Proteinuria this month, babies’ poo, bedwetting and a bit more on paediatric hypertension. Please do leave comments below.
The burns triage tool this month plus a bit on urinalysis (pH) and the start of our decoding the FBC series. Also a reminder about the MAP guideline for management of CMPA in primary care, a link to some good courses on this topic and to a document I have put together on milks to use in the UK for CMPA.
With thanks to Dr Alexandra Briscoe and Professor Irene Roberts for their collaborative work.
The red cell count and haemoglobin (see February 2017 newsletter for normal ranges)
The red cell count is the actual number of red cells per mL of blood, and the haemoglobin (Hb) is the concentration of the Hb protein itself- the oxygen carrying protein.
A raised red cell count due to increased production of red cells is seen in children with chronic hypoxia, such as congenital heart disease and, in neonates, manifests as neonatal polycythaemia, usually due to chronic in utero hypoxia.
During the last 2 months of pregnancy erythropoiesis occurs at a rate of 3-5 x that of adults, consequentially the healthy newborn has a relative polycythaemia compared to infants and children- manifest as a raised Hb, red cell count and haematocrit.
The Hb falls over the first 2-3 months of life in response to several factors- with the onset of respiration at birth- oxygenation increases, erythropoieitin production and erythropoiesis is decreased via negative feedback. Neonatal red blood cells have a shorter half-life of 90 days compared to 120 days for red cells in healthy children and adults. In addition over this time period, neonates undergo rapid growth and weight increase with a subsequent increase in circulatory volume- leading to relative haemodilution. This physiological anaemia requires no intervention in otherwise healthy term infants and will rarely fall below 90g/L.
In contrast, infants born extremely prematurely at <28 weeks of completed gestation, will frequently require red cell transfusion. This is due to anaemia of prematurity. The cause is multifactorial, including low erythropoietin, shortened red cell lifespan, nutritional deficiency and iatrogenic blood letting, however the nadir in Hb occurs earlier (4-8 weeks compared to 8-12 weeks in term babies) and is more severe. Premature red blood cells have a life span of 35-50 days, and infants have a circulating blood volume of 90- 105 mls/kg, which could be as little as 45mls in a 24 week 500g infant. In addition, these infants do not receive maternal iron transfer via the placenta. Preterm infants also have a slow erythropoietin response to hypoxia and anaemia- this is because the site of production of erythropoietin is the liver rather than the kidney as per term infants. There is also evidence of increased metabolism of EPO in the preterm infant. (Strauss, 2010). Despite multiple studies into the use of exogenous erythropoietin for preterm infants, current guidelines recommend red cell transfusion for the management of anaemia of prematurity.
Ronald G. Strauss, Anaemia of prematurity: Pathophysiology and treatment, Blood Reviews, Volume 24, Issue 6, November 2010, Pages 221-225, ISSN 0268-960X, http://dx.doi.org/10.1016/j.blre.2010.08.001.
Vitamin D deficiency in children with thanks to Dr Jini Haldar, paediatric registrar at Whipps Cross University Hospital.
Vitamin D is an essential nutrient needed for healthy bones, and to control the amount of calcium in our blood. There is recent evidence that it may prevent many other diseases. There are many different recommendations for the prevention, detection and treatment of Vitamin D deficiency in the UK. The one outlined below is what we tend to do at Whipps Cross Hospital.
The Department of Health and the Chief Medical Officers recommend a dose of 7-8.5 micrograms (approx. 300 units) for all children from six months to five years of age. This is the dose that the NHS ‘Healthy Start’ vitamin drops provide. The British Paediatric and Adolescent Bone Group’s recommendation is that exclusively breastfed infants receive Vitamin D supplements from soon after birth. Adverse effects of Vitamin D overdose are rare but care should be taken with multivitamin preparations as Vitamin A toxicity is a concern. Multivitamin preparations often contain a surprisingly low dose of Vitamin D.
Indications for measurement of vitamin D
1. Symptoms and signs of rickets/osteomalacia
- Progressive bowing deformity of legs
- Waddling gait
- Abnormal knock knee deformity (intermalleolar distance > 5 cm)
- Swelling of wrists and costochondral junctions (rachitic rosary)
- Prolonged bone pain (>3 months duration)
2. Symptoms and signs of muscle weakness
- Cardiomyopathy in an infant
- Delayed walking
- Difficulty climbing stairs
3. Abnormal bone profile or x-rays
- Low plasma calcium or phosphate
- Raised alkaline phosphatase
- Osteopenia or changes of rickets on x-ray
- Pathological fractures
4. Disorders impacting on vitamin D metabolism
- Chronic renal failure
- Chronic liver disease
- Malabsorption syndromes, for example, cystic fibrosis, Crohn’s disease, coeliac disease
- Older anticonvulsants, for example, phenobarbitone, phenytoin, carbamazepine
5. Children with bone disease in whom correcting vitamin D deficiency prior to specific treatment would be indicated:
- Osteogenesis imperfecta
- Idiopathic juvenile osteoporosis
- Osteoporosis secondary to glucocorticoids, inflammatory disorders, immobility
Symptoms and signs in children of vitamin D deficiency
1. Infants: Seizures, tetany and cardiomyopathy
2. Children: Aches and pains: myopathy causing delayed walking; rickets with bowed legs, knock knees, poor growth and muscle weakness
3. Adolescents: Aches and pains, muscle weakness, bone changes of rickets or osteomalacia
Risk factors for reduced vitamin D levels include:
- Dark/pigmented skin colour e.g. black, Asian populations
- Routine use of sun protection factor 15 and above as this blocks 99% of vitamin D synthesis
- Reduced skin exposure e.g. for cultural reasons (clothing)
- Latitude (In the UK, there is no radiation of appropriate wavelength between October and March)
- Chronic ill health with prolonged hospital admissions e.g. oncology patients
- Children and adolescents with disabilities which limit the time they spend outside
- Institutionalised individuals
- Photosensitive skin conditions
- Reduced vitamin D intake
- Maternal vitamin D deficiency
- Infants that are exclusively breast fed
- Dietary habits – low intake of foods containing vitamin D
- Abnormal vitamin D metabolism, abnormal gut function, malabsorption or short bowel syndrome
- Chronic liver or renal disease
Management depends on the patient’s characteristics:
A. No risk factors
No investigations, lifestyle advice* and consider prevention of risk factors
B. Risk Factors Only
1. Children under the age of 5 years: Lifestyle advice* and vitamin D supplementation.
Purchase OTC or via Healthy Start
Under 1 year: 200 units vitamin D once daily
1 – 4 years: 400 units vitamin D once daily
2. Children 5 years and over – offer lifestyle advice*
C. Risk Factors AND Symptoms, Signs
- Renal function, Calcium, Phosphate, Magnesium (infants), alkaline phosphatase,
- 25-OH Vitamin D levels, Urea and electrolytes, parathyroid hormone
Children can be managed in Primary Care as long as:
- No significant renal impairment
- Normal calcium (If <2.1 mmol/l in infants, refer as there is a risk of seizures)
If further assessment is required consider referral to specialist. **
Patient’s family is likely to have similar risk of Vitamin D deficiency – consider investigation ant treatment if necessary.
*Life style advice
Exposure of face, arms and legs for 5-10 mins (15-25 mins if dark pigmented skin) would provide good source of Vitamin D. In the UK April to September between 11am and 3pm will provide the best source of UVB. Application of sunscreen will reduce the Vitamin D synthesis by >95%. Advise to avoid sunscreen for the first 20-30 minutes of sunlight exposure. Persons wearing traditional black clothing can be advised to have sunlight exposure of face, arms and legs in the privacy of their garden.
Vitamin D can be obtained from dietary sources (salmon, mackerel, tuna, egg yolk), fortified foods (cow, soy or rice milk) and supplements. There are no plant sources that provide a significant amount of Vitamin D naturally.
**Criteria for referral
- Criteria for management in primary care not met
- Deficiency established with absence of known risk factors
- Atypical biochemistry (persistent hypophosphatemia, elevated creatinine)
- Failure to reduce alkaline phosphatase levels within 3 months
- Family history (parent, siblings) with severe rickets
- Infants under one month with calcium <2.1mmmol/l at diagnosis as risk of seizure. (Check vitamin D level of mothers in this group immediately and treat, particularly if breast feeding.)
- If compliance issues are anticipated or encountered during treatment.
- Satisfactory levels of vitamin D not achieved after initial treatment.
Vitamin D levels, effects on health and management of deficiency
|< 25 nmol/l (10micrograms/l)||Deficient. Associated with rickets, osteomalacia||Treat with high dose vitamin D
Lifestyle advice AND vitamin D (ideally cholecalciferol)
• 0 – 6 months: 3,000 units daily
• 6 months – 12 yrs: 6,000 units daily
• 12 – 18 yrs: 10,000 units daily
|vitamin D 25 – 50 nmol/l (10 – 20micrograms/l||Insufficient and associated with disease risk||Over the counter (OTC) Vitamin D supplementation (and maintenance therapy following treatment for deficiency) should be sufficient.
• Lifestyle advice and vitamin D supplementation
< 6 months: 200 – 400 units daily (200 units may be inadequate for breastfed babies)
Over 6 months – 18 years: 400 – 800 units daily
|50 – 75 nmol/l (20 – 30micrograms/l)||Adequate||Healthy Lifestyle advice|
|> 75 nmol/l (30 micrograms/l)||Optimal Healthy||None|
Course length is 8 – 12 weeks followed by maintenance therapy.
Checking of levels again
As Vitamin D has a relatively long half-life levels will take approximately 6 months to reach a steady state after a loading dose or on maintenance therapy. Check serum calcium levels at 3 months and 6 months, and 25 – OHD repeat at 6 months. Review the need for maintenance treatment. NB: the Barts Health management protocol uses lower treatment doses for a minimum of 3 months and then there is no need for repeat blood tests in the majority of cases of children satisfying the criteria for management in primary care.
Serum 25 OHD after 3 months treatment Action
|>80nmol/ml||Recommend OTC prophylaxis and lifestyle advice||as required|
|50 – 80 nmol/mL||Continue with current treatment dose||reassess in 3 months|
|< 50 nmol/mL||Increase dose or, in case of non-adherence/concern refer to secondary care.|
It is essential to check the child has a sufficient dietary calcium intake and that a maintenance vitamin D dose follows the treatment dose and is continued long term.
Some recommend a clinical review a month after treatment starts, asking to see all vitamin and drug bottles. A blood test can be repeated then, if it is not clear that sufficient vitamin has been taken.
Current advice for children who have had symptomatic Vitamin D deficiency is that they continue a maintenance prevention dose at least until they stop growing. Dosing regimens vary and clinical evidence is weak in this area. The RCPCH has called for research to be conducted. The RCPCH advice on vitamin D is at http://www.rcpch.ac.uk/system/files/protected/page/vitdguidancedraftspreads%20FINAL%20for%20website.pdf
We have seen a lot of cases of scarlet fever this year so thanks to Dr Lock for his text box this month on recognising and managing this strep infection. Comprehensive information on paediatric dizziness from Mr Sharma, ENT registrar, and a bit about asthma in schools and some of my own CPD on birthmarks caused by a Mum whose view that the internet knew more than me was a little unsettling – for a while. We have all been there, I’m sure.
Do leave comments below.