132 e-Letters

  • History must not be allowed to repeat itself

    In order to avoid repetition of the mistakes that have been made in the ascertainment of asymptomatic status in adults who might have COVID-19 infection(1) healthcare practitioners in paediatrics must ascertain the full currently known range of COVID-19 symptoms before a child is declared to be asymptomatic. In the event of an oligosymptomatic or monosymptomatic clinical presentation each of those children with sparse or atypical symptoms should be fully followed up to ascertain if the "stand alone" symptoms are "joined" by new symptoms or whether the oligosymptomatic status persists throughout the course of that child's illness.
    Finally, in conformity with the principles of Bayes' Theorem, frontline healthcare workers should be issued with a nomogram spelling out the post test probability of COVID-19 infection(2) in the event of a negative RT-PCR test result. The nomogram should be the subject of regular re-evaluation and updating, on the basis of new information about the authenticity of new symptoms reportedly associated with COVID-19.
    I have no funding and no conflict of interest
    (1) Saurabh S., Vohra S
    What should be the criteria for determining asymptomatic status in COVID-19
    QJMed 2020;doi.org/10.1093/qjmed/hcab002 Article in Press
    (2) Chan GM
    Bayes theorem, Covid-19, and screening tests
    Amer J Emerg Med 2020;38:2011-2013

  • It is still an apprenticeship

    Dear Sir,
    Mulholland et al. make some very important points but I think understate the importance of bedside teaching. The only learning that ever stuck with me as a junior doctor was when it took place in relation to a clinical scenario involving a patient. Nothing has hurt training more than the reduction in exposure to patients either as in-patients or in the out-patient setting. It is an unavoidable consequence of the reduction in working hours but the feedback trainers give to trainees when reviewing patients is still the most important part of their learning. The only problem now is that the trainee is probably not rostered on for the next week.
    The importance of this patient interaction is highlighted by the fact that undergraduates are now learning their basic anatomy, physiology etc. in the context of clinical scenarios and meeting real patients. This is a major step forward for undergraduate training and something I am very pleased to be involved in. Unfortunately, in my opinion, post graduate training has gone in the opposite direction and there is not a lot we can do about it other than increasing the length of training programs. The way we now work means that trainees see fewer patients and therefore learn more slowly. We can organise as many study days as we like but it does not compensate for that loss.

  • Be careful about using normal saline as maintenance fluid.

    There is a section on short-term management in the original article and I think it needs correcting. Currently the opening statment is: "Following initial fluid resuscitation, maintenance fluid was continued as normal saline with 5% dextrose infusion at a rate of 100 mL/kg/day." This will lead to too rapid a correction of serum sodium concentration and I would recommend starting with 0.45% saline following the bolus normal saline that will have appropriately been given as resuscitation fluid. The composition of the maintenance fluid can then be adjusted based on urine sodium results. It is improtant to impress on the laboratory that the results are needed urgently.

  • Skeletal Surveys in a District General Hospital - coming from the opposite direction.

    We read this paper with great interest. We have been investigating the use of skeletal surveys in our hospital and have come to an entirely different conclusion due to very different results. We have collected data over 13 years during which time 117 skeletal surveys were undertaken as part of the investigation into possible non accidental injury (NAI). We only detected additional fractures in 4 cases each of which presented with significant risk factors -E.g. multiple injuries, very young age, rib fractures. We have been concerned that the number of SS undertaken with a negative result suggests that we have been overusing this investigation.

    Our results reflect a fairly liberal interpretation of the RCPCH guidance that 'when physical abuse is suspected, thorough investigation to exclude occult injury is required' 1. In practice most children under 2 presenting with any unexplained injury will have a skeletal survey.

    As with every investigation we need to decide what levels of sensitivity and specificity are realistically obtainable, if every skeletal survey that we do shows additional fractures we are clearly not doing enough, but if they are only detected occasionally we are probably doing too many.

    It is likely that the use of SS is variable across the country, and perhaps a national review of practice and outcomes would allow us to to produce more clear instructions - as highlighted in this paper to determine which children need a s...

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  • 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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  • 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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