Canine heartworm disease. Review article and case report

After providing an overview of the occurrence (Figure 1), etiopathogenesis and clinical aspects of canine heartworm disease, a case report is presente d to demonstrate the hazard of introducing the disease with animals having lived in endemic countries. A five-year-old male dog of mixed breed was adm itted into the clinic, with a two-days long history of depression, exercise intolerance, dyspnea, anorexia, vomitus and voiding of reddish urine. The dog lived in the United States for years with the owner and they returned t o Hungary some months before the date of referral. Vaccination history was uncertain and no preventive anthelminthic therapy was performed previously. Clinical examination revealed poor general condition, pale and icteric muc ous membranes, and some small, patchy bleedings on the oral mucousa. Mixed type dyspnea with inspiratory efforts was noted, while thoracic auscultatio n revealed adventitious, non-musical respiratory sounds. No cardiological a bnormalities but tachycardia and weak, small pulse were recorded. Abdominal palpation could not be performed due to marked abdominal tension. Blood bi ochemistry demonstrated hepatic dysfunction and uremia. Hemoglobinuria was detected during urinanalysis. The animal died within some hours after admis sion, therefore no further examination could be performed. Necropsy reveale d several adult Dirofilaria immitis in the blood clots within the caudal ve na cava (Figure 2) and within the dilated right ventricle (Figure 3). Centr olobular dystrophy of the liver and bronchopneumonia with pulmonal edema we re the additional findings. Post mortem histology demonstrated intercellula r myocardial edema and interstitial bronchopneumonia. Microfilaria were fou nd within the capillaries of the myocardium, interstitial pulmonary capilla ries (Figure 4) and in other organs, including spleen and liver. In additio n, hemosiderin-containing cellular elements were found in the interstitium of the lung (Figure 5). Microfilaria were demonstrated in the peripheral bl ood smears with Giemsa staining (Figure 6), as well as in smears taken from blood clots and surfaces of the heart, spleen and liver. Vena cava syndrome due to the oclusion of the caudal vena cava by adult fil aria together with blood clots was diagnosed by necropsy and this complicat ion was stated as the cause of sudden deterioration and death of the patien t.