Case description

A spayed female 12-year-old domestic shorthair cat was presented to a referral hospital (Western Australian Veterinary Emergency and Specialty) for an 8-month history of intermittently reduced appetite and gradual weight loss. The patient did not have any ocular abnormalities prior to presentation. Abdominal ultrasonography revealed a mid-jejunal mass and mesenteric lymphadenomegaly. The patient subsequently underwent a coeliotomy where a jejunal resection and anastomosis were performed. An oesophagostomy tube (O-tube) was placed on the left side of the patient’s neck for assisted feeding to ensure adequate caloric intake as the patient was hyporexic preoperatively.

During recovery the patient was placed in right lateral recumbency and the left cervical region was prepared for surgery. A 10 F red rubber catheter was measured to the level of the distal third of the oesophagus. Curved Rochester–Carmault forceps were inserted into the oral cavity and directed distally into the oesophagus equidistant between the thoracic inlet and the pharynx, and the tips of the forceps were used to deviate the oesophagus laterally. A sharp incision was made with a size 15 Bard–Parker scalpel blade between the tips of the forceps. The tube was grasped with the forceps and pulled out orally, then redirected aborally into the oesophagus. The tube was sutured in place with a Chinese fingertrap suture using 3/0 polydioxanone. A soft padded bandage was applied around the neck to hold the tube in place.

Two hours after surgery the patient developed miosis and enophthalmos in the left eye (OS) consistent with Horner syndrome. Four days later a full ophthalmic examination confirmed ptosis, miosis, enophthalmos, prolapse of the nictitans membrane, narrowed left naris and decreased nasal airflow on the left side (Figure 1a, also see video in the  supplementary material). One drop of phenylephrine 1% was applied topically OS for neurolocalisation; pupillary dilation and resolution of ptosis were observed 10 mins after application, identifying the lesion as post-ganglionic.¹ The rest of the ocular examination was unremarkable. Physical examination was unremarkable other than good healing of the abdominal incision and O-tube stoma. Histopathology of the resected jejunal mass identified small cell T-cell lymphoma, so the patient was started on prednisolone (2 mg/kg PO q24h [Pred X-5 Apex]) and chlorambucil (4 mg PO q24h for the first 4 days and then once every 3 weeks [Leukeran; Aspen Pharmacare]). A repeat ocular examination performed 2 weeks later revealed that the signs of Horner syndrome were starting to resolve.

Figure 1

A 12-year-old domestic shorthair cat after placement of O-tube. (a) Cat at day 4 showing signs of Horner syndrome in the left eye (OS), including miosis, enophthalmos and protrusion of the third eyelid; (b) cat at day 20 exhibiting signs of Pourfour du Petit syndrome OS, including mydriasis and a widened palpebral fissure

On day 20 after the O-tube placement the patient developed signs clinically resembling Pourfour du Petit syndrome, including mydriasis and a widened palpebral fissure OS (Figure 1b). The ipsilaterally narrowed naris and nasal congestion had resolved at that point. The patient remained clinically well and there were no other ocular abnormalities. Between days 25 and 26 the patient developed mild miosis OS consistent with Horner syndrome again. On day 32, the O-tube was removed as the stoma was inflamed and the patient was eating well on its own. Repeat examination on day 33 revealed complete resolution of mild miosis OS. Repeat examination 15 months later did not show any recurrence of ocular signs.

Discussion

This report discusses a cat that developed alternating ipsilateral Horner and Pourfour du Petit syndrome after placement of an O-tube. In this particular cat, it was hypothesised that the initial surgical trauma due to O-tube placement led to stretching of the vagosympathetic nerve trunk and subsequently neuropraxia, leading to Horner syndrome. During placement of an O-tube, the oesophagus is elevated laterally with forceps placed through the oral cavity into the oesophagus, and a skin incision is made into the oesophagus to pass the O-tube. The vagosympathetic trunk is located in close proximity to the oesophagus (Figure 2). It would be reasonable to assume that tension placed on oesophageal tissue would also cause tension on the vagosympathetic nerve, making secondary neurological complications from inserting an O-tube a potential, although uncommon, complication.

Figure 2

Anatomy of the major nerves in the cervical region of the cat, illustrating the close proximity of the vagosympathetic trunk and the oesophagus²

Horner syndrome is caused by a loss of sympathetic innervation to the ocular muscles. Signs include ptosis, miosis, enophthalmos and protrusion of the nictitating membrane. Idiopathic Horner syndrome is the most common, but other identifiable causes include trauma, otitis media and interna, brachial plexus root avulsion and neoplasia.³ The prognosis for recovery from idiopathic Horner syndrome is excellent, with resolution of signs starting to occur in 4 weeks.⁴ This patient also developed reduced nasal airflow, a complication of Horner syndrome that has not been well documented in the veterinary literature but has been recognised in people.⁵ Decreased nasal airflow in Horner syndrome results from venous engorgement within the nasal mucosa because of reduced sympathetic tone, leading to reduced nasal patency.^4,5 It is possible that this occurs in veterinary patients, but the incidence is unknown as checking for nasal airflow does not typically form part of the normal ophthalmological examination.

Pourfour du Petit syndrome is caused by sympathetic hyperactivity; signs include mydriasis, exophthalmos and a widened palpebral fissure. There is a case report of three cats developing signs similar to Pourfour du Petit syndrome after undergoing saline irrigation of the middle ear.⁶ One of the cats in this case report also developed signs of Horner syndrome 4 days later. In people, Pourfour du Petit syndrome has been associated with blunt trauma, neoplasia, nerve blocks, central venous catheters and surgical positioning.

There is a single online report detailing the development of Horner syndrome as a complication of O-tube placement.² A review of complications associated with O-tubes in 248 cats found that the most common complications were infection of the stoma site, self-removal by the patient or dislodgement.⁷ The subsequent swelling and inflammation sustained by the vagosympathetic trunk and surrounding tissue secondary to the tension placed on the tissues during O-tube placement could have led to irritation of the nerve fibres, causing sympathetic hypersensitivity and ipsilateral Pourfour du Petit syndrome. The complete resolution of ocular abnormalities 24 h after O-tube removal further supports the likelihood that the ocular abnormalities were related to O-tube placement.

There are a few possibilities as to why this cat sustained a postganglionic lesion rather than a preganglionic one, as would have been expected if the Horner syndrome was due to neuropraxia of the vagosympathetic trunk, which is a second-order neuron. One possible explanation is that the presence of the tube itself could have caused some generalised swelling around the pharyngeal area, hence causing a third-order lesion. It is also possible that vascular injury associated with O-tube placement could have affected the cranial cervical ganglion and hence caused a postganglionic lesion rather than a preganglionic one. This effect has been documented in horses, where intravenous administration of medication into the external jugular vein causes inadvertent haemorrhage within the adjacent carotid sheath, leading to denervation of skin from the nose to the cranial portion of the neck.⁸ Neurolocalisation of Horner syndrome with 1% phenylephrine is commonly used, but this test has also not been studied in cats; the sensitivity of the test in detecting third-order lesions is unclear in cats at this stage.⁸

Conclusions

This report documents an unusual occurrence where both Horner and Pourfour du Petit syndrome occurred ipsilaterally in the same cat following O-tube placement with spontaneous resolution of all ocular signs after removal of the feeding tube 5 weeks later. The cause for this is suspected to be due to neuropraxia sustained during placement of the O-tube. This report highlights potential neurological complications secondary to O-tube placement, which should be monitored for in the postoperative period.