Category Archives: General paediatrics

Non-specific effects of childhood vaccines

General paediatrics, Immunology

Systematic review.

BCG and Measles vaccine appear to reduce all cause mortality, not just TB and Measles (relative risk 0.7 in trials, 0.5 in observational studies, roughly same for both vaccines).

That’s wonderful, until you see that DTP vaccine appears to increase mortality (in 7 of 9 observational studies).

So are live vaccines “immune boosting” in some general way, whereas inactivated vaccines are not, or actually deleterious?

Large proportion of data from studies in Guinea-Bissau so high risk of bias!

[BMJ 2016; 355]

Systematic review of immunological effects of BCG found evidence of changes in non-specific immunological variables (eg IFN-gamma prodution, enhanced lymphocyte proliferation in response to candida, HBsAg, staph etc) but inconsistent, dubious clinical relevance, and certainly not geographically generalisable.

Ultimately, better designed studies, linked to epidemiology, needed before policy changes can be justified.

 

Thalassaemia

General paediatrics, Haem/Oncology

Normal newborn has 90%+ HbF (alpha-gamma chains), dropping with age. In childhood, normal HbF is <2%. HbA2 (alpha-delta instead of alpha-beta) is normally <3.5%, and HbA:HbA2 ratio should be at least 40:1.

Alpha thalassaemia

4 genes for alpha chains. Africans, Afro-Caribbean (provided no Chinese ancestry), South Asians tend to carry the deletional α+ allele (“alpha plus” thalassaemia) which has no health consequences for person or their children (but causes endless confusion…). If both parents have alpha plus, child can just end up alpha plus.

Mediterranean, Middle Eastern, East Asian, SE Asian can have alpha plus or “–” (“zero”) defect, that is more serious.

  • If alpha zero, there is usually mild microcytic anaemia, easily confused with iron deficiency. No treatment required, though. Risk of “HbH” disease if other parent alpha plus – abnormal tetramers form viz Hb Barts (4 deltas) and HbH (4 betas). There is mild to moderate anaemia, Heinz bodies (accumulations of excess beta chains) and splenomegaly. Most people do not need any treatment, however.
  • If both parents alpha zero, risk of all 4 alpha genes being abnormal – “alpha zero major” – survival is not possible. The baby develops hydrops (as the unstable Hb forms do not deliver oxygen appropriately, so organ failure), and death occurs in utero or soon after birth.

Electrophoresis will show high quantities of Hb Barts in alpha zero thal major. In the trait form, there are often normal levels of HbA and HbA2 so need to do gene deletions.

Beta thalassaemia

Seen in the Mediterranean, Africa, SE Asia. Just 2 genes, so a heterozygote is a carrier, may have mild microcytic anaemia. In the Mediterranean form, the gene is usually a zero producer, so the disease is more severe than in Africa, where production is reduced but not absent.

Beta thal Major (homozygous) present after 6 months of age with anaemia, frontal bossing, growth failure, hepatosplenomegaly.

In Beta-thal trait, HbA2 is obviously increased eg 3.5-7%, and ratio reduced eg 20:1. The only exception is if there is co-existing severe iron deficiency. In beta-thal disease, you may not see such an increase if there’s lots of HbF around (about half the cases), and increased HbF is not specific; but the clinical picture doesn’t leave much doubt. Inclusions (alpha chains) seen esp post splenectomy. Retic count surprisingly normal due to severe intramedullary erythroblast destruction.

Treatment is with folate and regular blood transfusion, which then leads to cirrhosis, pigmentation, diabetes etc. Splenectomy reduces transfusion requirements but because of the increased vulnerability to pneumococcal infection this is usually deferred until later childhood.

Deferipone is oral chelating agent, used in Europe but not licensed in US. Acrimonious debate between lead researcher and drug company about research.

An intermediate beta thal exists, where transfusion is only required at times of increased stress.

Combined alpha thalassaemia and sickle cell disease tends to give less anaemia, but more vaso-occlusive crises.

Family support at https://ukts.org/

Sacral dimple

Clinical, Congenital, General paediatrics, Neurology

Typical sacral dimples are <5mm in diameter, within 25mm of anus and located in midline.  Rate of spinal  dysraphism (bifida occulta) less than 1%.

Higher risk if do not fulfill these criteria. Lipomas, deviated/bifurcated crease are the most likely to be associated with dysraphism.  Otherwise you expect at least 2 or more cutaneous markers (hair tuft, haemangioma, Mongolian spot, skin tag/tail).

Reports of high frequency of hair tufts in diastematomyelia probably refer to more striking lesions (“faun tails”).

Royal College of Radiology has policy  – ignore sacral dimples unless atypical, or in combination with other lesions.

USS if neonate, but MRI if US abnormal or equivocal, where neurological signs (bladder, bowel, lower limb) or lesion discharging.

[Arch Derm 2004]

Episodic autonomic symptoms

Clinical, General paediatrics, Neurology, OPD

Antibiotic resistance

General paediatrics, Infectious disease, Microbiology

Penicillin resistance

Resistance to penicillin is usually due to Beta lactamase enzymes.  Therefore adding a  beta-lactamase inhibitor eg clavulanate (as found in co-amoxiclav) overcomes the resistance and extends the spectrum.

An alternative resistance mechanism however is production of defective Penicillin Binding Proteins – this is the mechanism of resistance in Pneumococci.  Beta lactamase inhibitors therefore do not help.

Macrolide resistance

Variable resistance seen; sometimes effective against penicillin resistant staphylococci including some MRSA, but poor activity against Haemophilus. Variable resistance seen in streptococcus, pneumococcus. Resistant mycoplasma are rare but do exist – try cipro, else tetracycline.

Using Azithromycin probably improves efficacy in Haemophilus (more active) but pneumococci that are resistant to erythromycin (approximately 5 to 20% of strains currently) will also be resistant to azithro, and no difference in in vitro activity between the newer and old macolides against other common respiratory pathogens.

Multiresistant organisms

In theory, you should use a combination of antibiotics (if possible) to treat a multiresistant organism, to prevent resistance developing (as in TB).  However there is no good clinical data to support this, beyond TB treatment (which is slow growing, so probably different).  On the contrary, meta-analyses demonstrate no difference in clinical outcomes between the two treatment strategies (for infections with Gram-negative bacteria), but there are well-documented increased toxicities with combination therapy.

Having said that, given the greater mortality associated with delays in appropriate and effective antimicrobial treatment, starting with combination therapy in critically ill patients seems sensible.

If there is poor response to treatment, rather than simply adding a second agent, consider:

  • dose, frequency – are you achieving adequate time above MIC?  Consider prolonged antibiotic infusion strategy
  • route – give IV if not already
  • duration – extended treatment course?

[doi: 10.1128/CMR.05041-11 Clin. Microbiol. Rev. July 2012 vol. 25 no. 3 450-470]

ESBL – extended spectrum beta lactamase

Scenario 1: lower renal tract infection with ESBL producing Gram negative

Bacteriuria with urinary symptoms but minimal systemic symptoms and no fever

  • Treatment duration 3 days
  • First line – trimethoprim / nitrofurantoin  (not used in under 3 months)
  • Depending on sensitivities and age alternative options include ciprofloxacin, single dose aminoglycoside, pivmecillinam or fosfomycin

Scenario 2: upper renal tract infection with ESBL producing Gram negative

Bacteriuria with urinary symptoms and associated systems symptoms including fever

  • Treatment duration 7-10 days (as per NICE)
  • Always consult with infection management specialist
  • First line – if seriously unwell or under 3 months carbapenem  + consider one dose of aminoglycoside
  • Alternative: tazocin and consider one dose of aminoglycoside (if sensitive and not seriously unwell and after discussion with local microbiologist)
  • OPAT : Ertapenem
  • Daily IVOST review required
  • Potential IVOST options when afebrile, clinically improving, falling CRP and able to take and absorb oral medicines: ciprofloxacin, trimethoprim
  • There was less consensus on the role of pivmecillinam and its ability to penetrate renal tissue. It should be considered only to offer an oral option to finish a course of antibiotics in a clinically improving child

Scenario 3 – infection with ESBL producing Gram negative outside the renal tract (except for meningitis)

  • As per IDSA – carbapenem, meropenem (especially if child unwell)
  • Stepdown co-trimoxazole or ciprofloxacin (would consider fosfomycin on rare occasion)
  • Temocillin not empirical therapy until we understand PK/PD profile better plus expensive and difficult to obtain – consider not including
  • Recommendation would need caveat, how unwell, age of child.  Not experienced discuss with infection specialist. BNFC reference
  • Ertapenem OPAT

Scenario 4 – meningitis complicating ESBL producing Gram negative

  • Carbapenem, limited ability to step down
  • Treatment duration – 3 weeks
  • Lumbar puncture to ensure infection cleared.

[Conor Docherty]

Non-accidental injury – fractures

Community, General paediatrics, Sociology,

Abuse should be considered if:

  • multiple fractures
  • rib fractures (7 in 10 NAI)
  • femoral fracture (see below)
  • Under 3 with humeral fracture (1 in 2 NAI)
  • Mid shaft humeral fracture more frequently NAI, supracondylar less frequently
  • Infant/toddler skull fracture (1 in 3 NAI).  Type and location not helpful

Formerly known as CORE Info, the RCPCH Child Protection Portal hosted on the RCPCH website provides evidence-based guidance for health professionals concerned about non-accidental injury 

  • Fractures in the abuse group occurred predominantly in children less than 1 year of age.
  • Femoral fractures under 1 year of age are significantly associated with abuse.
  • One-third of isolated femoral fractures under 3 years of age were abusive.
  • Abusive femoral fractures occur predominantly in infants (evidence level IIb) [3].
  • Significantly more abusive femoral fractures arise in children who are not yet walking (evidence level IIb) [3].
  • Mid-shaft fractures are the most common fracture in both abuse and non-abuse groups (analysed for all age groups) (evidence level IIa) [3].
  • Under 15 months of age, a spiral fracture is the most common type of abusive femoral fracture p=0.05 (evidence level IIb) 

2014 Systematic review on bites has been withdrawn pending new review – interim advice on RCPCH child protection portal but need to be member.

Rib fractures with callus are at least 2 weeks old.  Other than that, unable to date.

Systematic reviews of various NAI issues at https://childprotection.rcpch.ac.uk/child-protection-evidence/

Rickets

General paediatrics, Nutrition, Orthopaedic

Acquired bone disease, due to vitamin D deficiency. In UK, mostly black and Asian children, due to dark skin and low levels of sun exposure, also diets often rich in phytates and oxalates.

More common in boys, perhaps due to higher bone mineral density.

Safeguarding concerns note uncommon.  2 deaths reported in BPSU study, multiple risk factors, rickets only diagnosed post mortem

Clinically:

  • Leg deformity (bowing or knock-knees)/Swollen wrists or knees or ankles or ribs (rachitic rosary), AND
  • 25OH vitamin D <25nmol/L PLUS one or more abnormalities of serum calcium, alkaline phosphatase, phosphate, parathyroid hormone

Else radiological Rickets:

  • Widening, cupping, splaying of metaphysis (of any long bone) AND
  • 25OH vitamin D <25nmol/L

Other clinical features:

  • Delayed motor development 
  • Pain, limp

These are strict research definitions – some cases seen with abnormal PTH and radiological features but have dietary calcium deficiency and less severe vitamin D insufficiency (between 25 and 50), these would be called nutritional rather than Vit D deficiency rickets.  There is no clear cut off below which rickets occurs!

Incidence seemed to be rising but not borne out in most recent BPSU study (2020).

Differential

  • Vitamin D dependent rickets e.g. 1α hydroxylase deficiency
  • Vitamin D resistant rickets e.g. familial or X-linked hypophosphataemic rickets
  • Rickets associated with other chronic diseases e.g. malabsorption, liver disease, chronic renal disease
  • Metabolic Bone Disease of Prematurity (infants whose corrected age is < 3 months at presentation, who were born < 36 weeks gestation and weighing <1.5kg

Complications

  • Often cow’s milk allergy seen, else these are usually breast fed babies.
  • Fractures (usually femoral) can be a clue.
  • Hypocalcaemic seizures
  • Dilated cardiomyopathy can be seen, usually in older children where bone growth is more advanced already. Worth an echo!

Evidence from BPSU study that DOH guidance on Vitamin D supplementation not being followed, either in mothers or children themselves.

Wide variation in Vitamin D treatment prescriptions. Alfa-calcidol is potentially toxic and should be avoided.

Venom immunotherapy

Allergy, General paediatrics, Immunology

Pharmalgen® no longer available. Alutard is an option (but no SMC submission) for the treatment of IgE-mediated bee and wasp venom allergy in those who have had [www.nice.org.uk/TA246]:

  • a severe systemic reaction to bee or wasp venom;
  • a moderate systemic reaction to bee or wasp venom PLUS:
    • a raised baseline serum tryptase concentration,
    • a high risk of future stings,
    • or anxiety about future stings.

Comes as an initial treatment set, with graded doses, plus a maintenance set.  For treatment, start with subcut at 1000th of SPT threshold dose or 10th of intradermal threshold, increase every 3-7 days until a threshold is reached.  Rush or modified rush regimens also available.  Then maintain maximum tolerable dose (typically 100mcg)  at 4 weekly intervals initially, gradually extending, for at least 3 years.

If symptoms or signs of hypersensitivity to therapy develop (e.g. rash, urticaria, bronchospasm, faintness), even if mild, the child should be observed until these have resolved completely. [BNFc] High baseline tryptase may make reactions to immunotherapy more likely – but still appropriate to do.

Asthma is not a contraindication but severe asthma (specified as FEV persistently below 70% despite treatment) is.

No age cut off, but data “sparse” for children under 5.

Some patients tolerate venom immunotherapy well but still have systemic reactions! So challenge tests with subcut venom not reliable – use live insect! Done sometimes to identify candidates for immunotherapy, or to identify those on maintenance immunotherapy to see who is not yet protected esp at high risk of sting or high risk of fatal reaction.

Efficacy of immunotherapy is related to adherence to treatment!  High adherence at 5 years to subcut immunotherapy.  Recent contraindications more flexible than previous ones.  [Pitsios, Allergy 2015;70:897]

Venom immunotherapy is 95% effective against wasp, 80% against bee.  Consider VIT if mild reaction but high tryptase, high risk of sting or major QOL issue.  But kids have better prognosis so only VIT for most severe.  Don’t do VIT without positive test.  Usual duration of VIT in UK is 3 yrs.

Intraosseous needle technique

Clinical, General paediatrics

Proximal humerus preferred in adults! Less pain, nearer heart. Lay elbow across abdomen. Half way between axilla and lateral aspect, feel for neck. 45 deg angle.

All sizes are same gauge, just length different. Judge soft tissue depth with thumb. If you can’t see first black line then prob too short for safety!  Don’t put patient into MRI!

Contra indications: local infection, previous attempt, fracture. Osteoporosis is less of an issue with EZIO driver, cf Cook’s needle.

Hard flush initially to help flow. Pain of infusion is severe – often worse than pain of insertion.  Consider lidocaine (without adrenaline) 0.5mg/kg IO over 2 mins, then allow 1 min dwell time, BEFORE flush.

Compartment syndrome is major complication (due to extravasation) – diproportionate pain, esp on passive stretching.  Later pallor, paraesthesiae, pulseless.

72hr life.  Removal can be tricky – secret is to remove extension tube and attach syringe directly to hub, for better grip.