What causes high hemoglobin in dogs?

Understanding the Causes of High Hemoglobin in Dogs

When a dog has high hemoglobin, it's usually a sign that their red blood cell count is elevated. This condition is medically known as polycythemia or erythrocytosis. While rare, it can be serious if not addressed. Let's break down what leads to this issue and how you might recognize and address it.

Types of Polycythemia in Dogs

There are three main types of polycythemia:

• Relative polycythemia: This happens when the liquid part of the blood (plasma) decreases, making it look like there are more red blood cells than normal. Dehydration is the usual culprit here—think vomiting, diarrhea, or not drinking enough water. Severe burns or any situation causing fluid loss can also trigger this.
• Transient polycythemia: This type is temporary and often caused by stress, anxiety, seizures, or even excitement. When a dog's spleen contracts (which can happen during these events), it releases more red blood cells into circulation for a short time.
• Absolute polycythemia: Here, there's a true increase in the number of red blood cells. It can be primary (polycythemia vera), where the bone marrow produces too many red cells on its own, or secondary, where another condition—like chronic low oxygen levels or certain tumors—stimulates extra production.

Main Causes of High Hemoglobin

The following are some common reasons dogs develop high hemoglobin:

• Dehydration: Loss of fluids from vomiting, diarrhea, or simply not drinking enough concentrates the blood.
• Strenuous exercise or excitement: These states can cause a temporary spike due to splenic contraction.
• Heatstroke or severe burns: Both lead to fluid loss and relative polycythemia.
• Bone marrow disorders (polycythemia vera): The marrow goes into overdrive producing red blood cells for no good reason.
• Chronic hypoxia: Conditions like heart defects, lung disease, or living at high altitude mean less oxygen in the blood; the body responds by making more red cells to compensate.
• Erythropoietin-secreting tumors (often kidney-related): These tumors produce hormones that tell the bone marrow to make more red blood cells.

Certain breeds—like Greyhounds—naturally have higher red cell counts. For them, high hemoglobin may not signal disease.

Symptoms to Watch For

You might notice signs only when things get severe (when packed cell volume exceeds 65%). Some symptoms include:

• Lethargy and weakness
• Bright red or purplish gums and mucous membranes
• Increased thirst and urination
• Bloodshot eyes or neurological changes (like seizures)
• Nosebleeds or other bleeding issues
• Trouble breathing or rapid breathing

A few dogs show no symptoms at all—the problem gets picked up during routine lab work.

The Diagnostic Process

If your vet suspects high hemoglobin/polycythemia, they’ll dig deep with:

1. A complete blood count (CBC) for measuring RBCs and hemoglobin levels.
2. Chemistry panels to check organ function and rule out other causes.
3. Plasma protein measurement—to separate dehydration from true polycythemia.
4. Pulse oximetry for oxygen saturation and tests for erythropoietin levels if needed.

X-rays or ultrasound may help spot heart disease, lung problems, or kidney masses. Sometimes a bone marrow biopsy is necessary if a primary marrow disorder is suspected.

Treatment Options for High Hemoglobin in Dogs

• If dehydration's to blame: intravenous fluids quickly restore balance and dilute the concentrated blood back to normal levels.
• If absolute polycythemia: vets may perform phlebotomy (removing some blood) while giving IV fluids to prevent dehydration. This helps thin out thickened blood so organs get enough oxygen again.

If repeated phlebotomies are needed (especially with primary polycythemia), medications like hydroxyurea suppress excessive red cell production but require close monitoring due to possible side effects such as gastrointestinal upset or rare bone marrow suppression.
Surgery might be an option if a tumor's causing excess erythropoietin production.
Treating underlying heart, lung, or kidney disease also helps manage secondary cases.

Long-Term Management & Prognosis

Your dog might need ongoing care—sometimes repeated phlebotomies every few weeks—and regular checkups. Chronic removal of blood can lead to iron deficiency over time; supplements may help if this develops. Prognosis varies: many dogs do well with proper management for months or years; others with untreatable underlying conditions may face a poorer outlook. In severe cases where treatment isn’t possible, humane euthanasia may be considered to prevent suffering.

Can You Prevent High Hemoglobin?

You can't always prevent primary forms tied to genetics or bone marrow disease. But you can reduce risk by:

• Keeping your dog hydrated—especially during illness or hot weather.
• Avoiding situations where your dog could overheat (never leave them in hot cars).
• Seeking prompt veterinary attention if you notice lethargy, neurological changes, difficulty breathing, or other concerning symptoms.
• Sustaining regular vet visits for early detection of subtle changes before complications arise.
• If your dog has chronic heart/lung/kidney issues: careful management lowers risk of secondary polycythemia.

The Takeaway on High Hemoglobin in Dogs

This condition often sneaks up slowly; some dogs seem fine until things get serious. Early detection really matters—it lets you manage complications like clots and organ strain before they threaten your dog's quality of life. With attentive care and regular follow-up with your veterinarian, many affected dogs continue enjoying their days with minimal disruption. If you ever notice unusual symptoms in your dog—or just want peace of mind—a quick vet visit and some simple tests go a long way toward keeping them healthy!