Page 358 - Feline Cardiology

Chapter 24: Comorbidities 373

an excellent quality of life for a year or more when the rule that diuretics and fluids should not be given
performed as needed (up to biweekly or weekly if together: fluids and diuretics may be coadministered
necessary), whereas for others repeated centesis is if the fluids are a vehicle for other therapies (e.g.,
undesirable and declined by the owner. constant-rate infusion of potassium chloride in a
• Avoid administering diuretics and intravenous or sub- severely hypokalemic cat, using low volume of fluids
cutaneous fluids simultaneously. Giving diuretics and such as 1/4 to 1/6 maintenance rates), or if a patient
parenteral fluids together is a common and easily has been dramatically overtreated and the effects of
made error. The reasoning appears to be aimed at treatment need to be reversed. In the latter case, such
decreasing diuretic-induced prerenal azotemia via as overzealous fluid administration warranting diuretic
fluid administration, or conversely, decreasing the risk treatment, or overzealous diuretic administration war-
of parenteral fluid-associated iatrogenic congestive ranting fluid therapy, both diuretics and fluids may be
heart failure by giving diuretics. The reasoning in administered concurrently for a period of 12–24
both contexts is flawed: all commonly used diuretics hours, after which the treatment is adjusted and only
(furosemide, thiazides, torsemide, spironolactone, one of the two continues to be given.
etc.) act by increasing renal loss of electrolytes and
water, while injectable crystalloid fluids consist When a cat’s serum creatinine and blood urea nitrogen
mainly of electrolytes and water. The administration concentrations increase over time in conjunction with
of both together serves the same purpose as adminis- higher diuretic dosages needed to control congestive
tering a drug and its reversal agent at the same time. heart failure, the clinician may justifiably give a more
A more logical approach consists of reducing the guarded prognosis. Ultimately, end-stage kidney and
dosage of one and not giving the other. Therefore, a heart disease do occur simultaneously because in so
patient receiving diuretics and requiring “protection” many cases the underlying diseases are irreversible and
from prerenal azotemia does not need fluids simulta- progressive. However, such an outcome usually occurs
neously, but rather a lower dosage of diuretics. only months to years after the initial diagnosis of the two
Similarly, a patient receiving parenteral fluids where disorders, and before giving a patient a guarded or poor
a concern exists for intravascular volume overload prognosis, it is the clinician’s responsibility to identify
should not receive both fluids and a low dose of and correct complicating factors (see Table 24.1) to the
diuretics, but simply a lower dosage of parenteral fullest reasonable extent allowed by the client and patient.
fluids. If such an approach is felt to be very likely to
result in decompensation of the dominant problem
(cardiac or renal), then the clinician should review the CARDIAC DISEASE AND IDIOPATHIC CYSTITIS/
FELINE LOWER URINARY TRACT SIGNS
case with particular attention paid to the concurrent
or associated factors listed in this chapter (Table 24.1) Although there is no known association between heart Comorbidities
that could be corrected and thus reduce the need for disease and lower urinary tract signs/disease (FLUTS) in
diuretics or parenteral fluids. Two exceptions exist to cats, treatment of either disorder has been postulated to

Table 24.1. Complicating or concurrent factors to consider when managing cardiac and renal disorders simultaneously in a feline
patient

Acute Management Chronic Management
Identify and address reversible causes (sodium ingestion, Verify client compliance: administering the medication
glucocorticoids, acute tachycardia; pyelonephritis) Verify patient compliance: accepting the medication
Assess for onset of gallop heart sound during fluid therapy Identify diuretic resistance: measure urine specific gravity
Identify and correct hypokalemia Identify and treat systemic hypertension
Diuretic as constant-rate IV infusion instead of boluses Decrease diuretic dosage to lowest effective level
Confirm diagnostic uncertainty, especially radiographic Avoid dietary sodium excess and consider sodium-restricted diet
diagnosis of pulmonary edema Differentiate between advanced/end-stage disease and acute-on-
Identify normal echocardiographic atrial size, lowering chronic disease
likelihood of congestive heart failure Correct anemia if present
Centesis/drainage for large-volume body cavity effusions Correct hypokalemia/hypomagnesemia, if present
Avoid administering parenteral fluids and diuretics Periodic centesis/drainage for large-volume body cavity effusions
simultaneously Avoid administering parenteral fluids and diuretics simultaneously