Lesson 18, Topic 3
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  1. Signalment:

    – Dogs are at least 6 months of age; usually middle aged
    – Males and large breed dogs are more often infected than are females and small dogs
  2. History:
  1. Asymptomatic cases:
    – positive on yearly testing
  2. Symptomatic cases:
    – having frequented a heartworm endemic area (south eastern US)
    – weight loss, anorexia
    – chronic non-productive cough
    – labored respiration, exertional dyspnea
    – exercise intolerance, syncope
    – if heart failure present, may note abdominal distention
  3. Physical Examination:
    Most cases examined annually as a screen for heartworm infection show no clinical signs
    • Mild HWD:
      • cough on tracheal manipulation
    • Moderate HWD:
      • increased rate and depth of respiration
      • normal lung sounds or fine crackles on pulmonary auscultation
      • mild weight loss, partial anorexia
    • Severe HWD:
      • signs of right heart failure (elevated right atrial preload) – jugular distention or pulsation, ascites
      • increased rate and depth of respiration
      • fine crackles on pulmonary auscultation
      • split second heart sound on cardiac auscultation
      • emaciation, anorexia
      • distended abdomen