Colic - Peritoneal Fluid Analysis
Assessing the pertioneal fluid can give information about the disease process in the very early stages. Some disease processes such as peritonitis and enteritis produce changes in the peritoneal fluid before the onset of clinical signs. This allows for the early diagnosis of the disease which will favour an improved prognosis for the patient. Strangulating obstructions produce changes in the peritoneal fluid within a few hours of the obstruction occurring. Horses with an intussusception may have normal peritoneal fluid initially as the peritonitis that develops is localised to the portion of entraped bowel.
Peritoneal fluid should be assessed for colour, turbidity, specific gravity, total nucleated cell count and examined under the microscope for cytology. Normal peritonel fluid is clear to yellow in colour and has a specific gravity of 1.005 mg/dl. The fluid becomes yellow or white and increasingly turbid when there is more protein or cells in it. The initial changes seen in the fluid during gastrointestinal disease are a serosanguinous appearance and an increased red blood cell count and total protein level. The fluid becomes yellow or white and increaingly turbid when there is more protein or cells in it. When the affected portion of bowel becomes ischaemic and necrotic, it leaks cells into the peritoneal fluid. White to yellow, cloudy fluid or exudate will be high in white blood cells. This is seen in septic peritonitis. Red, brown or green fluid can indicate rupture of the gastrointestinal tract and plant material may be present in the sample.
| Clinical Condition | Appearance | Total Protein (g/dl) | Total Nucleated Cells/L | Cytology |
|---|---|---|---|---|
| Normal | Clear - Yellow | < 2.0 | < 7.5 x109 | 20 - 80% mononuclear cells, 40 - 80% neutrophils |
| Non-strangulating Obstruction | Clear - Yellow, Slightly turbid | < 3.0 | < 3.0 - 15.0 x 109 | Mostly neutrophils (preserved) |
| Strangulating Obstruction | Red - Brown, Turbid | 2.5 - 6.0 | 5.0 - 50.0 x 109 | Mostly neutrophils (degenerate) |
| Proximal Enteritis | Yellow - Red, Turbid | 3.0 - 4.5 | < 10.0 x 109 | Mostly neutrophils (preserved) |
| Bowel Rupture | Red - Brown - Green, Turbid with or without particulate matter | 5.0 - 6.5 | 20 - 150 x 109 | > 95% neutrophils ( severely degenerate), intracellular or extracellular bacteria, with or without particulate matter |
| Septic Peritonitis | Yellow - White, Turbid | > 3.0 | 20.0 - 100.0 x 109 | Mostly neutrophils (degenerate) |
| Accidental Enterocentesis | Brown - Green, with or without paticulate matter | Variable | < 1.0 x 109 | Free bacteria, plant material, few cells |
| Intraabdominal haemorrhage | Dark red | Similar TPP to peripheral blood | White Blood Cell Count increases with time | PCV less than peripheral blood, erythrocytophagia, few if any platelets |
| Post-celiotomy | Yellow - Red, Turbid | Variable | Variable | Mostly neutrophils (moderate degeneration), no intracellular bacteria |