Anaemic dog

"Zephyr"

Zephyr is a 14 year old, female spayed German Shepherd dog, who presented with a 3-4 week history of progressive malaise. Yesterday she stopped eating and began to pant heavily. Initially the owner elected for screening blood work (biochemistry and complete blood count) which demonstrated a microangiopathic  anaemia.  Given the elderly age and breed, neoplasia was suspected.

Thoracic radiographs were obtained to evalute the tachypnoea. A three view study was performed; the left lateral and ventrodorsal projections are presented here.

1. Evaluate this study in a systematic way. What are your radiographic findings? Does the patient have radiographic evidence of neoplasia?

2. What would you do next to evaluate what is causing Zephyr to be unwell? What do you think her prognosis is?

 

 

Answers

1. An excerpt from the radiographic report is presented here. The films are annoted below with the symbols seen in the text.

Radiographic findings:

Thorax: the heart is within normal limits for size and shape. In the midzone of the caudal segment of the left cranial lung lobe, there is a focal region of dense interstitial infiltrates with a faint air bronchogram visible, ~20x15mm in size (^). The remainder of the lungs are within normal limits.  A small amount of gas is present in the mid thoracic oesophagus (*), considered within normal limits for a sedated patient. In the cranial mediastinum dorsal to the second sternebra, there is a faintly increased, ovoid soft tissue opacity ~3x2cm (> <). On the caudal aspects of both humeral heads, a large (2-3mm) pointy, well mineralised osteophyte is present.

The cranial portion of the abdomen is included in this study. Superimposed over the cranioventral aspect of the liver are multiple small (5x10mm), ovoid, well defined gas bubbles (^^). The gastric axis is caudally displaced.

 

Conclusions:

1. Parenchymal hepatic gas: differentials include hepatic abscessation or necrosis. 2. Equivocal sternal lymphoadenopathy, suggestive of peritoneal cavity disease. 3. Focal region of interstitial-alveolar infiltrates in the midzone of the caudal segment of the left cranial lung lobe: differentials include aspiration (although this is an atypical location, it could be early on in the course) vs an atypical metastatic lesion (eg nodule). Should surgical exploration of the abdomen be considered, thoracic CT may help to further define this mass. 5. Chronic osteoarthritis of both shoulder joints considered incidental to the abdominal disease.

There is no clear evidence of metastatic neoplasia on this study. The abdominal changes require further investigation.

 

2. Zephyr appears to be suffering from an acute abdomen caused by hepatic necrosis or abscessation. She had an abdominal ultrasound performed, although obtaining radiographs of the abdomen would also be an appropriate next step in the diagnosis. An ultrasound image of the right liver is presented here. It shows a large, rounded mass with complex echogenicity (mixed hypo- and hyperechoic regions). The parenchymal gas is visible as hazy echogenic foci, with reverberation or comet-tail artifacts, in the left half of the image.

 

The mass was focal in the right aspect of the liver, with the central and left regions appearing to be unaffected. The gas suggests hepatic abscessation (infection or necrosis). Differentials for the mass include primary hepatic neoplasia (hepatoma, hepatobiliary carcinoma, haemangiosarcoma) or less commonly other neoplasia (histiocytic sarcoma, lymphoma, mast cell neoplasia). A non-neoplastic cause (eg lobar torsion and necrosis, infarction) is also possible and biopsy would be required to differentiate this further.  Fine needle aspirates of the mass demonstrated a uniform population of bacilli (rods), neutrophilic inflammation and hepatocellular changes consistent with either dysplasia or neoplasia. Surgical resection of the infected lobe was offered, however the owners declined.

This is a good example of pathology that is visible on the edge of the view and a reminder to always evaluate all of the structures on the film, including the regions which may not be considered the primary region of interest.

 

 


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