Related Experiment Video
Updated: Jul 16, 2026
Creating Radio-cephalic Arteriovenous Fistula in the Forearm with a Modified No-Touch Technique
Published on: April 1, 2022
[A case of pulmonary arteriovenous fistula]
Kozo Morimoto1, Takefumi Saito, Takio Takaku
1Department of Respiratory Medicine, National Hospital Organization Ibarakihigashi National Hospital.
Abstract:
A 31-year-old man presenting with abrupt onset of convulsions was transported by ambulance to a nearby neurosurgery hospital. Imaging examination of the brain revealed a brain abscess in the left parietal lobe. Surgical excision of the abscess was performed. After the operation, the patient was referred to our hospital because of abnormal radio-opacities on the chest X-ray film, which were subsequently diagnosed to represent pulmonary arteriovenous fistulae in the lower lobes of both lungs. The fistulae were successfully embolized with detachable coils. Orthodeoxia (worsening of hypoxemia on assuming the upright from the supine position) was confirmed by measuring the partial pressure of oxygen in the arterial blood. We examined the shunt ratio by both the 100% O2 inhalation and 99mTc-MAA methods, and a higher ratio was obtained with the radioisotope method than with the 100% O2 inhalation method. Although it is known that the 99mTc-MAA method is more precise than the 100% O2 inhalation method, the latter is easier to perform and therefore more useful in practical clinical situations.
Insights
A patient with a brain abscess developed pulmonary arteriovenous fistulae, causing orthodeoxia. Embolization resolved the fistulae, but the study compared methods for measuring shunting, finding the 99mTc-MAA method more precise than 100% O2 inhalation.
Area of Science:
- Neurosurgery
- Pulmonary Medicine
- Radiology
Background:
- Brain abscesses can present with neurological symptoms.
- Pulmonary arteriovenous fistulae (PAVF) are abnormal connections between pulmonary arteries and veins.
- Orthodeoxia, or worsening hypoxemia in an upright position, can indicate intrapulmonary shunting.
Observation:
- A 31-year-old man with a left parietal lobe brain abscess developed abnormal chest X-ray findings post-surgery.
- These findings were diagnosed as bilateral lower lobe pulmonary arteriovenous fistulae.
- The patient exhibited orthodeoxia, confirmed by arterial blood gas measurements.
Findings:
- Pulmonary arteriovenous fistulae were successfully treated with embolization using detachable coils.
- Shunt ratios were evaluated using 100% O2 inhalation and 99mTc-MAA methods.
- The 99mTc-MAA method yielded a higher shunt ratio compared to the 100% O2 inhalation method.
Implications:
- This case highlights a rare association between brain abscesses and pulmonary arteriovenous fistulae.
- Accurate measurement of shunt fraction is crucial for managing hypoxemia.
- While 99mTc-MAA is more precise, the 100% O2 method offers clinical practicality due to its ease of performance.
