Frequency of pulmonary mineralization and hypoxemia in 21 dogs with pituitary-dependent hyperadrenocorticism

Case Report: Mineralized Pulmonary Artery Thrombi in Two Dogs Treated for Meningoencephalitis of Unknown Origin

Meningoencephalitis of unknown origin (MUO) is a relatively common and very serious canine neurologic condition, which is typically associated with a poor long term prognosis despite treatment. This case series chronicles two dogs diagnosed with MUO who were treated with long term corticosteroids and cytosine arabinoside and lived well-beyond the typical survival time for this condition. Both eventually succumbed to respiratory signs associated with mineralized thrombi in their pulmonary arteries. Adverse effects from the two drugs used for treatment are reviewed in order to propose a possible mechanism to explain how long term use of these medications could result in such a phenomenon.

Clinicopathological and imaging features of pulmonary alveolar microlithiasis in a dog - a case report

Background

The aetiology of pulmonary alveolar microlithiasis (PAM) in animals is still unknown. In humans, this pulmonary disorder is a rare autosomal recessive disorder triggered by a mutation in the gene SLC34A2, which causes deposition and aggregation of calcium and phosphate in the pulmonary parenchyma with formation of microliths. Although histopathological examination is required for a definite diagnosis, in humans, imaging modalities such as computed tomography can demonstrate typical patterns of the disease. This is the first description of the computed tomographic (CT) features of a histologically confirmed PAM in dogs.

Case presentation

The following report describes a case of a 7-year-old female Boxer dog evaluated for paroxysmal loss of muscle tone and consciousness with excitement. The main differential diagnoses considered were syncope, seizures, and narcolepsy-cataplexy. The results of the complete blood count, serum biochemistry panel, urinalysis, arterial blood pressure, echocardiography, abdominal ultrasound, Holter monitoring, and ECG were all within normal limits. Additional exams included thoracic radiographs, head and thorax CT, bronchoalveolar lavage (BAL), and CT-guided cytology. Thoracic radiographs revealed micronodular calcifications in the lungs, with sandstorm appearance. Computed tomography of the thorax showed the presence of numerous mineralized high-density agglomerates of multiple sizes throughout the pulmonary parenchyma, a reticular pattern with ground glass opacity and intense mineralized fibrosis of the pleural lining. Head CT was unremarkable. BAL and CT-guided cytology were inconclusive, but imaging features strongly suggest the diagnosis of PAM, which was histologically confirmed after necropsy.

Conclusions

This case report contributes to the clinicopathological and imaging characterization of pulmonary alveolar microlithiasis in dogs. In this species, the diagnosis of PAM should be considered when CT features evidence a reticular pattern with ground glass opacity and the presence of an elevated number and size of calcifications.