The autosomal dominant genetic disease NF1 affects approximately 1 in 3000 births [3]. Patients often suffer from malignant neoplasms and various other comorbidities [4,5,6], thus requiring continuous medical support. Vasculopathy is less common though severe complication with an incidence of only 3.6% [7]. The occurrence of hemothorax in the perinatal period has been reported in only three cases of NF1, all postpartum [5, 6]. To the best of our knowledge, this is the first case of massive hemothorax in a pregnant patient with NF1.
In small arteries such as the intercostal artery, invasion by neurofibroma causes intimal thinning of the media, elastic fragmentation, and aneurysmal dilatation, which are influenced by the fragile nature of the vascular tissue [8]. Vascular lesions of small arteries are often asymptomatic and may thus go undetected before severe complications occur.
Hemothorax develops when other factors, such as tumors and aneurysms, overlap with vascular vulnerability [4]. Furthermore, pregnancy might be considered a precipitating factor for hemothorax in patients with NF1. Pregnancy exacerbates NF1 itself [5, 6]; furthermore, increased intrathoracic pressure, blood volume, and cardiac output lead to increased blood pressure. Elevated steroid hormone levels also increase vascular fragility.
Hemorrhagic shock may be overlooked in late pregnancy. Blood volume in late pregnancy is 40–50% higher and the blood pressure may drop after 40% of circulating blood volume (1.5 L) is lost [9]. The fetus is directly affected by this decreased blood flow. In our case, the patient seemed hemodynamically stable despite persistent bleeding. Therefore, we focused on the fetus and performed emergency caesarean section within 1 hour from admission, which was a very high risk procedure for the patient.
Rapid infusion in the emergency room usually targets a blood pressure of 100 mmHg. However, this infusion was insufficient in our patient to maintain fetal circulation. More infusion may have improved the fetal condition and caesarean section could have been avoided. Embolization should be performed immediately with adequate infusion. In our patient, the time to embolization was only 90 min. Her blood pressure improved to 160 mmHg after embolization, indicating the severity of bleeding. Complete bleeding could be halted after 5 h from the time of arrival and there is a dire need to significantly cut down this timing to achieve better outcomes.
For hemorrhagic shock associated with obstetrical bleeding, transport to the operating room and emergency caesarean section should be a priority. However, since our patient presented with hemorrhagic shock from an unknown cause, scrutiny and discussion with obstetrician were necessary. We believe that the fetus could have been rescued if the patient was operated soon after presenting to the hospital. However, embolization delayed more without scrutiny in emergency room.
Several treatments have been reported for hemothorax, including conservative treatment with drainage, thoracotomy, and endovascular coil embolization [3]. In this case, the bleeding site was detected on contrast-enhanced CT; therefore, endovascular treatment was feasible. Surgical repair would not have been safe as the field of view would have been obscured by the massive hematoma and dural ectasia. Furthermore, the proximity of the site of bleeding to the dural ectasia implied a risk of perforation during the procedure. In cases there the site of bleeding extends further to the proximal side, intrathoracic surgical repair is no feasible. Therefore, considering the fragility of the artery, the site of bleeding, and the presence of dural ectasia, surgical repair would have been extremely risky.
This case study demonstrates that, even in cases without gross lesions such as tumors and aneurysms, patients with NF1 have the potential to develop massive hemothorax during the perinatal period. Since it is difficult to prevent this outcome, strict hospitalization or blood pressure control, especially late in pregnancy and postpartum, should be considered in these patients. When massive hemothorax does occur, immediate endovascular treatment with adequate infusion should be preferred.
