What Is Secondary Hyperparathyroidism?
Secondary hyperparathyroidism happens when the parathyroid glands produce too much parathyroid hormone (PTH). This usually happens because of low calcium levels in the body over a long period.
In Australia, the most common cause is chronic kidney disease (CKD). However, it can also occur due to:
- Vitamin D deficiency (long-term)
- Malabsorption syndromes (where the body can’t absorb nutrients properly)
- Chronic lithium use (a medication for mental health conditions)
This guide will focus on secondary hyperparathyroidism caused by chronic kidney disease.
Why Does It Happen in Chronic Kidney Disease?
When kidneys don’t work well:
- They don’t produce enough vitamin D, which is important for calcium absorption.
- They can’t get rid of phosphate properly, leading to high phosphate levels.
This combination causes:
- Low calcium levels (hypocalcemia)
- High phosphate levels (hyperphosphatemia)
- Low vitamin D levels
These changes make the parathyroid glands work harder, producing too much PTH. A hormone called FGF-23 also plays a role in this process.
What Are the Symptoms?
High levels of PTH can cause:
- Bone problems (like brittle bones or bone pain)
- Muscle aches and pains
- Severe itching (pruritus)
- Calcium deposits in soft tissues (can lead to serious conditions like calciphylaxis, which affects the skin and blood vessels)
- Higher risk of heart problems (cardiovascular disease)
How Is It Diagnosed?
🩺 Blood Tests:
- PTH and calcium levels: Shows how severe the condition is.
- Phosphate and vitamin D levels: Helps guide treatment.
- Bone markers: Like alkaline phosphatase and beta-crosslaps to assess bone health.
🖥️ Imaging Tests: (Used if surgery is considered)
- Parathyroid Sestamibi Scan: To find any parathyroid glands in unusual locations.
- Neck Ultrasound: Checks for enlarged parathyroid glands and thyroid nodules.
If abnormal thyroid nodules are found, they may need a biopsy to rule out other issues.
How Is It Treated?
Treatment often starts with medications and may progress to surgery if needed.
💊 Medical Treatment (Managed by a Kidney Specialist):
- Phosphate binders: To control high phosphate levels.
- Vitamin D supplements: To support calcium absorption.
- Calcium supplements: If needed.
🔬 Calcimimetics (e.g., Cinacalcet):
- This medication helps the parathyroid glands sense calcium better, reducing PTH levels.
- It can reduce the need for surgery but doesn’t improve survival or quality of life.
- Available through private prescription or special programs via kidney specialists.
🏥 When Is Surgery Needed?
Parathyroid surgery (parathyroidectomy) is the gold standard treatment when medications don’t work. It improves both quality of life and survival rates.
Surgery Is Considered If You Have:
- Worsening blood test results despite treatment
- Ongoing symptoms like bone pain, muscle aches, or severe itching
- Complications from calcium deposits (e.g., calciphylaxis)
- If you are preparing for a kidney transplant
Types of Parathyroid Surgery:
- Subtotal Parathyroidectomy: Removes 3.5 glands, leaving a small portion to maintain some hormone production.
- Total Parathyroidectomy: Removes all parathyroid glands.
- Total Parathyroidectomy with Auto-Transplantation: Removes all glands, but small pieces are transplanted into muscles (like in the neck or arm) to help maintain some hormone balance.
The goal is to balance the risk of the condition returning (recurrence) with the risk of having permanently low calcium levels after surgery.
Risks of Surgery:
- Bleeding or infection
- Injury to the vocal cords (laryngeal nerve damage)
- Low calcium levels after surgery (hypocalcemia)
After surgery, patients may need to stay in a high-dependency or intensive care unit (HDU/ICU) for close monitoring, especially for low calcium levels, which may require IV calcium infusions.
What Are the Outcomes?
- Surgery is highly effective for treating secondary hyperparathyroidism.
- It is the only treatment proven to improve both quality of life and long-term survival.
- Medical treatments help manage the condition but don’t replace the benefits of surgery when it’s needed.
If you have secondary hyperparathyroidism, talk to your doctor or kidney specialist about the best treatment options for you.