Plasma lactate concentrations in septic peritonitis: A retrospective study of 83 dogs (2007-2012)

OBJECTIVE

To determine if absolute plasma lactate concentration or lactate clearance in dogs with septic peritonitis is associated with morbidity or mortality.

DESIGN

Retrospective cohort study from 2007 to 2012.

SETTING

University teaching hospital.

ANIMALS

Eighty-three dogs with septic peritonitis were included. Patients had at least 1 plasma lactate measurement during the course of the hospitalization.

RESULTS

Sixty-four percent of the patients survived to discharge, 22% were euthanized, and 14% died during hospitalization. Plasma lactate concentration >2.5 mmol/L on admission (29% of the patients) was associated with mortality (P = 0.001). Median admission plasma lactate concentration (n = 81) was significantly different between nonsurvivors (2.5 mmol/L, range 0.5-8.4) and survivors (1.4 mmol/L, range 0.5-9.7; P = 0.007). Admission plasma lactate concentration >4 mmol/L yielded a sensitivity of 36% and a specificity of 92% for nonsurvival. The inability to normalize plasma lactate concentration within 6 hours of admission (n = 10/24) yielded a sensitivity of 76% and specificity of 100% for nonsurvival. Postoperative hyperlactatemia (plasma lactate concentration >2 mmol/L; n = 18/76) had a sensitivity of 46% and specificity of 88% for nonsurvival. Persistent postoperative hyperlactatemia (n = 11/18) had a sensitivity of 92% and a specificity of 100% for nonsurvival. Lactate clearance less than 21% at 6 hours (n = 20) had a sensitivity of 54% and specificity of 91% for nonsurvival. Lactate clearance less than 42% at 12 hours (n = 18) had a sensitivity of 82% and a specificity of 100% for nonsurvival.

CONCLUSIONS

Admission plasma lactate concentration and lactate clearance were good prognostic indicators in dogs with septic peritonitis.

Ehrlichia canis infection in a dog with no history of travel outside the United Kingdom

A two-year-old female neutered Tibetan terrier was referred following a one-month history of lethargy, inappetence and pancytopenia, which had been poorly responsive to immunosuppressive and fluoroquinolone treatment. The dog was diagnosed with pure red cell aplasia and was found to be positive for Ehrlichia canis by both antibody titre measurement and polymerase chain reaction. The dog lived in London and had not travelled outside the UK. The dog was treated with doxycycline, prednisolone and ciclosporin, but died as a result of gastrointestinal tract haemorrhage. To the authors' knowledge, this represents the first reported case of Ehrlichia canis in a dog in the UK with no previous travel history.

Ionized calcium concentrations in cats with septic peritonitis: 55 cases (1990-2008)

OBJECTIVE

To report the prevalence of ionized hypocalcemia (iHCa) in cats with septic peritonitis, and to determine whether hypocalcemic cats had increased morbidity and mortality when compared with normocalcemic cats.

DESIGN

Retrospective clinical study.

SETTING

University teaching hospital.

ANIMALS

Fifty-five client-owned cats with septic peritonitis.

MEASUREMENTS

Medical records of 55 cats with confirmed septic peritonitis meeting the study inclusion criteria were reviewed. Information obtained included signalment, cause of peritonitis, length of hospitalization (LOH), length of ICU stay, and outcome. Results from serum biochemical analysis, blood gas analysis, and coagulation testing from the time of diagnosis, and all ionized calcium (iCa) measurements during hospitalization were recorded. Systolic blood pressure, the presence of arrhythmias and administration of vasopressor agents, blood products, and sodium bicarbonate were documented. iCa concentration at the time of diagnosis and lowest recorded value during hospitalization were compared with LOH and length of ICU stay, survival to hospital discharge, and clinical and clinicopathologic data.

MAIN RESULTS

iHCa (iCa<1.20 mmol/L) was found in 89% of cats (49/55) at the time of diagnosis of septic peritonitis and 93% (51/55) at any time during hospitalization. There was no association between the presence or severity of iHCa at diagnosis and survival to hospital discharge. LOH (P=0.046) and duration of ICU stay (P=0.026) were significantly correlated with the lowest iCa recorded during hospitalization. Failure to normalize iCa during hospitalization was associated with a decreased survival rate to discharge (P=0.029) in patients with iHCa. iHCa was not associated with an increased prevalence of hypotension, coagulopathy, arrhythmias, or evaluated therapies.

CONCLUSIONS

iHCa is more prevalent in cats with septic peritonitis than described previously. Failure of iCa to normalize during hospitalization may be a negative prognostic indicator. iHCa may be predictive of a longer LOH and ICU stay, but is not necessarily associated with a poorer prognosis.

Development of a multiple-marker polymerase chain reaction assay for detection of metastatic melanoma in lymph node aspirates of dogs

OBJECTIVE

To develop a reverse transcriptase-polymerase chain reaction (RT-PCR) assay to detect canine melanoma-associated antigens (MAAs) and to use this technique to screen aspirates of lymph nodes (LNs) for evidence of metastatic spread of oral malignant melanoma.

ANIMALS

7 dogs with oral malignant melanoma and 4 dogs with multicentric lymphosarcoma.

PROCEDURES

We prepared cDNA from melanoma tumor biopsies and fine-needle aspirates obtained from submandibular LNs of dogs with oral malignant melanoma or multicentric lymphosarcoma. The RT-PCR assay was performed by use of tyrosinase, Melan-A, gp100, tyrosinase-related protein 2 (TRP-2), or melanoma antigen-encoding gene B (MAGE-B)-specific primers.

RESULTS

We detected MAGE-B mRNA in canine testicular tissue but not in melanoma biopsy specimens. Tyrosinase, Melan-A, gp100, and TRP-2 mRNAs were detected in tumor biopsy specimens and in 2 of 5 LN aspirates from dogs with melanoma, suggesting metastatic spread in those 2 dogs. We did not detect MAAs in LN aspirates obtained from dogs with multicentric lymphosarcoma. Sequencing of canine Melan-A and gp100 PCR products confirmed the specificity of the assay for these genes.

CONCLUSIONS AND CLINICAL RELEVANCE

Clinical staging of dogs with oral malignant melanoma is useful to assist in designing appropriate treatments. However, results of histologic examination of LN biopsy specimens can be inconclusive and, in humans, can underestimate the number of patients with metastatic disease. Molecular staging of melanomas in dogs can be achieved by screening LN aspirates for MAA mRNA, and this can be performed in combination with cytologic examination to aid in detection of metastatic disease.

Immunosuppressive cytokines in the regional lymph node of a dog suffering from oral malignant melanoma

A 10-year-old male cross-breed dog was referred for investigation of oral malignant melanoma. Fine-needle aspirates were taken from the draining submandibular lymph node. The presence of metastatic melanoma cells was confirmed by cytological examination and reverse transcription polymerase chain reaction (RT-PCR) using primers for the melanoma-associated antigens: tyrosinase and mart-1/melan A. Cytokine expression in the lymph node was evaluated by multiplex RT-PCR, which demonstrated the presence of mRNA for IL-10 and TGF-beta1. However, IL-2, IL-4 and IFNgamma mRNA could not be detected, suggesting a lack of immune activation. Thoracic radiographs showed a lesion within the caudal lung fields suggestive of pulmonary metastasis. The dog developed signs of dyspnoea and collapse and was euthanased four days later. This case illustrates that molecular techniques can be used to aid clinical staging of canine oral malignant melanoma, and suggests that immunosuppressive cytokines could be involved in the pathogenesis of disease.