20. Differential diagnosis of abdominal fluid accumulation Flashcards
Pathophysiology of fluid accumulation?
Pathophysiology of fluid accumulation
Physiologically, there is continuous filtration from the arteriolar
capillaries which are then absorbed by the venous & lymphatic
circulation.
Fluid accumulation is caused by a defect to this mechanism, such as:
§ ↑ Hydrostatic pressure of the capillaries
§ ↑ Hydrostatic pressure of the interstitium
§ ↑ Capillary permeability
§ ↓ Oncotic pressure (hypoalbuminaemia)
§ Problems with the lymphatic circulation
Difference between transudate and exudate?
Types of fluid accumulation
TRANSUDATE AND EXUDATE
Transudate (stagnation)
§ Low protein content (clear appearance)
§ Fluid is pushed through capillaries due to high pressure
Exudate (inflammation)
§ High protein content (opaque)
§ Fluid leaks around capillary cells caused by inflammation
Difference between tansudate and exudate( SG, protein, WBC, RBC)
Potential causes of the different fluid types?
Differentiate between causes of transudate?
Differentiate between causes of transudate
PLE; PLN; Liver cirrhosis; Portal hypertension
§ Proteinuria: Exclusion by UPC measurement
§ Portal hypertension: US
Protein-losing enteropathy is suspected if all these apply:
§ ✗ Proteinuria
§ ✗ Portal hypertension
✓ Hypoalbuminaemia
Differentiate between uroperitoneum, tumours & exudate?
Differentiate between uroperitoneum, tumours & exudate
Uroperitoneum
Localisation of leakage is not always possible
Cause: Urinary bladder rupture
Always measure creatinine from abdominal fluids
Tumour
Not always visible on X-ray/US
Mixing of neoplastic/reactive mesothelial cells
If all other causes are excluded: Laparotomy
Exudate
Cause of inflammation is not always visible on X-ray/US
Cause: Corrugated intestines; Peritonitis; Pancreatitis
In case of septic exudate: Laparotomy
Chyloperitoneum ?
CHYLOPERITONEUM
Mesenteric lymph vessel = Cisterna chyli
DDx: Tumour; Lymphangiectasia
Haemorrhagic fluid?
HAEMORRHAGIC FLUID
DDx: Tumour; Trauma; Coagulopathy; Uroperitoneum; Intestinal
strangulation
Ascites?
Ascites
Abdominal fluid accumulation
Cats: Ascites + Ø pleural effusion → Ø Likelihood of cardiac origin
Dog: Could be of cardiac origin
Causes of different fluid types?
CAUSES OF DIFFERING FLUID TYPES
§ Heart failure: Mod. transudate (RSHF); Rarely chylous
§ Tumour: Mod. Transudate; Haemorrhagic fluid; Exudate
§ Infection: Exudate
§ Thrombosis: Mod. Transudate
§ Hypoproteinaemia: Transudate
Diagnosis?
DIAGNOSIS
Physical exam
Lab. D
§ Rivalta test: Differentiate between transudate & exudate
§ Modified transudate → Not pure transudate
Undulation test
Ultrasound (non-specific)
§ Anechoic, particulated fluid
§ Differentiate from dilated bladder; Obesity
§ Facilitates the sampling of fluid (ascites; urine)
Radiology
