Hypertension

Sarah Caney

doi:10.22233/9781910443149.5.18

Hypertension

British Small Animal Veterinary Association , 238 (2013); https://doi.org/10.22233/9781910443149.5.18

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Hypertension

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Author: Sarah Caney
From: BSAVA Manual of Feline Practice
Item: Chapter 5.18, pp 238 - 243
DOI: 10.22233/9781910443149.5.18
Copyright: © 2013 British Small Animal Veterinary Association
Publication Date: January 2013

Abstract

Systemic hypertension (a persistent increase in the systemic blood pressure) is now commonly recognized in feline practice. There are several reasons for this, including an increased awareness of hypertension as a feline problem, increased access to diagnostic facilities and, possibly, an increased prevalence of this condition related to the increasing average age of the cat population. This chapter looks at clinical findings, diagnosis, management and prognosis. Quick reference guides: Measuring blood pressure; Treatment of hypertension.

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5.18.2

Fundus image showing early evidence of hypertensive damage. The main visible abnormality is a green circular area (from around 7 to 10 o’clock) representing a large serous bullous retinal detachment. Retinal vessels over this area can be clearly seen, although they are out of focus (indicating a serous effusion). Many smaller green/grey circular and oval areas indicative of retinal oedema and focal detachments are visible on the remainder of the retina. Oedema can be a prelude to retinal detachment. Both eyes had similar changes, and pupil size and pupillary light responses were normal. At this relatively early stage vision did not appear to be affected. (Courtesy of Sheila Crispin.) © 2013 British Small Animal Veterinary Association

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5.18.2 Fundus image showing early evidence of hypertensive damage. The main visible abnormality is a green circular area (from around 7 to 10 o’clock) representing a large serous bullous retinal detachment. Retinal vessels over this area can be clearly seen, although they are out of focus (indicating a serous effusion). Many smaller green/grey circular and oval areas indicative of retinal oedema and focal detachments are visible on the remainder of the retina. Oedema can be a prelude to retinal detachment. Both eyes had similar changes, and pupil size and pupillary light responses were normal. At this relatively early stage vision did not appear to be affected. (Courtesy of Sheila Crispin.)

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5.18.3

Fundus image showing significant evidence of hypertensive damage. Many abnormalities are present. There is widespread attenuation of the retinal arterioles, and arteriolar occlusion (AO) is apparent in a number of them. An aneurysm (A) is visible in a retinal arteriole. This swollen portion of arteriole is vulnerable to rupture, leading to intraocular haemorrhage. Multiple areas of retinal haemorrhage (H) are visible over the entire retina. In the centre of the image the retina appears bright and hyper-reflective, consistent with retinal degeneration (RD), which can occur as a consequence of any ocular pathology. Dorsal to this region there is retinal detachment (D) because of exudation (serous detachment). Part of the optic disc (OD) is visible at the bottom of the photograph; its definition is poor because of peripapillary and papillary oedema. Both eyes were similarly affected; the pupils were moderately dilated, the pupillary light response sluggish and incomplete, and vision was compromised. (Courtesy of Sheila Crispin.) © 2013 British Small Animal Veterinary Association

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5.18.3 Fundus image showing significant evidence of hypertensive damage. Many abnormalities are present. There is widespread attenuation of the retinal arterioles, and arteriolar occlusion (AO) is apparent in a number of them. An aneurysm (A) is visible in a retinal arteriole. This swollen portion of arteriole is vulnerable to rupture, leading to intraocular haemorrhage. Multiple areas of retinal haemorrhage (H) are visible over the entire retina. In the centre of the image the retina appears bright and hyper-reflective, consistent with retinal degeneration (RD), which can occur as a consequence of any ocular pathology. Dorsal to this region there is retinal detachment (D) because of exudation (serous detachment). Part of the optic disc (OD) is visible at the bottom of the photograph; its definition is poor because of peripapillary and papillary oedema. Both eyes were similarly affected; the pupils were moderately dilated, the pupillary light response sluggish and incomplete, and vision was compromised. (Courtesy of Sheila Crispin.)

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5.18.4

Mydriasis. Dilation of the pupils is one potential indication of blindness associated with bilateral retinal detachment as a consequence of systemic hypertension. (a) Under normal consulting room light conditions, both pupils appear abnormally large. (b) When the room is darkened and a bright light is shone into the cat’s eyes, there is a complete absence of both direct (constriction of the stimulated pupil) and consensual (constriction of the contralateral pupil) pupillary light response (PLR; see QRG 1.3) and both pupils remain the same size as before. Using a bright light source (a Finhoff transilluminator attached to an otoscope/ophthalmoscope handle in this case), the retina can be clearly seen in both eyes as a grey membrane containing blood vessels. Small retinal haemorrhages are visible billowing forwards within the vitreous in the left eye (red arrows). The retina usually remains attached around the optic nerve head and at the periphery, which is why it has the bulging appearance with folds as seen in the right eye. This retinal appearance is an abnormal finding, indicating bilateral serous retinal detachment. Unfortunately the blindness was permanent in this cat. © 2013 British Small Animal Veterinary Association

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5.18.4 Mydriasis. Dilation of the pupils is one potential indication of blindness associated with bilateral retinal detachment as a consequence of systemic hypertension. (a) Under normal consulting room light conditions, both pupils appear abnormally large. (b) When the room is darkened and a bright light is shone into the cat’s eyes, there is a complete absence of both direct (constriction of the stimulated pupil) and consensual (constriction of the contralateral pupil) pupillary light response (PLR; see QRG 1.3) and both pupils remain the same size as before. Using a bright light source (a Finhoff transilluminator attached to an otoscope/ophthalmoscope handle in this case), the retina can be clearly seen in both eyes as a grey membrane containing blood vessels. Small retinal haemorrhages are visible billowing forwards within the vitreous in the left eye (red arrows). The retina usually remains attached around the optic nerve head and at the periphery, which is why it has the bulging appearance with folds as seen in the right eye. This retinal appearance is an abnormal finding, indicating bilateral serous retinal detachment. Unfortunately the blindness was permanent in this cat.

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