Atherosclerosis in Birds
TL;DR. Atherosclerosis is a chronic, progressive hardening of the arteries that commonly affects older pet birds, leading to reduced blood flow, exercise intolerance, and potentially sudden death.
Atherosclerosis primarily affects the major blood vessels branching from the avian heart, including the aorta and brachiocephalic arteries.
What is it?
Birds possess a highly efficient cardiovascular system designed to support the intense metabolic demands of flight. A bird's heart beats rapidly, and their blood pressure is naturally higher than that of mammals of a similar size. Atherosclerosis disrupts this high-performance system. It is a chronic, degenerative, and inflammatory disease of the arterial walls, characterized by the accumulation of fats (lipids), inflammatory cells, and scar tissue (fibrosis).
As these substances build up, they form hard plaques (atheromas) inside the arteries. The disease primarily targets the aorta—the main artery leaving the heart—and the brachiocephalic arteries, which supply blood to the wings, chest, and head. Over time, these plaques narrow the interior of the blood vessels, restricting blood flow and making the vessel walls stiff and fragile.
For bird owners, this condition is particularly dangerous because birds are prey species. In the wild, showing signs of illness makes a bird an easy target for predators. Consequently, companion birds have evolved to hide physical weakness or discomfort until a disease is incredibly advanced. Atherosclerosis is often a silent killer, developing over years without outward signs until a major cardiovascular event occurs.
Causes & risk factors
Several factors contribute to the development of atherosclerosis in companion birds. While some risks are genetic, many are closely linked to how birds are cared for in captivity:
- Dietary Imbalance: The most significant risk factor is a high-fat, seed-only diet. Seeds are naturally high in fats and lipids but lack essential vitamins and minerals. When a bird consumes excess dietary fat over many years, the level of cholesterol circulating in the blood rises, initiating plaque formation.
- Sedentary Lifestyle: Wild birds fly miles every day to forage for food. Captive birds, even those allowed out of their cages, live a highly sedentary lifestyle. A lack of physical exercise leads to poor cardiovascular conditioning and obesity, which accelerates arterial damage.
- Age: Atherosclerosis is primarily a disease of middle-aged to older captive birds. The longer a bird lives on a sub-optimal diet with minimal exercise, the more time plaques have to accumulate.
- Chronic Inflammation: Ongoing inflammatory processes in the body, such as chronic infections or reproductive disorders, can damage the delicate inner lining of the blood vessels, making it easier for cholesterol to stick and form plaques.
- Gender: Female birds may experience higher risks due to the metabolic demands of egg production. During the laying cycle, a female's body naturally elevates blood lipid levels to transport fats to the developing egg yolk, which can contribute to vascular plaque buildup over time.
Signs to watch for
Because birds hide their symptoms, the signs of atherosclerosis can be incredibly subtle. Owners must pay close attention to minor changes in behavior and physical capability.
- Dyspnea (Common): Difficulty breathing or labored breathing. In birds, an enlarged heart or severely widened blood vessels can press directly on the internal air sacs, causing respiratory distress even if the lungs themselves are healthy.
- Exercise Intolerance (Common): A bird that previously flew across the room may now land heavily after a short distance, panting with an open beak, or may refuse to fly altogether.
- Lethargy (Common): Spending more time fluffed up on a perch, sleeping on two feet instead of tucking one up, or showing a general lack of interest in toys, foraging, and social interaction.
- Sudden Death (Common): Tragically, because the disease is so well-hidden, sudden death due to a complete arterial blockage or heart failure is often the very first sign an owner observes.
- Paresis (Occasional): Weakness or partial paralysis, particularly in the legs. This occurs when plaque fragments break off and block blood flow to the lower body or spinal cord.
- Ataxia (Occasional): A lack of coordination, stumbling, or falling off the perch. This can mimic neurological conditions or strokes due to reduced blood flow to the brain.
Subtle signs like a slightly open beak or tail bobbing while resting can indicate underlying cardiovascular or respiratory distress.
How vets diagnose it
Diagnosing atherosclerosis in a living bird is highly challenging. A standard physical examination may reveal obesity or a heart murmur, but these findings are not specific to arterial plaque. To reach a diagnosis, your vet will rely on advanced diagnostic tools.
Your vet will likely begin with plasma biochemistry to measure circulating cholesterol and triglyceride levels. While high lipid levels indicate that a bird is at a high risk for cardiovascular disease, they do not definitively prove that plaques have already formed in the arteries. Standard radiography (X-rays) may also be performed. X-rays can show an enlarged heart silhouette or, in very advanced cases, visible calcification of the great blood vessels. However, early to moderate plaque accumulation is invisible on standard X-rays.
To achieve a definitive diagnosis in a living patient, the gold standard test is Computed Tomography (CT) Angiography. This advanced imaging technique involves injecting a contrast dye into the bird's bloodstream and performing a rapid, high-resolution CT scan. This allows the veterinarian to visualize the exact internal structure of the blood vessels, identifying narrowing, blockages, and plaque deposits with high precision.
If a bird passes away suddenly, post-mortem histopathology remains the ultimate gold standard. Microscopic examination of the arterial tissue after death is often the only way to confirm the exact severity and extent of the disease across a bird population or within a multi-bird household.
Over time, cholesterol and inflammatory cells build up inside the arterial walls, severely restricting vital blood flow.
Treatment options
There is no cure for avian atherosclerosis. Once arterial plaques have formed and calcified, they cannot be dissolved or reversed. Treatment focuses entirely on managing clinical signs, improving blood flow, and preventing the formation of new plaques.
Dietary and Lifestyle Modifications
The absolute cornerstone of managing atherosclerosis is a complete overhaul of the bird's diet and lifestyle. Your vet will guide you through transitioning your bird from a high-fat seed diet to a formulated, high-quality pellet diet. This transition must be done carefully and gradually, as some birds will refuse to eat new foods to the point of starvation. Additionally, increasing physical activity through supervised flight, walking, and active foraging toys is essential to help the bird lose weight and improve cardiovascular health.
Medical Management
When lifestyle changes are not enough, or if the disease is advanced, medical therapy is required.
- Peripheral Vasodilators: Isoxsuprine is a peripheral vasodilator commonly used as a second-line medical therapy. It works by relaxing the smooth muscles within the blood vessels, widening the pathways to allow blood to flow more easily around existing plaques.
- Lipid-Lowering Drugs: Your vet may prescribe medications similar to human statins to help lower the concentration of cholesterol and triglycerides in the blood, slowing the progression of new plaque deposits.
- Anti-inflammatory Medications: Because atherosclerosis is fundamentally an inflammatory disease, low-dose anti-inflammatory drugs may be used to reduce vascular inflammation and improve overall comfort.
Prognosis
The prognosis for a bird diagnosed with atherosclerosis is guarded to poor once clinical signs are present. Because symptoms only appear after the disease has reached an advanced stage, the arterial damage is typically severe and irreversible by the time treatment begins.
However, if the disease is caught early—such as during routine screening of a high-risk bird—the prognosis for maintaining a good quality of life is much better. With strict dietary management, lifestyle changes, and lifelong medical monitoring, many birds can live comfortably for years. Owners must commit to regular veterinary checkups, routine blood work, and daily medication administration.
Prevention
Because treating advanced atherosclerosis is so difficult, prevention is your bird's best defense.
- Establish a Pellet-Based Diet Early: Feed your bird a high-quality, commercially formulated pellet diet as their primary food source from a young age. Seeds should only be used as occasional treats during training.
- Encourage Daily Exercise: Ensure your bird has ample opportunity to move, climb, and fly in a safe environment. Foraging toys that force your bird to work for their food are excellent for physical and mental stimulation.
- Routine Veterinary Screenings: Schedule annual wellness exams with an avian veterinarian. For older birds or predisposed species, ask your vet about routine blood work to monitor cholesterol and triglyceride levels before physical symptoms develop.
When to call your vet
Cardiovascular events in birds can escalate rapidly into life-threatening emergencies. You should contact your veterinarian immediately if you observe any of the following red flags:
- Open-beak breathing or constant tail bobbing (the tail moving up and down with every breath).
- Sudden weakness, inability to grip a perch, or falling to the bottom of the cage.
- Sudden loss of coordination, stumbling, or partial paralysis in one or both legs.
- Extreme lethargy, sitting fluffed up on the cage floor, or unresponsive behavior.
For specific breeds
Cockatiels are highly predisposed to developing atherosclerosis. Research suggests that cockatiels may have unique genetic differences in how they metabolize lipids, making them far more vulnerable to the damaging effects of high-fat diets than other species. Because cockatiels are frequently kept on seed-only diets by well-meaning owners, they represent a significant portion of clinical avian atherosclerosis cases. If you own a cockatiel, proactive dietary management and early veterinary screening are vital to ensuring a long, healthy life.
Sources
Because specific textbook citations were not provided for this record, the clinical guidelines and medical details outlined in this article are based on standard-of-care avian veterinary medicine and consensus recommendations from leading avian health resources:
- Clinical Avian Medicine, Volume I and II.
- Current Therapy in Avian Medicine and Surgery.
