Benign enlargement of the subarachnoid space in infancy (BESS)

Case history: a 5-month-old boy was referred to clinic because his head circumference had jumped from below the 25th to the 75th centile and his GP felt that he had a prominent anterior fontanelle. He was developmentally normal with some noticeable frontal bossing. There had been concerns about his mother having had “hydrocephalus” when she was a baby.

Benign enlargement of the subarachnoid space in infancy (BESS)

  • usually involves the frontal lobe subarachnoid spaces
  • characterised clinically by a widened fontanelle, macrocephaly and/or frontal bossing
  • M > F
  • often a family history
  • majority are neurodevelopmentally normal
  • head circumference climbs through the centiles, plateauing on one of the top 2 centiles in late infancy
  • unclear pathophysiology
  • a transient accumulation of cerebrospinal fluid in the frontal region or delayed development or function of the arachnoid villi at the sagittal sinus?
  • cranial ultrasound / MRI show extra fluid around the brain frontally but no ventricular enlargement
  • There’s a more scientific and detailed radiological description at https://radiopaedia.org/articles/benign-enlargement-of-the-subarachnoid-space-in-infancy
  • can be complicated by chronic subdural haemorrhage possibly secondary to the stretching of subdural veins (Papasian, 2000)
  • type 1 glutaric aciduria also presents with increasing head size but these children are not developmentally normal and have other signs on their cranial imaging (Biswas, 2016)
  • more information at J Pediatr Neurosci. 2014 May-Aug; 9(2): 129–131 although I’m not convinced of the need for the follow up imaging advocated here, especially if it requires a general anaesthetic
  • The literature suggests that BESS resolves spontaneously by 2 years.
  • The macrocephaly is likely to persist

The head circumference of the baby presented above plateaued between the top 2 centiles at 10 months. He remains neurodevelopmentally normal.

Picture courtesy of Dr Abdel-Rahman Abdel-Halim, from the case https://radiopaedia.org/cases/29

Safeguarding: Run, Hide, Tell

With thanks to Nicci Wotton, safeguarding nurse consultant at Imperial College NHS Trust  for this month’s safeguarding item.
Today’s children are used to filming their lives and sharing with their friends via Snapchat, Instagram etc. Let children know what to do in the
event of a terrorist attack – 5 simple actions:
  1. Run to a place of safety
  2. Hide
  3. Turn your phone onto silent
  4. Turn off vibrate
  5. Only when safe call police on 999

Lyme Disease

The sun’s come out here in the UK and people are venturing into forests for picnics. Timely then for NICE to spoil the fun and publish its guideline on Lyme Disease (NG95, April 2018)
  • Caused by a tick-borne spirochaete of the Borrelia species, which is spread by a bite from  an infected tick
  • Ticks live in many woodland and grassy areas but only a small number carry the bacteria that causes Lyme disease
  • 2,000 to 3,000 diagnoses each year in England and Wales.
  • erythema migrans rash, examples here.
  • Flu-like symptoms to start with. Other symptoms include migratory inflammatory arthritis, uveitis, pain or numbness, trouble with memory, heart block, pericarditis
  • ELISA and immunospot testing are used for diagnosis but false negatives are possible especially in first 4 weeks
  • Treated with doxycycline or amoxicillin
Distribution map of UK cases here as part of a 2017 paper in Brit JGP on Lyme disease as a cause of Bell’s palsy in children as well as adults.

Should I treat an incidentally found high ASOT in a well child?

Antistreptolysin O is an antibody produced by Group A streptococci (GAS). Levels rise 1 – 4 weeks after an infection, peak between week 3 and 5 and may remain detectable for a few weeks after an infection. >200 is abnormal in adults, opinions differ in the literature as to whether children should have the same cut off but most clinicians use this number for everyone.
ASOT does not predict which people will get complications of GAS eg. rheumatic fever, glomerulonephritis. Click here to comment and join the discussion on when ASOT should be measured and what to do with the result

Viral Gastoenteritis: Could it be Cyclical Vomiting?

Children above the age of 5 in the UK can usually cope with viral gastroenteritis without needing medical input. They vomit a few times, move on to the diarrhoeal stage, get thirsty and a bit dehydrated and start drinking just as it all stops, thereby successfully rehydrating themselves and getting on with their lives.  So if a vomiting 9 year old is brought to us by a parent who says they’ve been admitted 4 times before for iv fluids , it is probably worth taking a closer look. The shocked, prostrate child we saw in the ED this weekend (a re-presentation) may have cyclical vomiting. More information about this here. Early treatment with anti-emetics and benzodiazepines may help avoid the need for iv fluids.

table showing stages of cyclical vomiting and therapies
Cyclical Vomiting
Schematic representation of the four phases of Cyclic Vomiting Syndrome and their therapeutic goals. Fleisher et al. BMC Medicine 2005 3:20 doi:10.1186/1741-7015-3-20 Li BUK et al. North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition Consensus Statement on the Diagnosis and Management of Cyclic Vomiting Syndrome. Journal of Pediatric Gastroenterology and Nutrition 2008; 47 : 379–393 (full text, doses etc.)

May 2018 newsletter published

Cyclical vomiting this month as the message from the front line, BESS as a learning point for those monitoring the size of an infant’s head, milia also for the babies and the perennial problem of whether or not montelukast works to control episodic wheeze.  Do leave comments below:

April 2018 newsletter uploaded

NICE on Lyme disease this month – just in time for the weather to pick up and the tics to start biting.  Also a reminder on the risk factors for SIDS, what to do in a terrorist attack, how to manage a child with a non-blanching rash and a discussion on the use of the antistreptolysin O titre.  Do leave comments below:

Late night musings on ASOT

A patient was referred to me in the paediatric cardiology clinic because of a risk that he may have had missed Kawasaki’s disease a couple of weeks earlier and was therefore at risk of having coronary artery aneurysms.  The referring doctor had carried out an antistreptolysin O titer (ASOT) in case the symptoms of a red, sore mouth, rash and later peeling fingers had been secondary to a streptococcal infection rather than KD.  The result came back as 400units/ml (normal is < 200units/ml).  The child was very well when I saw him and had a normal echocardiogram.  What should I do with the elevated ASOT result?

I needed a quick text box as a gap filler for the April edition of the Paediatric Pearls newsletter and thought ASOT results would be a suitable topic but, when I sat down to write it, I opened up a can of worms.  No one really knows what to do with high ASOTs in a well child.  In fact, authors can’t even agree on whether 400 is elevated in a young person.

My reading list is at the foot of this article.  Salient points from these sources are summarised below.

  • The ASOT is ordered primarily to determine whether a previous group A Streptococcus infection has caused a poststreptococcal complication, such as rheumatic fever or glomerulonephritis.  So the start point should be on-going clinical symptoms of strep infection or the effect of a recent infection.  If used in this way, it can be a useful pointer to a causative organism and will guide management.  Rheumatic fever is treated with long term antibiotics.  The ASO test does not predict whether complications will occur following a strep infection, nor does it predict the type or severity of the disease. If symptoms of rheumatic fever or glomerulonephritis are present, an elevated ASO level may be used to help confirm the diagnosis.
  • ASO antibodies are produced a week to a month after an initial strep infection. The amount of ASO antibody (titer) peaks at 3 to 5 weeks after the illness and then tapers off but may remain detectable for several months after the strep infection has resolved.
  • A negative ASO or ASO that is present at very low titers means the person tested most likely has not had a recent strep infection. This is especially true if a sample taken 10 to 14 days later is also negative (low titer of antibody) and if an anti-DNase B test is also negative (low titer of antibody). A small percentage of people with a complication related to a strep infection will not have an elevated ASO. This is especially true with glomerulonephritis that may develop after a skin strep infection.
  • An elevated titer of antibody (positive ASO) or an ASO titer that is rising means that it is likely that the person tested has had a recent strep infection. ASO titers that are initially high and then decline suggest that an infection has occurred and may be resolving.

My conclusion at the end of reading about ASOT and the management of streptococcal infections and complications is that I should only do the ASOT if the child is symptomatic.  If I think they have rheumatic fever, I should treat with antibiotics for a long time (up to 10 years in some cases).  If they do not satisfy the Jones criteria for rheumatic fever and indeed are well now, I do not need to blindly treat an elevated ASOT but it may be prudent to repeat the test a couple of weeks later to ensure it is dropping.

Very good summary article on rheumatic fever: https://patient.info/doctor/rheumatic-fever-pro

Why treat sore throats at all? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1949249/

Cochrane on short term antibiotics: https://www.ncbi.nlm.nih.gov/pubmed/22895944

https://www.annemergmed.com/article/S0196-0644(13)01448-0/fulltext on same topic

https://www.uptodate.com/contents/treatment-and-prevention-of-streptococcal-pharyngitis

March 2018 PDF in time for Easter

NICE on faltering growth this month, paediatric stroke, a reminder of the new epilepsy classification and a contribution from the safeguarding team on what constitutes a “legal high”?  Do leave comments below:

Epilepsy classification changes again…

Actually the classification of seizures changed in July 2017 but I’ve only just been brought up to date by Emily O’Connor, a medical student who writes blog posts for Paediatric Pearls.  Here is her article:

In 2017 the International League Against Epilepsy revised their classification of seizure types, with the aim of creating greater flexibility, accuracy and transparency in the naming of seizures. Below, is a brief guide to applying this new approach to classification and a summary of the changes in terminology.

The new approach can be applied by asking two or three questions about the seizure:

  1. Where was the onset of the seizure?
    • It could be: focal/generalised/focal to bilateral/unknown
  2. What was the patient’s level of awareness during the seizure?FOR FOCAL SEIZURES ONLY
    • It could be: focal aware/focal impaired awareness
  3. What was the first prominent sign or symptom of the seizure?
    • It could be: motor/non-motor
    • This can then be further classified according to the specific symptom

This new classification system for seizures has led to a change in some of the traditional terminology used to describe seizure types, the below table shows a summary of these changes:

Traditional/‘Obsolete’ Term New/‘Replacement’ Term
Partial seizure Focal seizure
Simple partial seizure Focal aware seizure
Complex partial/Dyscognitive seizure Focal impaired awareness seizure
Psychic seizure Cognitive seizure
Primary generalised seizure Generalised seizure
Secondary generalised seizure Focal to bilateral tonic-clonic seizure

 

For more information on the ILEA 2017 classification system, please see the below references:

1.       Fisher et al. Operational classification of seizure types by the International League Against Epilepsy: Position Paper of the ILAE Commission for Classification and Terminology. Epilepsia. 2017. 58. 4. 522-530.

2.       Epilepsy Foundation of America. 2017 Revised Classification of Seizures. [online] Epilepsy Foundation of America. 2017. 18/02/2018. <https://www.epilepsy.com/article/2016/12/2017-revised-classification-seizures>