Hypoglycemia and Tumor Lysis Syndrome Associated with Peritoneal Mesothelioma in a Horse

Abstract

A n 11-year-old Lipizzaner mare was referred for lethargy, abdominal distention, coughing, and weakness of 1 month's duration. The mare had been regularly dewormed and vaccinated against tetanus, influenza, and Eastern and Western equine encephalitis. Serum agar gel immunodiffusion assay for equine infectious anemia was negative. The mare was weak, lethargic, and mildly dehydrated. Abdominal distention was prominent (Fig 1), and borborygmi were absent. Mucous membranes were pale with a capillary refill time of 3.5 seconds. Heart (86 beats/min) and respiratory (40 breaths/min) rates were increased, and rectal temperature was 99.8uF. Body weight was 605 kg, but the mare was judged to be thin. Ventral abdominal subcutaneous edema was evident. Per rectum abdominal palpation identified a nongravid uterus. Moderate anemia (packed cell volume, 21%), mild lymphopenia, and hyperfibrinogenemia (0.5 g/dL; reference range, 0.1-0.4 g/dL) were present on the CBC. Serum biochemical analysis identified hypoglycemia (glucose, 47 mg/dL; reference range, 72-114 mg/dL), azotemia (BUN, 89 mg/dL; reference range, 8-27 mg/ dL; creatinine 5 8.8 mg/dL, reference range, 0.6-1.8 mg/dL), hyponatremia (sodium, 121 mmol/L; reference range, 132-144 mmol/L), hypochloremia (chloride, 86 mmol/L; reference range, 94-102 mmol/L), hyperka-lemia (potassium, 6.3 mmol/L; reference range, 2.7-4.9 mmol/L), hypoproteinemia (protein, 4.8 g/dL; reference range, 4.9-6.9 g/dL), hypoalbuminemia (albumin, 2.1 g/dL; reference range, 2.5-4.2 g/dL), hypocalcemia (calcium, 9.9 mg/dL; reference range, 10.7-13.4 mg/dL), hyperphosphatemia (inorganic phosphate, 13.9 mg/dL; reference range, 1.9-5.4 mg/dL), hypertriglyceridemia (triglyceride, 2,720 mg/dL; reference range, 4-44 mg/ dL), unconjugated hyperbilirubinemia (3.7 mg/dL; reference range, 0.1-1.9 mg/dL), and increased serum enzyme activities (CK, 3,147 U/L; reference range, 90-565 U/L; aspartate aminotransferase (AST), 2,268 U/L; reference range, 205-555 U/L; lactate dehydrogenase (LDH), 32,582 U/L; reference range, 520-1,480 U/L; gamma glutamyl transferase (GGT), 59 U/L; reference range, 12-45 U/L). Urinalysis indicated dilute urine (urine specific gravity [USG], 1.016) and hyaline casts (15 to 20 casts per low power field) were observed. The bladder was normal on endoscopic examination. Abdominal ultrasonography identified a large volume of anechoic abdominal fluid and revealed irregular cauliflower-like masses adherent to the abdominal wall at many locations, evidently fused to the peritoneum and characterized by mixed echogenicity (Fig 2). Other smaller masses were identified on the surface of the mesentery and adjacent to the dorsal aspect of the spleen. Abnormalities were not seen in the liver, kidneys, and intestines. Mild to moderate anechoic bilateral pleural effusion was observed. Abdominocentesis yielded a large volume of serosan-guineous peritoneal fluid (PF) characterized by a normal nucleated cell count (659 nucleated cells/mL), moderately increased protein concentration (3.2 g/dL), and a hematocrit...

Paraneoplastic manifestations of cancer in horses

“…2001; Swain et al . 2005; LaCarrubba et al . 2006), theoretical explanations have included failure of compensatory mechanisms to offset hypoglycaemia, hepatic failure, increased circulating tumour necrosis factor‐alpha (TNFα), enhanced glucose consumption by neoplastic cells and production of circulating insulin‐like activity by tumour cells (Kriersberg and Pennington 1970; Sakamoto et al .…”

“…Although it has been reported rarely in horses, TLS was suspected in one horse affected with mesothelioma in which characteristic metabolic perturbations (hyperkalaemia, hyperphosphataemia, hypocalcaemia), acute renal failure, extensive tumour burden with a high‐grade histopathological classification, and marked increase in serum LD activity were identified (LaCarrubba et al . 2006).…”

“…Hypoglycaemia is an uncommon finding in mature horses and must be carefully distinguished from the pseudohypoglycaemia that results from delayed separation of plasma (or serum) from the cellular fraction of blood. Documented causes of hypoglycaemia in mature horses have included exhaustion (Carlson 2002), enteritis (Carlson 2002), small intestinal strangulation (Davis et al 1992;Carlson 2002), endotoxaemia (Davis et al 1992), hyperlipaemia (Carlson 2002), emaciation (Carlson 2002), paraneoplastic syndromes (Roby et al 1990;Baker et al 2001;Swain et al 2005;LaCarrubba et al 2006) and insulinoma (Ross et al 1983).…”

Electroencephalographic alterations in a mare with presumed intermittent neuroglycopenia caused by severe hypoglycaemia‐associated with nonislet cell tumour

“…In other cases, there were no overt signs of seizure and the reported degree of hypoglycaemia was not severe enough (LaCarrubba et al . ; Gold et al . ), but this could have been a matter of time such that eventually the hypoglycaemia would intermittently become severe enough to lead to overt clinical signs of seizure.…”

“…), as well as mesothelioma (LaCarrubba et al . ) and gastrointestinal stromal tumour (Haga et al . ).…”