Clinical Practice Guideline
Developed for the
Aerospace Medical Association
by their constituent organization
Overview: Spontaneous pneumothorax is best defined as “air in the pleural space of non-traumatic cause.” Secondary spontaneous pneumothorax is one that occurs in the presence of underlying parenchymal or airway disease, and for aviation purposes will not be considered further. Primary spontaneous pneumothorax, by default, is one that occurs in the absence of such underlying disease. However, it would be incorrect in such cases to define the lung as normal, since the vast majority prove to have visceral subpleural blebs at thoracoscopy. Most cases of primary spontaneous pneumothorax occur at rest, and it is actually unusual to see cases in the athletic realm.
Primary spontaneous pneumothorax typically peaks in the 10 to 30 year age group, affecting males about 5 to 10 times more frequently than females. The age-adjusted incidence in males is estimated to be about 7.4/100,000/yr and 1.2/100,000/yr in females (1979 data from Olmstead County, Minnesota). It occurs primarily in tall, thin individuals and is rare in those over the age of 40. Smoking has been shown to increase the risk of primary spontaneous pneumothorax by a factor of 20 in a dose-dependent manner. More than 20,000 new cases of spontaneous pneumothorax occur each year in the United States at a cost of more than $130 million (2006 costs). Although the incidence in the general population is usually quoted as 9 per 100,000, the real incidence is probably higher. In most large series, 1% to 2% are incidentally found on chest film; since small pneumothoraces resolve themselves within a few days, the odds of identifying an asymptomatic pneumothorax in this way are slim, arguing that the disease is probably more common than thought.
The classic presentation in a symptomatic patient with spontaneous pneumothorax is dyspnea and pleuritic chest pain. The chest pain is almost always ipsilateral and may radiate to the shoulder, neck, and into the back. Physical exam may demonstrate tachycardia, tachypnea, hyperresonance to percussion, diminished breath sounds, and asymmetrical chest wall expansion may be present. There are also a multitude of possible ECG changes that can be seen in the setting of a pneumothorax. The diagnosis is best confirmed with a standard chest film. Expiratory films are no more sensitive than inspiratory films in detecting pneumothoraces and are not recommended. If present on the chest film, it will demonstrate a pleural line.
A specific subcategory that deserves mention is catamenial pneumothorax. This is a spontaneous pneumothorax occurring in a female within 48 to 72 hours of the onset of menses. Although these are often ascribed to endometriosis, pleural endometrial implants have been identified in only a third of patients. It is important to question any female with a spontaneous pneumothorax about the timing in relationship to menses, since the initial treatment of catamenial pneumothorax is hormonal. Should the patient fail a trial of contraceptive steroids, this disorder responds well to the same prophylactic surgical treatments described below.
Depending on the size of the pneumothorax, acute treatment may consist of observation, usually combined with oxygen, which hastens resolution (rate of pleural air absorption in the absence of supplemental oxygen is 1.25%/day; this is increased 3-4X in the presence of supplemental oxygen); simple aspiration of the air, which is successful about 65% of the time; or catheter or tube thoracostomy. There has been discussion for many years as to the emergency management of spontaneous pneumothorax. For many years, the gold standard was insertion of a chest tube (tube thoracostomy). Recent evidence indicates that needle aspiration is at least as safe and effective as tube thoracostomy and also carries the benefit of fewer hospital admissions and shorter length of hospital stay.
The major issue with spontaneous pneumothorax is recurrence. After an initial pneumothorax, the chance of recurrence in the absence of definitive treatment is 20 to 50%, a risk which probably rises after subsequent episodes. (some researchers have shown that after two pneumothoraces, the risk of a third is 62%; of those who have had three episodes, 83% will have a fourth). The clinical standard care for a number of years has been to perform a definitive surgical procedure after the second pneumothorax, but with the availability of thoracoscopic pleurodesis, there are many who feel that surgery is indicated after the first episode, particularly in those who are at high risk because of their occupation or because of travel to remote areas.
The definitive procedure until relatively recently was pleurodesis which was accomplished via the chest tube by inserting a sclerosing substance into the pleural space causing the pleura to adhere to the chest wall thereby preventing recurrences. The most common substances used were tetracycline or talc. The recurrence rate with each of these was not totally acceptable and also was potentially fraught with unacceptable side effects. Problems with talc therapy range from pain and fever to respiratory failure and ARDS. The newer and more successful interventions are surgical. Thoracotomy can lead to recurrence prevention by either mechanical abrasion pleurodesis or pleurectomy.
Aeromedical Concerns: The most likely symptoms are chest pain and dyspnea, either of which could be incapacitating in aircrew. There is also the concern with gas expansion at altitude in untreated pneumothorax in aviators. In a review of 112 aviators with spontaneous pneumothorax, 37% admitted they could have been incapacitated had the episode occurred during flight. Overall, seventeen percent of the episodes occurred under operational conditions. Eleven percent actually occurred during flight, although it was unclear how many of these resulted in mission aborts. Of note, another 6% occurred in the altitude chamber, and all but one of those occurred after rapid decompression.
Medical Work-up: Medical evaluation for an aviator with the diagnosis of pneumothorax should include a complete history of the event to include any possible predisposing factors. Also, report documentation of all treatments given and all labs/imaging reports. Copies of all operative reports and a statement from treating physician are also necessary.
Air Force: Current Air Force policy states that a history of spontaneous pneumothorax or pulmonary blebs/ bullae are disqualifying for aviation duties. A single episode of spontaneous pneumothorax does not require waiver if PA inspiratory and expiratory chest radiograph and thin-cut CT-scan show full expansion of the lung and no demonstrable pathology which would predispose to recurrence. After a second pneumothorax, or if CT demonstrates residual blebs, waiver may be considered only after definitive surgery to prevent recurrence. Pneumothorax is not disqualifying for FC IIU, nor for GBC/ATC or SMOD personnel.
In summary, any form of definitive surgical pleurodesis is acceptable for waiver, but thoracoscopic abrasive pleurodesis appears to offer the best combination of efficacy and minimal morbidity. Chemical pleurodesis with talc, tetracycline compounds, or other pleurodesing agents is generally not acceptable for waiver. If chemical pleurodesis has been completed prior to entry into the military service or an aviation career field, a waiver may be considered on a case-by-case basis after review by the ACS.
Army: Spontaneous Pneumothorax is disqualifying for aviation training. Army concerns are identical to those of the Air Force. Previous history of a spontaneous pneumothorax is disqualifying for initial flight applicants who normally are not granted waiver for this history. In rated aircrew, a single instance of spontaneous pneumothorax requires no waiver, but the crewmember must be grounded locally for at least 2 months or until complete recovery, normal PFTs, and no underlying pathology is documented. Waiver may be possible for patients with recurrent spontaneous pneumothorax after surgical pleurodeisis and a satisfactory 6 month observation period. The initial work-up of spontaneous pneumothorax focuses on looking for underlying associated pathology and abnormal anatomy. It includes a chest x-ray, thin cut CT and PFTs.
Navy: Traumatic Pneumothorax: Traumatic or surgical pneumothorax during the preceding year is Considered Disqualifying (CD). Waivers are considered on a case by case basis during the first year following the injury after complete healing and when the member is determined to be fit for full duty by the pulmonologist or surgeon. After one year, the condition may not be disqualifying (NCD) when the same consultation criteria are met. If a waiver is requested and granted, during the first year following the event, another Aeromedical Summary must be submitted to NAMI for subsequent consideration of removing the waiver to a medically qualified status when appropriate.
Spontaneous Pneumothorax: Primary spontaneous pneumothorax is CD. A waiver can be considered based upon the guidelines below. A subsequent reoccurrence of spontaneous pneumothorax is CD. No waiver will be recommended unless surgical or chemical pleurodesis has been performed.
Single episode of spontaneous pneumothorax: The applicant may be considered for waiver of standards one year after the resolution of the pneumothorax if treated solely with chest tube reinflation. High resolution CT scan must prove no pathology (blebs or underlying parenchymal disease) and pulmonary function tests must be within normal limits. If treated surgically or chemically, a waiver may be considered six months following resolution, provided the required studies are normal. All applicants must first be granted a waiver for commissioning before an aviation waiver can be considered. The commissioning waiver document must be submitted to NAMI with the aviation waiver request. Altitude chamber runs are not required for disposition and/or waiver recommendation.
Recurrent spontaneous pneumothorax: Permanently disqualifying. No waivers will be recommended unless chemical or surgical pleurodesis has been performed resulting in a normal high-resolution chest CT scan and normal Pulmonary Function Testing (PFT).
Single episode of spontaneous pneumothorax: A waiver request may be submitted three months after resolution of the condition. The submission must include the required information. For designated personnel who undergo chemical or surgical pleurodesis, a waiver request may be submitted three months after resolution of the condition. An altitude chamber run is not required for disposition and/or waiver recommendation.
Recurrent spontaneous pneumothorax: CD, waiver not recommended. Waivers may be considered only after definitive treatment (chemical or surgical pleurodesis) to prevent recurrence. Designated personnel who undergo chemical or surgical pleurodesis may be returned to flying status after three months
INFORMATION REQUIRED FOR WAIVER CONSIDERATION:
1. Thin cut, high-resolution chest CT scan demonstrating full lung expansion and no pathology that could predispose to recurrence
2. Normal Pulmonary Function Test results
3. Thoracic surgery consultation (in recurrent cases, or in cases with structural abnormalities)
All recognized forms of treatment (chemical or surgical pleurodesis) are acceptable for waiver consideration. Recurrence rate after chemical pleurodesis is higher than after thoracotomy and pleural abrasion.
Civilian: Depending on the pulmonary evaluation that the airman provides this may result in a request for a CT scan of both lungs looking for blebs. Should there be blebs, issuance may not occur. This will generally result in the case being referred to a FAA Pulmonary consultant. If a second pneumothorax occurs a CT scan will definitely be required and the airman may not gain issuance if there are pulmonary blebs.
Air Force: AIMWTS review revealed 66 aircrew members with an aeromedical summary and the diagnosis of pneumothorax. There were 20 FC I/IA cases, 23 FC II cases, 0 FC IIU cases, 23 FC III cases, and 0 GBC/ATC/SMOD cases. Fifty-three of the 66 cases were granted a waiver. Of the 13 disqualified (four FC I/IA, four FC II, and five FC III), eight were due to either multiple episodes of pneumothoraces, inadequate treatment, or major side effects of pneumothoraces.
Army: Spontaneous Pneumothorax has been a relatively uncommon diagnosis among rated Army aviators. Most people with predisposing conditions are eliminated as applicants. Between 2009 and 2011 there was an average rated aviator population of 14919 as identified by having an annual flight physical. During this period, there was an average of 3.67 cases carrying the diagnosis of spontaneous pneumothorax yielding an average one year period prevalence of 2.46 cases per 10,000 aircrew. A review of the incidence of spontaneous pneumothorax cases during this period shows that there were 3 rated aircrew discovered and 6 applicants newly discovered to have this history on annual exam. In all cases but one the pneumothorax was not felt to be significant. Only one person, an applicant, was found to be disqualified, though in this case it was for an unrelated finding so his history of spontaneous pneumothorax did not affect his disposition.
Navy: Not available at this time
Civilian: As of December 2011 there were 266 first-, 110 second-, and 273 third-class airmen currently issued who have had a pneumothorax.
ICD 9 codes for Pneumothorax
Spontaneous tension pneumothorax
Other spontaneous pneumothorax
Traumatic pneumothorax and hemothorax
Traumatic pneumothorax without mention of open wound into thorax
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Prepared by Drs. Hans Bruntmyer, Joshua Sill, and Dan Van Syoc
May 21, 2012