Asthma or vocal cord dysfunction? Would you know the difference

Vocal cord dysfunction vs Asthma flare up. 

The patient comes in, breathless, panic stricken coughing and has a wheeze, audible from the doorway.  She is pale, distressed and clutching at her "puffers" claiming they are not working.

The usual approach to managing this "Asthma Attack**" is to sit her upright, and administer a battery of doses of salbutamol. 

Standard dose is 4 puffs via her metered aerosol using a spacer device.  

One puff-4 breaths

One puff-4 breaths

One puff-4 breaths

One puff-4 breaths

Wait 4 minutes and repeat.

But for many people suffering an asthma flare up (** new term for asthma attack), the routine use of a SABA (short acting beta agonist) like Ventolin, will be ineffective.

It is estimated that up to 75% of asthma flares could be vocal cord  dysfunction (VCD).

Where salbutamol exerts its effectiveness, is on the smooth muscle in the lower airways. During VCD the dyspnoea is caused by the closing of the vocal cords, and unlike asthma which is allergic or hyperresponsiveness to a trigger, VCD is often psychogenic.  It responds not to drugs, but calm breathing, and relaxation.

Now we are not saying "don't give salbutamol", but there is immense value in adjuncting breath coaching during assessment and management of what may be asthma, but might just be VCD.

So how would you differentiate the two?  Three fairly simple assessments.

1. Asthma wheeze is primarily on expiration. It is a low airways disease. Auscultation of a wheeze in lung fields should exclude a throat wheeze (called stridor).  In VCD there is no lung noise, it is all upper airway.

2 Asthma cough is the first symptom to manifest, it is associated with over production of white to cream sputum from the Goblet Cells lining the bronchial tree.  In VCD the secretions being coughed are watery, spittle and salivary. It lacks the viscoelastic lustre of true bronchial sputum.

3 Desaturation is usually not present in VCD.  Being all laryngeal obstruction, alveoli gas exchange impairment, and gas trapping is not a feature, as it is in Asthma.

Anxiety is the dominant feature in VCD. I know all you asthmatics out there will say "not being able to breathe does make you anxious... And it does!! But this is a Chicken or the egg scenario.

In Asthma, real asthma, a physiological trigger is the norm, leading to a flare up then anxiety follows. Asthma is bronchial restriction

In VCD anxiety is the trigger which crescendoed into a worsening Shortness of breath.

VCD is often idiopathic. It is all in the vocal tissue.

And while it causes asthma-like symptoms. It is all too commonly misdiagnosed as an asthma attack. When you treat VCD as an assumed asthmatic with oxygen and bronchodilators, and you find these modalities have very little to no effect and may even exacerbate anxiety and symptoms, a focus on anxiety reduction is key.

In these patients, stay with the person, and have them focusing on their breathing.  Talk them down, and offer encouragement.

Oxygen is not indicated for either condition unless O2 sats are <93% ( <95% in kids).