Negative pressure pulmonary edema due to nasopharyngeal polyps in a cat

Document Type : Clinical Report

Authors

1 Animal Medical Center, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo, 183-8509, Japan

2 Ichikawa General Hospital, Kariya Animal Hospital Group, 2-6-14 Ichikawa, Ichikawa, Chiba 272-0034, Japan

3 Laboratory of Veterinary Imaging, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo, 183-8509, Japan

4 Laboratory of Veterinary Clinical Oncology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo, 183-8509, Japan

10.30466/vrf.2025.2057596.4723
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, the cat did not suffer from NPPE after the polyp disappeared. 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.

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Articles in Press, Accepted Manuscript
Available Online from 23 August 2026

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