Negative-pressure pulmonary edema due to nasopharyngeal polyps in a cat

Document Type : Clinical Report

Authors

1 Animal Medical Center, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan

2 Ichikawa General Hospital, Kariya Animal Hospital Group, Chiba, Japan

3 Laboratory of Veterinary Imaging, Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan

4 Laboratory of Veterinary Clinical Oncology, Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan

Abstract
A 5-month-old male Himalayan cat presented with labored tachypnea and abnormal inspiratory sounds (stertor) in the upper airways. Chest and head radiography revealed amorphous interstitial and alveolar patterns in both lung fields and a soft tissue mass occupying the nasopharynx dorsal to the soft palate. The owner reported that the cat had continuously made sustained inspiratory efforts, which had become more severe on the day of visit. Based on these findings, we considered that the clinical signs were due to negative-pressure pulmonary edema (NPPE) caused by a nasopharyngeal polyp. The cat responded well to symptomatic treatments, including oxygen therapy and intravenous furosemide, and was discharged with surgical treatment planned at the secondary hospital. Although the cat had one recurrence of NPPE before the polyp was surgically removed, however, not suffered from NPPE after the polyp disappeared. The NPPE is a rare disease in cats, and its association with nasopharyngeal polyps has not been previously documented. Nasopharyngeal polyps located above the larynx can cause NPPE because mouth breathing is uncommon in cats. Veterinarians should consider NPPE in cats exhibiting inspiratory effort, particularly when chest radiographs show signs of pulmonary edema. Careful and detailed interviews with the owners/caregivers about respiratory patterns and nasopharyngeal examinations are essential.

Keywords

Subjects

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Volume 17, Issue 9
September 2026
Pages 681-684

  • Receive Date 14 April 2025
  • Revise Date 15 November 2025
  • Accept Date 10 December 2025