eLetters

29 e-Letters

published between 2017 and 2020

  • Authors response to e-Letter: "Be careful how quickly you correct hyponatraemia"

    Thank you for highlighting the recommendation for avoiding too rapid correction of hyponatraemia and the need for close monitoring of urinary electrolytes. The focus of the article (problem solving in clinical practice) was the differential diagnosis rather than the nuances of management but we agree that regular assessment of urinary electrolytes will help to guide fluid management in the sick hyponatraemic baby. The importance of focusing on urine content as well as blood electrolytes has been an important component of clinical practice in our unit for many years (1).

    In our experience infants recover very quickly after the initial resuscitation and can frequently be fed enterally within a matter of hours. Osmotic demyelination syndrome is very uncommon in paediatric practice (an interesting story in itself) and one wonders whether there are more subtle differences in outcome that can be linked to initial management. The reality (we suspect) is that many hyponatraemic babies are managed without close, detailed regular scrutiny of urinary electrolytes and perhaps this is a topic for further study.

    Dr Smith and Maderazo rightly states that ‘Healthy kidneys can cut urinary sodium losses to almost zero’ however please note that babies with adrenal disorders such as 21-hydroxylase deficiency often require relatively high doses of mineralocorticoid as well as sodium supplements for several months.

    1. Coulthard MG. Will changing maintenance intravenous f...

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  • Vaccine-hesitant parents

    I appreciate as ever the careful encouragement of Helen Bedford and David Elliman about ways to engage with parents hesitant about having their children vaccinated. Implicit throughout the article, but I think worth making explicit, is the importance of building trust between professional and parent(s) around this issue. With this in mind, it is clearer why telling stories, and discussing feelings (for example parents' fears of hurting or harming their children, and professionals' frustration at apparent conflicts of interests that advocates of anti-MMR or anti-vaccine stances may have), can work so well. Those engaging in these conversations may do well to make relationship, feelings and trust the centre points of respectful dialogue with parents who are feeling hesitant about vaccines.

  • Be careful how quickly you correct hyponatraemia

    Dear Sir,

    We read with interest the problem solving article by Tse et al. looking at the management of infants presenting with hyponatraemia plus hyperkalaemia1. They recommend the administration of intravenous 0.9% NaCl to correct hyponatraemia until oral feeds can be given. We are concerned that this protocol will produce a rise in serum [Na+] faster than recommended. The guidance is that once any acute symptoms have been addressed the rise in serum [Na+] should not exceed 8 mmol/L/day in order to minimise the risk of developing Osmotic Demyelination Syndrome (ODS). Certainly the rise should be less than 10-12 mmol/L in any 24-hour period or 18 mmol/L in any 48-hour period2.

    No specific comment is made about the speed of correction of the serum sodium concentration in case 1 other than that there was "gradual resolution of both the hyponatraemia and hypokalaemia". However in case 2 the serum sodium concentration is said to have normalised within 48 hours. The starting sodium concentration was 108 mmol/L and the normal quoted as 133-146 mmol/L so the minimum rate of rise was 12.5 mmol/L/day, exceeding the recommended rate of rise.

    As illustrated by the two cases, these patients usually present with extracellular fluid (ECF) contraction and require replacement of the ECF volume deficit. This should be with a fluid that matches the electrolyte composition of the ECF but we tend to only cater for a normal ECF [Na+] and use 0.9% NaCl. However i...

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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

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