History:
A 3-year-old Domestic Shorthair presented at Rockaway Animal Hospital for a history of dysphagia. The patient was reported to prehend food normally, then cough and run away. Dr. Harrs recommended CT and fluoroscopy to determine “Dysphagia – neurologic vs cricopharyngeal vs other”.
Current medications: Pyridostigmine 60mg/5ml (0.3mls) , Gabapentin 50mg SID
We would like to extend our thanks to Rockaway Animal Hospital and Dr. Harrs for their continued trust and collaboration. We appreciate your referral to The Sonopath Imaging Center and are grateful for the exceptional care you provide to your patients. Thank you to Sonopath’s Radiologist, Sebastian Schaub, DVM, Dr. med. vet., Dipl. ECVDI (Radiology) for his excellent case interpretation of both CT and fluoroscopy studies.
referring vet.
The patient was referred to the Sonopath Imaging Center for a fluoroscopic swallow study due to ongoing complaints of dysphagia, including difficulty initiating a swallowing reflex and the appearance of food getting stuck in the throat. Upon arrival, the patient was positioned upright and ate barium coated food. Real-time X-ray imaging was used to assess the coordination and efficiency of the swallowing mechanism across the oral, pharyngeal, and esophageal phases. The study aimed to identify any signs of aspiration, residue, or structural abnormalities contributing to the patient’s symptoms. Throughout the procedure, the patient did very well and tolerated all consistencies without distress.
FLUOROSCOPY FINDINGS OF THE NECK:
The patient presents a normal oral phase of swallowing with normal prehension and bolus formation. The bolus was transported aborally into the pharynx. In the study performed 11/19/24, in only one swallowing a large bolus is propelled through the cricopharyngeal sphincter and propelled aborally by the expected primary and secondary waves of the esophagus. The esophagus is mild to moderately gas filled. The following boluses are incompletely propelled through an insufficiently opened upper esophageal sphincter with contrast stained material being partially propelled into the trachea or being retained in the pharynx. There is a lack of interrelation between pharyngeal contraction and opening of the cricopharyngeal sphincter.
FLUOROSCOPY DIAGNOSIS & THERAPEUTIC RECOMMENDATIONS:
- Cricopharyngeal dysphagia
INTERPRETATION OF THE FINDINGS & FURTHER RECOMMENDATIONS
The findings are consistent with cricopharyngeal achalasia.
Following completion of the fluoroscopic swallow study, which provided dynamic visualization of the patient’s oropharyngeal and esophageal function, the patient was then prepped for the CT scan for further evaluation. The transition to computed tomography was prompted by findings that warranted a more detailed anatomical assessment, particularly to investigate potential structural abnormalities or complications not fully captured on fluoroscopy. The patient remained stable throughout the transfer and was positioned comfortably for the CT scan to ensure optimal imaging quality.
COMPUTED TOMOGRAPHIC STUDY OF THE HEAD & NECK
A high resolution pre- and post-contrast CT study of the head and neck is provided for review.
COMPUTED TOMOGRAPHIC FINDINGS
- Multiple teeth are absent.
- The nasal cavity presents the expected aerated spaces between thin & even conchae and turbinates with smooth mucosal lining.
- Both temporomandibular joints present congruent joint spaces with even subchondral bone surfaces and are considered within normal limits.
- Both tympanic bullae are aerated, the mucosal lining is not seen, the bony wall is smooth and thin. The external ear canals are within normal limits.
- The brain presents no deviation from normal anatomy and symmetry. The brain parenchyma is homogeneous and within normal limits for attenuation and distribution of contrast enhancement. The ventricular system is non-dilated and symmetric.
- The submandibular and medial retropharyngeal lymph nodes are small and elongated with a normal short-to-long-axis-ratio of < 0.5; the attenuation and contrast enhancement pattern is uniform.
- The esophagus is generalized mild to moderately distended by contrast stained material and a small volume of gas.
- The remainder of the osseous and soft tissue structures of the neck are within normal limits.
COMPUTED TOMOGRAPHIC DIAGNOSIS
• Generalized esophageal dilation
• Multiple absent teeth
INTERPRETATION OF THE FINDINGS & FURTHER RECOMMENDATIONS
The generalized distended esophagus can be accentuated by general anesthesia. A differential is megaesophagus – potential causes are idiopathic megaesophagus, hypothyroidism, myasthenia gravis, hypoadrenocorticism or paraneoplastic (no evidence of intrathoracic neoplasia).
What is Cricopharyngeal Achalasia?
Cricopharyngeal achalasia is a type of phyarngeal dysphagia. This means that the patient is able to form a food bolus, but cannot pass it from the oropharynx into the esophagus due to inability of the cricopharyngeal muscle to relax during the cricopharyngeal phase of swallowing. During the cricopharyngeal phase of swallowing, the thyropharyngeal muscle contracts and the cricopharyngeal muscle relaxes. When food is maintained in the pharynx versus transferring to the esophagus, regurgitation, gagging, aspiration, and coughing are all possible.
While cricopharyngeal achalasia is a rare condition affecting dogs, with Springer and Cocker Spaniels seeming to be predisposed, it is a scarcely documented diagnosis in the feline patient. Most patients become symptomatic shortly after weaning when they begin eating solid food. As described in this patient, a voracious appetite may be noted. Affected patients are generally of a smaller stature, and some will demonstrate failure to thrive, anorexia, and weight loss.
Diagnosis requires survey radiographs and ultimately a swallowing study with fluoroscopy. In the normal canine patient, the duration of the entire swallowing process is approximately 0.1 seconds. In patients with cricopharyngeal achalasia, the duration is prolonged with some being 0.17 to 0.45 seconds.
As in this patient, bloodwork is generally normal.
An acetylcholine receptor antibody test, as performed in this pet, may be performed to rule out myasthenia gravis. Other differentials to consider include oral disease, masses, cleft palate, dental disease, megaesophagus, peripheral neuropathy, etc.
While botulinum toxin can be used for a short duration (2-4 months) of treatment, cricopharyngeal myotomy/myectomy alone or in conjunction with thyropharyngeal myotomy/myectomy, is the treatment of choice. In one study, 49% of patients had complete resolution of signs.
Patient Outcome: Unfortunately, this patient was lost to follow-up and it is unknown if the owner elected to pursue surgical options. An acetylcholine receptor antibody test was performed, but results were not found in the medical records.
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