Page 323 - Feline Cardiology

332 Section I: Systemic Hypertension

uncommonly recognized as the principal manifestation PHYSICAL EXAMINATION
of systemic hypertension in cats.
The initial, hands­off portion of the examination is
extremely informative in the cat known or suspected to
Incidental Finding of Hypertension or have systemic hypertension. Prior to handling the
Hypertension-Associated Abnormality patient, the clinician can assess demeanor, mentation,
A cat’s BP may appropriately be measured for the first gait, and posture. Deficits in these simple but vital
time when the diagnosis of chronic kidney disease or parameters could suggest the presence of hypertensive
hyperthyroidism is made. If systemic hypertension is encephalopathy. A cat’s ability to walk around the exam
identified, questions in the history should seek to better room normally identifies its ability to see, whereas its
define the extent of clinical signs associated with the bumping into walls and cabinets suggests vision loss. A
primary disease (e.g., polyuria, polydipsia, appetite poor haircoat may indicate chronic illness such as
alterations, perceived weight gain or loss, vomiting, chronic kidney disease or hyperthyroidism, and the
stamina) as well as investigate signs of ocular compro­ latter condition is further suspected if the body condi­
mise or encephalopathy. tion is poor despite a good appetite. The presence or
The unexpected finding of an elevated arterial BP in absence of blood around the nostrils should be noted,
an otherwise healthy­appearing cat should invariably since systemic hypertension is a recognized cause of epi­
prompt investigation rather than intervention. staxis. Respiratory effort is evaluated at this stage also;
Specifically, the history should be reviewed to identify abnormalities beyond those expected with exam­room
medications such as alpha­2 agonists (e.g., dexmedeto­ anxiety suggest respiratory compromise or, in a very
midine) that elevate BP. The presence in the history lethargic cat, possibly metabolic acidosis as seen with
severe chronic kidney disease. Specifically, dyspnea or
of clinical signs consistent with diseases that cause sys­
Systemic Hypertension skepticism to avoid over­ or underestimating their ratory disease, pleural effusion, or pulmonary edema.
tachypnea should lead to the suspicion of primary respi­
temic hypertension should be viewed with reasonable
Although systemic hypertension is not known to rou­
impact on the patient. The lack of such signs, further­
tinely cause these disorders, it may contribute to other
more, increases the suspicion of a spuriously elevated
diseases and cause decompensation.
BP reading. Next, the BP measurement must have been
The ophthalmic examination is essential in all patients
performed under ideal conditions eliminating all pos­
sible stressors or other elements likely to artificially
tension. Ocular signs, consisting of retinal hemorrhages,
increase it. If that was not the case, it should be repeated suspected of having, or known to have, systemic hyper­
in an optimal environment (see Figure 21.1). A truly detachments, or both, were found in 28/58 (48%) hyper­
hypertensive patient that appears otherwise healthy tensive cats, compared to a prevalence of 3/113 (3%) in
should have a complete physical exam, including fundic normotensive peers (Chetboul et al. 2003). As men­
exam, and should undergo basic diagnostic testing (see tioned previously, blindness occurs in a fraction of
below). hypertensive cats with ocular lesions; 8 of the 58 cats in
In many cats, an abnormality is identified that is this case series (14%) were blind. Systolic BP was signifi­
thought to exist because of systemic hypertension, but cantly higher in hypertensive cats with retinal lesions
systemic hypertension had not been considered until (average = 262 mm Hg) than in hypertensive cats
then. This finding leads to BP measurement and can without retinal lesions (average = 221 mm Hg), sup­
confirm systemic hypertension. Such “tip of the iceberg” porting the logical deduction that retinal lesions occur
lesions include ocular—especially fundic—changes, when systemic hypertension is more severe (Chetboul et
asymmetrical or diffuse intracranial signs, left ventricu­ al. 2003). Fundic abnormalities in systemic hypertension
lar hypertrophy, epistaxis, and proteinuria. The history can include increased tortuosity of retinal vessels, retinal
in these patients can be very different from the history edema, foci of intrarenal serous exudates, and pinpoint
typical of hypertensive patients. An echocardiogram retinal hemorrhages (see Figures 21.3–21.5). These
reveals left ventricular hypertrophy after having been abnormalities reinforce the diagnosis of systemic hyper­
prompted by the auscultation of a murmur or gallop, or tension or first lead to its suspicion if they are noted
the observation of cardiomegaly on thoracic radio­ before the BP is ever measured. These lesions rarely
graphs taken for some other reason; proteinuria is noted cause impairment of vision. Hypertensive ocular lesions
on a routine urinalysis performed because of an unre­ that are more severe include large intraretinal or prereti­
lated issue; or ocular or neurologic abnormalities are nal (i.e., within the vitreous or anterior chamber) hem­
noted during a routine exam. These scenarios are typical orrhages, large retinal detachments, and possibly
of the history for this category of patient. resultant hyphema with or without secondary glau­