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.

Diagnosis of spontaneous hyperadrenocorticism in dogs. Part 1: Pathophysiology, aetiology, clinical and clinicopathological features

Hyperadrenocorticism is a relatively common endocrine disorder in dogs. It occurs as a result of a functional pituitary or adrenal tumour, although other causes have been rarely reported. Canine hyperadrenocorticism has been extensively described but diagnosing this disease remains challenging. Few studies have investigated the clinical and clinicopathological features helpful in differentiating dogs with hyperadrenocorticism from dogs in which the disease is suspected but eventually excluded. Ultimately the diagnosis is based on a combination of multiple pieces of information emanating from the signalment, history, clinical findings, and a variety of diagnostic tests. The first part of this review aims to critically appraise the available data on epidemiology, clinical and laboratory features of naturally occurring canine hyperadrenocorticism.

Radiographic characteristics of alveolar microlithiasis and pulmonary ossification following chronic corticosteroid therapy in a dog

A 10-year-old, neutered female, Australian Shepherd was referred for acute respiratory distress and a history of chronic exogenous steroid administration. On thoracic radiographs, a severe increase in mineral opacity characterized as a generalized unstructured interstitial pulmonary pattern, diffuse calcinosis cutis, and moderate hepatomegaly were noted. Cor pulmonale was identified on echocardiography. The patient developed a pneumothorax following sampling and had a cardiac arrest. Postmortem histopathology of the lungs revealed pulmonary interstitial mineralization and alveolar microlithiasis. This report supports including generalized pulmonary mineralization due to chronic exogenous steroid administration as a differential diagnosis for dogs with these clinical and imaging findings.

Urinary excretion of calcium and phosphate in dogs with pituitary-dependent hypercortisolism: case control study in 499 dogs

Pituitary-dependent hypercortisolism (PDH) in dogs is frequently associated with high serum phosphate and parathormone concentrations which are in turn associated with prognosis and clinical presentation. The pathogenesis of such abnormalities remains unknown. The aim of the present study was to evaluate the serum and urinary concentrations and the urinary fractional excretion of phosphate and calcium in dogs with PDH. Medical records of newly diagnosed PDH dogs before treatment from one referral centre were retrospectively evaluated. One clinically normal and one sick dog for each dog with PDH were included as controls. One hundred and sixty-seven dogs with PDH were included. The serum phosphate concentration in PDH dogs was significantly (P<0.0001) higher compared with clinically normal control dogs (CNDs) and sick control dogs (SCDs). The serum calcium concentration in PDH dogs was significantly higher compared with SCDs but not different compared with CNDs. Urinary fractional excretion of phosphate in PDH dogs was significantly lower compared with CNDs and SCDs. Urinary fractional excretion of calcium in PDH dogs was significantly higher compared with CNDs and SCDs. In conclusion, PDH dogs have lower phosphaturia and higher calciuria compared with control dogs. These findings suggest that, at least in part, high serum phosphate concentrations are related to the renal retention of phosphate.

Diagnosis of spontaneous canine hyperadrenocorticism: 2012 ACVIM consensus statement (small animal)

This report offers a consensus opinion on the diagnosis of spontaneous canine hyperadrenocorticism. The possibility that a patient has hyperadrenocorticism is based on the history and physical examination. Endocrine tests should be performed only when clinical signs consistent with HAC are present. None of the biochemical screening or differentiating tests for hyperadrenocorticism are perfect. Imaging can also play a role. Awareness of hyperadrenocorticism has heightened over time. Thus, case presentation is more subtle. Due to the changes in manifestations as well as test technology the Panel believes that references ranges should be reestablished. The role of cortisol precursors and sex hormones in causing a syndrome of occult hyperadrenocorticism remains unclear.

Recent advances in the diagnosis of Cushing's syndrome in dogs

Hypercortisolism is a common condition in dogs and can be defined as the physical and biochemical changes that result from prolonged exposure to inappropriately high plasma concentrations of (free) cortisol, whatever its' cause. This disorder is often called Cushing's syndrome, after Harvey Cushing, the neurosurgeon who first described the human syndrome in 1932.

Diagnosis of canine hyperadrenocorticism

Canine hyperadrenocorticism is one of the most common endocrinopathies in dogs. Diagnosis remains difficult in some cases due to factors such as the presence of non-adrenal illness and limitations in the tests. Differentiation between the pituitary and adrenal forms is important for providing accurate prognostic information and delineating treatment options and protocols. This article reviews the tests available for diagnosis (screening) and differentiation and evaluates their advantages and disadvantages. Recommendations for testing are made.