15 e-Letters

published between 2019 and 2022

  • 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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