Spontaneous Pneumothorax

We all see a myriad of patients who complain of chest pain and/or shortness of breath.  We can rapidly develop the differential diagnosis and deftly sort through it without much effort; however, we often still end with the question of whether to order a CXR. I commonly will justify getting a CXR by stating that a spontaneous pneumothorax could be present.  Yes, I know it is rare, but it is a needle in the haystack of disease that warrants consideration.

Basics

• Spontaneous pneumothorax (SPtx) is uncommon… it occurs more commonly in adults than children.
• Most recent data: incidence = 2.6 cases per 100,000
• Primary vs Secondary SPtx
  1. Etiology of SPtx is, bascially, due to connective tissue alterations that predispose to leakage of air from the airways into the pleural space.
  2. Primary SPtx– occurs in the absence of known underlying lung condition
     1. There seems to be a subset of Familial Primary SPtx – so Family Medical History is important.
  3. Seconday SPtx– occurs as a consequence of underlying lung pathology
     1. Asthma, Cystic Fibrosis, Emphysema
     2. Marfan Syndrome, Ehlers-Danlos, Lupus, other connective tissue disorders
     3. Infections
     4. Malignancies (ex, lymphoma)
     5. Foreign Bodies
     6. Congenital malformation
     7. Catamenial (associated with menses)
  4. Secondary SPtx can occur in patient with history of asthma WITHOUT having an asthma exacerbation.

Who is at risk?

• Kids 10-17 years of age are at greatest risk (~94% of SPtx occurred in kids 10 yrs and older).
• Male predominance (~80% of cases are males).
• History of Asthma or tobacco use increases risk.

Presentation

• Most will have Acute Onset of Chest Pain and/or Shortness of Breath
• While actions that increase intrathoracic pressure (lifting, straining, Valsalva, etc) can precipitate SPtx, it often occurs while at rest.
• Patients may actually present in a delayed fashion and note slowly resolving symptoms over the past 1-3 days, but still have a SPtx.
• Examination may be abnormal (decreased breath sounds, symmetric chest rise, etc); however, small Ptx’s or Ptx’s in smaller children may produce no identifiable physical exam abnormalities.
• Minority of patients (6.6% of all SPtx cases) will present with tension physiology (ideally, we’d identify that on examination).

Diagnosis

• Chest X-Ray
  • Upright CXR is most common method to diagnose
  • Can do Decubitus Views to increase sensitivity
•  CT
  • Superior to CXR; however, does that increased sensitivity outweigh the radiation risk (see Radiation Morsel)?
  • CT may be warranted in the work-up of the patient with known pneumothorax to investigate for Secondary Etiology (ex, lung mass) and risk stratify for recurrence (Blebs detected on the contra-lateral side may portend future occurrences).
  • Best to discuss the utility of CT with the surgeon on a case by case basis.
• Ultrasound
  • There are plenty of studies  that demonstrate that U/S is more sensitive than supine CXR in the setting of adult trauma.
    • U/S – ~90% sensitive
    • Supine CXR – ~50% sensitive
    • Erect CXR has increased sensitivity (~90%), naturally.
  • U/S is naturally operator dependent… and in this case the operator is you… so are you dependable?
    • This is a quick basic review of thoracic ultrasound.
    • Look here for a quick demonstration by Dr. Tony Weekes.

Change My Practice?

My humble opinion: For the child that presents with chest pain and/or dypnea you should consider pneumothorax, but that doesn’t necessarily mean you need to obtain a chest xray on all of them.  If the story is concerning (ex, acute onset, persistent, associated with straining/valsalva) then you need to image. Your threshold to image should be lower for those who have history of asthma, use tobacco, have a family history of SPtx, or are older than 10 years of age.

How should you image?  Well, I would advocate for starting with bedside ultrasound (if you are savvy). It has essentially the same sensitivity as erect CXR and has several advantages.

1. It doesn’t require the child to wait for radiology.
2. The kids, particularly the older kids, think it is cool … which earns you patient satisfaction points.
3. There is no radiation, and you can “sell” that to the parents and earn even more satisfaction points.
4. When you are done, you have an answer and that delivers even more satisfaction points!

If U/S is not an option for you… Erect CXR is the answer.  Save CT for pts who have increased risk for other pathology (PE, malignancy, etc).

Management

• Many patients can be managed without intervention (small pneumothorax, minimal symptoms).
• If you are going to do an intervention, consider the most minimally invasive approach first (see procedure videos).
  • Needle aspiration
  • Pigtail Catheter
  • Chest Tube