Pectus carinatum in a Cat

Resumo

Background: Pectus are congenital sternal deformities considered rare in small animals, and they are divided into two types. Pectus excavatum causes a concave aspect in the ventral portion of the animal’s thorax, which is known as “funnel chest,” while pectus carinatum produces a convex appearance and is therefore called “pigeon chest.”  The etiology of these anomalies has not yet been fully elucidated, but it is assumed that there is genetic involvement. The diagnosis is based on clinical examination and is confirmed by thoracic radiography. This report describes a case of pectus carinatum in a one-month-old domestic cat.

Case: An unspayed female domestic cat, about one month old, weighing 0.1 kg, was admitted to the Veterinary Hospital of the Federal University of Piauí (UFPI). When her history was taken, her owner reported that he had rescued the animal the previous day and noticed that showed difficulty breathing, so naturally worming and vaccination were not reported. Upon physical examination, the patient showed an abdominal breathing pattern, severe dyspnea, pale mucosa, nasal discharge, apathy, poor nutritional status (body score 1), signs of apparent dehydration and a temperature of 38.5ºC. Palpation revealed increased volume in the thoracic region. X-rays were ordered due to suspicion of diaphragmatic injury. The chest X-ray report indicated ventral segment displacement of the 4^th to the 8^th sternebra, with accommodation of the cardiac silhouette in the right lateral, left lateral and dorsoventral projections, suggesting pectus carinatum. Pulmonary radiodensity was also augmented, with greater intensity in the right middle lobe, an alveolar pattern, radiographic signs suggestive of an infectious process (pneumonia), and pulmonary hyperinflation. A qualitative analysis revealed cardiac silhouette whose dimensions showed no radiographic evidence of alterations at the moment of the examination. The diaphragmatic dome was intact. Normally aerated thoracic trachea, with preserved dorsoventral diameter.

Discussion:  Although deformities of the chest wall are infrequent and cases of pectus carinatum (PC) have rarely been published in veterinary medicine, reports of pectus excavatum (PE) in both dogs and cats are more easily found. Therefore, epidemiological data on PC are unknown, and moreover, most veterinary clinicians and surgeons are unaware of this anomaly. In the case of this kitten, pectus carinatum was diagnosed based on imaging tests allied to a clinical evaluation. The pathophysiology of the deformity has not yet been fully elucidated. In a case reported in a Shih Tzu dog, it was pointed out that one of its siblings had died at birth, and that the parents had no kinship and no congenital or hereditary abnormality. In another case of a five-month-old miniature pinscher, born from a consanguineous gestation, several anomalies were observed, in addition to pectus carinatum, such as dental malocclusion, poor limb alignment and locomotion difficulty, bilateral cryptorchidism and umbilical hernia. Because it was a rescue dog, the appearance of the anomaly could not be attributed to consanguinity in the reported case. No other anomalies were observed. Therefore, it is worth emphasizing that the earlier the diagnosis the better the animal’s prognosis. However, further studies are needed in order to clarify the etiology, determine possibilities of intervention and devise treatments.