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Case 33
 | Class III heartworm infection with severe
pulmonary hypertension |
| Heartworm extraction |
| First Day 20:00 Problem #1 Heartworm w/
pulmonary hypertension-S/O: See pertinent history and physical examination.
T=100.5, P=160, R=pant. Heartworm antigen test today was weak positive.
Echocardiogram showed increase in chamber size of right atrium and right
ventricle, along with right ventricular free wall
concentric hypertrophy. Septal flattening is evident in systole
and diastole. Pressure gradient across the tricuspid valve=70
mmHg, which indicates severe pulmonary hypertension.
Heartworms were visualized in right pulmonary artery on echo. ECG shows
S waves indicative of right ventricular enlargement.
Thoracic radiographs show severely dilated pulmonary arteries (main, right and
left branch). Also see radiopaque areas in lung which are suggestive of
emboli. Fisher had a good appetite tonight and appeared comfortable in his
run. A: Class III heartworm disease causing severe pulmonary hypertension
and clinical signs of coughing and lethargy.
Enlarged right heart chambers along with hypertrophied RVFW,
systolic flattening of the interventricular septum, and the increased pressure
gradient across the tricuspid valve indicate a
severe acquired pressure overload
due to pulmonary hypertension. ECG changes
consistent with right ventricular hypertrophy. Dilated pulmonary arteries
consistent with presence of heartworms. P: Surgically remove as many worms as
possible from pulmonary arteries via right jugular vein. Pre-treat with
prednisone 30 mg PO tonight and 15mg PO BID starting
in AM. Also start diphenhydramine 2mg/kg
BID. No food after midnight, NPO after 6
AM. |
| First Day 20:00 Problem #2 Melena-S/O: Feces
appeared dark and tarry on walk this afternoon. A: Most likely due to coughing
up blood (hemoptysis) and swallowing it.
The hemoptysis is indicative of small pulmonary artery
rupture. P: Continue to monitor feces. |
| Second Day 08:00 Problem #1 Heartworm
w/pulmonary hypertension-S/O: T=100.8, P=112, R=pant. Mild coughing. No harsh
lung sounds ausculted. Given 15mg prednisone PO, 12.5 mg diphenhydramine PO.
A: Stable and comfortable. P: Surgical removal of heartworms today. Induction
planned for 10:00. |
| Second Day 08:00 Problem #2 Melena-S/O: No sign
of blood in feces this morning. A: Has not been coughing much since being
hospitalized, which may mean less/no blood being swallowed. P: Problem
resolved. |
| Second Day 20:00 Problem #1 Heartworm
w/pulmonary hypertension-S/O: Still sedate, T=99.7, P=96, R=36.
Fisher was anesthetized. A surgical cutdown of the right
jugular vein was performed. An Ishihara flexible
alligator forceps as used to successfully
remove 8 heartworms from the pulmonary arteries (2 male worms and 6 female
worms; 6 from the right and 2 from the left). No
complications were encountered during surgery and
anesthesia and recovery was uneventful. Owner
visited and Fisher was still too sedate to go home. Given 15mg prednisone PO.
Urinated and defecated normally. No redness, swelling or discharge at incision
site. A: Successful recovery of eight worms from the pulmonary arteries.
Resting comfortably in run. P: Discharge tomorrow. Prescribe prednisone 15mg
PO BID until recheck on 2/10/03. |
| Third Day 08:00 Problem #1 Heartworm w/pulmonary
hypertension-S/O: BARH, T=101.3, P=120, R=pant. Incision looks good. Appetite
good-fed 1 cup dry dog food and 1/4 can
P/D. Urinated on walk, no feces. A: Recovering well
from surgery. Stable and comfortable. P: Discharge at noon today. Recheck and
initiate medical heartworm treatment
in one week. Send home with prednisone 15mg PO BID.
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| Echocardiogram: Severe pulmonary hypertension secondary
to heartworm disease causing mild, high-velocity tricuspid
regurgitation, large dilated pulmonary arteries,
septal flattening from elevated right ventricular systolic pressure;
diastolic septal flattening due to right heart failure, and
a severely enlarged right heart. Heartworms were
not seen around the tricuspid valve but were
observed in the right pulmonary artery
branch. |
| ECG: regular rhythm. Deep S waves present in leads I, II, III, and aVF,
indicative of right ventricular hypertrophy.
|
| Heartworm antigen test: weak positive |
| Thoracic radiographs: severely enlarged/dilated pulmonary arteries and
pulmonary vasculature. Lung parenchyma does not appear significantly affected.
|
| Conclusion: Severe pulmonary hypertension due to
class III heartworm infection. |
| Treatment consisted of a small incision
to expose his right jugular vein and subsequent
introduction of a flexible alligator forceps into
his pulmonary arteries to remove the worms.
The procedure was successful and eight worms
were removed. Fisher's right jugular vein was ligated and will remain
non-functional for life. Fisher recovered uneventfully. He was sent home the
next day on prednisone at 15 mg PO BID (0.5mg/kg) for one week. |
| Fisher's CBC showed a regenerative anemia
(HCT=31%) and an eosinophilia of 2,992/uL. His
chemistry panel revealed a hypoalbuminemia (2.1 gm/dl)
and an increased globulin (5.4 gm/dl). Urinalysis
showed SG=1.023 and 3+ proteinuria. Generally the most
effective treatment for heartworm-induced glomerular disease is eradication of
the adult worms. |
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