Transcript:

[0:00]

Hi everyone, welcome back to Mad Barn Academy. If you’re new here, welcome — we hope to earn your subscription today, and as always, we appreciate and thank you for your support. I’m Dr. Fran Row, one of the veterinary nutritionists here at Mad Barn. Today I’m going to be discussing a topic that was a special request — shoutout to Patricia — progressive ethmoid hematoma. If you have a topic you’d like to see covered in a future video, comment below.

[0:27]

So let’s get started. An ethmoid hematoma is a non-cancerous, or benign, mass of the nasal cavity and/or paranasal sinuses. To break that down a bit, it’s a hematoma — a blood-filled mass — that originates from the ethmoid turbinates, which are located in the very back of the horse’s nasal passage. The ethmoid turbinates communicate with the nasal passage and the surrounding sinuses in the head. In this graphic, the ethmoid turbinates are the pink, fan-shaped structure.

[1:04]

The ethmoid turbinates are thin, scroll-shaped bones covered in respiratory epithelial cells. This tissue is highly vascular, meaning there’s a large concentration of small blood vessels. The primary job of the ethmoid turbinates is to clean, warm, and humidify the air that’s breathed in.

[1:27]

The cause of ethmoid hematoma is largely unknown. However, we understand that for some reason, a small bleed occurs within the tissue covering the ethmoid turbinates. This causes the tissue to balloon and form a hematoma. Instead of resorbing and going away — which would be normal — the tissue becomes thickened and instead forms a capsule.

[1:55]

Depending on where the hematoma forms on the ethmoid turbinate, the mass can expand into the nasal cavity and/or the surrounding sinuses. In this graphic, the ethmoid turbinates are labeled six — the gray fan-shaped structure — and the sinus cavities are in red and blue, with their names listed on the slide.

[2:23]

Even though these aren’t cancerous masses, they are locally invasive and destructive as they grow, meaning they can destroy the bony architecture of the nasal cavity and sinuses as they expand over time.

[2:42]

The literature is a little inconsistent on demographics, depending on the paper you read, but ethmoid hematomas are thought to occur most commonly in male, middle-aged Thoroughbreds. However, they have been reported in many other breeds — drafts, warmbloods, light breeds — and the age at diagnosis can range anywhere from about 3 years old into the 20s. The prevalence in hospital populations is estimated to be about 1 in 2,500 horses, meaning it’s likely even less frequent in the general population. Additionally, ethmoid hematomas account for around 4% of horses with sinus disease. Overall, this is not a particularly common issue in horses.

[3:41]

In many cases, owners will simply report a small trickle of blood or blood staining from one or both nostrils. Often, blood in the nostrils is intermittent — it comes and goes. If the mass extends into the nasal cavity itself and begins to block normal airflow, owners may also report new-onset respiratory noise. Less common clinical signs include malodorous breath, facial swelling, head shyness, and head shaking — but it’s variable.

[4:21]

To investigate the cause of blood from the nostrils or new respiratory noise, the veterinarian will most likely start with scoping the upper airway and taking radiographs of the skull to determine where the blood or noise is coming from. On endoscopy, ethmoid hematoma is suspected when a mass is seen originating from the ethmoid turbinates. The color of these masses can range from reddish-purple to gray, green, or yellow. Radiographs may also show a soft tissue mass originating from the ethmoid region and extending into nearby sinuses.

[5:07]

In some cases, the hematoma grows into a sinus that cannot be visualized with endoscopy or radiographs, and in these cases, advanced imaging like CT or MRI may be necessary to determine the location and extent of the mass.

[5:30]

For a definitive diagnosis — to be confident it’s an ethmoid hematoma and not another type of mass like cancer — the mass can be sent for histopathology, so the tissue can be examined under a microscope. This might be a biopsy of the mass prior to surgery, or, if the horse goes to surgery right away, the entire mass can be submitted.

[6:02]

While ethmoid hematoma is not generally considered life-threatening, it can limit performance and lead to secondary airway and sinus complications if left untreated. There are two main treatment options today. The first is intralesional injection with formalin. This procedure is best performed on small masses and is only an option if the mass is accessible via endoscope. For this procedure, the mass is injected repeatedly at frequent intervals with formalin until it resolves or can no longer be injected. The time between injections is usually 2 to 4 weeks. One case study listed five injections as the mean, but it ranged from 1 to 18 injections.

[7:00]

The goal is complete resolution of the mass, but recurrence can occur. Remission times have been reported anywhere from less than one year to nearly two years, depending on the case.

[7:21]

The other treatment option is surgical excision or surgical debulking. This is best for very large masses, those that can’t be accessed via endoscope, or if formalin injections fail and the mass recurs. Cryotherapy or laser ablation can also be used with surgical removal. Surgery can be done standing or under general anesthesia, and through a sinus flap — shown in this picture here as a closed sinus flap after surgery. The sinus flap allows the surgeon to access the sinus directly. Recurrence in these cases depends on the completeness of excision — masses that cannot be completely excised are more likely to return.

[8:27]

Okay, you guys — that’s it for today. References, and I really appreciate you taking the time to listen. If you liked this video, like and subscribe, and check back for more videos in the future. Until next time — thanks.