History
NSHPT represents a severe form of hyperparathyroidism observed in neonates, with a high mortality rate if untreated. Symptoms include dehydration secondary to polyuria, feeding difficulties and vomiting, altered mental status, hypotonia, respiratory distress and fractures. FHH is milder, often asymptomatic. [18]
Unlike adults, the majority of children and adolescents with primary hyperparathyroidism are symptomatic, with symptoms secondary to hypercalcemia or the effects of PTH on target organs. Hypercalcemia affects cell depolarization leading to gastrointestinal, neurologic and cardiac signs and symptoms. Gastrointestinal symptoms are common, and are partly due to increased gastric acid secretion. These symptoms include abdominal pain, nausea, anorexia, constipation and vomiting. Polyuria is caused by the direct effects of hypercalciuria on the nephron and by the stimulation of the CASR in the collecting tubules leading to decreased antidiuretic hormone action. Headache, depression, fatigue, and anxiety are amongst the most frequent neurological symptoms. Renal calculi, hematuria, dehydration, bone pain, and fractures are presenting symptoms in more than 50% of pediatric cases. [4] Bradycardia and heart block may be observed with severe hypercalcemia. In cases where hyperparathyroidism is part of a multiglandular syndrome, there may be a history of symptoms associated with other endocrine tumors, and a positive family history for similar tumors. The proportion of asymptomatic pediatric patients diagnosed by the incidental finding of hypercalcemia during routine blood chemistry is lower than that reported in adults, with a range of 14 to 25% in a pediatric series.
Physical Examination
Clinical features include the following:
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Depressed mood, anxiety, and altered mental status
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Poor weight gain and failure to thrive in younger children and infants
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Bradycardia, with or without irregular heartbeat
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Signs of dehydration, such as dry mucous membranes, prolonged capillary refill, tenting of skin
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Abdominal pain due to increased gastric acid secretion, constipation, peptic ulcers, or acute pancreatitis
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Hypotonia
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Flank pain due to renal calculi
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Signs of fractures such as bone pain and deformities are more common in neonates with NSHPT
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Normal parathyroid glands as seen during a thyroidectomy. The large arrow points to the superior parathyroid. The thinner arrow points to the inferior parathyroid. The forceps points toward the recurrent laryngeal nerve. The patient's head is toward the right.
Tables
Cause |
Gene |
OMIM |
1. Neonate/Infant |
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|
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- Familial hypocalciuric hypercalcemia |
Heterozygous inactivating CASR mutations |
145980 |
- Neonatal severe hyperparathyroidism |
Homozygous inactivating CASR mutations |
239200 |
|
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- Maternal hypoparathyroidism |
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- Maternal pseudohypoparathyroidism |
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- Maternal Vitamin D deficiency |
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2. Child/adolescent |
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|
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- Sporadic adenomas |
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- Familial |
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* Familial hypocalciuric hypercalcemia (FHH) |
CASR |
145980 |
* Multiple Endocrine Neoplasia type 1 (MEN1) |
MEN1 |
131100 |
* Multiple Endocrine Neoplasia type 2a |
RET |
171400 |
* Multiple Endocrine Neoplasia type 4 |
CDKN1B |
|
* Familial hyperparathyroidism jaw tumor syndrome (HRPT2) |
CDC73 | 145001 |
|
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- Autoantibodies to the CASR |
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|
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- Renal failure/post renal transplant |
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- Chronic hyperphosphatemia |
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- Vitamin D deficiency |
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* Nutritional |
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* Malabsorption |
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-Vitamin D dependent rickets type 1 VDDR1 |
CYP27B1 | 264700 |
|
|
|
- Vitamin D dependent rickets type 2 VDDR2 |
Vitamin D receptor | 277440 |
|
|
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-Other causes of hypocalcemia |
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Poor intake Drugs |
