Rare disease

CASE REPORT

Major ischaemic stroke caused by an air embolism
from a ruptured giant pulmonary bulla
Johanna F Gudmundsdottir,1 Arnar Geirsson,1 Petur Hannesson,2
Tomas Gudbjartsson1,3
1

Departments of Cardiothoracic
Surgery, Landspitali University
Hospital, Reykjavik, Iceland
2
Department of Radiology,
Landspitali University Hospital,
Reykjavik, Iceland
3
Faculty of Medicine, University
of Iceland, Reykjavik, Iceland
Correspondence to
Professor Tomas Gudbjartsson,
tomasgud@landspitali.is
Accepted 12 February 2015

SUMMARY
We report an extremely rare complication of a major
ischaemic cerebral event caused by an air embolism due
to spontaneous rupture of a giant pulmonary bulla that
occurred during an airline flight. Shortly after take-off,
the patient experienced sudden right-sided hemiplegia
and dyspnoea. Following an emergency landing in
Reykjavik, a CT scan of the brain showed minute air
bubbles consistent with air emboli within the left-sided
intracerebral arteries, and MRI showed signs of acute
ischaemic cerebral infarction in the left hemisphere. The
patient later underwent a pulmonary lobectomy and
survived this life-threatening complication with relatively
mild neurological sequelae.
BACKGROUND
Giant pulmonary bullae (GPB) are air-filled spaces
within the parenchyma of the lung that fill more
than one-third of the hemithorax. GPBs can cause
complications, such as pneumothorax, haemorrhage or lung infections. We report an extremely
rare complication of GPB where major ischaemic
stroke occurred during an airline flight caused by
air embolism from a ruptured GPB.

CASE PRESENTATION

Figure 1 A chest CT scan 2 days after admission, which
shows a giant bulla in the left lung and several smaller
cysts.
admission the GPB was surgically removed with an
upper left lobectomy (figure 4). Pathological examinations revealed a benign thick-walled bulla and
emphysematous lung tissue.

A 58-year-old non-smoking male, previously
healthy, suddenly experienced aphasia and right
hemiplegia during a trans-Atlantic flight, about
20 min after take-off. After emergency landing in
Iceland, he was transported to our hospital in
Reykjavik. On admission he reported left-sided
chest pain with dyspnoea.

INVESTIGATIONS

To cite: Gudmundsdottir JF,
Geirsson A, Hannesson P,
et al. BMJ Case Rep
Published online: [please
include Day Month Year]
doi:10.1136/bcr-2014208159

A chest X-ray showed a large left-sided pneumothorax; a chest tube was inserted. Owing to incomplete lung expansion it was decided to perform a
CT of the thorax, which revealed a 15×13 cm thinwalled GPB in the left upper lobe (figure 1). Urgent
CT of the brain was also performed and showed
several minute air bubbles, consistent with air
emboli, within the left-sided intracerebral arteries
(figure 2). Furthermore, a MRI of the brain showed
signs of acute ischaemic cerebral infarction in the
left hemisphere (figure 3). These findings were compatible with cerebral air embolism and thought to
originate from the GPB in the left hemithorax.

TREATMENT
Our patient received conventional oxygen therapy
and his symptoms improved. One month after

Figure 2 A CT scan of the brain soon after admission,
which shows filling defects in arterioles from the left a.
cerebri media due to air emboli.

Gudmundsdottir JF, et al. BMJ Case Rep 2015. doi:10.1136/bcr-2014-208159

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Rare disease

Figure 3 An MRI of the brain 2 days after admission, which shows
ischaemia in the left hemisphere.

OUTCOME AND FOLLOW-UP
The patient tolerated the operation well and was discharged
2 weeks later. He was then transported back to England, where
he is recovering from his stroke.

DISCUSSION
GPBs are rare, especially in non-smokers. They do not participate in ventilation or gas exchange and have the tendency to
grow and compress the surrounding normal lung tissue, causing
dyspnoea. Most GPBs, however, are diagnosed incidentally on
chest X-ray in middle-aged heavy smokers.1 When complications occur or the bullae occupy more than half of the hemithorax, surgical removal is usually recommended.1

Ischaemic stroke caused by air embolism due to a ruptured
GPB during an aeroplane flight is extremely rare, with only two
cases being previously reported.2 3 In both cases the patients
suffered primary brain injury with sudden onset of unconsciousness shortly after take-off. The clinical presentation of cerebral
gas embolism is determined by the quantity of gas and the areas
of the brain that are affected, ranging from minor motor weakness and headache to convulsion, loss of consciousness and
coma.4 Our patient never lost consciousness and had only mild
cerebral oedema; in contrast, in the two other GPB cases, both
patients lost consciousness, with extensive bilateral intraparenchymal air bubbles and cerebral oedema, one with lethal
outcome.5
Air embolism in patients with pre-existing lung pathology
during air flight is thought to be pulmonary barotrauma due to
pressure change during ascent. The pressure drop causes an aircontaining bulla to expand, which can cause tears of its wall
and leakage into the circulation.5 The GPB in the present case
most likely ruptured into the pulmonary veins, from where the
air travelled to the left heart and embolised to the arterial cerebral circulation. The cerebral involvement is probably due to the
sitting position of the patient.
Neurological deficit due to cerebral air embolism may be
reversible. Treatment usually consists of administration of
oxygen, which can counteract ischaemia and reduces the size of
air bubbles by depleting intravascular nitrogen.4 Hyperbaric
therapy has also been suggested in intracerebral air embolism,
compressing the bubbles and reducing the extent of inflammation caused by their presence.4 However, to our knowledge,
there are no cases reported where this treatment has been used
in a case due to ruptured GPB.
Our patient received only conventional oxygen therapy and
his symptoms improved. The outcome was favourable, mostly
related to small areas of cortical involvement.
This case demonstrates how previously healthy patients can
suddenly develop severe neurological deficits from ruptured
GPB during air travel.

Learning points
▸ A pulmonary bulla is generally asymptomatic and the
diagnosis is incidental. Complications are uncommon.
▸ Surgical resection of giant pulmonary bullae is indicated for
patients who present with complications, such as rupture,
pneumothorax, bleeding and infection.
▸ Changes in atmospheric pressure can lead to rupture of a
previously asymptomatic pulmonary bulla and cause gas
embolism into the circulation.
▸ Patients with cerebral gas embolism can benefit from
hyperbaric oxygen treatment and resection of the pulmonary
lesion to avoid further complications.
▸ Patients with known pulmonary bullae should be warned of
the possibility of expansion of the bulla in situations of
variations of atmospheric pressure, such as air travel and
deep sea diving.

Figure 4 A picture of the resected left upper lobe. The giant bulla
has been cut open.
2

Contributors JFG contributed in the study design, collection and analysis of the
data, and writing and revision of the manuscript. AG and PH contributed in the
analysis and collection of data, and revision of the manuscript. TG is the guarantor,
and was involved in the management of the case, study design, collection and
interpretation of the data, writing and revision of the manuscript.
Gudmundsdottir JF, et al. BMJ Case Rep 2015. doi:10.1136/bcr-2014-208159

Rare disease
Competing interests None.
Patient consent Obtained.

2
3

Provenance and peer review Not commissioned; externally peer reviewed.

REFERENCES
1

Greenberg JA, Singhal S, Kaiser LR. Giant bullous lung disease: evaluation, selection,
techniques, and outcomes. Chest Surg Clin N Am 2003;13:631–49.

4
5

Salameh J. A 62-year-old woman with cerebral artery air embolism during
commercial air travel. Neurologist 2010;16:136–7.
Yeung JTH, Ma JKF, Lam VSC. Fatal cerebral air embolism related to an air flight.
Hong Kong Med J 2013;19:352–3.
Muth CM, Shank ES. Gas embolism. N Engl J M 2000;342:476–82.
Almeida FA, Desouza BX, Meyer T, et al. Intrapulmonary bronchogenic
cyst and cerebral gas embolism in an aircraft flight passenger. Chest
2006;130:575–7.

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Gudmundsdottir JF, et al. BMJ Case Rep 2015. doi:10.1136/bcr-2014-208159

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