Peritoneal fluid in horses is a serous fluid found within the abdominal cavity, surrounding the internal organs. It serves as a lubricant, reducing friction between the abdominal organs and the body wall during movement. The composition and volume of peritoneal fluid can change in response to various physiological and pathological conditions, making it a valuable diagnostic tool in equine medicine. Analysis of peritoneal fluid can provide insights into conditions such as colic, peritonitis, and abdominal trauma. Key parameters assessed in peritoneal fluid analysis include cell count, protein concentration, and the presence of bacteria or other abnormal substances. This page compiles peer-reviewed research studies and scholarly articles that explore the characteristics, diagnostic applications, and clinical relevance of peritoneal fluid analysis in horses.
Brownlow MA, Hutchins DR, Johnston KG.Cells in the peritoneal fluid from 159 horses were examined in Giemsa stained preparations using light microscopy. Normal mesothelial cells showed an oval nucleus with finely reticular chromatin and pale blue cytoplasm. Activated mesothelial cells occurred in fluids derived from mesothelium under acute or subacute, non-septic stimulus and were remarkable for their pleomorphism and intense basophilia which may mimic neoplasia. Transformed mesothelial cells seen in chronic inflammatory fluids were sometimes phagocytic and showed conspicuous cytoplasmic vacuolation.
Brown MP, Stover SM, Kelly RH, Farver TB.Six adult mares were given a single dose of ampicillin trihydrate (250 mg/ml) intramuscularly at a dosage of 20 mg/kg body weight. Serum, synovial fluid, peritoneal fluid and urine ampicillin concentrations were measured serially over a 48 h period. The mean peak serum ampicillin concentration was 2.49 micrograms/ml at 6 h. Ampicillin was found in synovial fluid and peritoneal fluid, which obtained mean peak ampicillin concentrations of 1.65 micrograms/ml and 1.81 micrograms/ml at 6 h and 4 h respectively. These concentrations declined in parallel with serum concentrations and were still detec...
Brown MP, Stover SM, Kelly RH, Farver TB.Six healthy adult mares were given a single dose of kanamycin sulfate (200 mg/ml) IM at a dosage rate of 5 mg/kg of body weight. Kanamycin concentrations in serum, synovial fluid, peritoneal fluid, and urine were measured serially over a 48-hour period. The mean peak serum kanamycin concentration was 12.55 microgram/ml at 1 hour. Mean peak kanamycin concentrations in synovial fluid and peritoneal fluid were 7.25 microgram/ml and 9.27 microgram/ml at 2 hours and 3 hours, respectively. These concentrations decreased steadily in parallel with serum concentrations and were still measurable at 48 h...
Stover SM, Brown MP, Kelly RH, Farver TB.Six healthy adult mares were given a single dose (25 mg/kg of body weight) of sodium oxacillin IM. Oxacillin concentrations in serum, synovial fluid, peritoneal fluid, and urine were measured serially over a 48-hour period. The mean peak serum oxacillin concentration was 9.75 microgram/ml at 0.5 hour after injection. Mean peak oxacillin concentrations in synovial and peritoneal fluids were 1.45 microgram/ml and 2.60 microgram/ml at 1 hour and 2 hours, respectively. These concentrations decreased in parallel with serum values and were not measurable at 48 hours. Urine concentrations of oxacilli...
Froscher BG, Nagode LA.The origin of increased alkaline phosphatase (ALP) activity in peritoneal fluid (PF) of horses with clinical signs of abdominal pain was investigated to determine the usefulness of measuring ALP in PF in the diagnosis of small intestinal injury. The ALP isoenzymes in PF from 10 clinically normal horses and from 50 horses with clinical signs of acute abdominal pain were analyzed for their sensitivities to inhibition by L-phenylalanine, L-homoarginine, and levamisole and to inactivation by heat (56 C, 15 minutes). The enzymes also were discriminated by their patterns of migration during polyacry...
Brownlow MA, Hutchins DR, Johnston KG.Twenty horses, aged one to 17 years (mean age 6 years), presented for elective destruction and subsequently found at autopsy to have no significant peritoneal alterations, were used to determine a variety of reference values for peritoneal fluid. Samples were collected ante mortem or within 1 h post mortem. Each cavity contained 100 to 300 ml of usually clear, pale yellow fluid which in a clinical refractometer showed a mean specific gravity 1.010 (range 1.0081-1.0116) and mean (+/- standard deviation) total protein 7.7 +/- 3.6 g/litre. The mean total nucleated cell count (+/- sd) was 4.33 +/-...
Stover SM, Brown MP, Kelly RH, Farver TB, Knight HD.Six adult mares were given a single dose of aqueous suspension procaine penicillin G (300,000 IU/ml) IM at a dosage of 22,000 IU/kg of body weight (15.4 mg of penicillin G/kg). Serum, synovial fluid, peritoneal fluid, and urine penicillin concentrations were measured serially over a 48-hour period. The mean peak serum penicillin concentration was 1.42 microgram/ml at 3 hours. Penicillin was detected in synovial fluid and peritoneal fluid, which obtained mean peak penicillin concentrations of 0.62 microgram/ml and 0.58 microgram/ml, at 4 hours and 3 hours, respectively. These concentrations ste...
Brown MP, Stover SM, Kelly RH, Farver TB, Knight HD.Six adult mares were given a single intravenous injection of oxytetracycline HCl (50 mg/ml) at a dosage of 5 mg/kg. Serum, synovial fluid, peritoneal fluid, and urine oxytetracycline concentrations were measured serially over a 48-h period. The highest measured serum oxytetracycline concentration was 8.01 mcg/ml at 1/2 h. Oxytetracycline was detected in synovial fluid and peritoneal fluid, which obtained mean peak oxytetracycline concentrations of 4.43 mcg/ml and 4.20 mcg/ml, at 1/2 h and 1 h, respectively. These concentrations steadily declined in parallel with serum concentrations and were n...
Dumas MB, Spano JS.Alkaline phosphatase isoenzymes of equine tissues, peritoneal fluid, and serum were characterized by their electrophoretic mobilities, using polyacrylamide gel disc electrophoresis. The alkaline phosphatase isoenzymes in liver, kidney, spleen, small intestine, placenta, bone, small colon, and large colon tissue samples were extracted and separated by electrophoresis. The resulting isoenzyme mobilities and spectrophotometric scans were evaluated for their tissue specificity and for their possible use in determining the tissue contribution of alkaline phosphatase to serum and peritoneal fluid. T...
Adams SB, Fessler JF, Rebar AH.Cytologic examination of serial peritoneal fluid samples of nine experimental ponies was performed during a 72 hour period following laparotomy. Six of the ponies had jejunal infarction induced by occlusion of the corresponding vasculature. Cytologic examination was also performed on the peritoneal fluid of a series of horses with naturally occurring abdominal crises presented to the Large Animal Clinic. A rapid staining technique allowed evaluation of smears within 5 minutes of obtaining the fluid. Alterations in peritoneal fluid of the experimental and clinical cases reflected an acute infla...
Gay CC, Lording PM.Actinobacillus equuli was the cause of peritonitis in 5 horses. In 3 the onset was sudden with intestinal stasis and acute abdominal pain as predominant findings. Two others presented with chronic disease and weight loss. Characteristically the peritoneal fluid had a high nucleated cell count with non-degenerate neutrophils as the predominant cell type. Four horses were treated and recovered.
Reynolds DJ, Nicholl TK.A 5 month old colt foal with recurrent pyrexia and a loud pansystolic murmur later developed signs of cardiac failure. Peritoneal fluid and blood samples both demonstrated an extreme leucocytosis and neutrophilia. At post-mortem both a cranial mesenteric arteritis and the congenital cardiac anomaly, Tetralogy of Fallot were found. The detailed clinical and post-mortem findings contributing to the case are described.
Rumbaugh GE, Smith BP, Carlson GP.internal abdominal abscesses in 25 horses, including 8 horses that died or were euthanatized, were found to be caused by Streptococcus equi, Streptococcus zooepidemicus, or Corynebacterium pseudotuberculosis. Breed or sex predilection was not found. Although horses of all ages were affected, those under 5 years of age were more commonly affected. Nearly all of the horses had a history of respiratory catarrh or lymphadenitis. Horses with internal abdominal abscesses also had intermittent, prolonged colic or chronic weight loss. Most horses had increased rectal temperature, increased heart and r...
Moore JN, Traver DS, Turner MF, White FJ, Huesgen JG, Butera TS.Peritoneal fluid from each of 15 clinically healthy horses and five horses with acute abdominal disease was evaluated for lactic acid concentration. The normal range was 2-7--13-4 mg/dl. Simultaneous blood and peritoneal fluid samples from healthy horses revealed consistently lower lactic acid concentrations in the peritoneal fluid than in the blood, whereas peritoneal fluid lactic acid levels were consistently greater than blood levels in the diseased horses. The diseased horses had highly significant (P less than 0-005) increases in both blood and peritoneal fluid lactic acid concentrations ...
Merritt AM, Cimprich RE, Beech J.Granulomatous enteritis was diagnosed in 9 horses between 1 and 11 years of age. The complaint in all cases was persistent weight loss. Four of the horses had chronic diarrhea. Two consistent diagnostic features were hypoalbuminemia and decreased phagocytic activity of mesothelial cells in the peritoneal fluid. In 2 cases the diagnosis was confirmed by biopsy of the rectal mucosa. Remaining cases were definitively diagnosed by exploratory laparotomy and biopsy or at necropsy.
Swanwick RA, Wilkinson JS.This paper evaluates the usefulness of abdominal paracentesis as a diagnostic aid in abdominal disease in the horse and in particular considers whether or not it can be effectively utilised as an indication for surgical intervention in cases of colic. The results are based upon peritoneal fluid samples collected from 20 normal horses and from 20 cases of colic and peritonitis. Peritoneal fluid was collected from standing horses by inserting a bovine teat cannula into the horses abdomen through the linea alba after desensitisation of the skin on the ventral midline with local anaesthetic. Usual...
Brown MP, Kelly RH, Gronwall RR, Stover SM.Six healthy adult mares were given a single IV dose (25 mg/kg of body weight) of chloramphenicol sodium succinate. Chloramphenicol concentrations in serum, synovial fluid, peritoneal fluid, and urine were measured serially over a 48-hour period. The highest measured serum chloramphenicol concentration was 6.21 micrograms/ml at 0.5 hour. Chloramphenicol was detected in synovial and peritoneal fluids, with mean peak concentrations of 3.89 micrograms/ml and 3.50 micrograms/ml, respectively, at 0.5 hour. Serum and synovial concentrations declined rapidly and were not measurable at 3 hours. Chloram...
Beccati F, Nannarone S, Gialletti R, Lotto E, Cercone M, Dante S, Bazzica C, Pepe M.The aim of this study was to evaluate the transabdominal ultrasonography as a tool for predicting the success of abdominocentesis in horses. Patients were included in the study if a complete transabdominal ultrasonography examination and abdominocentesis were performed as part of the clinical work-up. Ultrasonographically, the amount of peritoneal fluid was assessed using a 4-point grading system, as well as the amount of peritoneal fluid collected. A χ(2) or Fischer exact test was performed to test for an association between the ultrasonography findings and fluid retrieved, and between the t...
Alonso JM, Schmidt EMS, Eckersall PD, Kjelgaard-Hansen M, Alves ALG, Rodrigues CA, Watanabe MJ, Crescencio AP, Hussni CA.The acute phase response is a response to injury and depends on the severity of the trauma. Heparin is routinely used for postsurgical treatment of horses to prevent abdominal adhesions; however, its effect on inflammation is unknown. This study aimed to assess systemic inflammatory response of horses subjected to small colon enterotomy and to evaluate heparin effects on postsurgical inflammation. Ten adult horses were subjected to small colon enterotomy and were assigned to a control or a treatment group. Both groups received prophylactic antibiotics and flunixin, and the treatment group rece...
Grindem CB, Fairley NM, Uhlinger CA, Crane SA.Peritoneal fluid was analysed from 17 foals, aged 13 to 134 days with a mean age of 68 days. Cytologically, the peritoneal fluid was characterised by a mean total cell count of 0.45 x 10(9)/litre (range 0.06 to 1.42 x 10(9)/litre), rare eosinophils, rare cytophagia and variable percentages of neutrophils and mononuclear cells. These data indicate that peritoneal fluid nucleated cell counts over 1.50 x 10(9)/litre in the foal should be interpreted as elevated. Biochemical evaluation revealed a mean biuret protein level of 12 g/litre, mean refractive index protein level of 16 g/litre and urea ni...
Hamouzová P, Dobešová O, Řeháková K, Stehlíková Š, Čížek P, Drábková Z, Jahn P, Doubek J.This study is the first to provide information on the lymphocyte subpopulations in peritoneal effusions in horses. Peritoneal transudates (n = 12), peritoneal exudates (n = 6) and a pleural exudate (n = 1) were analyzed. The total nucleated cell count (TNCC), total protein (TP) and matrix metalloproteinase-9 (MMP-9) concentration determined by ELISA were measured and routine cytological evaluation was performed. CD3, CD4, CD8 and CD21 positive cells were detected by flow cytometry. A higher percentage of neutrophils (P < 0.05) and higher MMP-9 (P < 0.01) levels were found in ex...
Delgado MA, Monreal L, Armengou L, Segura D, Ríos J.Peritoneal D-Dimer concentration can be determined to assess peritoneal fibrinolysis activity in horses with gastrointestinal disorders. However, blood contamination of peritoneal fluid may occur during collection and could alter peritoneal D-Dimer concentration. Objective: Blood contamination in peritoneal fluid does not affect interpretation of peritoneal D-Dimer concentration in horses with colic. Methods: Thirty-four horses with colic and 4 healthy horses. Methods: Peritoneal fluid and blood samples were simultaneously collected upon admission. Then, peritoneal fluid was serially contamina...
Estepa JC, Lopez I, Mayer-Valor R, Rodriguez M, Aguilera-Tejero E.The aim of this study was to evaluate the influence of two commonly used anticoagulants (K3EDTA and lithium heparin) on refractometric and spectrophotometric measurement of total protein (TP) concentration in equine peritoneal fluid samples. The influence of a commercial solution of K3EDTA, a solution of K3EDTA in distilled water and lithium heparin on the refractometric and spectrophotometric (biuret) quantification of TP content in peritoneal fluid samples was assessed. Total protein concentration measured by refractometry was consistently overestimated in samples with commercial K3EDTA. The...
Easter JL, Hague BA, Brumbaugh GW, Nguyen J, Chaffin MK, Honnas CM, Kemper DL.To evaluate the effect of peritoneal lavage on pharmacokinetics of gentamicin sulfate in healthy horses after experimental celiotomy. Methods: 13 clinically normal horses. Methods: Horses were randomly assigned to control or experimental groups. All horses received gentamicin (6.6 mg/kg of body weight, IV, q 24 h) before surgery, underwent experimental abdominal surgery, and had abdominal drains placed percutaneously. Horses of the experimental group received postoperative peritoneal lavage; horses of the control group did not receive peritoneal lavage. The day after surgery, 24 hours after th...
Milne EM, Doxey DL, Gilmour JS.The analysis of peritoneal fluid is of value in the differential diagnosis of equine colic but its characteristics have not been evaluated in grass sickness. Peritoneal fluid was collected from 15 normal horses and from 11 cases of medical colic, 11 cases of surgical colic, 20 cases of acute grass sickness and 13 cases of subacute grass sickness. The fluid was analysed for its appearance, total and differential white cell count, specific gravity, total protein concentration and total and intestinal alkaline phosphatase activity. Fluid from cases of medical colic was normal in these respects. S...
Brown MP, Gronwall RR, Houston AE.Four healthy adult mares were each given a single injection of sodium cefoxitin (20 mg/kg of body weight, IV), and serum cefoxitin concentrations were measured serially during a 6-hour period. The mean elimination rate constant was 1.08/hour and the elimination half-life was 0.82 hour. The apparent volume of distribution (at steady state) and the clearance of the drug were estimated at 0.12 L/kg and 259 ml/hr/kg, respectively. Each mare and 2 additional mares were then given 4 consecutive IM injections of sodium cefoxitin (400 mg/ml) at a dosage of 20 mg/kg. Cefoxitin concentrations in serum, ...
Pratt SM, Christian JA, Paige Jackson L, Hawkins JF, Sojka JE.A 16-year-old castrated male Arabian horse was presented to the Purdue University Veterinary Teaching Hospital with a 4-hour history of colic. Initial examinations provided strong evidence for small intestinal obstruction. Abdominal surgery revealed a strangulating lipoma, and 25 feet of small intestine were resected. Postoperatively, the horse developed obstructive ileus due to adhesion formation, which required a second laparotomy. During and after surgery, the abdomen was lavaged with sodium carboxymethylcellulose (CMC). One week after the second surgery, evaluation of peritoneal fluid reve...
Reynolds DJ, Nicholl TK.A 5 month old colt foal with recurrent pyrexia and a loud pansystolic murmur later developed signs of cardiac failure. Peritoneal fluid and blood samples both demonstrated an extreme leucocytosis and neutrophilia. At post-mortem both a cranial mesenteric arteritis and the congenital cardiac anomaly, Tetralogy of Fallot were found. The detailed clinical and post-mortem findings contributing to the case are described.
Lacerenza MD, Arantes JA, Reginato GM, Passarelli D, Balieiro JCC, Amaral AR, Vendramini THA, Brunetto MA, Dória RGS.β-glucan is part of the cell wall of fungi and yeasts and has been known for decades to have immunomodulating effects on boosting immunity against various infections as a pathogen-associated molecular pattern that is able to modify biological responses. β-glucan has been used in rat models and in vitro studies involving sepsis and SIRS with good results, but this supplement has not been evaluated in the treatment of endotoxemia in horses. This study aims to evaluate the effects of preventive supplementation with β-glucan in horses submitted to endotoxemia by means of inflammatory response m...
Rapezzano G, Marcatili M, Stephenson R, Pereira R, Hallowell G, Duz M.Peritoneal fluid lactate concentration is an important diagnostic tool in horses with abdominal pain. Information on peritoneal lactate concentrations is lacking following parturition in the mare. To compare blood and peritoneal lactate concentrations in a population of mares within 36 h post-partum, report a normal reference range and identify any impact of retained foetal membranes (RFMs). This is a retrospective study evaluating healthy mares from which blood and peritoneal samples had been obtained within 36 h of parturition. Exclusion criteria included signs of abdominal pain within thi...
Karam B, Arndt S, Magdesian KG, Cullen T, Dechant JE.A newborn (5 h old) quarter horse colt was presented because of lethargy and severe abdominal distention. Uroperitoneum was suspected during initial workup, based on sonographic imaging and peritoneal fluid analysis. Definitive diagnosis was confirmed during exploratory celiotomy. Surgery revealed a congenitally abnormal allantoic stalk/urachal remnant and a failure of embryological fusion of the dorsal bladder wall. Recovery was successful and the animal is now a healthy, 4-year-old western performance gelding. These specific congenital abnormalities have not been previously documented in the...
Wright JP, Gray SM, Bishop RC.To describe and demonstrate the collection of abdominal fluid from a standing, sedated equine patient. Unassigned: 1 healthy university-owned animal was used for abdominocentesis demonstration. Images from various clinical cases from the University of Illinois Veterinary Teaching Hospital are shown. Unassigned: Under standing sedation, a 10 X 10-cm area is clipped and aseptically prepared on the most dependent portion of the abdomen to the right of midline. One to 2 mL of 2% lidocaine is instilled subcutaneously and into the abdominal musculature at the abdominocentesis site. A stab incision i...
Parra-Moyano LA, Cedeño A, Darby S, Johnson JP, Gomez DE.The effectiveness of the peritoneal fluid L-lactate-to-total solids ratio (PFL:PFTS) as a diagnostic marker for strangulating lesions of the small intestine (SI) and large colon (LC) has not been investigated. Objective: Describe and compare the PFL:PTFS and blood lactate (BL), peritoneal fluid lactate (PFL) and PFL:BL difference and PFL:BL ratio of horses with SI and LC strangulating (SO) and non-strangulating (NSO) obstructions and determine sensitivity and specificity to predict SO. Methods: A total of 282 horses, 117 with SI lesions (59 classified as SINSO and 58 as SISO), and 165 with LC ...
Bishop RC, Arrington JV, Wilkins PA, McCoy AM.Peritoneal fluid (PF) is intimately associated with the gastrointestinal tract, and changes in the PF may directly reflect abdominal pathology. We aimed to quantify differences in the PF proteome between intestinal lesion type (ischemic vs. non-ischemic) and location (small vs. large intestine). PF samples were collected at hospital admission from horses presenting for abdominal pain (colic). Cases were clinically categorized by lesion type and location after resolution (10 per group). PF proteins were extracted and quantified by label-free liquid chromatography-tandem mass spectroscopy. Data ...
Granello ME, Young JM, Cleff DB, Banks EBM, Trumble TN.To describe characteristics of postoperative peritoneal fluid following exploratory laparotomy for naturally-occurring gastrointestinal lesions in horses. Methods: Prospective, observational cohort study. Methods: A total of 26 client-owned horses that underwent exploratory laparotomy for naturally-occurring gastrointestinal lesions. Methods: Abdominocentesis was performed pre- or intraoperatively, and at three time points postoperatively (24, 72, and 168 h). Peritoneal lactate, total protein (TP), total nucleated cell count (TNCC), cytology, and systemic lactate were performed at each time ...
Salcedo-Jiménez R, Kenney DG, Dubois MS.This case series reports four late pregnancy broodmares that were diagnosed with bladder rupture. The initial presentations were abdominal discomfort (n = 3) and dystocia (n = 1). All mares (n = 4) were overdue or at their expected time of delivery. Three mares showed clinical signs related to bladder rupture: pollakiuria (n = 2) and hematuria (n = 1). At the time of diagnosis, three mares had increased peritoneal fluid creatinine, the mean peritoneal: serum creatinine ratio was 4.1, and the bladder tear was observed via cystoscopy in 3 cases. Two mares were discharged from the hospital. Compl...
