25: Edema, Hyperemia, & Congestion

Fun sign of pulmonary edema in ruminants

Very expanded interlobular septa

Why is brain edema bad

There is no space for brain expansion, so edema results in increased intracranial pressure, and sometimes brain stem herniation

Common location of edema that is largely unproblematic

SQ edema

Draft horse disease that often causes edema

Chronic progressive lymphedema

Cause of CPL in draft horses

Decrease elastin cross linking in lower limbs and weak lymphatics

Lesions associated with CPL

• Pitting edema

• Inflammation

• Concurrent bacterial or mite infection

Type of edema that can accompany canine adenovirus, if the patient lives long enough to develop a type 3 hypersensitivity

Corneal edema

Hyperemia

Active increase of arterial blood to a location

Mechanisms of hyperemia

Neurogenic (epi) or mediator (inflammatory) driven

T/F: hyperemia is always pathologic

F, can be physiologic

Physiologic reasons for hyperemia

• Blushing

• Heat dissipation

• Raynaud’s phenomenon in response to cold

Primary cause of pathologic hyperemia

Inflammation

Chemosis

Ocular edema and hyperemia

Why might hyperemia be accompanied by edema

More blood flow → increased hydrostatic pressure

• May likely also have inflammatory edema due to leaky vessels

Congestion

Passive accumulation of blood in an area due to decreased venous outflow

Term for postmortem congestion

Hypostatic congestion

Where do we see hypostatic congestion

On the down-side organs of cadavers; due to gravity

Why might congestion be accompanied by edema

Increased hydrostatic pressure

Signs of acute passive congestion in the liver (honestly, anywhere)

Very thick and very red tissue

Signs of chronic passive congestion in the liver

NUTMEG LIVER!!

What can cause chronic passive congestion in the liver

CHF