Hypoparathyroidism and Digeorge Syndrome
Endocrinology and Diabetes Clinic Disorders of Calcium 4480 Oak Street, Vancouver, BC V6H 3V4 604-875-2117 1-888-300-3088 x2117 and Phosphorus http://endodiab.bcchildrens.ca
Hypoparathyroidism the parathyroid cells. The body has developed cells that destroy some of its Hypoparathyroidism occurs when the body own tissue. This may include other does not produce enough parathyroid organs and endocrine glands, causing hormone (PTH). This hormone is made in 4 type 1 diabetes, Addison disease or or 5 parathyroid glands, located behind the other autoimmune diseases. thyroid tissue in the neck area. They are 2. Surgery or radiation to the thyroid gland very small—the size of peas. Their only job which damages the parathyroid glands. is to produce PTH, which keeps the calcium levels in the blood in the right range. 3. Iron deposits in the parathyroid glands, a side-effect of repeated transfusions to The name “hypo-parathyroid-ism”, means a treat thalassemia or other blood condition of low parathyroid hormone. diseases
What does PTH do? How is hypoparathyroidism diagnosed? PTH balances the calcium level in the blood, keeping it in the right range. When the Something will have happened to make your calcium level is low, PTH is produced and it doctor request special blood tests. Perhaps raises the calcium level by: a heart problem is discovered during a routine pregnancy ultrasound or at birth, or 1. Moving calcium from the bones into the perhaps your baby or child became very sick blood. with symptoms of low blood calcium (see 2. Decreasing how much calcium is handout Disorders of Calcium and eliminated from the blood into the urine Phosphorus). Blood tests will be taken, and by the kidneys. if the tests confirm low calcium and PTH 3. Activating vitamin D to increase the levels in the blood, the diagnosis of amount of calcium and phosphorus hypoparathyroidism is made. There is no absorbed from the intestines into the easy way to scan the parathyroid glands. bloodstream. How is hypoparathyroidism treated? What causes hypoparathyroidism? The parathyroid hormone is generally not In some situations, hypoparathyroidism is replaced—it is an extremely expensive present from birth (congenital), such as medication and must be given by injection. occurs with DiGeorge syndrome and other The low calcium level is treated by taking rare inherited conditions (see next section). calcium pills or liquid. However, the calcium In others, hypoparathyroidism develops later itself will not be absorbed into the digestive in life as an acquired condition. system unless the activated form of vitamin D is taken as well. Both calcium and the Acquired hypoparathyroidism can be a result activated form of vitamin D, calcitriol of: (Rocaltrol®) or alfacalcidol (One-Alpha®), must be replaced in just the right amounts 1. An autoimmune process which destroys (see Appendix). The calcium must be taken
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frequently, possibly four times each day. If affected child has congenital the child isn’t taking enough calcium, the hypoparathyroidism, with low calcium and level can become so low that the child PTH levels. becomes extremely sick with seizures. This is an emergency, and the calcium will need Dr. Angelo DiGeorge, an to be given by intravenous. endocrinologist in Philadelphia, was the Blood and urine tests must be done first doctor to describe a group of frequently at first (daily or weekly) to be sure patients with these characteristics. that the calcium level is in the right range. This was reported in the mid 1960’s. Even after doses are just right, tests will be done every 2–3 months. Urine tests for What other problems can be seen calcium will show if extra calcium is being in DiGeorge syndrome? flushed from the body through the kidneys into the urine. Extra calcium and activated Other midline parts of the body may not be vitamin D can be harmful, as they can lead formed normally in DiGeorge syndrome. to side-effects such as calcium deposits in These can include: the kidneys (called nephrocalcinosis) or even calcium deposits in the blood vessels. 1. The roof of the mouth, leading to cleft Ultrasound scans of the kidneys may be palate with feeding, hearing and speech recommended every year or two to watch for difficulties. this problem. 2. The heart, leading to a number of serious cardiac malformations. Hypoparathyroidism is almost always a permanent condition, but it tends to be most 3. The thymus (an organ that assists the difficult to treat during periods of rapid bone body with immunity), leading to repeated growth, for example, during infancy and serious infections. during puberty. 4. Learning difficulties, particularly with math and conceptual thinking. There are many reasons for low 5. Certain facial features are characteristic calcium. of DiGeorge syndrome: small, wide-set eyes; small, cup-shaped, low-set ears; Regardless of cause, the small lower jaw; and a blunted nose with treatment is usually the same a bulbous tip.
DiGeorge syndrome As a result, many children with DiGeorge syndrome are often followed by a number of DiGeorge syndrome is also known as specialists (craniofacial experts, speech chromosome 22q11.2 deletion syndrome, or therapists, cardiologists, and CATCH-22. The velocardiofacial or immunologists). There are also specialists in Shprintzen syndrome is a closely related non-verbal learning disorders (NVLD) who condition. In DiGeorge syndrome, a small can offer guidance for the child having genetic area is missing from chromosome school problems. It is important to know that 22. This area is responsible for some midline DiGeorge syndrome is quite variable from development when the baby isn’t born yet— child to child. in fact very early in development— between the 2nd and 10th weeks. When this midline
development does not occur properly, the parathyroid glands are not formed. As a result, there is no PTH production, and the
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How is DiGeorge syndrome Q: Can I change my child’s calcium to a diagnosed? cheaper product?
When DiGeorge syndrome is suspected A: Talk with your doctor and pharmacist before clinically, the diagnosis can be confirmed by making a change. Each calcium product (see Appendix) has a different amount of a DNA test. elemental calcium. Some products have a low percentage of elemental calcium, and How is DiGeorge syndrome treated? your child would have to take a large amount. Some products may have more The low calcium levels in DiGeorge side-effects, such as diarrhea. syndrome are treated the same as for simple The calcium that your child takes has to be hypoparathyroidism (see above), using given 4 times each day, before each meal calcium supplementation and either calcitriol and at bedtime, to provide the body with a (Rocaltrol®) or alfacalcidol (One-Alpha®). steady supply of calcium. It cannot be taken all at one time. Is DiGeorge syndrome hereditary? Q: My baby seems very fussy after I give In some cases, DiGeorge syndrome is familial her calcium. (inherited from one parent), but in many cases, it happens by chance. If this is A: Some forms of calcium may be upsetting suspected, your child’s doctor can refer your the stomach. Give the calcium as part of the family to a Medical Geneticist for further feeding, not at the very beginning. It is also evaluation and counselling. possible that your baby has a lax muscular Note: Since DiGeorge syndrome can connection between the esophagus (the food include so many possible aspects, you pipe) and the stomach, allowing the acid may want to start a binder to collect the stomach contents to come up into the information. It is very hard to remember esophagus. This is called reflux. Your doctor so many specialists and so much may recommend a medication for this. information. Q: Can I use non- prescription vitamin Questions from families D instead of calcitriol (Rocaltrol®) or alfacalcidol (One-Alpha®)? Q: How do you give calcium to a baby? A: No! Vitamin D from the drugstore doesn’t A: There are many forms of calcium which may work in the body until is turned into the activated be used (see Appendix). Your doctor is form of vitamin D. Because of his or her medical planning to give your child a certain amount condition, your child’s body is not able to convert of elemental calcium per day. vitamin D into the activated form. Calcium may be in a pre-mixed solution. NOTE THE INFORMATION ON THE Q: My son is booked for a surgical CONTAINER AND SHAKE WELL IF procedure soon. I’ve been told he should INSTRUCTED. This means shaking hard for have nothing to eat or drink before the 2–3 minutes while watching the clock. surgery. Does this include the calcium Otherwise, the calcium settles out, and you are giving your child less than the and calcitriol (Rocaltrol®) or alfacalcidol recommended dose. (One-Alpha®)? Calcium may be in the form of antacid tablets A: Speak with your endocrinologist about such as Tums®. Cut the tablet to the required this— it can be dangerous to miss any doses. If size, crush and dissolve in milk or formula.
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the calcium level drops too low, the surgery will Websites and support groups for be cancelled. Often the doctor recommends taking all doses of medication with just a tiny sip disorders of calcium and phosphorus of water. The Hypoparathyroidism Association: Q: What should I do if my child is http://www.hypoparathyroidism.org vomiting and can’t keep his medicine Endocrine Web: Hypoparathyroidism: down? http://www.endocrineweb.com/hypopara.html 22qfamiliesbc (blog) A: Since it can be dangerous to miss doses, http://22qfamiliesbc.blogspot.ca/ you should speak to your endocrinologist about this. 22q11.2 Society http://www.22qsociety.org/ Q: I don’t like giving my child medicine. The Dalglish Family 22q Clinic (for Can I give her a special diet instead of adults, Toronto) the calcium and Rocaltrol® or One- http://www.22q.ca/ Alpha®? The 22q and You Center (Philadelphia): http://www.chop.edu/centers-programs/22q- A: Every day a child’s body needs calcium— between 700 and 1300 milligrams a day. While it and- you-center remains important to have a diet with lots of 22q Central calcium (dairy products, fortified soy milk, and http://www.22qcentral.com green vegetables), that unfortunately won’t be enough for your child, because her body cannot Chromosome 22 Central: VCFS absorb calcium normally. Much of calcium in the http://www.c22c.org/vcfs.htm foods she eats is lost through the digestive International 22q11.2 Deletion Syndrome system, and so she needs supplements as well. One of the activated forms of vitamin D, either Foundation, Inc.: calcitriol (Rocaltrol®) or alfacalcidol (One- http://www.22q.org Alpha®), is also needed in order for the calcium HealthLink BC: Food Sources of Calcium from the diet and from supplements to be and Vitamin D: absorbed by the digestive system. https://www.healthlinkbc.ca/healthlinkbc- files/sources-calcium-vitamin-d As you can see, the process of treating your growing child with a disorder of calcium or Medic Alert Canada: phosphorus involves taking medications http://www.medicalert.ca regularly and checking blood and urine to be sure the amounts are right for her. At first, it will More links are available from the take a lot of care, but soon it will become part of BC Children’s Hospital Endocrinology & your everyday life, and you will be able to enjoy Diabetes Unit: your child for the unique child that he or she is. http://endodiab.bcchildrens.ca
Children with low blood calcium levels should wear a Medic Alert bracelet, to tell emergency personnel about potential calcium deficiency.
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Appendix
Selected Canadian Calcium Products Normal Levels of Common Lab Tests for a Child 6–12 Months of Age* Elemental Generic Name / Brand Name Test Normal Range Calcium Tums® Regular 500 mg 200 mg/tab calcium* 1.87–2.50 mmol/L Tums® Extra Strength 750 mg 300 mg/tab ionized calcium* 1.10–1.30 mmol/L Tums® Ultra Strength 1000 mg 400 mg/tab phosphorus* 1.29–2.58 mmol/L magnesium* 0.78–1.03 mmol/L Viactiv® Chews 500 mg/chew intact PTH 1.0–5.5 pmol/L BCCH Pharmacy suspension 80 mg/mL alkaline phosphatase 110–320 U/L Note: The regular Tums® tablet, for example, is called Tums® 500 mg. Since calcium carbonate is 25-hydroxy-vitamin D 25–110 nmol/L 40% elemental calcium, Tums® 500 mg actually 1,25-dihydroxy-vitamin D 40–190 nmol/L contains only 200 mg of elemental calcium. urinary calcium/creatine ratio* <1.69 mmol/mmol
*Normal levels vary depending on the age of the child and the lab method used. Canadian Vitamin D Products
Generic Name Trade Name and Dosages
Available Canadian Phosphorus Products Multivitamins: most contain 400 IU Trade Name and Generic Name Supplements: usually 400 IU or Dosage Available Cholecalciferol 1000 IU JAMP-Sodium Phosphate (vitamin D3) • Baby Ddrops®: 400 IU/drop Sodium phosphate fizzy tablets: 500 mg or • Kids Ddrops®: 400 IU/drop monobasic 16.1 mmol elemental • Adult Ddrops®: 1000 IU/drop phosphorus per tab One-Alpha®: Alfacalcidol • 0.25-microgram capsules Phoslax® oral solution, (1-hydroxy- • 1-microgram capsules Sodium phosphate 45-mL bottle: 129 mg or monobasic, dibasic 4.15 mmol elemental vitamin D) • 2 microgram/mL (0.1 phosphorus per mL microgram/drop) Calcitriol Rocaltrol®: Potassium phosphate K-Phos® Original (1,25-dihydroxy- • 0.25-microgram capsules monobasic 500-mg tabs: 114 mg or vitamin D) • 0.5-microgram capsules (Health Canada Special 3.68 mmol elemental Access Programme) phosphorus per tab Potassium Phosphates Injection USP, 50-mL Potassium phosphate vial: 93 mg or 3.0 mmol monobasic, dibasic elemental phosphorus per mL
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