Macrolides

Erythromycin, clarithromycin, azithromycin.

Bacteriostatic not bacteriocidal, but doesn’t necessarily mean inferior.

Broad spectrum, including things that aren’t even bacterial! eg Bordetella pertussis, syphilis.

Diarrhoea and vomiting as main side effects, not an allergy as such. True allergy is virtually unheard of! Other important issues:

  • Risk of pyloric stenosis in neonates
  • Prolong QT, so beware other things that also prolong QT including electrolyte disturbance

Shared Decision Making

[NICE guidance 2021] See also participatory medicine and family centred care.

First bullet point is that this should be embedded at organisational level! Includes:

  • provide access to patient decision aids (PDAs) or information about risks and benefits
  • review how “information systems” might help record discussions and decisions, for example through patient held record
  • prompt patients (through media, posters, letters) to ask questions about options, and “making the decision that’s right for me

Staff training:

  • evidence based model eg three-talk model (introduce choice, describe options, help explore preferences and make decision)
  • communication skills – avoiding jargon, explaining technical terms
  • communicating with families and others the patient would like involved

Note that NHS England has “accessible information standards”.

In practice:

  • Agree an agenda
  • Ensure the person understands they can take part as fully as they want in making choices about their treatment or care
  • When it comes to tests or treatments, explain what the health care aim is of each option, and discuss how that might align with patients “aims, priorities and wider goals”
  • chunk and check information
  • check understanding eg teach back
  • Give information away at time of discussion or very soon after, including contact details
  • Write letters to the patient rather than to their doctor, in line with Academy of Medical Royal Colleges’ guidance on writing outpatient clinic letters to patients (and to patient, unless they don’t want a copy).

Communicating risk:

  • Make clear how information applies to them personally, and how much uncertainty applies
  • Use mixture of numbers, pictograms and “icon arrays” (repeated icons, with different colours, to see proportions), to allow people to see both positive AND negative framing
  • Be aware that different people interpret terms such as ‘risk’, ‘rare’, ‘unusual’ and ‘common’ in different ways
  • Use absolute risk rather than relative risk. For example, the risk of an event increases from 1 in 1,000 to 2 in 1,000, rather than the risk of the event doubles.
  • Use 10 in 100, rather than 10%
  • Use the same denominator
  • State both positive and negative framing

Participatory medicine

Patient led campaign for better involvement of patients in their own care.

Manifesto has 5 principles:

  • Share and listen – acknowledge patients are experts in their own lives and bodies, use plain language.
  • Respect one another
  • Share information responsibly – help patients access the information they need, and respect confidentiality
  • Promote curiosity – be clear even when it is difficult to explain, encourage patients to do their own research and get involved in patient communities
  • Be a teambuilder – treat patients as collaborators, respect their goals, values and preferences

These are shared responsibilities, the patient has their own duty to be honest, ask questions, advocate themselves.

Institute of Medicine describes a continuously learning system (in respect of healthcare in the US), the second feature of which is Patient-clinician partnerships. This is explained as “engaged, empowered patients – a health care system anchored on patient needs and perspectives, and promoting the inclusion of patients, families and other care givers as vital members of the team“.

Unclear this happens on any significant level, especially when it comes to communication outside the hospital or clinic room. Studies have found that when patient portals or messaging systems are used, patients often respond with further questions or comments, which suggests unmet need and desire to engage further. Other studies have found that only a tiny minority of messages in such systems are initiated by the health care team, which suggests a reactive rather than active contribution to the partnership.

Arnold Chiari malformation

Thought to be congenital but often only picked up in adulthood when symptoms develop.

Type 1 most common, where cerebellar tonsils protrude into spinal canal, potentially putting pressure on brainstem, spinal cord and cause obstruction to flow of cerebrospinal fluid.

Can be found incidentally. Symptoms however include:

  • headache (especially occipital)
  • neck pain
  • numbness or paraesthesiae of fingers, arms, lower limbs
  • Coordination problems, dizziness

Can be complicated by upper spinal syringomyelia.

Rarely familial.

SVT

Supraventricular tachycardia – where abnormal rhythm initiated above atrioventricular node, so narrow complex (with normal conduction down bundles of His). Typically rate over 220, with abrupt onset (can be inferred from history).

ECG showing SVT and effect of adenosine
SVT showing effect of adenosine

Accessory pathway that bypasses the AVN is the usual reason, esp infants, but nodal reentrants quite common in older kids. Get a 12 lead before doing anything, unless absolutely impossible.

An accessory pathway usually has a delta wave (upsloping PR). If retrograde conduction, then inverted P wave seen immediately after the QRS. If a nodal reentrant, P wave is subsumed into QRS complex.

If decompensated then synchronised cardioversion (under IM/IN ketamine).

Vagal manoeuvres do work, such as doing a valsalva manoeuvre (get child to blow through straw!), bag of icy water held to face (count to 5). Older kids can stand on their hands! Carotid sinus massage is the least effective.

But best to go straight to IV adenosine if access available. Adenosine causes sinus arrest, which feels terrifying for child. Within a few seconds, wears off and spontaneous return of rhythm, hopefully a normal one. Can also induce wheeze. Give in antecubital fossa, so as close to heart as possible.

Starting dose lower if over 1yr. Then increase by 50-100mcg/kg each time. If adenosine doesn’t work:

  • check max dose (different for neonates and older children, 12mg max)
  • check rapid bolus and flush
  • check diagnosis is correct.

Digoxin is good for babies and infants but needs 2 loading doses 6 hours apart, and you may not get a result until then. Propanolol is contraindicated in asthma. Amiodarone should be used before 3rd shock. Verapamil is contraindicated under 1 year as can cause arrest.

Prognosis

SVT usually settles down by 6-12 months but may recur around the age of 8yrs. Onset outside infancy will probably not resolve spontaneously. Prevention needs to be discussed: some families will be happy just treating episodes as they occur. Otherwise use digoxin in infancy to prevent, propanolol later.

Rare forms

Rare forms:

  • Permanent form of Junctional Reciprocating Tachycardia (PFJRT) – chronic SVT, so may go unrecognised and then cause cardiomyopathy. The accessory pathway is resistant to DC shock and adenosine. Inverted P wave seen.
  • Ectopic atrial tachycardia – due to an ectopic focus. May also be chronic. Demonstrates warm up and slow down in rate, whereas others tend to have fixed rate. First degree block seen. Resistant to DC shock and adenosine.
  • Atrial flutter usually seen only in congenital heart disease but does occur in neonates with normal hearts! In which case it tends not to recur. Ventricular rate divides neatly into 300.
  • Atrial fibrillation – needs anticoagulation before DC conversion so control rate first with digoxin while loading warfarin.

Schistosomiasis

Egg in freshwater taken up by snails.  Cercariae released into water and penetrate skin.  With this first infection, urticaria, discrete raised lesions 1-3cm and immune response (to dying larvae, rather than living!).  These then migrate into lungs, so acute schistosomiasis causing immune complex deposition, lymphadenopathy, eosinophilia, pulmonary infiltrates. 

Larvae mature in liver.  Adult worms migrate to mesenteric vessels of bowel, where eggs are laid.  Chronic blood loss from gut lesions. Hepatomegaly, splenomegaly, eventually varices if fibrotic. 

Worms can live 3-10 years.  Immunity only really develops where lots of dead worms, not necessarily high worm burden!  Eggs only start appearing 8 weeks after infection, and multiple samples required (intermittent excretion, perhaps every few days). 

Serology only really useful in travellers as persists? Praziquantel often causes abdo pain, rash, headache.  Only acts on adult worms.   

Latex allergy

The name for pure natural rubber. Found all over the place – foam (mattresses), condoms, balloons, seals, adhesives. In hospitals, BP cuffs, elastic bandages, catheters and ET tubes, pulse oximeters… Not so often in surgical gloves now. Can cause mild and severe (anaphylaxis) reactions, plus delayed (non type 1) allergy. Allergy first described in 1979, became epidemic in 1980s.

The rubber tree Hevea brasiliensis is not the same as “rubber plants” (Ficus) you get as pot plants, although you can be allergic to those too, of course.

About half of latex allergic patients also have fruit allergies, especially avocado, banana, kiwi, melon but also chestnut and tree nuts.

Certain high risk groups:

  • Spina bifida
  • Health care workers

Atopic or irritant dermatitis may also be caused by rubber chemicals rather then latex itself.

Diagnosis

  • Blood IgE test – as with other IgE tests, potential for false positives esp with grass/fruit allergy.
  • Skin prick test with standardised latex
  • Prick through suspected glove! Needs latex free environment, of course. Potential for reaction to powder, rather than latex…
  • Glove test – wet hand! Risk of anaphylaxis.

Risk of Anaphylaxis

As with other allergies, seems to vary between individuals. And previous reactions do not reliably predict future reactions.

With health care, difficult. First on surgical list. Label patient. Latex free environment, as far as possible. Reports of probable reactions from IV fluids and needle puncture of bungs in IV sets.

Need for careful occupational advice.

Fabry’s disease

Alpha-galactosidase defect, one of the lysosomal storage disorders, with accumulation in various tissues.

X-linked but females get disease, so not correct to call them carriers.

Classically, “pain attacks”, affecting the extremities. In the abdomen, can mimic appendicitis. Due to accumulation in nerves. Since nothing to really see on examination, easily misdiagnosed as functional.

Other features:

  • Renal impairment and failure.
  • Angiokeratomas – a more specific feature, but not always present, and seen in other lysosomal disorders.
  • Corneal changes
  • Cerebrovascular and cardiac problems

[Omim]

Campylobacter

Common cause of bloody diarrhoea. As with other causes of bloody diarrhea, often associated with fever and abdominal cramps.

Usually self resolving within a week. Antibiotics help if symptoms severe enough.

Excretion continues for a number of weeks, although risk of spreading infection after diarrhoea has settled of course much less, assuming decent hygiene.

Chronic excretion can occur with continuous symptoms rarely, certainly in immunosuppressed patients. Asymptomatic carriers exist, although seems to be more common in developing countries (so malnutrition probably a factor) and reinfection can also occur, of course.

About 1 in 1000 cases develop Guillain Barre syndrome after the infection. Inflammatory bowel disease seems more common after campylobacter infection?

Liver Function Tests

Bilirubin needs to be around 60 to see visible jaundice.

AST is less specific than ALT – also produced in kidney, brain etc. But perhaps changes more quickly than ALT. Most important other source of AST and ALT is muscle – so check CK too, especially if bilirubin normal. Myopathies, viral myositis, muscular dystrophy can all present with “abnormal LFTs”.

Gamma GT is also found in other tissues so not 100% specific but typically suggests cholestasis or other biliary problem (together with alkaline phosphatase).

Alkaline phosphatase also produced in bone, so look at calcium, phosphate and vitamin D as well as signs of rickets or renal disease. Most common cause of isolated high alkaline phosphatase is benign transient hyperphosphatasaemia.

Falling transaminases can be ominous in situation of bilirubin, albumin, coagulation deteriorating…