What Is Your Diagnosis?

April M. Durant Hollywood Animal Hospital, 2864 Hollywood Blvd, Hollywood, FL 33020.

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History

A 12-week-old female Cavalier King Charles Spaniel was examined because of a cough and mucopurulent ocular discharge of 1 month's duration. Initial radiography revealed signs of inflammatory pulmonary and pleural disease. A diagnosis of bronchopneumonia was made, and the dog was subsequently treated with amoxicillinclavulanic acid (25 mg, PO, q 12 h). The owner noticed a decrease in severity of coughing episodes while the dog was being treated with the antimicrobial; however, resolution of clinical signs did not occur. When the owner noticed nonspecific signs of lethargy for a period of 24 hours, the dog was readmitted for further evaluation.

Figure 1—
Figure 1—

Left lateral and ventrodorsal radiographic views of the thorax of a 12-week-old female Cavalier King Charles Spaniel with a cough and mucopurulent ocular discharge of 1 month's duration.

Citation: Journal of the American Veterinary Medical Association 232, 2; 10.2460/javma.232.2.197

Physical examination revealed a serous nasal discharge with a productive cough. Thoracic auscultation revealed crackles and expiratory wheezes in all lung fields. A CBC revealed leukocytosis (30,300 cells/μL; reference range, 6 to 18 × 103 cells/μL) characterized by a mature neutrophilia (22,725 cells/μL; reference range, 3 to 15.3 × 103 cells/ ML) and a mild regenerative anemia (PCV of 39% and reticulocyte count of 3.2%; reference range, 43.3% to 59.3% and < 1%, respectively). Thoracic radiographic views were obtained (Figure 1).

Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page

Radiographic Findings and Interpretation

Diffuse interstitial and peribronchial infiltrate, visible pleural margins, fusion of the fourth and fifth and sixth and seventh sternebral bodies, and thoracic and abdominal situs inversus totalis are evident (Figure 2).

Figure 2—
Figure 2—

Same images as Figure 1. Notice the diffuse interstitial infiltrate throughout the lung and localized peribronchial infiltrate within the ventral aspect of the right middle lung and left caudal lung lobes. On the left lateral (A) image also notice the cranial vena cava entering the dependent (left) crus of the diaphragm (a) and gas within the nondependent fundus of the stomach (b). On the ventrodorsal (B) image, the descending aorta (a) is on the right, the caudal vena cava (b) is on the left, and the fundus of the stomach (c) and the head of the spleen (d) are on the right.

Citation: Journal of the American Veterinary Medical Association 232, 2; 10.2460/javma.232.2.197

The clinical diagnosis was inflammatory or infectious pulmonary and pleural disease compatible with bronchopneumonia and an unexpected finding of complete thoracic and abdominal situs inversus totalis. Other differential diagnoses based on the radiographic pattern of infiltrate included mycosis, parasitic disease, and infectious tracheobronchitis.

Comments

Situs inversus totalis occurs when organs of the body are formed as a mirror image reversal of asymmetric structures but is usually not associated with fatal malformations.1,2,3 Situs inversus totalis is believed to be an abnormal distribution of internal organs during embryogenesis. This syndrome is usually diagnosed incidentally; however, it can be associated with respiratory tract abnormalities such as sinusitis, bronchitis, and bronchiectasis.4

Detection of situs inversus totalis and evidence of recurrent bronchopneumonia on thoracic radiographic examination, combined with this dog's history of rhinitis, led to a presumptive diagnosis of Kartagener's syndrome. Kartagener's syndrome is a specific form, or subset, of primary ciliary dyskenesia (PCD), an inherited defect in microtubule formation affecting cilia of the respiratory tract, urogenital tract, and auditory canal.5 Patients with Kartagener's syndrome have the classic triad of situs inversus totalis, rhinitis, and bronchiectasis. A diagnosis of Kartagener's syndrome is supported radiographically when situs inversus totalis and bronchopneumonia are evident6; however, a definitive diagnosis of PCD requires electron microscopic evaluation of ciliary ultrastructure to demonstrate the classic defects in structure and function. Computed tomography of the nasal passages or brain may reveal mucosal thickening and hydrocephalus, respectively, and is supportive of PCD. Mucociliary scintigraphy may reveal delayed mucociliary clearance and can be supportive of a diagnosis of PCD.6,7

Treatment is aimed at controlling infection to facilitate the clearance of respiratory secretions. Broad-spectrum antimicrobials, nebulization, and coupage are the mainstays of medical treatment. Early intervention and treatment are necessary to avoid permanent sequelae such as chronic sinusitis, pneumonitis with associated microatelectasis that may progress to bronchiectasis, and pulmonary fibrosis.8 Despite treatment, patients are prone to recurrent episodes of pneumonia.

Bronchoalveolar lavage was performed on the dog of this report 2 days after admission. Cytologic examination of the specimen retrieved revealed neutrophils, macrophages, and cocci and diplococci. Bacteriologic culture of the specimen yielded scant growth of Proteus mirabilis, Pseudomonas aeruginosa, and β-hemolytic Streptococcus spp, which were susceptible to enrofloxacin and amoxicillin-clavulanic acid. Thoracic radiography performed 4 weeks after treatment with these 2 antimicrobials did not reveal substantial changes in the interstitial and peribronchial infiltrates. Pleural fibrosis was suspected on the basis of rounding of pleural margins and incomplete inflation of the right cranial lung lobe. Radiography performed after 8 weeks revealed resolving bronchopneumonia, and bronchoalveolar lavage at 12 weeks after treatment revealed a few neutrophils, macrophages, and well-differentiated epithelial cells. Bacteriologic culture did not yield growth. Cough, serous nasal discharge, and increased bronchovesicular sounds did not resolve. Treatment continued with nebulization and coupage performed 3 to 4 times a day. Because of the expense and risk to the dog, the owner declined further diagnostic evaluation.

References

  • 1.

    Casey, B. Genetics of human situs abnormalities. Am J Med Genet 2001;101:356358.

  • 2.

    Fisher KR, Wilson MS, Partlow GD. Abdominal situs inversus in a Holstein calf. Anat Rec 2002;267:4751.

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    McQuinn TC, Miga DE, Mjaatvedt CH, et al. Cardiopulmonary malformations in the inv/inv mouse. Anat Rec 2001;263:6271.

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    Kittelson MD, Keinle RD. Other congenital cardiovascular abnormalities. In: Duncan L, ed. Small animal cardiovascular medicine. 2nd ed. St Louis: Mosby, 1998;282296.

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  • 5.

    Aylsworth AS. Clinical aspects of defects in the determination of laterality. Am J Med Genet 2001;101:345355.

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    Neil JA, Canapp SO Jr, Cook CR, et al. Kartagener's syndrome in a Dachshund dog. J Am Anim Hosp Assoc 2002;38:4549.

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    Clercx C, Peeters D, Beths T, et al. Use of ciliogenesis in the diagnosis of primary ciliary dyskinesia in a dog. J Am Vet Med Assoc 2000;217:16811685.

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  • 8.

    Armengot Carceller M, Carda Batalla C, Escribano A, et al. Study of mucociliary transport and nasal ciliary ultrastructure in patients with Kartagener's syndrome [in Spanish]. Arch Bronconeumol 2005;41:1115.

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