Pediatrics
Minerals: Iron, Iodine and Calcium
Pediatric minerals for MBBS: iron deficiency anaemia labs and dosing, iodine deficiency disorders, calcium and zinc, mapped to NMC codes PE13.1 to PE13.14.
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Minerals: Iron, Iodine and Calcium
Pediatric minerals for MBBS: iron deficiency anaemia labs and dosing, iodine deficiency disorders, calcium and zinc, mapped to NMC codes PE13.1 to PE13.14.
This chapter covers the key minerals iron, iodine and calcium along with magnesium, zinc, copper, selenium and fluoride, including deficiency states, laboratory diagnosis, treatment and national supplementation programmes. It emphasises iron therapy dosing, iodine deficiency disorders and calcium emergencies.
High-yield: Minerals: Iron, Iodine and Calcium
- Iron deficiency anaemia progresses through iron depletion (low ferritin only), iron-deficient erythropoiesis (low serum iron, high TIBC), and finally frank microcytic hypochromic anaemia.
- The hallmark laboratory pattern of iron deficiency anaemia is low ferritin, low serum iron, high TIBC, low transferrin saturation and elevated RDW.
- A high RDW helps distinguish iron deficiency anaemia from thalassaemia trait, which typically has normal ferritin and normal RDW.
- The oral iron dose is 3 to 6 milligrams per kilogram per day of elemental iron, continued for 3 months after haemoglobin normalises.
- Iron dose is calculated as elemental iron, and ferrous sulphate contains only about 20 percent elemental iron.
- The National Iron Plus Initiative gives 20 mg iron biweekly for 6 to 59 months, 30 mg weekly for 5 to 9 years and 60 mg weekly for 10 to 19 years.
- Endemic cretinism from iodine deficiency has a neurological type (deaf-mutism, spastic diplegia) and a myxoedematous type (short stature, hypothyroid features).
- The NIDDCP targets a median urinary iodine of 100 to 199 micrograms per litre, iodised salt coverage above 90 percent and a total goitre rate below 5 percent.
- Hypocalcaemic tetany is treated with 10 percent calcium gluconate 1 to 2 millilitres per kilogram given slowly intravenously, and magnesium must be checked if calcium fails to correct.
- Trousseau sign is more specific than Chvostek sign for latent tetany.
- Hypercalcaemia shortens the QTc interval and is managed by hydration with normal saline first, then furosemide, never furosemide before hydration.
- Zinc in diarrhoea is given as 10 mg per day under 6 months and 20 mg per day for 6 months to 5 years for 14 days.
- Wilson disease is an ATP7B defect causing copper excess with liver, brain and Kayser-Fleischer ring involvement, while Menkes disease is an ATP7A defect causing copper deficiency with kinky hair.
- Dental fluorosis occurs only during enamel formation from birth to about 8 years, while skeletal fluorosis needs chronic intake over years.
Key mineral facts
- **Oral iron:** 3 to 6 mg/kg/day elemental iron, continued 3 months after Hb normalises.
- **Iron deficiency labs:** Low ferritin, low serum iron, high TIBC, low saturation, high RDW.
- **Zinc in diarrhoea:** 10 mg/day if < 6 months, 20 mg/day if 6 months to 5 years, for 14 days.
- **Hypocalcaemic tetany:** 10% calcium gluconate 1 to 2 mL/kg slow IV; check magnesium.
NMC competencies in this chapter
- **PE13.1:** Iron deficiency anaemia: epidemiology, pathophysiology and clinical features
- **PE13.2:** Laboratory diagnosis of iron deficiency anaemia
- **PE13.3:** Iron therapy: oral, parenteral and transfusion criteria
- **PE13.4:** Iron supplementation programmes: NIPI and weekly iron and folic acid supplementation
- **PE13.5:** Iodine deficiency disorders: goitre, cretinism and spectrum
- **PE13.6:** Iodised salt and the National Iodine Deficiency Disorders Control Programme
- **PE13.7:** Calcium metabolism: requirements, deficiency and hypocalcaemic tetany
- **PE13.9:** Magnesium metabolism: hypomagnesaemia and hypermagnesaemia
- **PE13.10:** Zinc deficiency: acrodermatitis enteropathica and diarrhoea management
- **PE13.11:** Copper metabolism: Wilson disease and Menkes disease
- **PE13.13:** Fluorosis: dental and skeletal
- **PE13.14:** Counselling on mineral-rich foods and dietary sources
Frequently Asked Questions
What is the laboratory pattern of iron deficiency anaemia?
Iron deficiency anaemia shows low serum ferritin, low serum iron, high total iron binding capacity, low transferrin saturation and an elevated red cell distribution width, which distinguishes it from thalassaemia trait that has normal ferritin and RDW.
What is the oral iron dose and duration?
The oral therapeutic dose is 3 to 6 milligrams per kilogram per day of elemental iron, continued for 3 months after the haemoglobin has normalised to replenish stores. Doses are calculated as elemental iron, not as the salt.
How is hypocalcaemic tetany treated?
Hypocalcaemic tetany is treated with 10 percent calcium gluconate 1 to 2 millilitres per kilogram given slowly intravenously with cardiac monitoring. If calcium fails to correct, serum magnesium must be checked because hypomagnesaemia causes refractory hypocalcaemia.
How do Wilson and Menkes disease differ?
Wilson disease is an ATP7B defect causing copper excess with liver disease, neurological signs and Kayser-Fleischer rings, whereas Menkes disease is an ATP7A defect causing copper deficiency with kinky hair and neurodegeneration.
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