*4.1.15 Imaging tools*

Radiographical imaging is useful in detailing small amounts of ascetic fluid as well as diagnosis of aetiology of ascites [49]. Abdominal ultrasonography can detect as little as 100 ml of intraperitoneal fluid [50]. The sensitivity of radiography is enhanced through the use of computed tomography which detects minute quantities of ascetic fluid. Radiography enhances the picture of internal organs and aids in detection of cirrhosis, intra-abdominal tumour and organ enlargements. Thickening of mesentery and bowel wall, matting of bowel loops and enlargement of mesenteric lymph nodes may provide a guide in the diagnosis of tuberculosis

peritonitis in affected patients. A contrast computed tomography (CT) may be used to demonstrate enhancement of peritoneal lining. Cases of cirrhosis and large hydrothorax can be diagnosed with the aid of scintigraphy with technetium sulphur colloid or radiolabelled albumin [6].

#### *4.1.16 Bacterial culture*

Spontaneous bacterial peritonitis may arise due to decreased level of compliments which serve as antibacterial factors in ascetic fluid. Suspected cases of SBP are cultured in both aerobic and anaerobic blood media for isolation of organisms [51]. Cultured ascetic fluid should be subjected to sensitivity test to identify effective antimicrobiological agent in treatment.

The DNA of *Mycobacterium tuberculosis* in ascetic fluid can be detected using polymerase chain reaction in suspected cases. PCR for *Mycobacterium tuberculosis* offers a high sensitivity (94%) test compared to microscopic acid-fast bacilli smear (−0%) and mycobacterial culture (−50) [38].

## **5. General treatment options in ascites**

Ascites is treated symptomatically while addressing the primary cause of the condition. Efforts are geared towards relieving manifesting symptoms and preventing progression of ascites. The main goal in congestive heart failure is to improve cardiac contractility, normalise cardiac arrhythmias and enhance cardiac output. Cardiac drugs such as dopamine and digoxin can be used at recommended dosages in cases of congestive heart failure in dogs. Dogs with right-sided heart failure should be placed on cage rest and on sodium-restricted diet [52]. Paracentesis is applied to relieve abdominal tension on the diaphragm and enhance normal respiration. Repeated paracentesis is not required except in cases of failing treatment [52]. Paracentesis should not exceed 1.0 kg weight per day for dogs with both ascites and peripheral oedema and less than 0.5 kg weight per day for patients with only ascites. Serum albumin sometimes is depleted during paracentesis and therefore should be monitored and replaced intravenously in case of depletion at the same quantity of fluid removed. The administration of albumin dosed at 1.5 g/kg on the first day and 1.0 g/kg on the third day ensured renal preservation and reduced mortality [53]. In cases of syncope, a balanced isotonic crystalloid fluid replacement such as Plasma-Lyte A, Normosol R and 0.9% saline may be used in resuscitation and other conditions such as hypernatraemia, hyponatraemia, hypercalcemia, metabolic alkalosis or oliguria renal failure. Diuretics are used in addition to paracentesis to relieve ascites. Diuretics may be dosed once daily. Spironolactone has a half life of 24 hours and is given at the dose of 100 mg/day max 400 mg/day for response [54]. The dose may be spread out every 2 hours stat in dogs under hospitalisation and close monitoring at 2 mg/kg × im and at 3 mg/kg × per os at night. Spironolactone could be substituted with either triamterene or amiloride since both drugs have good antagonistic effect on aldosterone action on the collecting tubules [55]. Furosemide is often the first line of treatment in cases of ascites with a half life of 1.5 hours and given at the dose of 40 mg/day and max 160 mg/ day in case of nonresponders to furosemide [39]. The dose may also be spread in divided doses of 3 mg/kg × IV every 2 hours and at 4 mg/ kg per os at night. Bumetanide and spironolactone could be used in combination with furosemide at the ratio of 100:40 to reduce chances of furosemide resistance. The dose ratio ensures efficient natriuresis and flow of water and also reduces the risk of potassium deficit from the use of furosemide [39, 56]. Other diuretics such as torsemide and bumetanide have shown better efficacy than most diuretics [57].

#### *Review on Ascites in Pets DOI: http://dx.doi.org/10.5772/intechopen.84767*

Torsemide has a longer half life than both furosemide and bumetanide [57]. Patient with cirrhotic ascites often presents with complications of SBP, portal hypertension and HRS [28]. Cases without such complications are described as "uncomplicated ascites" [58]. The standard treatment for SBP in humans involves immediate administration of third-generation cephalosporin such as intravenous ceftriaxone 1 to 2 g daily for 5 days [52]. The dose could be given at 1 g daily in dogs. The use of oral fluoroquinolones is equally effective in the treatment of SBP [59, 60]; alternatively piperacillin and tazobactam could be considered [61]. The choice of antibacterial agent depends on culture and sensitivity test to reduce problems of drug resistance. Antibiotic treatment is usually given for an extended period to ensure complete cure of the bacterial infection.

Portal hypertension is managed by the use of antihypertensive medications. A drug such as metolazone (Mykron, Zaroxolyn) aids in the elimination of oedema in congestive heart failure. It enhances sodium excretion by inhibition of sodium reabsorption from the distil tubules, a function which is beneficial in renal conditions [55]. Mannitol (Osmitrol) inhibits tubular reabsorption of electrolyte by increasing the osmotic pressure of glomerular filtrate and urine output [55]. Cases of recurrent ascites in humans from portal hypertension may require the use of TIPS [28]. TIPS functions as a side-to-side portacaval anastomosis between the high portal pressure end and low hepatic vein pressure end, thereby effectively decongesting the portal system which may be useful in pets. A reduction in the portal hypertension brings a secondary decrease in RAAS activation and consequent increase in sodium excretion [62]. Persistent ascites from cirrhosis may be managed through liver transplant and removal of the damaged liver. The hepatic cells naturally possess high regenerative capacity and can regenerate after undergoing severe degenerative condition. The hepatocytes in addition can perform at full capacity even with few viable cells, and therefore liver transplant is only required as a last resort after application of all remedial medications.

Renal failure is managed by controlling blood pressure with drugs; avoid the use of hepatotoxic medications in treatment of ascites and the use of non-steroidal anti-inflammatory agents (NSAIDs) such as acetaminophen. Kidney dialysis is recommended in severe kidney damage. A continuous venovenous haemodialysis (CVVHD) is recommended compared to intermittent renal dialysis.

Cases of complications of encephalopathies from hepatic failure are best managed in intensive care units (ICU) [18]. Cases of early complication of encephalopathy may be treated as outpatient; nevertheless such a patient is closely monitored for further deterioration to grade II encephalopathy which would require prompt transfer to an intensive care unit. Such a patient is placed on routine check on mental balance, and signs of restlessness could be slightly sedated with low dose of short-acting benzodiazepines. Patients under sedation are placed on undisturbed bed rest avoiding extensive movement which may enhance chances of intracranial pressure/hypertension. Dyspnea is prevented in late encephalopathy through placement of intratracheal intubation to avoid further complications of aspiration pneumonia. The conditions of cerebral oedema and intracranial hypertension manifest at the late phase of encephalopathy and are prevented through routine checks on the patient's renal parameters; biochemical profile including liver enzymes, total protein, glucose, electrolytes and acid/balance; and neurological evaluations for signs of elevated levels [4]. Cases of severe bleeding result from problems of coagulopathies which can be treated by addressing the coagulopathy through transfusion of coagulation products such as fresh frozen plasma and platelets and administration of vitamin K. Severe conditions may be boosted by transfusion of packed red blood cells. Continuous bleeding after massive replacement infusions may indicate possible retroperitoneal bleeding [18]. A good number of herbal and

antioxidant medications have shown to be beneficial in the treatment of ascites of hepatic origin. The use of these drugs remains controversial, but despite this the drug N-acetylcysteine and *Silybum marianum* still remain the drug of choice in the treatment of hepatic damage from acetaminophen toxicity and hepatic dysfunction, respectively [63].

Conclusion: Ascites is a disease condition commonly seen in pets of various age brackets with high incidences occurring in middle-aged dogs. Ascites is a common manifestation of a decompensate cirrhosis, cardiac diseases and several other aetiologies and is best diagnosed through established standard procedures of physical and clinical examinations, complete blood picture, cytology and various biochemical analyses. Recent novel techniques such as platelet indices, leucocyte esterase reagent strip, tumour markers, bacterial DNA, cytokines and other proteins are available for the advancement of biochemical laboratory techniques and efficient diagnosis of ascites. Treatment is centred on effective diagnosis of the aetiology.
