76 | Three essential things you need to know about chylothorax (to help you give great nursing care)
In episode 76 of the Medical Nursing Podcast, we’re chatting all about something that honestly baffled me when I was working in general practice (and in my very early referral nursing days), and that’s chylothorax.
Now I want to be completely honest with you, because I’m very aware that some of what I talk about sounds like absolute gibberish. And, in fact, if I were listening to this episode earlier in my career, I’d be wondering how on earth it’s possible to know the ins and outs of these weird and wonderful diseases. So hear me when I give you a healthy dose of reality and say that early-ish RVN Laura had absolutely NO idea what a chylothorax was.
As far as I was concerned back in 2015, before I lived and breathed medicine, a chylothorax would have been just another patient needing a thoracocentesis.
I didn’t understand what was causing the disease or the impact it had on the patient. And aside from them being a respiratory patient and needing monitoring, I had NO idea what nursing actions I could take to make things better - I didn’t really know how to help.
But when I started learning what a chylothorax was, why it happens, and what we can do to help these patients? That’s when I stopped feeling out of my depth, and realised that I CAN make decisions as a vet nurse, and my actions WILL help my patients.
So in this episode, I want to share the three essential things you NEED to know about chylothorax - and more importantly, how to turn that knowledge into nursing care that really helps your patient. So next time you’re handed a patient with chylothorax, you’ll know exactly what to watch out for and exactly how to help them.
1: What is chylothorax, and why does it happen?
Chylothorax is a specific type of pleural effusion where chyle, a milky, fat-rich modified lymphatic fluid, accumulates in the pleural space.
But before we get into chylothorax properly, we need to backtrack a LITTLE bit and talk about what chyle actually is.
When a patient eats, their food is broken down both mechanically and chemically through digestive enzymes and gastric juices. Nutrients are then absorbed via the enterocytes, where they enter the circulatory and lymphatic systems.
Think of the lymphatic system as the circulatory system’s kind-of boring cousin; they work together (ish), but no one really pays THAT much attention to the lymphatic system - unless you work in oncology or internal medicine, that is 😅
Fat is digested and absorbed across the GI tract (like all of those other nutrients) and turned into triglycerides, which are then packaged into chylomicrons inside the intestine. These chylomicrons enter the lymphatic system, and the lymphatic fluid, now rich in chylomicrons, is referred to as chyle.
The lymphatic and circulatory systems meet at one common point - the thoracic duct, which drains into the vena cava. Here, chyle can enter the circulatory system, allowing those nutrients from digestion to enter the circulation and be transported to their target sites.
But when this system is disrupted - whether by trauma, pressure, blockage or inflammation - that chyle leaks into the pleural space instead.
The result for our patients is the same as all the other pleural space diseases we’ve discussed in the last few episodes: the fluid compresses the lungs, prevents the lungs from expanding, and causes hypoventilation as a result.
Our patients can’t get enough oxygen-rich air into their alveoli; therefore, there’s not enough oxygen to diffuse into the bloodstream, meaning our patients become hypoxaemic, can’t deliver oxygen to their cells, and dyspnoea quickly results.
As more and more chyle accumulates, our patient becomes more and more distressed. Now add to that the lethargy, exercise intolerance, weakness and anorexia these patients also present with (because who wants to eat when you’re too busy trying to breathe?!), and they’re often feeling pretty lousy by the time they get to us.
Ok, so that’s what a chylothorax is. But why do they happen?
Now, our patients can develop chylothorax for several reasons, but often we won’t find a cause. We refer to this as (my favourite term; IYKYK) idiopathic chylothorax, and it’s more common than you might think, particularly in cats.
Nevertheless, there are SOME specific conditions that cause chylothorax - and these include:
Right-sided heart disease (including congestive heart failure)
Pericardial effusion
Thromboembolic disease
Mediastinal masses (eg, lymphoma or thymoma compressing the thoracic duct, since the duct sits within the mediastinal tissue)
Thoracic duct trauma (eg, from previous surgery, or due to blunt force trauma to the chest, such as from an RTA)
Congenital abnormalities (eg, malformation of the thoracic duct)
Heartworm disease, depending on your location (in endemic regions)
In terms of breed predisposition, Siamese and Himalayan cats are reported to be more commonly affected, as are Afghan hounds and Shiba Inu dogs.
However, we can see chylothorax in any breed - the ones I’ve seen most recently have included Schnauzers, British Shorthairs, Dobermans and DSHs!
2: How do we SPOT a chylothorax?
As we’ve touched on, the clinical signs you’ll see with chylothorax are really similar to any other pleural space disease.
And unless you’ve tapped the chest and you’ve got a chyle sample in front of you, you won’t be able to tell chylothorax from pyothorax or haemothorax just by looking at the patient. Instead, you’ll diagnose pleural effusion based on clinical signs and imaging, and THEN identify its chyle on sampling.
Signs to look out for include:
Dyspnoea
Tachypnoea, even at rest
Orthopnoea, where our patient adjusts their body position to ease ventilation and get more air in with each breath
Restrictive breathing pattern with shallow, rapid breaths
Abdominal effort
Lethargy, inappetence, and exercise intolerance
Weight loss, particularly in chronic cases
Open-mouth breathing or cyanosis in severely dyspnoeic patients (but remember that a patient can still be hypoxaemic with pink MMs!)
On your physical exam (because you DON’T need to be an MRCVS to perform a physical exam, just working under their direction), you’ll likely find:
Muffled heart and lung sounds, especially ventrally
Decreased body condition in chronic patients
3: Ok, so our patient has a chylothorax - what do we DO about it?
Your first priority, just like any other respiratory patient, is to stabilise them. Like we’ve mentioned in our last few episodes, that means an initial ‘hands-off’ approach, with minimal stress/handling, and oxygen therapy.
Let the patient calm, choose a posture they’re comfortable in and can breathe easily in, and get oxygen on board whilst you prepare for things like point-of-care ultrasound (POCUS) and thoracocentesis.
Once they’re a bit more stable, assist with an initial thoracocentesis if needed, to relieve pressure on the lungs and ease ventilation.
And after this, once your patient is calmer, their breathing is easier, and their saturation has improved, it’s time to start thinking about diagnostics and treatment. And this is where we really come in as nurses and technicians.
Let’s start by looking at thoracocentesis.
If you’ve been listening to the rest of this series you’ll know the drill by now: if you’re in the US, you’ll likely be performing this; if you’re elsewhere in the world, you may not be legally able to - so always check your local regulations and work within them.
If you’re performing the centesis, then:
Always use aseptic technique
Tap the ventral thorax at around the 7th–9th intercostal space, walking off of the cranial border of the rib to avoid the vessels and nerves running along the caudal side.
Drain as much fluid as the patient safely tolerates, avoiding excessive suction on the syringe, which can damage the pleural membranes
Record the volumes obtained, and keep samples in EDTA and sterile plain tubes for cytology and culture.
If the fluid is milky white or pink and opaque, with a ‘strawberry milkshake’ like appearance, it’s likely you’re dealing with a chylothorax. You’ll need to confirm it by running a fluid triglyceride level - if it IS a chylothorax, the triglyceride levels in the fluid will be higher than the patient’s blood.
A quick last, but very important, point from me on thoracocentesis - we don’t want to excessively drain a chylothorax. Chyle contains lots of fats, electrolytes, water, proteins, fat-soluble vitamins and more nutrients from digestion, so draining lots of chyle can quickly cause fluid and electrolyte imbalances and impact our patient’s nutritional status.
What other diagnostic results will we see?
Bloodwork may reveal a high or low lymphocyte count, or mixed inflammation (depending on the chronicity of the disease), alongside a low cholesterol: triglyceride ratio, hyperlipidaemia and hypoalbuminaemia.
Diagnostic imaging, including thoracic ultrasound, radiographs or CT, is often performed to look for mass lesions, effusion or other abnormalities. An echocardiogram is also recommended, since cardiac causes are common.
OK, your patient OFFICIALLY has a chylothorax. How will we treat it?
Well, there are two ways - medically or surgically.
Medical management includes repeated thoracocentesis or drainage via a chest drain as needed to manage the patient’s respiratory signs, alongside feeding them a low-fat diet to minimise chyle production.
Other treatments include rutin and octreotide. Rutin is a plant pigment sourced from health food shops. This supplement is thought to improve lymphatic drainage, though evidence for it is limited. Rutin can cause nausea and diarrhoea, so supportive treatment (eg, with antiemetics) is often also needed.
Octreotide is a somatostatin analogue which acts directly on vascular receptors to minimise the excretion of lymphatic fluid. However, it has a low success rate and is expensive, so not commonly used.
But whilst medical management can help temporarily, it’s rarely curative. These patients often need surgery, specifically, a thoracic duct ligation, where the leaking thoracic duct is tied off. This is often performed alongside a pericardectomy to reduce pressure on the thoracic duct and further prevent leakage.
And of course, these patients require a thoracotomy to access the pericardium and thoracic duct, so they’ll be recovering with a chest drain in situ to evacuate any postoperative pneumothorax, and they’ll have increased nursing needs postoperatively too.
It can often take a little while for the fluid to completely disappear, so we’ll likely still be draining these patients somewhat regularly and incorporating things like a low-fat diet at least initially.
And what about nursing these patients?
Like many of our other respiratory patients, these guys can be complex. Their initial dyspnoea is challenging to manage, their chest drain management is often intensive, they have increased nutritional needs since they’re losing nutrients in their chyle, AND they’re recovering from major thoracic surgery in many cases.
So, to care for these patients effectively, we need to focus on:
Monitoring respiratory pattern, rate, and effort regularly
Performing or assisting with thoracocentesis as needed
OR managing the patient’s chest drain appropriately
Recording their fluids in and out, to prevent dehydration from the pleural drainage
Providing good quality, appropriate nutrition that meets their energy needs
Monitoring the patient’s weight, body condition, and nutritional status in the hospital
Pain monitoring and management, including multimodal analgesia (PS - you can’t put local down the chest drain of a pericardectomy patient, so that’s not an option for these guys!)
And all of the other day-to-day nursing things our complex medical patients need!
There you have it - the three essential things you need to know about chylothorax, so that you can spend less time worrying about not knowing enough about it, and more time focusing on giving care that HELPS your patient.
We’ve learned what chylothorax is and how it ends up in the pleural space, the impact it has on our patient, and how we can treat and care for these patients, whether medically or surgically.
Chylothorax might not be the most common pleural space disease, but when we do see it, it’s one of the hardest (but most rewarding) to manage - and, as always, there are lots of ways we can use our nursing skills in the process.
Did you enjoy this episode? If so, I’d love to hear what you think. Take a screenshot and tag me on Instagram (@vetinternalmedicinenursing) so I can give you a shout-out and share it with a colleague who’d find it helpful!
Thanks for learning with me this week, and I’ll see you next time!
References and Further Reading
PS - a couple of these papers are quite old, apologies! But there is not a huge amount of evidence out there so I wanted to include as much literature as I could.
Atkins CE, Gallo AM, Kurzman ID et al. 1993. Risk factors, clinical signs, and survival in dogs with a confirmed diagnosis of idiopathic chylothorax: 37 cases. Journal of the American Veterinary Medical Association, 203(9), pp.1245-1249.
Bahlmann KN, and Stanley BJ. 2025. Use of a pleural access port in the staged management of idiopathic chylothorax in a cat. Journal of Feline Medicine and Surgery, epub ahead of print [Online] Available from: https://journals.sagepub.com/doi/full/10.1177/20551169251326747
Boothe HW, Hobson HP, Ho, AM et al. 1999. Chylothorax in 34 dogs. Veterinary Surgery, 28(2), pp.116-121.
Fossum, TW, 2019. Small Animal Surgery. 5th ed. St. Louis, MO: Elsevier.
Fossum, TW. 2016. Chylothorax in cats: is there a role for surgery? Journal of Feline Medicine and Surgery, 3(2), pp.73-79.
Gaylord L and Raditic D. 2023. Nutritional management of chylothorax [Online] Today’s Veterinary Practice. Available from: https://todaysveterinarypractice.com/nutrition/nutritional-management-of-chylothorax/
MacDonald KA, and Cagney O. 2012. Chylothorax in dogs and cats. Compendium, 34(3), pp.E1-E5.
Nelson RW, and Couto CG, 2020. Small Animal Internal Medicine. 6th ed. St. Louis, MO: Elsevier.
Radlinsky MG, 2012. Surgical management of chylothorax. Veterinary Clinics of North America: Small Animal Practice, 42(6), pp.1109-1115.
Reiner, CR, 2024. Diseases of the pleural space. In: SJ Ettinger, EC Feldman and E Côté, eds. Textbook of Veterinary Internal Medicine. 9th ed. St. Louis, MO: Elsevier.
