Download diseases of the cardiovascular system

DISEASES OF THE CARDIOVASCULAR
SYSTEM
ACQUIRED VALVULAR DISEASES
CHRONIC MITRAL VALVE INSUFFECIENCY
SMALL BREED/TOY BREED DOGS, USUASLLY OLDER THAN 10 YEARS
THE PREVALENCE OF THIS DISEASE INCREASES WITH AGE, AND IS
PROGRESSIVE. IT ACCOUNTS FOR ~95% OF ALL HEART FAILURE CASES
CHRONIC MITRAL VALVE INSUFFICIENCY
ONE OF THE MOST COMMON
CAUSES IS CHRONIC PERIODONTAL
DISEASE!
BACTERIA THAT LIVE IN TARTAR,
GET SHOWERED INTO THE BLOOD
STREAM AND COLONIZE IN THE
VALVE LEAFLETS.
CHRONIC MITRAL VALVE INSUFFICIENCY
CHRONIC PERIODONTAL DISEASE CAN AFFECT SEVERAL ORGAN SYSTEMS
1.Lungs: Pulmonary fibrosis, bronchitis, and
chronic obstructive pulmonary disease.
2.Heart: Endocarditis, mitral valve
regurgitation, and myocardial
degeneration.
3.Liver: Hepatic parenchymal inflammation
and hepatopathy.
4.Kidneys: Interstitial nephritis and
glomerulonephritis.
MITRAL VALVE INSUFFICIENCY
THIS IS THE OPEN LEFT
VENTRICLE SHOWING THE
MITRAL VALVE LEAFLETS.
WHAT ARE THE STRING-LIKE
STRUCTURES THAT ATTACH
THE VALVES TO THE
PAPILLARY MUSCLES?
CHORDAE TENDINEAE
MITRAL VALVE INSUFFICIENCY
MITRAL VALVE INSUFFICIENCY
TOP LEAFLET IS NORMAL
BOTTOM LEAFLET IS
THICKENED AND NODULAR. THIS
IS DUE TO INCREASED
FIBROBLASTIC TISSUE WITHIN
THE VALVE LEAFLETS
CHRONIC MITRAL VALVE INSUFFICIENCY
THE STIFF MALFORMED VALVE
FAILS TO CLOSE SUFFICIENTLY
DURING SYSTOLE.
DURING LEFT VENTRICULAR
CONTRACTION, BLOOD FLOWS
BACK INTO THE LEFT ATRIUM
MITRAL VALVE INSUFFICIENCY
IF BLOOD CONTIUES THIS BACKWARD
FLOW, THE ANIMAL MAY EXPERIENCE
LEFT-SIDED HEART FAILURE
CHARACTERIZED BY PULMONARY
EDEMA
CHRONIC MITRAL VALVE INSUFFICIENCY
• DIAGNOSIS:
– Radiographs
– Echo
– Systolic murmur at left apex; “whooping” quality
• There is no treatment to delay the onset of clinical
signs. Treatment is aimed at improving symptoms
of heart failure
– Diuretics (lasix)
– ACE inhibitor, vasodilator (Enalapril)
– Diet change: low sodium
TRICUSPID VALVE INSUFFICIENCY
TRICUSPID VALVE INSUFFICIENCY
TRICUSPID INSUFFICIENCY RESULTS
IN RIGHT-SIDED HEART FAILURE
CHARACTERIZED BY PLEURAL
EFFUSION
TRICUSPID VALVE INSUFFICIENCY
RIGHT-SIDED HEART FAILURE ALSO
LEADS TO ASCITES
NOTE: THE LOSS OF ABDOMINAL
DETAIL
TRICUSPID VALVE INSUFFICIENCY
• Treatment and client info are the same as for
mtiral insufficiency; repeated
abdominocentesis may be needed in these
cases.
LIVE LIFE TO THE FULLEST!
“You only live once, but if you
work it right, once is enough.”
-Joe E. Lewis, comedian
DISEASES OF THE CARDIOVASCULAR
SYSTEM
HEARTWORM DISEASE
CANINE HEARTWORM DISEASE
• PARASITE CAUSING HEARTWORM DISEASE:
DIROFILARIA IMMITIS
MICROFILARIA OF D. IMMITIS
ADULT HEARTWORMS
CANINE HEARTWORM DISEASE
ONLY FEMALE MOSQUITOES BITE
DISTRIBUTION OF CANINE HEARTWORM DISEASE
CANINE HEARTWORM DISEASE
ADULT HEARTWORMS LIVE
IN THE PULMONARY
ARTERIES. THE HEART MUST
WORK EXTRA HARD TO PUMP
AGAINST THIS OBSTRUCTION.
CANINE HEARTWORM DISEASE
ADULT HEARTWORMS IN
RIGHT VENTRICLE AND
PULMONARY ARTERY
CANINE HEARTWORM DISEASE
• PREDOMINANT PATHOLOGY: DAMAGE TO THE
PULMONARY ARTERY FROM ADULT HEARTWORMS
– Endothelial damage and sloughing
– Inflammation (leukocytes, platelets)
• Risk of thromboemboli
– Pulmonary hypertension
– Disruption of vascular integrity
• Thickened, fibrosed
• RIGHT VENTRICULAR HYPERTROPHY AND RIGHTSIDED HEART FAILURE
– The right ventricle compensates by dilating and increasing
muscle thickness
– Ultimately, there is decompensation and heart failure
CANINE HEARTWORM DISEASE
• Severe infection can lead to CAVAL
SYNDROME
– Worms back up into the right atrium and venae
cavae
• Found in heavy worm burdens (>60)
• Associated with a poor prognosis
• Surgical treatment: pull worms from the right heart
and venae cavae via jugular venotomy
CANINE HEARTWORM DISEASE
CANINE HEARTWORM DISEASE
IDEXX SNAP TEST
ADULT FEMALE ANTIGEN
CANINE HEARTWORM DISEASE
CANINE HEARTWORM DISEASE
CANINE HEARTWORM DISEASE: PREVENTION
• HEARTGARD/IVERHEART
– Ivermectin/pyrantel pamoate
• INTERCEPTOR/SENTINEL
– Milbemycin oxime/ milbemycin oxime+lufeneron
• REVOLUTION
– Selamectin
• ADVANTAGE MULTI/PROHEART 6
– Moxidectin
– Q 6 month injectable
• TRIFEXIS
– Moxidectin + spinosad
CANINE HEARTWORM DISEASE: TREATMENT
STANDARD PROTOCOL: 1 epaxial injection, followed
By a second injection on the opposite side 24 hours later
ALTERNATIVE PROTOCOL: 1 Injection given followed in
4-6 weeks by 2 injections given 24 hours apart
ONLY KILLS ADULT (L5) STAGE WORMS; DOXYCYCLINE IS REC. AS
COMPLIMENTARY TX