Croup

#KYJ - Croup.

Laryngotracheobronchitis, commonly called Croup is a mild viral upper respiratory tract infection which causes a characteristic Seal-like barking cough. 

Despite it being almost always viral, and mild, I need to make mention that rarely, some children  are very ill and airway compromise can be a cause of mortality.  In our not too distant past, the major cause of croup was diphtheria, which killed thousands of children until the advent of vaccination.

Today, the vast majority of croup is caused by a parainfluenza virus, and occasionally Respiratory Synctical Virus (RSV).

Patho

Croup causes inflammation of the  lower pharynx, larynx and trachea. This inflammation narrows the upper airway lumen (pipe) causing dyspnoea, cough and stridor.

Symptoms

The course is typically viral with a slow onset of miserableness, sore throat and runny nose (head cold symptoms).  It is accompanied by a fever that is mostly low grade (up to 39.5). There is often a cough, in the early morning or night time. This cough is not usually sputum producing, but characteristic in its seal barking tone.  At its worst, the child with croup has an inspiratory stridor which sounds like the child is choking.  This symptom is often the antecedent to ED presentation.

Assessment

Vital signs reveal tachycardia, and rapid Resp rate if the child is a little dehydrated. Important to note,  is no desaturation. This is not a lung condition, so gas exchange is not normally affected.  If there is low sats, then consider that this is not plain croup, but a secondary chest infection/pneumonia or asthma.

Points of difference

Chest infections are 45% mixed viral/bacterial in kids, (15% in adults), croup will have normal sats, but chest infections often desaturate.

Asthma and croup both cough, but asthma cough often demonstrates exploratory wheeze, whereas croup is dry cough with inspiratory stridor.

Both can coexist. Croup can trigger asthma in a susceptible child.

Treatment

Viral infections respond to time, rest, and oral fluids.  So there is no magic bullet.  Symptoms usually resolve in 5-6 days, and if they don't, invariably indicate concomitant opportunistic bacterial infection, or viral invasion to the bronchioles and lungs. Taking a timeline history is therefore important. 

There is a role in managing stridor  with steroidal anti-inflammatories.  In kids, Prednisolone (Predmix) is a favourite.  Alternatively inhaled corticosteroids eg Budesonide or Dexamethasone has been used.  These drugs are not curative, not antiviral, and can predispose the croup sufferer to a greater chance of opportunistic bacterial infection due to their strong immunocompromise effects.  That said, this is rare, and invariably will be used for severe stridor producing croups.  Note that they are slow to work (4-8 hours), so in extremis, when the kid is really working hard to breathe, a quick fix is needed.

As an ED nurse, my first line is adrenaline as a neb.  4mg neat, in the nebuliser and get it on that face.  This should be reserved for the exhausted patient who looks like they are really struggling.

Rarely is oxygen needed, and should not be used unless the sats are South of 95%.

Adrenaline is a vasoconstrictor, and immediately reduces swelling in the larynx and trachea.  Parenteral (subcutaneous or IM) epinephrine can also be used, but  last resort. 

I don't know if I've just been lucky in 25 years as an ED nurse or what, but I have never seen a pure croup need intubation.  In every case I've dealt with, those who crash are mixed URTI with some Asthma or pneumonia complication. 

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The video linked is an example of a child with croup cough

http://youtu.be/Qbn1Zw5CTbA