Surgical management of refractory massive hemoptysis from pulmonary artery pseudoaneurysm due to Streptococcus constellatus: a rare case report and literature review

Abstract

Pulmonary artery pseudoaneurysm (PAP) is a rare but potentially fatal vascular lesion resulting from focal disruption of the pulmonary arterial wall. Although hemoptysis from the pulmonary arterial system is uncommon, PAP carries a high risk of rupture, with reported mortality rates up to 50%. PAP is most often caused by trauma or infection, with pyogenic bacteria and fungi as typical pathogens, while Streptococcus constellatus is an exceptionally rare cause. A 60-year-old woman with well-controlled type 2 diabetes presented with recurrent massive hemoptysis, fever, and right-sided pleuritic chest pain, without prior lung disease or trauma. She initially underwent emergency bronchial artery embolization (BAE) and antibiotic therapy for necrotizing pneumonia-associated hemoptysis, with no clinical improvement. Following the second BAE for recurrent massive hemoptysis, a PAP, possibly related to a bronchial-pulmonary arterial shunt, was suspected in the right lower lobe on angiography and subsequently confirmed on contrast-enhanced computed tomography. Despite optimal medical therapy, repeated BAE, and coil embolization of the PAP, hemoptysis persisted, and respiratory status deteriorated. The patient ultimately underwent video-assisted thoracoscopic right lower lobectomy, with intraoperative cultures of lung tissue and pleural fluid confirming S. constellatus, and achieved complete recovery without recurrent hemoptysis. PAP is a rare but potentially fatal cause of hemoptysis that requires a high index of suspicion. Although endovascular intervention is effective for initial hemorrhage control, persistent infection or refractory hemoptysis may necessitate surgical resection to achieve definitive management. This case highlights S. constellatus as an exceptionally rare infectious cause of PAP and underscores the importance of a multidisciplinary approach in complex, antibiotic-resistant cases.

Introduction

Pulmonary artery pseudoaneurysm (PAP) is a rare but potentially life-threatening lesion resulting from focal disruption of the pulmonary arterial wall, in which the outer wall is formed by the media or adventitia together with surrounding tissues, rather than by all three arterial layers. ¹ Hemoptysis arising from the pulmonary arterial system accounts for only about 6.9%–10% of all cases with hemoptysis, and PAP is an exceptionally uncommon cause.^2,3 Despite its rarity, PAP carries a high risk of rupture, reported at approximately 42%, and rupture may result in massive hemoptysis with mortality rates reaching up to 50%.^{3 –5} The causes of PAP are heterogeneous, with trauma and infection representing the two most common etiologies.^4,6,7 Streptococcus constellatus is an infrequent cause of PAP, with only two cases reported to date.^8,9

Management of PAP is challenging due to its rarity, diverse etiologies, and unpredictable clinical courses. Treatment options include conservative medical management (including close monitoring, hemostatic therapy, and treatment of the underlying cause), endovascular intervention, and surgical resection.^7,10,11 Endovascular intervention is considered first-line therapy because it is minimally invasive and achieves high rates of hemoptysis control.^5,7,12 Surgical resection remains crucial in selected cases, particularly in patients with massive or refractory hemoptysis, infection unresponsive to antibiotics, failure or recurrence after endovascular treatment, or PAP caused by aggressive pathogens such as mucormycosis, where lobectomy may provide definitive salvage therapy.^5,6

Here, we report a rare and complex case of PAP secondary to S. constellatus infection in a patient presenting with recurrent massive hemoptysis. This case is notable for several unusual features, including the extreme rarity of the causative pathogen, the coexistence of necrotizing pneumonia, persistence of massive hemoptysis despite multiple bronchial artery embolizations (BAE) and pulmonary artery coil embolization, and the ultimate need for surgical lobectomy to achieve definitive control. This report underscores the importance of considering uncommon infectious pathogens in PAP and the complementary role of surgery in the multidisciplinary management of refractory hemoptysis.

We adhered to the relevant CARE guidelines (see Supplemental Material). ¹³ These guidelines require the inclusion of essential components such as the title, keywords, abstract, case presentation, patient details, clinical findings, diagnostic evaluation, therapeutic interventions, outcomes and follow-up, discussion, patient perspective, informed consent, and an ethics statement.

Case presentation

A 60-year-old woman with a history of well-controlled type 2 diabetes was admitted with massive hemoptysis (approximately 200 mL/day), a fever of 38°C, and right-sided pleuritic chest pain. She denied any history of malignancy, chest trauma, autoimmune connective tissue disease, pulmonary tuberculosis, bronchiectasis, anticoagulant use, or any prior episodes of hemoptysis. Twenty days before the current admission, the patient developed massive hemoptysis (400 mL/day) with right-sided pleuritic chest pain, persistent low-grade fever (38°C), and mild dyspnea. She presented to our hospital and underwent an emergency BAE using a 5F Cobra catheter, a 5F Shepherd’s hook catheter, and Asahi 2.6F microcatheters. Embolization of hypervascular branches in the lower third of both lungs, supplied by the left bronchial artery and the right intercostal-bronchial trunk, was performed using NBCA mixed with lipiodol (1:6) (Figure 1(a) and (b)), achieving complete occlusion (Figure 1(c)). A chest radiograph showed necrotizing consolidation in the lower lung fields bilaterally, with necrotic tumor or abscess formation not excluded. The patient did not undergo a contrast-enhanced chest computed tomography (CECT) before BAE due to ongoing massive hemoptysis. CECT was planned after clinical stabilization; however, the patient declined hospitalization and was discharged with a 14-day outpatient regimen consisting of amoxicillin/clavulanic acid 875/125 mg twice daily, clindamycin 300 mg three times daily, and tranexamic acid 250 mg three times daily.

Figure 1.

Endovascular interventional imaging. (a–c) were obtained during the first BAE, (d) during the second BAE, and (e, f) during coil embolization of PAP. Hypervascularity of vascular branches in the lower third of the right lung supplied by the right intercostal-bronchial trunk (a) and in the left lower third lung supplied by the left bronchial artery (b), with complete occlusion after NBCA embolization (c). Hypervascular vessels in the upper left lung are supplied by the left bronchial artery (d). PAP in the right lower lobe measuring 10 × 15 mm (yellow arrow) (e). Post-coil embolization angiogram showing complete occlusion of the PAP (blue arrow) (f).

BAE, bronchial artery embolization; PAP, pulmonary artery pseudoaneurysm

Over the next 20 days, the patient’s hemoptysis decreased to 50 mL/day but did not resolve. She became afebrile but continued to have mild right-sided pleuritic pain. On the day of the current admission, she developed recurrent massive hemoptysis (200 mL/day) and returned to the Emergency Department. She was alert, with a heart rate of 120 bpm, blood pressure of 110/70 mmHg, temperature of 38°C, and SpO₂ of 94% on 4 L/min nasal oxygen. Crackles were present in the lower right lung. A second emergency BAE, performed on hospital day 1, demonstrated hypervascular vessels in the left upper lobe supplied by the left bronchial artery, which were embolized using 500–700 µm Embosphere particles, achieving complete occlusion (Figure 1(d)). A pseudoaneurysm of a right lower-lobe pulmonary artery branch was also identified during evaluation of the bronchial arterial circulation, strongly suggesting the presence of a bronchial-to-pulmonary artery shunt. However, no hypervascularity was observed in the bronchial arterial branches supplying the right lower lobe, and these vessels had already been embolized during the first BAE. Therefore, no further empiric embolization was performed, and the procedure was concluded. Laboratory tests (Table 1) showed anemia with a normal white blood cell (WBC) count, and abdominal ultrasound, ECG, and transthoracic echocardiography were all normal. Sputum culture was not obtained due to the inability to expectorate. Chest X-ray on admission revealed consolidation with collapse of the right lower lung (Figure 2(a)). CECT, performed on hospital day 3, showed consolidation with central necrosis in the right lower lobe and a PAP arising from the A9 segmental artery within the necrotic area (Figure 3). Despite optimal conservative therapy, including nebulized adrenaline, tranexamic acid, antitussives, and fluid resuscitation, hemoptysis persisted at 100 mL/day during the first three hospital days. The patient subsequently underwent coil embolization of the PAP on hospital day 4, using three coils (Figure 1(e)), and post-procedural angiography confirmed complete occlusion (Figure 1(f)).

Table 1.

Laboratory findings of the patient during hospitalization.

Test (normal value)	Day 1	Day 7	Day 10	Day 15
Hemoglobin (120–170 g/L)	98	69	71	80
White blood cell counts (4–11 G/L)	8.5	13.7	27.61	12.5
%Neutrophil (45–75%)	48.7	73.4	83.2	75.6
Platelet counts (200–400 G/L)	291	428	303	242
Prothrombin time (10–13 s)	12.7
INR (1.0–1.2)	1.2
aPTT (26–37 s)	27.2
ALT (SGPT) (5–49 U/L)	17
AST (SGOT) (9–48 U/L)	36
Serum creatinine (0.7–1.5 mg/dL)	0.44		0.72
C-reactive protein (<6 mg/L)		185.7		60
HbA1C (4–7%)	5.36
Blood culture for bacterial	Negative

Abnormal values are highlighted in bold.

Figure 2.

Chest radiographs of the patient. At admission (day 1), showing consolidation with collapse of the right lower lobe and surrounding ground-glass opacity (a). On hospital day 6, demonstrating progression of consolidation and collapse of the right lower lobe, with the coil visible (red arrow) (b). Three-month follow-up, showing post-operative changes after right lower lobectomy (c).

Figure 3.

Contrast-enhanced chest computed tomography. High-attenuation embolic materials (red arrows) (a). Abnormal contrast extravasation suggestive of a pulmonary artery pseudoaneurysm (yellow arrows) within an area of consolidation with central necrosis (b and c). Pulmonary angiographic reconstruction revealing a round pseudoaneurysm arising from the A9 segmental artery of the right lower lobe, measuring 10 × 15 mm (yellow arrow) (d).

Despite optimal conservative therapy, two episodes of BAE and coil embolization of the PAP, the patient’s hemoptysis persisted. On hospital day 6, she continued to bleed (200 mL/day), developed high fever (39°C), and showed worsening respiratory failure requiring 6 L/min of oxygen to maintain SpO₂ at 92%. Laboratory tests revealed elevated CRP and leukocytosis (Table 1), and chest X-ray findings showed no improvement (Figure 2(b)), prompting initiation of intravenous (IV) vancomycin (1 g twice daily) and piperacillin/tazobactam (4.5 g four times daily). Between hospital days 6 and 12, hemoptysis improved markedly, decreasing to 20 mL/day. On day 13, she underwent video-assisted thoracoscopic right lower lobectomy, which revealed a consolidated, friable lobe. Histopathology showed bronchial fibrosis, glandular atrophy, chronic inflammatory infiltration, and columnar metaplasia, consistent with organizing pneumonia (Figure 4). Intraoperative cultures of lung tissue and pleural fluid grew S. constellatus, resistant to clindamycin and erythromycin but sensitive to vancomycin. She continued IV antibiotics, had her chest tube removed after 2 days, and was discharged 1 week later. A 3-month follow-up radiograph showed expected post-lobectomy changes, and she remained fully recovered without recurrent hemoptysis (Figure 2(c)).

Figure 4.

Histopathological findings of the resected lung tissue. (H&E, 100×) Fibrotic lung parenchyma with thickened alveolar septa and mixed inflammatory infiltrates consisting of lymphocytes, macrophages, neutrophils, and eosinophils (a). (H&E, 200×) Intrabronchiolar (red arrow), alveolar duct, and alveolar fibrosis with accompanying inflammatory infiltrates, including lymphocytes, macrophages, plasma cells, and eosinophils within the alveolar septa (b). (H&E, 400×) Nodular fibrosis (blue arrow) within the alveolar spaces. Eosinophils infiltrate the fibrotic nodules, and macrophages are present along the alveolar septa (c). (Masson-Trichrome, 400×) Fibrotic nodules within the alveolar spaces show light blue staining (d).

Discussion

This case adds to the existing literature by reporting a rare case of S. constellatus-associated necrotizing pneumonia that directly forms PAP. From this experience, several important clinical practices can be highlighted. First, computed tomography angiography (CTA) should be routinely performed in patients with hemoptysis, particularly before endovascular intervention, because catheter-based pulmonary or bronchial angiography may fail to detect PAP. Second, PAP should be considered in cases of massive or refractory hemoptysis, even when BAE appears technically successful. Third, in PAP caused by antibiotic-resistant pathogens, surgical resection should be considered early as definitive therapy, given the risk of persistent infection and pseudoaneurysm recurrence.

PAP remains uncommon, with reported prevalence ranging from 5% to 11% among hospitalized patients with hemoptysis undergoing bronchial or pulmonary angiography, and approximately 2% in large CTA-based series.^4,6 PAP is frequently overlooked in the differential diagnosis of hemoptysis, with up to 46% of cases missed on initial imaging, even on CECT.^1,6 These findings highlight the need for clinical suspicion, early diagnosis, and timely intervention, especially in high-risk rupture patients, to prevent catastrophic bleeding and improve clinical outcomes. Kalra and Shin proposed a classification system for PAP based on diagnostic modality, the arterial system supply to the pseudoaneurysm (pulmonary, bronchial, or non-bronchial systemic arteries), and the presence of bronchopulmonary arterial shunts, categorizing PAP into four types.^4,5,14 Our case most likely represents a type B PAP, which is typically detected only on selective pulmonary angiography of segmental or subsegmental branches. This pattern has been attributed to stenosis or occlusion of the feeding pulmonary artery or to prominent bronchopulmonary arterial shunts, resulting in reversed pulmonary arterial flow or reduced perfusion of the affected lung segment. The visualization of PAP on repeat BAE in our patient may be explained by bronchopulmonary shunting with flow reversal into the PAP. In contrast, type D PAPs are identifiable exclusively on CTA and are not visualized on catheter angiography, likely due to occlusion of the feeding pulmonary artery combined with delayed contrast filling and the absence of bronchopulmonary arterial shunts.^{3 –5,14,15} In a retrospective series of 58 PAPs, 86% were infection-related, with subtype distributions of 0% type A, 31% type B, 25% type C, and 2% type D. ⁴ Another study of 24 infection-associated PAPs reported frequencies of 21%, 42%, 21%, and 17% for types A, B, C, and D, respectively. ¹⁴ Collectively, these data suggest that infection-related PAPs show heterogeneous angiographic patterns, with PAP type B being the most frequently observed.

The etiologies of PAP are heterogeneous, with infection and trauma being the most common. The prevalence of each cause varies across centers, reflecting differences in patient populations, epidemiology, and disease patterns. In a U.S. retrospective study (2000–2014) involving 24 PAP patients, infection was the leading cause (33%), predominantly associated with tricuspid valve endocarditis and focal pneumonia, followed by trauma (17%) and malignancy (13%). ⁶ In contrast, a recent Chinese retrospective cohort (2019–2022) of 50 patients demonstrated a marked predominance of infectious etiologies (86%), largely related to prior or active pulmonary tuberculosis. ⁴ Infectious causes of PAP can be divided into pulmonary and systemic infections. Local pulmonary infections (e.g., necrotizing or cavitary pneumonia and lung abscess) directly erode adjacent pulmonary arteries via contiguous spread, leading to outside-in wall destruction and proximity to necrotic consolidation or cavities.^3,10,16 In contrast, systemic infections, including infective endocarditis, septic thrombophlebitis, and sepsis, cause PAP via hematogenous microbial seeding and formation of infected intraluminal thrombi, with vascular injury progressing from the intima outward. Consequently, PAPs secondary to systemic infection may occur isolated from parenchymal lung lesions and present as multiple PAPs.^2,3,6 Distinguishing between these mechanisms is clinically relevant for imaging interpretation, etiological assessment, and therapeutic decision-making. The spectrum of infectious pathogens is broad, including pyogenic bacteria (e.g., Staphylococcus aureus, Pseudomonas, Streptococcus, Klebsiella, Actinomyces), Mycobacterium tuberculosis, fungi (Aspergillus, Mucorales, Candida), and viruses (COVID-19, H1N1), underscoring the diverse infectious pathogens of PAP and the importance of accurate pathogen identification to guide treatment.^{1,4 –6,16} In our case, S. constellatus was isolated from intraoperative specimens, including lung parenchyma and pleural fluid. This organism is an exceptionally rare cause of PAP, and to our knowledge, this represents the third reported case in the current literature. Previously, Lesage described an 11-year-old girl with Lemierre syndrome who developed multiple PAPs with massive hemoptysis, in which S. constellatus was identified by positive blood cultures, representing indirect microbiological evidence of PAP. ⁹ Morinaga reported a 63-year-old man with pneumonia and massive hemoptysis who underwent surgical resection, with histopathology confirming PAP formation and S. constellatus isolated from surgical tissue, providing direct microbiological evidence. ⁸ The need for surgical sampling in our patient further highlights that accurate pathogen identification of PAP can be challenging.

PAP should be suspected in patients with sudden-onset massive hemoptysis, underlying diseases such as necrotizing or cavitary pneumonia or lung malignancy, recurrent or persistent hemoptysis despite technically successful BAE, unremarkable bronchial angiography, or the presence of a focal saccular or nodular contrast-enhancing lesion on CTA or CECT.^3,6 Currently, multidetector CTA has become the preferred first-line modality in patients with hemoptysis and suspected PAP due to its high resolution and noninvasive nature. CTA enables accurate characterization of the number, size, location, morphology, feeding pulmonary arteries, and associated bronchial-pulmonary arterial shunts, while also providing a comprehensive assessment of lung, cardiac, and mediastinal pathology to help diagnose the underlying etiology.^3,12,17 Importantly, CTA is recommended for initial evaluation, as catheter angiography may underestimate lesion size or miss PAP entirely, particularly in lesions detectable only on CTA (PAP type D). ⁵ Recent evidence highlights that wide-field CTA, performed from the neck to the L2 vertebral level, enables more accurate identification of the bleeding source and detection of non-bronchial systemic collaterals, thereby improving procedural planning and clinical outcomes, particularly in complex or recurrent hemoptysis cases.^18,19 In our case, CTA or CECT was not performed before the initial BAE, which may have contributed to the delayed diagnosis of the PAP.

There are currently no guidelines or consensus regarding the optimal indications or timing of intervention for PAP. Management strategies can be broadly categorized into conservative treatment (observation, hemostasis, and treatment of the underlying cause), endovascular therapy, and surgery. ³ Conservative management is generally reserved for small infection-related PAPs (<5 mm) or lesions without communication with the pulmonary arterial system.^3,4,10 Endovascular intervention plays a central role in PAP management; in infection-related cases, combined embolization of the pulmonary artery and the bronchial or other systemic arteries is often required, as chronic inflammatory lung disease may create bronchial-pulmonary or systemic-pulmonary shunts that supply the PAP from both circulations.^11,12,20 In our case, persistent hemoptysis after coil embolization may be explained by unrecognized systemic-pulmonary arterial shunts and incomplete control of S. constellatus infection, supported by the presence of bronchial artery hypertrophy, which has been reported in up to 50% of patients with necrotizing pneumonia. ¹⁰ These observations underscore the importance of PAP subtype classification and thorough assessment of systemic-pulmonary arterial communications when planning endovascular treatment. Surgical management is limited and reserved for carefully selected cases because of the high perioperative risk in patients with massive hemoptysis or impaired pulmonary function.^5,12 Indications include massive or refractory hemoptysis, hemothorax, invasive infection unresponsive to antibiotic therapy, or failure of endovascular therapy.^6,14 Lobectomy is the most performed procedure, whereas direct pulmonary arterial repair is rarely indicated.^6,7

S. constellatus is a facultatively anaerobic member of the Streptococcus anginosus group and a commensal organism of the oral cavity, oropharynx, gastrointestinal tract, and genitourinary system. ²¹ It can cause invasive infections at multiple sites, most commonly lung abscess, pneumonia, empyema, skin and soft tissue infections, and intra-abdominal infections.^{22 –24} Classically, infections due to the S. anginosus group occur in immunocompromised hosts or in patients with comorbidities such as diabetes mellitus, malignancy, chronic corticosteroid use, periodontal disease, or recent dental or oropharyngeal procedures.^{22 –24} In our case, diabetes may have predisposed to S. constellatus infection. Hemoptysis and PAP secondary to S. constellatus are exceedingly rare, with only two cases reported to date.^8,9 Antimicrobial susceptibility data for S. constellatus remain limited; reported effective agents include β-lactams (with or without β-lactamase inhibitors), fluoroquinolones, and vancomycin, whereas resistance to clindamycin is relatively common.^21,25,26

Conclusion

This case highlights a rare cause of PAP secondary to S. constellatus-associated necrotizing pneumonia, underscoring the diverse infectious etiologies of PAP. Early CTA is essential in patients with hemoptysis, particularly before endovascular intervention, as PAP may be missed on catheter-based angiography, and delayed diagnosis can be fatal. Persistent or recurrent massive hemoptysis despite technically successful BAE should prompt reconsideration of PAP and evaluation for ongoing infection or systemic-pulmonary arterial shunts. In selected cases involving refractory hemoptysis or antibiotic-resistant pathogens, surgical resection remains a definitive and life-saving approach.