Veterinary Clinical Medicine-I (General and Systemic)

PERICARDIAL EFFUSION

Etiology

 

• Neoplasia of the heart base, or pericardium
  • Right atrial hemangiosarcoma.
  • Chemodectoma.
  • Metastatic adenocarcinoma.
  • Lymphoma.
  • Thynoma
  • Undifferentiated carcinoma.
• Idiopathic pericardial hemorrhage.
• Congestive heart failure
• Peritoneopericardial diaphragmatic hernia.
• Pericardial cysts.
•  
• Infectious pericarditis
  • Bacterial (Actinomyces and Nocardia spp.).
  • Fungal (coccidioidomycosis).
  • Vital
  • Trypanosomal
• Noninfectious pericarditis (uremia).
• Cardiac rupture.
• External chest trauma.
• Foreign bodies ( foxtails, grass awns, etc.).
• Hypoalbuminemia
• Anticoagulant rodenticide toxicity.
• Other coagulopathies

Diagnosis

• History
  • The most common cause of pericardial effusion; right artrial hemangiosarcoms most commonly occurs in large breed eggs, particularly the German shepherd and golden retriever, five years of age or older. Feline infectious peritonitis is the most common cause in cats, so carefully evaluate cattery cats and outdoor cats.
  • Weakness, exercise intolerance, lethargy dyspnea and abdominal distension are common client complaints.

• Physical exam
  • Weakness.
  • Dyspnea
  • Ascites and /or pleural effusion.
  • Weak and thready femoral pulses.
  • Muffled heart sounds and muffled respiratory sounds.
  • Jugular pulse and peripheral venous distension.
  • Sinus tachycardia.
  • May have hepatomegaly.
  • Cachexia

• Thoracic radiographs
  • Pleural, hepatomegaly and ascites may be seen. If there is significant fluid accumulation in the pericardium, an enlarged globoid or mound heart shadow may be seen. Tracheal elevation may be observed, especially if a heart base neoplastic mass is present. Distension of the caudial vena cava and underperfusion of the pulmonary vasculature may also be observed.

• ECG
  • Sinus tachycardia, decreased R-wave amplitude with electrical alternans.

• CVP
  • The patients’s CVP is often>12 cm H₂O.

• Echocardiography
  • A fluid filled space is visible surrounding the heart, between the parietal pericardium and the epicardium. In severe cases of cardiac tamponade, the right atrium and ventricle may appear collapsed. Masses may be observed, as well as cardiac disorders.

• Laboratory findings
  • Routine CBC and serum biochemical profile is usually nonspecific , but may show hypoproteinmia, anemia, leukocytosis, possibly elevated hepatic enzymes due to congestion or mild azotemia if there is impairment of renal perfusion. Serum titers for FIP; coccidioidomycosis, ehrlichiosis and other infectious diseases could be measured. Thrombocytopenia, coagulation disorders, and erythrocyte abnormalities may be seen hamangiosarcoma.

Prognosis

• The prognosis is guarded to poor, depending upon the underlying etiology

Treatment

• Inform the client of the diagnosis, prognosis , and cost of the treatment.
• Place an intravenous catheter, administer intravenous fluids if in shock.
• Perform pericardiocentesis if serious cardiac tamponade exists
• Position the patient in either lateral or sternal recumbency.
• Clip and surgically prepare the right 5^th or 6^th intercostal space just above the costochondral junction.
• Attach ECG leads to the patient.
• Administer a lidocaine local anesthetic block.
• Use an intravenous catheter of sufficient length and diameter (8-French, 9 cm) to pentrate the pericardial sac
• Perform pericardicentesis by carefully advancing the catheter through the intercostal space and into the pericardial sac.
• Monitor the ECG continuously.
• Once pericardial fluid is obtained, advance the catheter over the stylet, attach extension tubing a three-way stopcock and a large 35-60 ml syring.
• Apply gentle suction and remove as much fluid as possible.
• Save a sample of any fluid obtained.
• If there is active , acute pericardial hemorrhage, the fluid will have a PCV similar to blood and will have clots in it.
• To determine whether blood aspirated is actually from the pericardial sac rather than a cardiac chamber, compare the PCV to that of peripheral blood. In active, chronic hemorrhage will have a lower PCV and will not clot when placed in a red-top collection tube.
• Administer Vitamin K, and fresh-frozen plasma or whole blood to treat anticoagulant rodenticide toxicity.
• Treat heart failure if that is the underlying etiology.
• Avoid the use of diuretics, unless indicated in the treatment of heart failure.
• Afterload-and preload-reducing agents (including ACE inhibitors) should be avoided.
• Surgical exploratory of the thorax and pericardiectomy will allow for detection of small masses, the collection of biopsy specimens, and avoidance of cardiac tamponade.
• Treat infectious pericardial disease with the appropriate antimicrobial agent.
• Actinomyces spp-penicillins.
• Nocardia spp-potentiated sulfonamides.
• Coccidioidomycosis-ketoconazole, itraconazole, fluconazole, or amphotericin B.
• Treatment of neoplastic pericardial disease with the appropriate chemotherapeutic agents can be directed based on the biopsy results.