Endocarditis

The Needle in the Febrile Haystack: Diagnosing Endocarditis in Children

Endocarditis is an infection that affects the lining of the heart, heart valves or blood vessels. It is rare but carries significant morbidity and has a mortality rate of 5% even with treatment. It can be spontaneous, but patients at risk of infective endocarditis are vulnerable to ‘cardiac seeding’ from circulating bacteria. Consideration should therefore be given to this diagnosis whenever these vulnerable children have a fever. HOWEVER – these kids are also going to get every virus going at school/nursery – along with their associated fevers! This complexity can make management really tricky

In this article we will talk though three fictitious cases and give you some important learning points to remember that might help you next time!

Before we start – who is at risk?

Patients with any type of cyanotic heart disease
Patients with repaired heart disease within 6 months of the repair
Patients with repaired heart disease where a residual shunt or regurgitation remains
Patients with prosthetic valvular material used to repair or replace a valve
Patients with a previous episode of infective endocarditis

Case 1

14 year old Simon has been brought to the Emergency Department complaining of chest pain for the past 24 hours. This pain came on gradually, it’s dull, and it moves through to his back. Simple analgesia hasn’t helped. He has no history of injury, no fever, but does feel ‘shivery’. He has had no vomiting/diarrhoea/dizziness/headache.

His Mum explains Simon had a VSD as a baby requiring surgical closure with a patch at 1 year of age. He is otherwise well and takes no regular medication.

You examine Simon. He looks well and is happy and chatty.

AB- Simon is talking in full sentences. RR 18, SPO2 97% in air. His chest is clear.

C- Simon is warm and well perfused. HR 80, BP 100/49. Systolic murmur is heard loudest over the sternal area.

D- Simon’s abdomen is soft and non-tender. There is no organomegaly

E- Simon has no rashes. His temperature is 36.7. Simon’s ears and throat appear normal.

You pause and think, feeling unsure! Why on earth does Simon have chest pain? Could his ‘shivery’ feeling be significant?! You discuss the case with your registrar and decide to do the following…

ECG
To look for evidence of pericarditis or pericardial effusion.
To look for blood and/or infection
Chest x-ray
Assess the cardiac size, the lungs and rule out spontaneous pneumothorax
Bloods (FBC, UE, CRP and blood culture)
Neutropaenia and thrombocytopenia are common findings in endocarditis
Persistently elevated CRP is associated with endocarditis.

Results

Hb 120

WBC 8

Neut 4

CRP 35

UE NAD

Urine dip +1 ketone

ECG – Sinus rhythm

CXR – NAD

So… Simon has had a possible fever at home and some chest pain. He looks well but his CRP his CRP is raised and you are sturggling to tie it all together! Beware that Simon has a murmur. This could be new, or it could be chronic after his operation, so reviewing his clinic letters would be really helpful, as a new murmur or a known valve issue increases his risk of endocarditis significantly.

When you look back, Simon had a murmur following his op which has been consistently present on subsequent reviews. You discuss him with the cardiology registrar who reassures you with the following discussion and key learning points:

Chest pain is unlikely to indicate infective endocarditis.
- A VSD patch in place for more than 6 months is usually endothelialized and as such the risk of endocarditis is similar to the rest of the population.
- The murmur is NOT new and there are no associated valve abnormalities

She advises a pair of blood cultures should be considered and the result needs to be chased up just in case an unusual cardiac bug is isolated.

You explain the above to Simon and his mother. His discomfort has eased following some simple analgesia and they understand your safety net advice. When you are back in 48 hours later you note that the blood culture was negative and let the family know. Simon is feeling much better.

Case 2

A few weeks after seeing Simon you meet 12 year old Sachin who is brought to the Emergency Department by his mum Jyoti. Jyoti informs you that Sachin has been having temperatures every day, on and off for 2 weeks. He tells you that he feels not quite himself. He has no cough/coryza/sore throat, no diarrhoea/vomiting/rash and is eating and drinking normally.

Jyoti tells you that Sachin was born with Tetralogy of Fallot and he’s had several procedures. Most recently he has had a new RV-PA conduit. You look this up (thank you Google!) and find that it is a surgically placed pipe to take blood from the right ventricle to the pulmonary artery.

You examine Sachin. He looks well and is comfortable and chatty.

A – Self

B- Chest clear. SPO2 96%, RR 20. No chest wall tenderness

C- HR 108, BP 93/57, H1+2+Systolic murmur left side of chest radiating to back.

No splinter haemorrhages

D- Soft abdomen. No masses or organomegaly

E- No palpable lymph nodes. Ears and throat appear normal. No visible rashes. Moving all 4 limbs freely and without pain.

So Sachin looks well but has had daily temperatures for 2 weeks and you can’t see a good reason for this. Due to his risk factors you discuss him with the cardiac centre who agrees this is suspicious for IE! Good spot! They advise bloods and admission but no antibiotics as yet.

Hb 132

WBC 6

Plts 169,

UE NAD

Clotting NAD

CRP 17

ECG normal for him

On the ward, Sachin has further blood cultures taken and an ECHO which shows a significant change in the blood flow through the conduit. His blood cultures are already growing gram negative bacilli so the ward team rediscuss him with the regional cardiac centre and he is transferred there urgently for further investigation and consideration for surgery.

Key points:

Major congenital defects like Tetralogy frequently have residual lesions. They may have Gore-tex tubing or artificial patches to create or repair tubes. They will often have turbulent flow and a murmur. This combination is what places them at risk of infective endocarditis.
It is crucial to isolate the organism prior to treatment where possible. This allows us to confirm the diagnosis and determine the correct duration and agent of antibiotic.
You should start antibiotics if the patient is clearly septic or has obvious emboli but you should be very aware that not starting antibiotics should be your default. Confirming the diagnosis and isolating the organism is important.
If you do need to start antibiotics in a septic child it is important to take 3 good volume cultures from separate sites over the first hour alongside the treatment.
Transfer to a specialist surgical centre is advised primarily due to the high mortality but specifically because detailed monitoring and potentially surgery are required.

Case 3

You’re working a night shift when you meet 9 month old Lauren, who has been brought to the emergency department by her aunt Helen. Helen is Lauren’s legal guardian and is concerned about some yellowish discharge Lauren has been having from her operation site.

Lauren had a Tetralogy of Fallot repair at the regional cardiac centre 3 weeks previously. Helen explains that initially the wound site looked fine but became puffy a week ago and over the past five days this has worsened and is now red, and Lauren has a fever. Her GP saw her earlier today and prescribed some erythromycin but since then her wound has been oozing.

You examine Lauren. She looks well and is interacting normally.

A- Self

B- RR 30, SPO2 96% in room air. Chest clear

C- HR 168, SBP 104/76. Heart sounds 1+2+Systolic murmur at left sternal edge

D- Soft abdomen with no masses.

E- Temperature 40.9. Tympanic membranes pink bilaterally. No exudate seen on throat. No rashes seen. Midline sternotomy scar looks full and opening slightly. There is a yellow discharge seen but no blood. It feels slightly warm to touch.

Hmm… Lauren, despite looking quite well and having a clear focus for infection, is still only a few weeks post cardiac surgery. With your recent cases fresh in your mind, you are worried so discuss her with the team at her surgical centre. They advise:

Three good volume cultures are taken.
To treat as a surgical wound infection. with IV antibiotics
Transfer to them in the morning for review
No need for ECHO at present as she has not been unwell for long

Key Points:

There is a recent operation and obvious superficial wound infection. It may look benign, but the possibility of involvement of the whole of the mediastinum and the surgical repair is real!
Early endocarditis infection often does not yield a positive transthoracic echo making a negative test falsely reassuring.

Summary

Hopefully these three cases show you how challenging it can be to separate normal childhood illness from infective endocarditis! Guidance to support your decision making can help with not over or under investigating children and young people. Remember that the risk is higher when there is turbulent flow or artificial tissue, and if you can safely delay antibiotics then this is important to allow isolation of the organism. If you do need to give then take at least three good volume cultures from different sites. Ensure very clear safety netting advice if discharging home, and chase any outstanding cultures!

Authors

Dr Vikram Baicher, PEM Consultant; Dr Mark Fenner, Paediatrician with Expertise in Paediatric Cardiology, both authors from Nottingham University Hospitals

Edited for PaediatricFOAM by Dr Sarah Walker