back. This affects dental alignment too [17]. Studies show this maxillo-mandibular retrusion is constant, with changes in facial proportions and cranial base angles. They might also have less jaw joint movement and weaker upper airway muscles [10]. All this narrows the upper airway, especially during sleep. One study found a strong link between how far back the jaw is and how severe OSA is [17].

Babies and young kids are particularly vulnerable because their airways are already small. Simple things like viral infections can make tonsils and adenoids swell, narrowing things even more. This risk doesn’t disappear; studies show the craniofacial features can become more pronounced with age, especially the upper jaw being set further back [17]. And let’s not forget increased weight or obesity, which is a known OSA risk factor in everyone and is common in achondroplasia [12].

The numbers are pretty stark: OSA affects 56–60% of infants and children with achondroplasia, compared to just 2–6% in the general population [12,13,14,31,32]. And it’s usually more severe, with a higher apnoea–hypopnoea index (AHI). Even kids and adults who’ve had surgery on their upper airways (like adenotonsillectomy) can still have mild, moderate, or severe OSA [10,12]. This really shows that surgery isn’t always a complete fix.

Skull and spine differences are also part of achondroplasia, and pressure on the spinal cord at the neck is common early in life [10,11,20,33]. This pressure, due to a narrow opening at the base of the skull (foramen magnum stenosis), can affect the brain stem and potentially cause CSA. However, the text notes CSA prevalence is relatively low in infants, suggesting the brain stem’s breathing control usually works okay, even after decompression surgery. Interestingly, studies haven’t found a link between the size of the foramen magnum or other MRI findings and CSA severity, highlighting the need for systematic sleep studies [34].

People with achondroplasia are also at risk of restrictive lung disease and NH because of their smaller chest, weaker breathing muscles, and chest/spine deformities. NH can happen with or without OSA or CSA. The smaller chest can lead to rapid, shallow breathing, which might not clear enough carbon dioxide (CO2), causing NH. So, for the same level of apnoea/hypopnoea, the risk of NH is higher than for someone without achondroplasia. Since CO2 isn’t always checked in sleep labs, NH might be underestimated, but it’s more likely with more severe SDB [10].

Missing OSA and CSA in babies increases the risk of sudden death, which happens in 2–5% of infants with achondroplasia [35,36]. This is why close monitoring and systematic sleep studies are absolutely critical during the first two years of life [23,36,37]. Later on, like in other kids, untreated OSA can mean trouble concentrating at school, irritability, daytime tiredness, wetting the bed, and morning headaches [27,28,29]. While these effects are well-known in other children, there’s less specific data for kids with achondroplasia. One study found concentration issues in some older kids [9]. It’s tough to isolate the exact effect of OSA because other things, like hearing loss, can also impact learning in achondroplasia.

Untreated OSA can also contribute to metabolic syndrome and heart stress in kids, though maybe less so than in adults. A study in Norway found that adults with achondroplasia and OSA had a significantly higher rate of high blood pressure (48%) compared to those without OSA (15%) [12]. With clear evidence linking OSA to increased heart disease risk [38], lifelong assessment and proactive management are non-negotiable. This means all healthcare providers and parents need to be aware of the high prevalence and symptoms of SDB [35].

Principle B: Tailoring the Assessment

The second principle emphasizes that assessment for SDB should be tailored to the needs, age, and symptoms of the individual. The best way to diagnose and understand SDB is with an overnight, attended polysomnography (PSG) in a sleep lab. It’s considered the gold standard. But if PSG isn’t available, the EAF suggests alternatives like ambulatory PSG, cardio-respiratory polygraphy (PG), or at least checking oxygen saturation (SpO2) and transcutaneous carbon dioxide pressure (PtcCO2) overnight.

The key points here are:

• In-lab PSG is the gold standard for diagnosing any SDB type.
• Alternatives like ambulatory PSG, PG, or SpO2/PtcCO2 can be used if PSG isn’t feasible.
• Sleep studies should be done by a sleep lab team to ensure signal quality.
• Equipment must be validated and suitable for the patient’s age and size.

PSG gives loads of info: not just breathing events, but also how long someone sleeps, sleep stages, and overall sleep quality. It’s especially useful for babies and young kids. The downside? PSG is expensive, access can be limited, and interpreting it takes time. PG is an alternative that records breathing signals but not brain activity (EEG), which means it might miss some hypopneas (shallow breathing events) that don’t cause a full awakening [22,23]. It’s often better tolerated by patients, though. Ambulatory studies (done at home) might work for some older, cooperative patients.

The simplest option is just recording SpO2 and PtcCO2 overnight. But this is limited; it only shows the *consequences* of SDB on oxygen and CO2 levels, not the type, number, or severity of the breathing events themselves. The quality of the recording signal is super important for getting usable results [39].

Babies with achondroplasia often breathe faster. Low oxygen (hypoxemia) and high CO2 (hypercapnia) are more common in them than in older patients or average kids. It’s crucial to use equipment that’s been validated for the patient’s age and fits their body size; not all devices work for kids under two [39]. To avoid missing NH, the EAF recommends systematically recording PtcCO2 overnight [9]. This is why it’s best for sleep studies to be done by a team experienced in paediatric sleep, and ideally, someone who also knows about achondroplasia should score and interpret the results.

Principle C: Screen Throughout Life, Especially Early On

This principle is pretty clear: Routine screening for SDB throughout life is needed, with a particular focus on the early years. The key points are:

• Symptoms, questionnaires, and physical exams aren’t reliable for diagnosing SDB; a sleep study is essential.
• The EAF suggests routine lifelong screening, focusing on early childhood.
• Screening should involve the achondroplasia MDT and local healthcare team.
• Currently, there aren’t specific recommendations for assessing SDB in adults with achondroplasia.

Symptoms of OSA in kids with achondroplasia can be similar to other kids: snoring, pauses in breathing, mouth breathing, neck hyperextension, night sweats, waking up at night, restless sleep [9,22,35]. Daytime signs might include poor school performance, trouble paying attention, irritability, tiredness, and headaches [1]. In younger kids, slow growth or high blood pressure could also be signs [23]. But, and this is a big “but,” these symptoms aren’t specific and aren’t reliable enough on their own to diagnose OSA. Sleep questionnaires aren’t much better for people with craniofacial differences like in achondroplasia, even when combined with symptoms or imaging [9,40,41,42]. And checking the upper airway physically can’t predict or diagnose OSA either [40,41,42]. So, the only way to definitively diagnose OSA is with an overnight PSG or PG [9]. Questionnaires *can* help decide who needs a sleep study sooner [1], and remember, having had upper airway surgery doesn’t mean someone is free of OSA [9].

Given that OSA affects up to 60% of both kids and adults with achondroplasia [12,13,17,30], the EAF is proposing routine screening throughout life. While SDB can pop up at any age, the focus should definitely be on those early years when it’s most common [1,23,35]. The achondroplasia MDT, working hand-in-hand with local doctors, should regularly check infants in their first year [35] and keep a close eye during the first two years [23,35,37]. If a child aged 1-18 with a condition like achondroplasia has symptoms suggesting OSA, the European Respiratory Society recommends screening with PSG [23]. International consensus already recommends a PSG for all infants with achondroplasia during their first year [35]. It’s worth noting there aren’t specific guidelines for assessing OSA in adults yet [12]. It’s a good idea for bed partners to know the signs of OSA too.

Unlike OSA, CSA often has few or no symptoms [43]. There aren’t questionnaires for screening for CSA. The same goes for mild NH, which can be asymptomatic. Only severe NH might cause daytime headaches, fatigue, nausea, or dizziness [43].

Principle D: Teamwork Makes the Dream Work (for Management!)

This principle is about making sure that if SDB is suspected, a sleep study is done and scored by a sleep specialist ASAP, and then the interpretation and therapeutic management should be performed within an achondroplasia MDT. This principle actually got a little tweak during the workshop!

The original idea was that the sleep specialist scoring the study needed to know about the specific breathing issues in achondroplasia. But the group agreed that while the scoring needs to be done by a sleep specialist, they don’t necessarily need to be an achondroplasia expert. What *is* essential is that an achondroplasia expert is available to review and discuss the results as part of the MDT. This aligns with previous EAF guidance emphasizing the MDT approach [37]. They also noted that asking the right questions of the sleep specialist is key to getting the most useful study and results.

The ideal scenario is for every skeletal dysplasia MDT to include a sleep specialist who can build experience with the unique challenges faced by this population. So, the principle was reworded to what it is now, highlighting the need for scoring by a sleep specialist and MDT interpretation/management.

Principle E: Treatment Needs to Be Personal

The final principle focuses on individualizing therapeutic management based on the age of the patient and the type and severity of SDB. This isn’t a one-size-fits-all situation.

Key recommendations include:

• Highly recommend sleep endoscopy before any surgery to check for all obstructive sites.
• Overnight observation is recommended for any child with achondroplasia and OSA having upper airway surgery.
• A follow-up sleep study is mandatory 2-4 months after upper airway surgery.
• If OSA persists after surgery, discuss orthodontic treatment, maxillofacial surgery, or CPAP with the MDT.
• CSA can often be fixed with cervico-occipital decompression.
• For NH, fixing OSA first might help; if not, non-invasive ventilation (NIV) is needed.

International consensus points to adenotonsillectomy (removing tonsils and adenoids) as the first go-to treatment for OSA in kids with achondroplasia [35]. However, other spots in the airway can be blocked too, like enlarged turbinates or lingual tonsils (at the back of the tongue), especially in older kids. This is why it’s strongly recommended to do a drug-induced sleep endoscopy *before* surgery. This lets doctors see exactly where the blockages are and address all of them [43,44].

Because there’s a higher risk of breathing and heart complications, any child with achondroplasia and OSA having upper airway surgery should ideally stay overnight in the hospital for observation [1,45,46]. And it’s non-negotiable to do another sleep study about 2 to 4 months after surgery. Why? Because there’s a significant risk that OSA might still be there (residual OSA) [1,35]. One review found that 18% of kids who had adenotonsillectomy initially needed more surgery [45].

If OSA hangs around after surgery, other options come into play. These include orthodontic work, maxillofacial surgery (like moving the mid-face forward), or using continuous positive airway pressure (CPAP) [1,35]. CPAP is considered when other treatments aren’t suitable, wanted, or haven’t worked. CPAP is great because it’s non-invasive and helps keep the airway open at multiple points during sleep. It can be used at any age, from babies to adults, thanks to different devices and masks. A potential downside of long-term CPAP use is that it *might* encourage the upper jaw to stay set back, so regular check-ups with a maxillofacial specialist are important, as is re-evaluating other treatment options. Using nasal pillows or cannulas might reduce facial changes, but these aren’t always available for very young kids.

For those with increased weight or obesity, weight loss can also help [1,47]. The role of upper airway surgery in adults with OSA is less clear [1]. Tracheostomy (creating a breathing hole in the neck) is a last resort for very severe, persistent OSA, but thankfully, with good MDT management, it’s rarely needed.

If CSA is the main issue, treating the cause, often cervico-occipital compression, with decompression surgery can resolve it. For NH, the first step is making sure any OSA is optimally treated. If NH is still present after fixing OSA, or if NH happens without OSA, then non-invasive bilevel ventilation (NIV) is indicated. Like CPAP, NIV should be started and followed up by a paediatric expert experienced in these therapies.

Looking Ahead

While SDB in achondroplasia isn’t usually an immediate life-or-death emergency, it can have significant long-term consequences throughout life that *can* be lessened [1]. This is especially true for babies and kids, where catching and managing it early is crucial to avoid those neurocognitive, heart, and metabolic problems [7]. By being proactive with OSA management, we can reduce daily issues like learning difficulties, behaviour problems, daytime tiredness, disrupted growth hormone, and increased accident risks, ultimately boosting quality of life [1].

Until now, there hasn’t been specific, comprehensive guidance just for identifying, managing, and treating SDB in people with achondroplasia. By developing these guiding principles, the EAF hopes to give healthcare professionals clear considerations that can be used pretty much anywhere. The goal is that by making the impact of SDB in achondroplasia clearer, everyone – from infants to adults – will get the best possible screening and management.

Sharing these principles widely within the achondroplasia community is a really important next step to improve care and quality of life. And, of course, checking back later to see how much of an impact this guidance has had will be valuable. These principles aren’t set in stone; they’ll need to be reviewed and updated as new research and practices emerge, making sure they stay relevant and helpful for the achondroplasia clinical community.

Source: Springer