Page 119 - Problem-Based Feline Medicine

8 – THE CYANOTIC CAT 111

TRAUMA
● Diaphragmatic hernia* (p 115)
Dyspnea and tachypnea may occur acutely or months or years following blunt trauma. Vomiting,
regurgitation, inappetence and weight loss may also occur.

● Central nervous system damage to the respiratory center (p 118)
Persistent or episodic weakness, Cheyne–Stokes respiration and cyanosis.
TOXIC

● Drug overdosage (p 117)
Excessive administration of barbiturates, narcotics, opiates, tranquilizers or anesthetic agents may
lead to decreased respiratory effort, loss of consciousness and cyanosis. During anesthesia,
reduced bleeding at surgical sites and indicators of a deep plane of anesthesia are present.
PERIPHERAL HYPOXIA
WHERE? – GENERALIZED
MECHANICAL

● Vasoconstriction* (p 118)
Peripheral hypoxia occurs due to vasoconstriction as a consequence of hypovolemic, cardiogenic
or septic shock or due to hypothermia. Clinical signs, physical findings and history point to one of
these causes. There may be evidence of shock, trauma, dehydration, pyrexia, blood loss or reduced
urinary output. Signs of cardiac failure include dyspnea, cardiac murmur, gallop rhythm, slow cap-
illary refill time, pale/cyanotic mucous membranes and pulse deficits. Frequent or severe vomiting,
diarrhea or diuresis may indicate fluid loss.

LOCALIZED
MECHANICAL
● Arterial thromboembolism** (p 120)
Ninety percent lodge at the distal aortic bifurcation causing bilateral hindlimb pain and paresis, weak
or absent femoral pulses, cold, cyanotic footpads and lack of spontaneous movement of the muscles of
the hindlimbs. Other areas embolized less commonly are the thoracic aorta, renal, mesenteric, coro-
nary, cerebral and branchial arteries which cause acute, severe and variable clinical signs.

● Venous obstruction (p 121)
Clinical signs relate to the area drained by the obstructed vein, mainly edema and vasodilatation
distal to the site of obstruction. Cranial vena caval obstruction results in edema of the neck, ventral
head, cranial thorax and forelimbs.
ABNORMAL HEMOGLOBIN WITH DECREASED OXYGEN-CARRYING CAPACITY
WHERE? – HEMOGLOBIN IN RED BLOOD CELLS
WHAT?

TOXICITY
● Paracetamol/acetaminophen toxicity (p 121)
Acute onset and rapid progression of salivation, vomiting and depression. Cyanosis develops
within 4–12 hours of ingestion. Subcutaneous edema of the face may be evident, which may be
accompanied by lacrimation and puritis. Hematuria, hemolysis and Heinz bodies occur associated
with methemoglobin formation.