Category Archives: General paediatrics

The Farm effect in allergy

Allergy, Gastro, General paediatrics, Nutrition

Children growing up on farms are less likely to develop allergies and asthma. Farming has been part of human culture for probably 7000 years.

It is widely accepted now that a symbiotic relationship with a diverse population of microbes in the environment, on the skin, in the gut and in the lung is necessary for a healthy immune system (“microbiome“). These microbes influence the balance between inflammation and immune tolerance. That relationship needs to be developed in early life, and nutrition is a major part.

Big European cross sectional studies – PARSIFAL and GABRIEL. Amish and Hutterites in US are genetically similar but Hutterites use industrial rather than traditional farming techniques (and have 4-6x the rate of hay fever and atopic sensitization).

Prenatal maternal exposure to farm animals is protective against eczema in the first 2 years of life, and against asthma symptoms pre-school.

Farm milk consumption in the first year of life is protective against respiratory allergies. Not clear what it is about it – more whey? Higher levels of cytokines or polyunsaturated fatty acids?

In children, exposure to cows and hay was protective against asthma. Some evidence for pigs, but risk seems to go up for sheep.

Mediators thought to potentially be N-gylcolylneuraminic acid (animals/pets) and arabinogalactan (plants).

Lipopolysaccharide (endotoxin) is widespread in the farm environment. Levels in mattresses inversely associated with hay fever, atopic sensitisation and asthma.

Lack of gut microbial diversity in first month of life predicts school age asthma.

Dietary diversity in first 2 years of life protects against asthma and allergic rhinitis. The link between gut microbes and lung health is thought to be short chain fatty acids, such as acetate and butyrate.

[Ped Allergy and Imm 2022]

In a study of 589 children, 1-year microbiota maturation (based on metagenomics – genetic material of a community of micro-organisms – and metabolomics – metabolites in environment) closely related to eczema, asthma, food allergy and allergic rhinitis at age 5 years. Found a core set of “functional and metabolic imbalances” characterized by compromised mucous integrity, elevated oxidative activity, decreased secondary fermentation, and elevated trace amines. [Hoskinson, BC, Canada – Nature communications . 14(1):4785, 2023 08 29.]

Skin prick testing

Allergy, General paediatrics

Not great, particularly in young infants, but probably the best method of testing for type 1 allergy other than direct challenge.

You do need a patch of healthy skin however, so if bad eczema all over then not an option. Easiest is the medial forearm, but failing that, the back.

Some medicines interfere with skin prick testing (suppress it) – most commonly antihistamines. Non sedating should ideally be stopped 7 days before testing, sedating 48 hours. Other problem medicines are:

  • Azelastine nasal spray (48 hours)
  • Steroids – some say short courses ok
  • Tricyclic antidepressants (7-14 days) but not SSRIs
  • Benzodiazepines!
  • Ranitidine (48 hours)! But not omeprazole
  • Omalizumab, obviously (6 months)
  • Topical tacrolimus yes, pimecrolimus no!?
  • Ciclosporin is ok

BSACI have SOP.

Anergy is the failure for testing to confirm allergy after a recent severe reaction – this is well recognised with venom allergy but in theory could affect both skin prick and IgE testing within a few weeks/months of a reaction. Conventional wisdom is to delay testing for 4-6 weeks, but at least one study has not found any evidence of this being a problem at 2 weeks after food anaphylaxis.

Urinary tract infection

Common, General paediatrics, Infectious disease, Renal

Upper, lower, atypical, recurrent – all have specific definitions;

Diagnosis is ideally by culture – minimum of 1.25 ml, pref 2.5ml of urine in a 7ml red top boric acid container. White top only acceptable if received at lab on same day or day before, within hospital. Collection method important, ideally clean catch.

But given delay in getting culture result, urinalysis more practical, if less sensitive/specific. Nitrites have high positive predictive value so treatment usually started pending culture. Microscopy (for white cells and bacteria) is routinely done in infants under 3 months but needs to be requested between 3 months and 3 years. Greater than 100 wcc or 1000 organisms considered “numerous”, above 40 wcc or 500 organisms “moderate”.

Contraception and sexual health

Child protection, General paediatrics, OPD

All methods with exception of condoms more than 99% effective  – if you use it as directed, of course! Combined – Rigevidon has safe(r) progesterone.  Evra is a patch (replace each week for 3 weeks then week free).  Nuvaring is monthly ring, less effected by GI problems but more expensive.

Contraindications for any combined product – migraine with aura, first 6 weeks breast feeding.  DVT risk related to which progesterone is in combination – risk triples with levonorgestrel (Rigevidon), norethisterone, norgestimate (Cilest) but quadruples for others.  But cf risk in pregnancy, more than 10x higher. UKMEC has risk table for family history etc.

Move towards only 4 pill free days – to avoid risk of ovulation if you miss day 1.  Ultimately going to 63-84 days continuously (3-4 packs) but potentially confusing as need to stop and start on different days of the week.

Progesterone only pills were just barrier methods, due to effect on mucus. Cerazette (desogestrel) different, inhibits ovulation without other oestrogen effects. Bleeding is quite common in early days.  Good for controlling cycle related problems eg menorrhagia, catamenial migraine. Good for young people because continuous. Depot good as lead in for implant (else weight gain as side effect).

Nexplanon is implant, under local, lasts 3 years.  But side effects include irregular bleeding. 

Enzyme inducers – cbz, phenytoin, topimarate! And st john’s wort! Rifampicin.  Lamotrigine is not an inducer, but interacts with COCP/POP so avoid unless no other option, in which case needs dose adjustment and must be continuous method.

Consent to sexual activity often confused! Under 13 cannot consent (so different from medical treatment consent).  Consent must be “free agreement” so sleep, coercion, under influence not allowed.  Disclosure of child protection concerns is tricky due to fear of disengagement with service.

Transition

Common, General paediatrics, OPD

Jargon for the process of transferring care of child to adult services, or to independent self management.

Paediatricians famously bad at discussing issues such as sex, drugs, alcohol, careers! And famously bad at seeing young people one to one, without parents present!

Raise contraception as soon as puberty comes up in clinic!? But remember that complications of pregnancy probably a bigger issue to discuss!

Ready, steady, go! is RCPCH document on the general principles, whereby you assess readiness for transition, and aim to provide information in an appropriate format (typically in small chunks) and at the right time (young person led). Then ideally one or more joint clinics with adult service, if appropriate.

Hemihypertrophy

General paediatrics, Genetics, Haem/Oncology, Orthopaedic

=Asymmetric overgrowth of one limb, or one side of the body, or just one side of the face.

Can be associated asymmetric overgrowth of internal organs.

Can be an isolated finding (of unknown cause) or associated with syndromes such as Beckwith-Wiedmann, Klippel-Trenaunay-Weber, or McCune-Albright syndromes.

Essentially a cosmetic problem. But increased risk of tumours, including Wilm’s tumour, adrenal cell carcinoma, hepatoblastoma and small bowel sarcoma.

Risk of tumour development in isolated hemihyperplasia is about 1 in 20 or approximately 5%. Given that oldest reported case was 6yrs and shortest interval between tumour presentation and ultrasound was 5 months, suggested that till age of 6 years these children should have abdominal ultrasound scans at three monthly intervals.

Focal epilepsy

General paediatrics, Neurology

As opposed to generalized epilepsy. Potentially associated with a brain lesion (congenital or acquired), but not always. EEG will usually confirm.

Associated with prolonged or focal febrile convulsion – chicken or egg?

See:

Temporal lobe epilepsy

The most common focal epilepsy.  Sense of déjà vu, phantom smells, panic attacks as possible aura symptoms! Talking gibberish, lip smacking, staring, posturing are more obvious.

Treatment

Levetiracetam or Lamotrigine first line, the former (Keppra) can be loaded more quickly though.

Honey in medicine

Allergy, General paediatrics, Infectious disease, Neurology, Nutrition

Contains a range of different sugars, aromatic oils, also pollens and bee proteins. Royal jelly and beeswax related, of course.

High fructose content can cause GI intolerance in some.

Allergic reactions can happen, often unrecognised, mostly due to specific pollens (depending on what flowers the bees feed on), in minority to bee proteins. Commercial honey tends to contain v low amounts of pollen, due to production techniques. IgE test for honey is available, but you may need to skin prick test with the specific honey if negative.

Honey eaten all year round is rumoured to prevent hay fever symptoms because of the pollens it contains, but this has not been proven, although it’s a nice idea related to immunotherapy. Depends on getting the right pollens of course – bees don’t like grass and birch flowers, probably. In some it may just trigger allergy symptoms.

Cross reaction between honey and bee venom is reported, not surprisingly, but not automatic.

Plant toxins can be present in sufficient quantities in honey to cause poisoning eg rhododendrons (some species).

Botulism reported in infants – failure to thrive, hypotonia, cranial nerve palsies. Clostridium and other bacteria cannot grow in honey due to the high sugar content, but spores can be present. So advice is not to give honey to infants.

Coagulation

General paediatrics, Haem/Oncology

Extrinsic pathway triggered by tissue factor on cells outside blood vessels.

Intrinsic pathway triggered by subendothelial surfaces activating factor XII, then XI, then IX.  IX and VIII combination with calcium and platelet membrane phospholipids activates X.

Common pathway then continues, with X combining with V, platelet membrane phospholipids and calcium to convert prothrombin to thrombin.

Thrombin converts fibrinogen to fibrin, to form thrombus.  Factor XIII stabilises clot.

Issues:

  • Vitamin K deficiency: 1:1200 breast fed (low levels), 1: 8500 formula fed. Preventable with single IM dose of Vitamin K. Can present up to 6 months later though typically 3 months.
  • Vitamin K may be affected in babies by maternal medicines eg anti-epileptics, or by liver disease.
  • Disseminated intravascular coagulation especially sepsis. Platelets fall too.
  • Haemophilia
  • Haemophagocytic syndrome (anaemia and other cell lines affected)
  • Thrombophilia

Fanconi anaemia

Genetics, Haem/Oncology

Autosomal recessive condition characterized by severe hypoplasia or aplasia of the bone marrow (so anaemia, low white cells and thrombocytopenia). Clue is congenital hand defect, but lower limb, head/eye/ear/genital abnormalities also common.

Majority also have cafe au lait spots.

It is possible to diagnose Fanconi anemia before bone marrow failure occurs, with potential to find bone marrow match.

Diagnosis is by Chromosomal breakage studies.