135 e-Letters

  • Figure ammendment: Bone strength in children: understanding basic bone biomechanics

    Dear Editor

    The manuscript, ‘Bone strength in children: understanding basic bone biomechanics’ [1] published in 2015 summarises key paediatric orthopaedic biomechanical concepts well, however, there appears to be an error in Figure 4. The authors state that osteopetrosis leads to more bone mineralisation and therefore an increased extrinsic stiffness, while both ductility and toughness are both reduced. In rickets, they correctly argue that decreased mineralisation leads to increased ductility and consequently higher ultimate displacement at the expense of reduced extrinsic stiffness which therefore decreased the ultimate load needed to fracture bone. These statements are in contradiction to Figure 4, a load-displacement curve comparing osteopetrosis and rickets to normal bone. This figure suggests that it is osteopetrosis which has a decreased ultimate load required to fracture, but greater ductility, compared to normal bone. It also suggests rickets which would have a greater ultimate load before fracture, decreased ductility and increased stiffness compared to normal bone. Figure 4 not only contradicts previous information stated in the paper, for example, extrinsic stiffness is the gradient of the linear region of the force-displacement curve, it also directly contradicts previous literature. Cole et al[2] graphically demonstrates stiffness, ultimate load, ductility and failure on a load-displacement curve for bone. I would suggest that the paper be edited and...

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  • Fifteen-minute consultation: Recognising primary immune deficiencies in children

    Dear Editor,

    We highly appreciate the valuable comments by Lyall and colleagues concerning the importance of congenital HIV as a differential diagnosis in any clinical setting where immunodeficiency is considered. Our paper is focusing on the concept of normality in terms of numbers and severity of infections, and clinical clues to primary immunodeficiency syndromes. Although secondary immunodeficiencies were not within the scope of our paper, we agree that it would have been a great opportunity to raise the awareness regarding the clinical presentation of HIV infection in children.

    Yours sincerely,

    Per Wekell, Olof Hertting, Daniel Holmgren, Anders Fasth

  • Response to "How to interpret polysomnography": A UK Perspective

    We read with interest the article by Leong et al. on the use of polysomnography (PSG) in children (Leong et al. 2019), covering indications for PSG, along with limitations of oximetry, and clearly outlining how to undertake and interpret polysomnography in paediatric patients. It briefly discusses limited channel recordings (respiratory polygraphy, RP) and concludes that this ‘is not standard practice’.

    In many paediatric centres RP is standard practice, and routinely used for assessment of sleep-disordered breathing (SDB) in children, with the most common diagnosis being obstructive sleep apnoea (OSA).

    In a recent survey of 20 United Kingdom and Republic of Ireland paediatric sleep centres (Russo, 2017), all centres reported use of RP for diagnosis of SDB, with 14 centres using this as the main diagnostic method. PSG was performed in 10 centres, contributing a small part of workload (median of total workload: 5% (range: 1%-15%)). The majority of all studies were performed within a hospital setting, with home oximetry/RP use reported in 25% of centres. Indeed, the UK has led the way in home RP (Kingshott 2019). As international leaders in the field acknowledge, ‘the times they are a changing.’ (Gozal 2015)

    RP utilises measures of airflow, respiratory effort by inductance plethysmography bands, oxygen saturation, carbon dioxide and heart rate monitoring. This allows accurate detection and discrimination of obstructive, central and mixed apnoeas/hypop...

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  • HIV is an essential differential in the diagnosis of suspected immune deficiencies

    Dear Editor,

    We read with interest the extensive review of clinical presentations of immunodeficiency in childhood in the Archives Education & Practice October edition, we enjoyed the way that clinical scenarios were presented, most useful for the front line paediatrician.
    However, we were surprised and disappointed that by far the most common single cause of paediatric immunodeficiency and the most important differential diagnosis, congenital HIV infection, was not mentioned at all in the piece.

    This seemed a significant oversight as in the UK, annually there are still 20-30 children per year diagnosed with HIV, either born here, or new arrivals to the country (https://www.ucl.ac.uk/nshpc/) . This is an important differential diagnosis for the infant presenting in respiratory failure with SCID, or the child with invasive pneumococcal disease, or recurrent shingles, or recurrent bacterial infections, or lymphopaenia. More importantly, this is now a highly treatable condition, and early treatment is correlated with the best long term outcomes.

    We hope that your readers may be reminded of this, and will rule out HIV infection, prior to embarking on costly and complex immune investigations.

  • Excellent article, but a slight error in Figure One

    I congratulate Uzuna, Bailie and Murray on an excellent summary of common oncological abdominal masses and an approach for the general paediatrician. Ensuring that children with abdominal masses are correctly identified, investigated and referred by their local paediatrician is crucial, particularly as there is evidence of later diagnosis in the UK compared to other European countries (Pritchard-Jones et al., 2016)

    They note that urinary catecholamines can be a useful rule-in test for suspected neuroblastoma (90% sensitivity). The Childrens Cancer and Leukaemia Group in the UK recommends that all children with a suspected renal tumour should also have urinary catecholamines assessed to reduce the risk of incorrectly treating a neuroblastoma as it may be difficult to determine if a mass is renal or adrenal by imaging alone. Biopsy of renal tumours in young children without features atypical of Wilms tumour is no longer recommended as it rarely changes clinical management, but this approach will only be successful if the child is fully assess for "atypical features", such as raised urinary catecholamines. In my experience there can be a significant wait for urinary catecholamine results and so having a sample sent by the local team is valuable.

    I would also like to highlight a small error in the legend that they have included for the Figure I provided (Figure 1). The National Cancer Registration and Analysis Service does not routinely include all...

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  • A more careful interpretation of meta-regression is required

    I read with interest Dr Rao's commentary on Nath et al.,'s meta-analysis of trials of atraumatic and traditional lumbar puncture needles. This is a high quality paper which complies with PRISMA guidelines for the reporting of systematic reviews and meta-analyses and provides strong evidence for the use of atraumatic needles to reduce the incidence of postdural post puncture headache (PDPH).

    However, Dr Rao is incorrect to state that the subgroup analysis of patients <18 years showed a significant difference in PDPH in this population. In fact the opposite is true as the p-value is >0.05 and the confidence interval for the RR spans 1. Instead Nath et al., show that having pre-specified age as a potential interactor/confounder there is no significant difference in the risk of PDPH for <18yr vs >18yr.

    This is a subtle, but important distinction. First because it is possible the meta-regression was not adequately powered to detect a difference if one is present (a false negative). Second because age is a continous variable and so dichotomising in this way reduces statistical power to detect differences at different ages (e.g. there is a benefit in older children but not in younger children).

    A more accurate interpretation of the study is that it shows that overall atraumatic lumbar puncture needles have lower risk of PDPH and that there is no evidence that this is not the case for patients under 18.

  • Pharmacological treatment of children presenting with psychosis.

    This is a very helpful article describing the approach to children presenting with psychosis in the ED. I welcome the emphasis placed on environmental measures taken to manage agitation, which is especially important for children with Learning Disability and/or neurodevelopmental disorders. Children and young people should always be offered the option of oral medication in the first instance. We have found Promethazine or Lorazepam to be useful if medication is required in the under 12 year olds. For those aged over 12 years they may also be helpful and if necessary could be augmented by Olanzapine, Quetiapine or Risperidone, rather than using Haloperidol in this age group due to its side-effect profile.

  • The Let-Down reflex and milk supply

    The most recent Infant Feeding Survey (2010)1 showed that the most frequently given reasons for stopping breastfeeding in the second week were: insufficient milk (28%) and the baby being ‘too demanding’ or ‘always hungry’ (17%).
    Mothers and those advising them therefore should pay great attention to the milk supply.
    The breast is not a bottle, milk is transferred to the baby by the action of the all-important let-down reflex as the pulses of oxytocin reach the breast alveoli. This reflex governs not only milk delivery (transfer) to the baby but also has a significant role to play in milk production, there are many oxytocin receptors in the milk producing breast alveoli.
    I had looked at the factors affecting the let-down reflex and feeding patterns in the article I wrote for Acta Paediatrica2.
    I agree with Doctors Levene and O’Brien’s comment in Figure 1 that ‘longer feeds may mean baby is not feeding effectively’. We had found (in a different study3) that long feeds seemed to be associated with poor weight gain.

    1Infant Feeding Survey 2010. McAndrew.F. Thompson J. Fellows L et al. The information Centre for Health and Social Care 20.11.12
    2Are we getting the best from breastfeeding. Walshaw C.A. Acta Paediatr 2010 Sept j 99(9) 1292-7 doi 10.1111/j 1651-2227.2010.01812
    3 Does breastfeeding method influence infant weight gain? Walshaw CA. Owens JM. Scally AJ et al Arch Dis Chld 2008 Apr;93(4):292-6

  • Hemihypertrophy

    I was fascinated by the recent article by Catherine Mark et al.
    The clinical approach suggested seems reasonable, however, this will miss a lot more clinical conditions that are/may be associated with hemihypertrophy.1 The list produced in figure 2 is too restrictive.
    The presence of cutaneous malformations and macrocephaly should be sought clinically. These may point towards PIK3CA-Related Segmental Overgrowth.2 3 The UK Genetic Testing Network do offer a gene panel for diagnosis. On occasions because of mosaicism, tissue biopsy may be necessary to clinch the diagnosis.
    New targeted treatment options include the use of mTOR inhibitors like Sirolimus or Everolimus.4


    1. http://www.overgrowthstudy.medschl.cam.ac.uk/for-health-care-professionals/

    2. https://decipher.sanger.ac.uk/gene-disorder/NBK153722#overview

    3. https://www.ncbi.nlm.nih.gov/books/NBK153722/

    4. https://clinicaltrials.gov/ct2/show/NCT02428296

  • Knowledge-Attitude-Practice gap in Breastfeeding Practices

    Dear Editor,
    We read with interest the article by Levene et al on the importance of breastfeeding and ways to improve it. [1] This article meticulously narrates the common barriers and possible solutions for them. It reminds me a famous quote by Keith Hansen “If breastfeeding did not already exist, someone who invented it today would deserve a dual Nobel Prize in medicine and economics”. [2] The Lancet breastfeeding series [3] meticulously calculated the individual as well as global physical, social and economic benefits of the breastfeeding. Despite knowledge about the benefits of the breastfeeding, there is a wide gap in attitude and practice of it. It is one of the paradoxes positive health practice which is more common among the low-income countries than the richer ones. For example, in countries like Rwanda and Sri Lanka, the exclusive breastfeeding rates are as high as 85% and 76% respectively. [3] So, there is something beyond the knowledge alone, i.e. attitude towards breastfeeding which is not stressed much. To bridge this KAP gap for this novel cost-effective investment, we need to work on improving the attitude of mothers as well as healthcare professionals towards breastfeeding. A practical solution will be to do quality improvement studies using PDSA cycles at small scales and identify the barriers at that particular setup. It might be possible that the barriers across the countries are significantly different, in that case, “one model fits all” strateg...

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