Canine Flash Notes - Heartworm Disease Flashcards
what is the most common clinical sign seen in heartworm positive dogs?
coughing
what is the common clinical presentation of a dog with heart worm disease?
NO SIGNS IN MOST DOGS
if signs, coughing, exercise intolerance, weight loss, syncope, ascites due to right sided heart failure, & manifestations of pulmonary hypertension such as PTE & dyspnea
what is the preferred test for diagnosing heartworm disease?
HW antigen test - detects female worms
what is the preferred treatment for heartworm disease?
pre-adulticide for 1-3 months - doxycycline & monthly HW prevention (for asymptomatic dogs at the time of presentation)
melarsomine 3 dose adulticide protocol: 2.5 mg/kg IM injection today followed by 2 more doses 24 hours apart given 1-3 months later
exercise restriction for 4-6 weeks after each dose & consider using NSAIDs/pred to reduce melarsomine injection site inflammation
how is heartworm disease prevented?
monthly macrolides - ivermectin, selamectin, moxidectin, & milbemycin
wide window of efficacy - up to 2 month reach back effect
what is caval syndrome?
adults obstruct tricuspid valve (RAV) & posterior vena cava
acute onset of severe lethargy, dyspnea, pallor, weakness, jugular pulses, systolic murmur, hemoglobinemia, & hemoglobinuria
what is the treatment for caval syndrome?
surgical extraction of worms or the dog is likely to die within 1-2 days
why do many clinicians start monthly heartworm prevention in positive asymptomatic dogs?
susceptibility window!!!
melarsomine adulticide does not kill HW larvae < 4 months old
HW-infected dog likely to have larvae < 4 months old in blood
if larvae < 4 months survive adulticide Rx, can re-infect dog
need to use monthly HW preventive to kill youngest larvae
what are your options for slow microfilaricides?
ivermectin, selamectin, & moxidectin
what is your option for a fast microfilaricide? what is the concern when using it?
milbemycin - need to pre-treat the animal with diphenhydramine & dexamethasone due to the probability of an adverse reaction as the worms die quickly
need to hospitalize & monitor for at least 8 hours after administration
