Spontaneous Haemoperitoneum in Cats: A Summary

Philip R Judge BVSc MVS PG Cert Vet Stud MACVSc (Vet Emergency and Critical Care; Medicine of Dogs)

Introduction

Spontaneous haemoperitoneum, or the accumulation of blood within the peritoneal cavity in the absence of external trauma or recent surgery, is a life-threatening condition in cats. While it is encountered less frequently than in dogs, its consequences are often debilitating. Our current understanding has been largely based on a small number of cases or extrapolated from canine literature, which is problematic given the significant species differences in underlying aetiology.

A pivotal retrospective study published in the Journal of the American Veterinary Medical Association (Culp et al., 2010) sought to characterize this condition more comprehensively, by reviewing 65 cases across seven large referral clinics. The study provides valuable insights into the signalment, clinical signs, aetiology, diagnostic findings, and outcomes for cats with spontaneous haemoperitoneum. This review summarises the key takeaways from that study to help inform clinical decision-making for this challenging presentation.

Aetiology

One of the most critical findings of this study was the distribution of underlying causes. In contrast to dogs, where neoplasia accounts for approximately 80% of spontaneous haemoperitoneum cases, the aetiology in cats was nearly evenly split between neoplastic causes 46% (30/65) and non-neoplastic causes 54% (35/65).

• Neoplastic Causes: Haemangiosarcoma was the most common neoplasm, diagnosed in 60% (18/30) of the cats with cancer. The spleen was the most frequent location for neoplasia (11/30; 37%), followed by the liver. Other reported neoplasms included hepatocellular carcinoma, lymphoma, and various adenocarcinomas.
• Non-Neoplastic Causes: The most common non-neoplastic causes were coagulopathies (23%) and hepatic necrosis (23%). Coagulopathies were secondary to conditions including sepsis, anticoagulant rodenticide toxicosis, and pancreatitis. Other notable causes included bladder rupture, hepatic rupture secondary to amyloidosis, and gastrointestinal ulceration.

The study highlighted that liver disease, whether neoplastic or non-neoplastic, was the most common organ system involved accounting for 40% (26/65) of all cases. This is a key differentiator from dogs, where the spleen is the predominant organ source

Clinical Signs

The study revealed the clinical presentation of spontaneous haemoperitoneum is often vague, which can lead to diagnostic delays. The most common historical findings were non-specific:

• Lethargy (58%)
• Anorexia (51%)
• Vomiting (29%)

On physical examination, the most common findings include: 

• Inadequate hydration (83%)
• Hypothermia (68%)
• Pale mucous membranes (40%)
• Depressed mentation (40%)

Importantly, while 46% of cats had an abnormal finding on abdominal palpation (such as distension or discomfort), a discrete abdominal mass was only palpable in 15% of cats that were ultimately found to have a mass lesion. This underscores that the absence of a palpable mass does not rule out an intra-abdominal source of bleeding.

Diagnostic Workup

Given the vague and at time non-specific clinical findings, a thorough diagnostic workup is essential. Key findings from diagnostic evaluation in cats with haemoabdomen included: 

• Haematology and Biochemistry:
  • Anaemia: 83% (50/60) of cats were anaemic on presentation (median PCV 20%). Notably, all cats that were not anaemic had hyperproteinaemia, suggesting that dehydration may have masked the true degree of blood loss.
  • Hyperlactataemia: Elevated lactate was common (79% of tested cats)
  • Elevated Liver Enzymes: High serum AST and ALT activities were present in 57% and 50% of cats, respectively. While this can be due to primary liver disease, it can also result from hepatic hypoperfusion. The study noted, however, that elevations were much less common in cats without hepatic disease.
• Coagulation Profiles:
  • Coagulopathies were a frequent finding, with approximately 77% of tested cats having a prolonged prothrombin time and 76% having a prolonged partial thromboplastin time. 

• Diagnostic Imaging:
  • Abdominal Ultrasonography was performed in 46% of cats, and was effective at detecting effusion (100% of cases) and identified abdominal masses in 43% of cases. The spleen and liver were the most common sites for identified masses.
• Abdominocentesis: This was the primary method for diagnosing haemoperitoneum (52% of cases). The mean PCV of the peritoneal effusion (21%) was similar to the mean peripheral PCV (22%), confirming active haemorrhage.

Treatment

Treatment of haemoabdomen requires intensive patient monitoring and intervention. This study highlighted both medical and surgical interventions:

• Medical Stabilization: Given the high prevalence of anaemia, hypoperfusion, and coagulopathies, aggressive medical management with intravenous fluids, blood transfusions (packed red blood cells or whole blood), and plasma products (for coagulopathies) is important regardless of whether surgery is pursued.
• Surgical Intervention: Surgery was performed in only 22% (14/65) of cats. Procedures included splenectomy, liver lobectomy, and exploratory laparotomy for biopsy. The authors suggest that more aggressive surgical exploration might be warranted, as over half of the cats had potentially treatable non-neoplastic conditions. Surgeons should be prepared to address hepatic disease, which was the most common underlying organ involvement.

Prognosis

The overall prognosis for cats with spontaneous haemoperitoneum in this study was poor. Only 8 of 65 cats (12%) survived to discharge. Of those that survived, median survival time was 54 days, with some living up to 5 years.

• The median survival time for cats with neoplasia was 11 days.
• The median survival time for cats with non-neoplastic disease was 61 days.
• The majority of cats (77%) were euthanized, which may reflect the severity of the underlying disease, financial constraints, or a perceived poor prognosis.

Differentiating Neoplastic from Non-Neoplastic Causes Preoperatively

The study attempted to identify factors that could help differentiate between neoplastic and non-neoplastic causes preoperatively, as an aid for surgical planning and client communication.

• Age: Cats with neoplasia were significantly older. An age ≥ 12 years had a high specificity (86%) for detecting neoplasia.
• PCV: Cats with neoplasia had significantly lower PCVs on presentation. A PCV ≤ 22% had a sensitivity of 85% for detecting neoplasia.

While these factors are not definitive, they can help inform the index of suspicion.

Conclusions

1. Consider Haemoabdomen in Sick Cats: Spontaneous haemoperitoneum should be on the differential list for any cat – particularly older cats presenting with vague signs of lethargy, anorexia, and clinical signs of shock and anaemia
2. Aetiology Differs from Dogs: Unlike dogs, the cause is nearly as likely to be non-neoplastic (e.g., coagulopathy, hepatic necrosis) as it is neoplastic (e.g., haemangiosarcoma) – with liver disease being a common underlying cause.
3. Stabilization: Intensive stabilisation efforts, including fluid therapy and blood product administration are cornerstones of initial management, especially given the high prevalence of coagulopathies and anaemia.
4. Surgery Warrants Consideration: Given that over half the cats in this study had potentially treatable non-neoplastic conditions, surgical exploration following stabilisation and correction of coagulopathies is a reasonable recommendation.
5. Prognosis is Variable: While the overall survival to discharge rate was low (12%) in this population of cats, those with non-neoplastic disease) can survive for months to years with appropriate treatment.

By understanding the unique characteristics of spontaneous haemoperitoneum in cats, clinicians are able to diagnose and stabilise more effectively, and have more informed conversations with owners about the potential causes and prognosis.

Reference:

Culp, W. T. N., Weisse, C., Kellogg, M. E., Gordon, I. K., Clarke, D. L., May, L. R., & Drobatz, K. J. (2010). Spontaneous haemoperitoneum in cats: 65 cases (1994–2006). Journal of the American Veterinary Medical Association, 236(9), 978-982.