Patient Presentation
A 14-year-old female came to clinic for her well-child examination. She was active in school sports, and social groups and was an average student.
The past medical history was positive for hypothyroidism due to thyroidectomy due to a suspicious large nodule that was determined to be benign after excision. The pathologists also identified 1 parathyroid gland that had been also excised. She had had transient hyperparathyroidism and hypercalcemia after surgery but this resolved within a month of surgery. She was stable on her thyroid hormone replacement and was being monitored regularly by her endocrinologist. The review of systems revealed no problems with constipation, fatigue/malaise, cold intolerance, and hair or skin changes. She denied any problems with muscle cramps, or bone or abdominal pain.
The pertinent physical exam showed a healthy female with growth parameters at the 25% and tracking. HEENT showed a well-healed surgical scar at the base of her neck without adenopathy. The rest of her examination was normal.
The diagnosis of a healthy female with appropriately treated hypothyroidism was made. The pediatrician reminded her that it was important to also remember that she not only had had her thyroid removed but that a parathyroid gland was also removed. “It hasn’t and shouldn’t cause any problems for you, but just so you know as you grow up in case it becomes important,” he remarked.
Discussion
The parathyroid glands are small, oval, anatomic structures that are about 5-6 mm in length and with a weight of 50 micrograms. They are located just posterior to the thyroid and during surgery are clinically indistinguishable from the thyroid visually; they can be located within the thyroid also. Usually there are four glands with 2 upper and 2 lower in 80% of people, but there can be fewer (14-15%) or more glands (5-6%). The glands are often ectopic (~16% found in the neck or mediastinum).
The parathyroid glands function to maintain calcium and phosphate homeostasis. Parathyroid hormone (PTH) is secreted when hypocalcemia is detected. PTH has a short half-life of 2-5 minutes. PTH acts on the bones, kidney and intestine to increase calcium. Rising calcium levels have a negative feedback loop on PTH production.
PTH stimulates osteoclast within the bone to resorb bone causing the release of calcium and phosphate. Calcitonin (from the thyroid gland) is the hormone that decreases osteoclast activity and prevents bone resorption. PTH increases renal reabsorption, mainly in the proximal convoluted tubule, but also in the loop of Henle. PTH also stimulates active Vitamin D production which acts to increase calcium reabsorption from the proximal tubules and also the intestine.
Hypercalcemia can cause arrhythmias, bone pain and osteoporosis, constipation, renal stones or nephrocalcinosis, and fatigue and depression. Some people remember the problems using the phrase: “bones (bone pain/osteopenia), groans (constipation, abdominal pain, pancreatitis), moans (fatigue and lethargy) and psychiatric overtones (depression).”
Metabolic evaluation for hypercalcemia usually includes: PTH, calcium, phosphorus, Vitamin D, magnesium, and albumin to better characterize the potential cause. Parathyroid ultrasound and scintigraphy are often used for locating the parathyroid gland prior to surgery, but other modalities are sometimes used.
Learning Point
Hyperparathyroidism
Primary hyperparathyroidism is not very common in pediatric patients compared to the adult population. In pediatric patients there is a bimodal distribution with neonatal and infantile hyperparathyroidism more commonly due to genetic abnormalities (e.g. familial hypocalciuric hypercalcemia, neonatal severe hyperparathyroidism, Williams syndrome, etc.), and subcutaneous fat necrosis, while uncommon, can follow a traumatic birth with subcutaneous pain nodules. Primary hyperparathyroid pediatric disease is seen in ages > 6 years usually due to single adenomas which are usually sporadic and not syndrome associated. Less commonly but more often in adults causes include multiple adenomas, hyperplasia and polyclonal hyperfunction. Parathyroid carcinoma is rare especially in pediatric patients. Treatment often is parathyroidectomy. Adenomas are slightly easier to identify at surgery as they are much larger than the regular sized glands.
Secondary hyperparathyroidism is due to elevated PTH as a compensatory response to hypocalcemia due to another pathological process such as renal failure or Vitamin D deficiency. This is treated by treating the underlying pathological process but parathyroid surgery can also be an option. Tertiary hyperparathyroidism is due to continued elevated PTH despite resolution of the underlying secondary hyperparathyroidism process. Usually this resolves with time, but parathyroid surgery can also be an option.
Hypoparathyroidism
The most common cause of hypoparathyroidism is iatrogenic due to parathyroid removal during surgery. This is more common in pediatric patients than adults. Pediatric patients are also more likely to have temporary hypoparathyroidism after neck surgery than adults but most do not have permanent hypoparathyroidism (0.6%). Other causes include congenital absence of the parathyroid glands, genetic causes, infiltrative or autoimmune processes. Medical management with calcium and Vitamin D is used for temporary or permanent problems.
Questions for Further Discussion
1. What causes hypercalcemia? A review can be found here
2. What are causes of thyroid nodules? A review can be found here
3. How much Vitamin D is in milk? A review can be found here
Related Cases
- Disease: Parathyroid Disorders | Thyroid Diseases | Calcium
- Symptom/Presentation: Health Maintenance and Disease Prevention
- Specialty: Endocrinology
- Age: Teenager
To Learn More
To view pediatric review articles on this topic from the past year check PubMed.
Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.
Information prescriptions for patients can be found at MedlinePlus for these topics: Parathyroid Disorders and Thyroid Diseases.
To view current news articles on this topic check Google News.
To view images related to this topic check Google Images.
To view videos related to this topic check YouTube Videos.
Jamshidi R, Egan JC. Pediatric parathyroid disease. Seminars in Pediatric Surgery. 2020;29(3):150923. doi:10.1016/j.sempedsurg.2020.150923
Khalatbari H, Cheeney SHE, Manning SC, Parisi MT. Pediatric hyperparathyroidism: review and imaging update. Pediatr Radiol. 2021;51(7):1106-1120. doi:10.1007/s00247-021-05050-7
Gorvin CM. Genetic causes of neonatal and infantile hypercalcaemia. Pediatr Nephrol. 2022;37(2):289-301. doi:10.1007/s00467-021-05082-z
Author
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa