Abstract

Epistaxis, or nose bleeds, are defined as an acute hemorrhage from the nasal area which includes the nostril and nasal cavity or nasopharynx. It is a common condition in humans in particular the young and the old. For many animal species epistaxis is much less common, but there are many similarities in anatomy, physiology and etiology that may be helpful for the marine mammal clinician to consider when faced with nasal hemorrhage.

In humans, the classification of epistaxis is based on its location, either anterior or posterior. It occurs in one out of seven people and is more common in colder months or in dry cool climates. Potential causes in humans include local trauma, facial trauma, foreign bodies, nasal or sinus infections, prolonged inhalation of dry air, intubation, upper respiratory infection, patients with AIDS, vascular fragility, and vascular abnormalities such as neoplasia, coagulopathy, septal perforation or deviation, arteriovenous malformation, endometriosis, barotrauma, DIC, and hemophilia. Other causes include rhinitis, sinusitis, hepatic failure, leukemia, chemical irritants, plant poisoning, and toxicity from substances such as cocaine, nonsteroidal anti-inflammatory agents, rodenticide, salicylate, and warfarin.

In other species, such as the dog, signs of nasal disease may include a chronic discharge, sneezing, dyspnea, nasal swelling as well as hemorrhage.¹ The differentials for animals may be similar to those in humans with emphasis on infection, foreign body, parasites, neoplasia and trauma. Three cases of epistaxis in the walrus illustrate clinical examples of nasal disease, and possible causes of nasal hemorrhage.

Case 1

A 20-year-old female walrus had developed intermittent epistaxis in March of 2003. During this period she had been housed with a male walrus and there was a high probability that there was some cranial trauma during breeding activity. As a result, she was separated from the male but the hemorrhage did not resolve so she was placed on oral vitamin K supplementation. Cultures and cytology of the nasal cavity were taken which were non diagnostic. After beginning vitamin K therapy there was no blood observed for the next few days. One week later, a small amount of blood was seen and the clinician noted some ulceration in the nasal cavity during inspiration. The walrus was started on antibiotics, antifungals and a herb noted to enhance clotting. The ulceration in the nasal cavity improved over the next week, and though the hemorrhage decreased in volume and frequency, it was still present. Cytology of the nasal area showed many neutrophils, lymphocytes, and eosinophils. A resistant Pseudomonas aeruginosa was cultured so the antibiotics were changed. Over the next week, the signs shifted to include anorexia, loose stool, and dyspnea. Pain management was attempted with nonsteroidals and narcotic administration. A few days later, when administering subcutaneous fluids, her respirations became labored and she rapidly became comatose. Unfortunately, resuscitation efforts including intubation and oxygen failed.

Gross necropsy findings of the head showed a near total replacement of the nasal mucosa with a rough, polyp like surface that extended from just caudal to the nasal opening to the caudal nasopharynx. The conchae were absent in many areas as was the ethmoid labyrinth resulting in two undefined nasal spaces with an intact septum. Histology revealed a severe marked chronic rhinitis with development of granulation tissue and polyps. There was marked inflammatory proliferation consisting of patches of lymphocytes, plasma cells, macrophages, giant cells and few neutrophils, eosinophils and mast cells. There was marked neovascularization and eroded surfaces had rare mixed bacteria and scattered moderate numbers of mites. The other notable finding was a moderate to severe pulmonary edema with parenchymal collapse and interstitial pneumonia. While nasal mites are usually considered nonpathogenic in marine mammals, they were found in relation to a severe rhinitis indicating a possible relationship.

Case 2

A 26-year-old female walrus that originated from Alaska had exhibited epistaxis in June of 2003. She was anesthetized for biopsy of a mass from her left eye. During this time, the clinicians performed nasal endoscopy to investigate a possible cause for nasal hemorrhage. Visually, the walrus had multiple raised nodules or polyps on the mucosal surface which were diagnosed histologically as lymphoid hyperplasia. No mites were seen, though the animal was given Ivermectin at 200 mcg/kg and no further epistaxis has occurred.

Case 3

A 32-year-old female walrus with a history of intermittent bilateral epistaxis had exhibited chronic health problems over the previous two years. In addition, she had shown recurrent suggestions of facial discomfort and had exhibited possible melena in the stool. One year previously she had been treated with Ivermectin.

She eventually succumbed to a bronchopneumonia and on gross necropsy an examination of the skull showed extensive destruction and loss of the nasal and ethmoid conchae. The caudal two thirds of the ventral nasal conchae were eroded or missing and a soft black fuzzy mat (an aspergilloma) replaced these areas. The tissue destruction extended caudally to the ethmoid conchae with more severe damage on the right side. There was also a focally extensive bronchopneumonia present.

The histologic evaluation of the nasal area demonstrated a severe diffuse, chronic active, granulomatous, ulcerative and proliferative rhinitis. There was extensive, mucosal ulceration, submucosal inflammation and reactive tissue destruction of bony underlying tissue. In this case there were large mats of fungal hyphae and conidia consistent with Aspergillus niger.

The pathophysiology of the nasal changes in the two cases examined at necropsy is unknown at this time. The histologic findings of mites may be significant, but there is inadequate information to tie this finding solidly to the massive changes seen in the two cases. It is interesting to note that the second animal that was grossly examined did receive Ivermectin one year previous to the necropsy which may have affected the findings. Fay and Furman² examined the nasal passages of 349 pinnipeds of seven species for halarachnid mites in 1982. While Steller sea lions (Eumetopias jubatus), harbor seals (Phoca vitulina), and spotted seals (Phoca largha) were infected, none of the 28 walrus (Odobenus rosmarus) examined were positive for mites. In spite of that investigation, at least one of these individuals did have mites although this may suggest a different species relationship or that the mites may burrow deeply and not be as evident visually. Other possible causes such as fungal and bacterial infections should also be considered until a better understanding of the changes can be clarified. The potential involvement of viruses has not been investigated.

After seeing the destruction of the nasal cavity described in the first case, walrus trainers were asked to train another of the older walruses for nasal endoscopy in an attempt to use this technique for evaluation of the of the nasal area in the other walrus. An older adult male walrus with a chronic history of drainage from the left tusk area that had been surgically removed many years before was chosen for the first attempt. Radiographically, there was evidence of aberrant tusk regrowth on the left side and it was unknown if this area had compromised the rhinal cavity. The training procedure relied heavily on the walrus' ability to maintain open nostrils on stimulus. That behavior was conditioned and its threshold increased to about 5-6 seconds duration before beginning desensitization of a scope substitute. The first approximations at this point used a gloved index finger of one of the trainers to condition the animal. The walrus was rewarded for keeping his nostrils open for extended periods of time while the finger was inserted deeper into the nasal cavity. In order to receive food reward (in addition to tactile and verbal praise), the walrus learned to eat food and breath through his mouth with his nostrils open. Once successful to 5.1 cm deep, the trainers used the reinforcement history and principles of generalization to their advantage. They then presented the walrus with a different object the size of a ten French rubber tube. Using the same threshold training and generalization the trainers eventually conditioned the walrus to accept a 5 mm tube and remain in a relaxed position for more than a minute. After three weeks of training, the adult male was positioned between restraint bars, and under the control of a trainer, a 5 mm video bronchoscope was gently placed in the right nostril. There was no resistance to the initial insertion and examination of the area, so cultures were taken through the scope. The procedure was repeated on the left side with full cooperation from the walrus during the session. Visually the conchae were still present though there may have been some blunting of the ethmoid cartilage.

Since this was the first endoscopic nasal evaluation we have attempted, the visual anatomic findings will need to be verified as normal by further investigation of the other animals in the collection. Other facilities which house walruses should consider endoscopic evaluation as part of the nasal evaluation. All walruses which die should also have a thorough nasal evaluation in order to help zoos and aquaria establish a better understanding of these findings.

Acknowledgements

The authors would like to thank the animal care and training departments at SeaWorld for their dedication and help in the care and treatment of these animals.

References

1.  Rothenhaus, Todd, Epistaxis, 5-21-03.

2.  Fay FH, Furman DP, Nasal Mites(Acari: Halarachnidae) in the spotted seal, Phoca largha Pallas, and other pinnipeds of Alaskan Waters, Journal of Wildlife Diseases, 18(1), 1982, pp63-68

3.  Ivomec® (Ivermectin), Merial limited, Iselin, NJ, U.S.A.