Abdominocentesis (see p. 293) was performed and a sample of the fluid retrieved. Cytology demonstrated large numbers of degenerate neutrophils with intracellular bacteria as well as a considerable number of extracellular bacteria (Figure 29.2). A diagnosis of bacterial peritonitis secondary to uterine rupture was made. Regrettably, due to financial constraints, the dog was euthanased.

Figure 29.2 Septic peritoneal fluid secondary to uterine rupture; several degenerate neutrophils with intracellular bacteria are visible.

Haemoabdomen

Causes of haemoabdomen are listed in Box 29.1.

Theory refresher

Canine haemangiosarcoma

Canine haemangiosarcoma is most commonly diagnosed in German shepherd dogs followed by golden retrievers. Other large breed dogs, such as Labrador retrievers and Boxers, are also over represented. The spleen is the most common site of origin but right atrial, pericardial and hepatic canine haemangiosarcoma are also reported relatively frequently. Any site in the body that contains vascular endothelium can theoretically be affected.

Haemangiosarcoma is presumed to have metastasized at the time of diagnosis in the vast majority of cases, regardless of whether or not metastases are detected by currently available imaging modalities. The prognosis is very poor, with survival times in the region of 2–4 months reported for splenic haemangiosarcoma following splenectomy alone; survival may in some cases be improved modestly by additional chemotherapy and immunotherapy.

In dogs presenting with haemoabdomen presumed to be secondary to rupture of a splenic lesion, splenectomy will be palliative and remove the risk of recurrent haemorrhage in the short term. It should be remembered that the nature (benign or malignant) of hepatic nodules that may be identified in such cases cannot be determined based on ultrasonographic appearance and surgical intervention therefore remains a rational choice. Palliative surgery is unlikely to be an option in primary hepatic haemangiosarcoma.

Abdominal counterpressure bandage

The purpose of an abdominal bandage is to apply external pressure that will increase intra-abdominal pressure and thereby tamponade bleeding. Realistically, intra-abdominal pressure is only likely to be increased sufficiently to exceed venous pressure and reduce venous haemorrhage. Therefore, excessively tight bandages do not offer any significant advantage and are likely to be associated with greater complications.

Traditionally a soft material has been used as the primary layer of an abdominal pressure bandage with an elastic material applied on top. In the author’s experience, however, these bandages are more likely to slip and the author prefers to use an elastic adhesive primary layer despite the inherent difficulties in subsequent removal. The bandage should be placed starting caudally, approximately at the level of the pubis, and moving in a cranial direction up to the xiphoid, stopping before the caudal rib margin.

The bandage should be removed once the patient has remained stable for a reasonable period. Removal should commence at the cranial end (i.e. in the opposite direction to how the bandage was placed) and should be staggered by cutting a small section every 30–60 minutes over a period of several hours. The patient should be monitored closely for signs of deterioration during removal of counterpressure.

Abdominal bandages should not be used in animals with respiratory compromise or those suffering from diaphragmatic rupture.

Case example 3

Presenting Signs and Case History

A 10-year-old male neutered German shepherd dog presented with a 7-day history of intermittent lethargy and exercise intolerance. The dog had been found collapsed and tachypnoeic with a distended abdomen on the day of presentation.

Major body system examination

On presentation the dog was obtunded. Cardiovascular examination revealed a heart rate of 180 beats per minute with no murmur detected; femoral and dorsal pedal pulses were absent. Mucous membranes were very pale with a prolonged capillary refill time. Respiratory examination revealed tachypnoea with appropriate lung auscultation and both marked distension and recumbency precluded reliable abdominal palpation.

Assessment

The dog was assessed as being in severe hypovolaemic shock that was most likely due to acute abdomen. Given the dog’s signalment and history, there was a high index of suspicion for haemoabdomen secondary to rupture of an intra-abdominal haemangiosarcoma lesion. The fact that some colour remained in the mucous membranes despite the severity of hypovolaemia suggested that severe anaemia was not present.

Emergency database

An intravenous catheter was placed in a cephalic vein and blood collected via the catheter for an emergency database. This revealed mild anaemia (PCV 31%, reference range 37–55%) with a more significant decrease in TS (40 g/l, reference range 49–71 g/l), findings that were compatible with acute haemorrhage. Peripheral blood smear examination showed the anaemia to be regenerative (moderate polychromasia, moderate anisocytosis). As a regenerative response often takes a minimum of 3 days to be detectable clinically in dogs, this suggested one or more prior episodes of haemorrhage in the days preceding presentation. Platelet count was considered adequate and a neutrophilia with left shift suspected.

Case management

Aggressive intravenous fluid resuscitation with an isotonic crystalloid solution was commenced (60 ml/kg bolus via pressure infusor). Abdominal ultrasonography revealed the presence of a large volume of echogenic peritoneal fluid. Abdominocentesis (see p. 293) was performed and the non-clotting haemorrhagic fluid was found to have a PCV of 30%; cytology of the fluid revealed red blood cells, occasional erythrophagocytosis, no platelets and no evidence of sepsis. An abdominal counterpressure bandage was applied and fluid therapy discontinued as soon as the dog was assessed as being adequately perfused. The dog remained stable subsequently and the abdominal bandage was removed gradually over several hours.

The following day the dog was referred for further management. Abdominal ultrasonography revealed a cavitary splenic lesion and although the liver was hyperechoic, no focal lesions were identified. Thoracic radiography was performed under general anaesthesia and found to be unremarkable. Complete splenectomy and a liver biopsy were then carried out, from which the dog made an uneventful recovery. Histopathology confirmed the suspicion of splenic haemangiosarcoma although no neoplastic cells were identified in the sample of liver submitted.

Clinical Tip

• In the author’s experience, free peritoneal fluid is readily detected and sampled in most animals presenting with clinically significant haemoabdomen and DPL is typically not required. However, if this technique is used, the subsequent dilution must be kept in mind when interpreting the results of fluid analysis. A packed cell volume of DPL fluid of 2–5% or more is reportedly suggestive of significant haemorrhage.