Surgical Treatment for Feline Hyperthyroidism 🐱🔪

By Dr Duncan Houston, BVSc

Surgical removal of the thyroid gland—thyroidectomy—remains a curative option for feline hyperthyroidism, particularly where radiotherapy isn’t accessible. In 2025, modern surgical techniques, improved imaging, and meticulous pre-op preparation have made thyroidectomy a viable and successful treatment. Let’s explore this option fully with Dr Duncan Houston. 🩺

📊 When Is Surgery Recommended?

Though radioiodine therapy (I‑131) is the gold standard for treating hyperthyroidism, surgery remains important when:

• 🚫 Radiotherapy isn’t geographically or financially accessible
• 🧬 A single thyroid lobe is clearly affected
• 🏥 The cat is a good candidate after stabilization

🧬 Understanding the Procedure

The surgical goal is to remove overactive thyroid tissue while sparing adjacent critical structures like the parathyroid glands and nerves. The thyroid sits beside sensitive tissues in the neck, making the procedure delicate—especially in older patients with hypertension or cardiac issues. 😺❤️

🛠️ Pre-Surgical Preparation

Preparation significantly improves safety and outcome. This includes:

1. Thyroid Regulation: Two to four weeks of methimazole to normalize hormone levels.
2. Cardiac Management: Beta-blockers like propranolol may control high heart rate.
3. Imaging: A nuclear scan determines if one or both lobes are affected and detects ectopic thyroid tissue.
4. Blood Pressure & Kidney Screening: Essential to minimize surgical risks and detect unmasked kidney disease.

🧪 Why the Nuclear Scan Matters

Approximately 20% of cats have functional thyroid tissue outside the main gland area. Without imaging, this tissue remains untreated, leading to persistent disease. Similarly, some cats have only one affected lobe—allowing a more targeted and lower-risk procedure. 🧠📸

✅ Pros of Thyroid Surgery

• 🎯 Potential cure with no ongoing medication
• 🧑‍⚕️ Available in most general surgical facilities
• 🧬 One-lobe disease often resolves swiftly with minimal risk

⚠️ Potential Surgical Risks

• 🩸 Bleeding or post-op hematoma
• 🧠 Nerve damage affecting voice or eyelid (Horner’s syndrome)
• 💊 Post-op hypothyroidism in some cats
• 🧪 Kidney function changes after normalizing thyroid hormones
• ⚡ Calcium crisis due to parathyroid gland disruption

🧂 Calcium Crisis Explained

Each thyroid lobe has two tiny parathyroid glands regulating blood calcium. If both thyroids are removed, there’s a high risk of damaging these glands.

Signs of hypocalcemia include:

• 😿 Facial twitching
• 😰 Anxiety or inappetence
• ⚡ Muscle tremors or seizures

This occurs 24–96 hours post-op and is managed with Vitamin D and calcium supplementation. Some cases resolve in days, while others require lifelong care. 🩹

📆 Post-Op Recovery Timeline

• 🛏️ 1–3 days of hospitalization
• 🧪 T4 and calcium checked at 24, 72 hours, and 1–2 weeks
• 🧬 Full thyroid stabilization: 1–3 months
• 📉 Monitor for hypothyroidism and adjust if needed
• 🧫 Kidney labs recommended 2–4 weeks post-op

🔄 One-Lobe vs Both-Lobe Surgery

Unilateral thyroidectomy (one lobe) carries far lower risk. Cats often recover swiftly without hypocalcemia or lifelong hormone therapy. Bilateral thyroidectomy increases risk but is sometimes necessary. 🔪

Some surgeons choose a staged thyroidectomy: remove one lobe, wait 2–3 weeks, then remove the second. This reduces calcium risks but involves two anesthetics. 🧠⚖️

🌩️ Thyroid Storm: A Rare but Serious Risk

This emergency occurs when excessive thyroid hormone surges due to stress or surgery. Symptoms include:

• 💓 High heart rate (tachycardia)
• 🔥 Fever
• ⚡ Arrhythmias
• 😵 Collapse or shock

Prevented by careful pre-op prep and stress control. Pre-medication with tranquilizers may be recommended to reduce anxiety at home and during travel. 🧘‍♂️

📱 Ask A Vet for Surgery Prep & Recovery

Planning thyroid surgery? The Ask A Vet app helps every step of the way:

• 📋 Pre-surgical planning and checklist
• 📲 Upload bloodwork and scan results for vet review
• 🩹 Post-op care instructions and emergency signs
• 💬 Live Q&A with licensed vets

🏁 Final Takeaway

Thyroidectomy offers a lasting solution to feline hyperthyroidism when properly planned and executed. While risks like calcium crisis and thyroid storm exist, modern techniques and careful prep make it safe and effective for many cats. Consult with your vet—and use the Ask A Vet app—for confidence, clarity, and the best care for your feline friend. 🐱❤️