Esophageal Motility: Achalasia

0:00Welcome to Board Pearls. This is episode two of four of the Esophageal Motility chapter, in the Esophageal Disorders module. Last episode built the three numbers manometry gives you, the IRP for the sphincter and the DCI, the distal latency, and the whole-wave check for the body. This episode is achalasia, which is where those numbers point most often, and we'll build it from the mechanism, because every strange thing about the disease falls out of one lesion.

0:25The nerves that get destroyed are the inhibitory ones in the wall of the esophagus, the ones that make nitric oxide and whose whole job is to tell the sphincter to relax and to time the wave so it travels in sequence. The excitatory nerves that keep the sphincter tight are left alone. Picture what that does. The sphincter now gets the signal to clamp but never the signal to release, so it sits tight and won't open on a swallow, and the body loses the timing that turns a squeeze into a traveling wave. From there the body can only do one of three things, and those three things are the three subtypes, so you're not memorizing a list, you're naming the three ways a body behaves once it can't make a proper wave.

1:04Before the subtypes, the presentation, because it's mechanism too. The giveaway is dysphagia to solids and liquids from the very start, and that "and liquids" is the tell, because a physical narrowing hangs up solids first while a failed wave fails on everything you swallow, thin or thick. So patients describe food stacking up in the chest, they wash meals down with big gulps of water, they stand and stretch to let gravity finish the job, and they reach for fizzy drinks because the carbonation builds a little column of pressure that forces the sphincter. They bring up undigested food, and the highest-yield version of that is regurgitating food onto the pillow at night, because that tells you the esophagus above the stuck sphincter has stretched into a stagnant pouch. Many report heartburn even though no acid is refluxing, and it's worth knowing why, it comes from food fermenting in that pouch and from the esophagus being stretched, not from acid, so it won't behave like reflux and won't respond to acid suppression. And weight loss stays mild in the real thing, which matters mostly because heavy weight loss is the clue that you're not dealing with primary achalasia at all, a point we'll come back to.

2:09The workup starts with endoscopy, and the reason is a rule-out, not a rule-in. You scope first to make sure a cancer at the junction isn't imitating all of this, because that changes everything. On the scope, real achalasia shows a dilated esophagus often holding old food, normal-looking lining, and a sphincter that's tight but gives way with gentle push, which feels different from the hard stop of a tumor. But the scope can look completely normal in a large fraction of achalasia, up to forty percent, so a clean endoscopy does not let you off the hook. A barium swallow shows the classic picture, a dilated esophagus tapering to a smooth narrow point at the sphincter, the so-called bird-beak, with the barium just sitting there and no wave stripping it down. Manometry then confirms it and tells you the subtype, so let's take the three.

2:57Type one is the silent body. The sphincter won't open, every swallow fails, and there's no pressure building anywhere, because the muscle has lost even the tone to generate passive pressure. That's why type one tends to show up later, in an esophagus that's already stretched out and given up. Its response to treatment is middling, better than the spastic type but not the best.

3:21Type two is the pressurizing body, and it's the one to be happy to see. The sphincter still won't open and no proper wave forms, but the muscle is very much alive, so when the swallowed column has nowhere to go it squeezes the whole length of the esophagus at once and the pressure climbs uniformly against the closed sphincter. That whole-length pressure rise, more than thirty above baseline spanning the esophagus on at least a fifth of swallows, is the definition, and its meaning is simple: the muscle still works, it just can't aim. That's exactly why type two responds best to every treatment you can offer, because you're relieving an obstruction in an esophagus that still has power behind it. So a stem where every swallow pressurizes top to bottom is handing you the best-prognosis patient.

4:04Type three is the spastic body, and here the sphincter won't open and the body, on top of that, fires those early, premature contractions in its lower part. The chest pain these patients get is those spasms. And type three is the one where a common treatment is simply wrong, which is the high-yield point. Stretching the sphincter open does almost nothing here, because the problem isn't only the sphincter, it's a spastic segment of muscle sitting well above it, and a balloon at the sphincter never touches that segment. What you need is a cut through the muscle that runs long enough to reach up and include the spastic part, and that's why type three is the one subtype with a clear preferred operation, which we'll get to.

4:45Now the treatments, and there's one principle that makes all of them make sense: none of them fix the muscle. Nothing restores the wave. Every option does the same single thing, it lowers the sphincter pressure so gravity and the weight of what you swallowed can push through, and every option fades over time. So you tell patients at the outset that this is a lifelong condition, that maybe one in three will need another procedure down the line, and that you're choosing among imperfect tools. With that in mind you generally start with the least invasive option that fits the patient and escalate only as needed.

5:17Medications, calcium channel blockers and nitrates under the tongue before meals, relax the sphincter a little, but the effect is weak and short and wears off, so they're really only for people who can't have a procedure at all.

5:29Botulinum toxin injected into the sphincter, eighty to a hundred units split around its four quadrants, blocks the excitatory nerves and drops the sphincter pressure for around six months before it wears off, and each repeat works a little less. It's the right choice for the frail or elderly patient for whom a stretch or an operation is too risky. But there's a real cost that drives a classic question: the injection scars the layer a surgeon later needs to work in, so a myotomy done afterward is much more likely to perforate. So injecting a healthy thirty-five-year-old who could have had a clean operation is a mistake, because you've spoiled the surgical plane for a temporary fix.

6:07Pneumatic dilation uses balloons, thirty to forty millimeters, to forcibly tear the muscle fibers of the sphincter. It works well up front, but a good share of patients relapse within a few years and need more, there's a small but real risk of tearing all the way through and perforating, and some develop reflux afterward. And remember, it's the wrong answer in type three, because the spastic muscle sits above the sphincter where the balloon can't reach.

6:33The surgical myotomy, done laparoscopically as a Heller, cuts the sphincter's muscle fibers under direct view and adds a partial wrap of the stomach around the junction to blunt the reflux that follows from leaving the sphincter open. The wrap is deliberately partial, either a Dor draped over the front at a hundred eighty degrees or a Toupet behind at two hundred seventy, and a full wrap is specifically avoided, because a paralyzed esophagus has no wave to force food through a complete wrap, so you'd just trade the dysphagia of a stuck sphincter for the dysphagia of a tight collar. Heller gives good, durable relief, with reflux in a minority as the main trade-off.

7:11POEM, the endoscopic myotomy, does the cut from inside: the operator tunnels under the lining, cuts the inner muscle of the lower esophagus and sphincter through that tunnel, then clips the entry closed. Its one defining advantage is that the operator chooses how far up to carry the cut, and that is precisely why it's the preferred operation for type three, where you need the cut to run long enough to reach the spastic segment. The trade-off is reflux, which is more common after POEM than after Heller because POEM doesn't add a wrap. So the way these actually compare is worth holding as reasoning rather than numbers: for type one and type two, stretching, Heller, and POEM all work about as well, and you choose based on local expertise, how much the patient wants to avoid reflux, and how durable a fix they want; POEM tends to last longer than stretching; POEM and Heller come out roughly even, with POEM buying you a bit more reflux. And for type three, POEM, because it's the one that reaches the spasm.

8:08One complication ties back to that spastic segment: a blown-out myotomy, where the esophageal wall at the cut balloons out over the following years, causing failure and regurgitation. It happens most after treating type three, because the leftover spastic contractions keep pushing against the weakened, cut wall until it bulges.

8:29Two situations break this whole framework, and both are favorite traps. The first is opioids, which is why you always ask. Chronic opioids do all the wrong things at once, they keep the sphincter from relaxing so the IRP climbs, they drive the squeeze too hard so the DCI climbs, and they make it fire too early so the latency shortens. The result can look exactly like type three achalasia, or like outflow obstruction, or like spasm, depending on which effect dominates. So when someone on chronic oxycodone or methadone or buprenorphine shows one of these patterns, the first move is not a procedure, it's to stop the opioid and repeat the study. Committing a chronic-pain patient to a myotomy for a tracing the drug produced is the exact error the question is testing.

9:14The second is pseudoachalasia, a cancer at the junction imitating the disease. Up to about one in twenty patients who meet the manometric criteria for achalasia actually have this, where a tumor produces the same picture by invading the same nerves, by physically narrowing the junction, or through a paraneoplastic effect, the classic one being small cell lung cancer with antibodies against those nerves. It gets missed on a routine scope because the tumor grows in the wall without a surface lesion to see. Three things should stop you: age over sixty, a short history of only a few months, and weight loss out of proportion to how long they've been symptomatic. When those line up, the next move is not treatment, it's endoscopic ultrasound to look into and behind the wall at the junction and cross-sectional imaging to hunt for a chest or upper-abdominal cancer. Running to a myotomy on that patient is the whole point of the question. And worth recognizing on history, Chagas disease destroys the very same nerves and produces the identical syndrome, so the patient from rural Latin America with an enlarged colon and a bird-beak esophagus is telling you the cause; you confirm it serologically and treat the esophagus the same way.

10:23So, short version. A sphincter that won't open with a body that makes no wave is achalasia, and what the body does on those failed swallows names the subtype: a silent body is type one, a body that pressurizes its whole length is type two, a body that spasms is type three. The subtype picks the treatment because it changes what the procedure has to accomplish, and the only firm rule is that type three needs the longer cut that reaches the spasm, so POEM, and stretching is wrong. And two patients don't fit the pattern at all: the one on opioids, where stopping the drug makes it resolve, and the older patient with a short history and real weight loss, where you have to rule out a cancer before you treat anything.

11:05In the next episode we take the other side of that first number, everything that happens when the sphincter relaxes normally and the trouble is in the body itself, starting with the body that contracts too much: spasm and the hypercontractile esophagus, and the type three achalasia that hides among them.

11:24For the full chapter, the practice vignettes, and the topic-tagged question bank, head to board pearls dot com. You'll find the rest of the series on Apple Podcasts, Spotify, or wherever you listen to podcasts. That brings us to the end of episode two of four of chapter two, and I'll see you in the next one.