Isolated unilateral absence of pulmonary artery presenting as hemoptysis: A case report.

A 34-year-old female was admitted to the gynecology ward for evaluation of post coital pain and bleeding. On evaluation, she was found to have chronic pelvic inflammatory disease, endometriosis, endo cervical polyp and bilateral cornual blockage. Surgical intervention was planned. Post-operatively, patient became hemodynamically unstable, presenting with hypovolemic shock due to suspected internal bleeding which was later confirmed via laparotomy to be caused by a ruptured follicle. On the 5th day after the 2nd surgery, she developed sudden onset of difficulty in breathing with minimal abdominal distension. Our team was thus consulted to review the patient. She reported to have mild transient episodes chest pain, hemoptysis and exertional dyspnea. On examination, she had normal vital signs including blood pressure, she was dyspneic but not cyanosed and had finger clubbing. Systemic examination revealed loud pulmonic component of second heart sound, murmur of tricuspid regurgitation and bilateral infrascapular crackles. A presumptive diagnosis of pulmonary hypertension was made secondary to pulmonary embolism. Brain natriuretic peptide (BNP) and other cardiac markers were within normal limits. Due to her age and presentation, we thought she may have an underlying autoimmune disease. Workup for autoimmune disease revealed a positive antinuclear antigen (ANA) and positive Anti-PO(RPP) and Anti-Ku antibodies. Chest x-ray ( Fig. 1 ) showed engorged left hilum and mildly blunted right costophrenic angle suggestive of pleural effusion. CT-Pulmonary Angiography ( Fig. 2 ) showed a dilated pulmonary trunk measuring 4.23 cm suggestive of pulmonary hypertension, an absent right pulmonary artery, enlarged left pulmonary artery measuring 2.57cm and dilated left lower lobar artery measuring 2.95cm suggestive of sequelae of chronic pulmonary hypertension. Prominent bronchial arteries supplying the right lung were seen posterior to superior vena cava. In the lungs, there was mild bilateral pleural effusion, with left segmental consolidative collapse of the lower lobe and multiple alveolar opacities involving the whole right hemi thorax suggesting pneumonia. Fig. 1 Chest X-ray showing an engorged vascular shadow in the left hilum. There was also mild blunting of the right costophrenic angle suggestive of mild pleural effusion. Fig. 1 Fig. 2 Axial and Coronal sections of contrasted computed tomography of the chest. A: Absent right pulmonary artery (arrow) and a dilated pulmonary trunk suggestive of pulmonary hypertension B: Dilated left pulmonary artery and left lower lobar artery C: Prominent bronchial arteries supplying the right lung D: Mild bilateral pleural effusion and left segmental consolidative collapse of the left lower lobe. Fig. 2 Chest X-ray showing an engorged vascular shadow in the left hilum. There was also mild blunting of the right costophrenic angle suggestive of mild pleural effusion. Axial and Coronal sections of contrasted computed tomography of the chest. A: Absent right pulmonary artery (arrow) and a dilated pulmonary trunk suggestive of pulmonary hypertension B: Dilated left pulmonary artery and left lower lobar artery C: Prominent bronchial arteries supplying the right lung D: Mild bilateral pleural effusion and left segmental consolidative collapse of the left lower lobe. Electrocardiogram (ECG) revealed right sided strain pattern, with sinus tachycardia and left ventricular hypertrophy. Echocardiography was highly suggestive of pulmonary hypertension evidenced by an increased right ventricular systolic pressure of 71 mmHg, mild tricuspid regurgitation, impaired diastolic filling and left ventricular ejection fraction of 60 %. The patient was prescribed intravenous ceftriaxone for the pneumonia, sildenafil 50mg daily, intravenous furosemide 40mg daily, spironolactone 25mg daily and digoxin 0.125mg daily. She improved significantly and was discharged from the ward with oral furosemide, spironolactone, sildenafil and digoxin with instructions to follow up at the pulmonology out-patient clinic.

Pauline Chale: Writing – original draft, Formal analysis, Data curation, Conceptualization. Sibtain M. Moledina: Writing – review & editing, Writing – original draft, Formal analysis, Data curation. Sylvia B. Nsato: Writing – original draft, Data curation. Hery O. Kimwela: Writing – original draft, Data curation. Damas Wilson: Writing – original draft, Data curation. Hedwiga F. Swai: Writing – original draft, Supervision, Formal analysis.

No funding was received for this work.

Isolated UAPA is a rare entity. Adult patients are often asymptomatic or minimally symptomatic and diagnosis is usually delayed until after complication develop such as pulmonary hypertension. Early diagnosis is crucial in order to correct the pathology before irreversible complications develop.

UAPA is a rare congenital malformation, which is often associated with congenital heart defects such as tetralogy of Fallot, atrial septal defect, coarctation of aorta and others [ 1 , 2 ]. When UAPA occurs without congenital heart defects, it is termed isolated UAPA, which is extremely rare. A review of the literature conducted in 2011 found 352 cases of UAPA, two-thirds of which were associated with cardiac anomalies [ 3 ]. UAPA is caused by involution of the proximal sixth aortic arch and persistence of the connection of the intrapulmonary pulmonary artery to the distal sixth aortic arch. If the ductus arteriosus closes after birth, the ipsilateral intrapulmonary pulmonary artery will lose its blood supply and reduce in size and thus will not be visible during imaging [ 1 ]. The clinical presentation of UAPA depends on age and associated anomalies. In infants and those with associated cardiac anomalies, UAPA usually presents as congestive cardiac failure with pulmonary hypertension. In isolated UAPA and in adults, the disease can be asymptomatic or in a few cases present with hemoptysis and/or exercise intolerance. Hemoptysis is caused by excessive collateral circulation which can be self-limiting and thus leading to delays in diagnosis. In a few cases, hemoptysis may progress to massive pulmonary hemorrhage and death. Some cases may be detected incidentally by chest imaging [ 1 ]. Our patient had a history of transient hemoptysis and exercise intolerance but the correct diagnosis was not made until after she developed serious complications and proper imaging was done. Patients with UAPA can also present with recurrent pulmonary infections due to impaired blood supply to the affected lung which impaired the lung defense mechanisms and contributing to inflammation [ 1 ]. Pulmonary hypertension in UAPA has been reported in other case reports and series [ 4 , 5 ].Blood flow directed to the remaining pulmonary artery leads to shear stress within the endothelium with subsequent release of vasoconstrictors such as endothelin. Chronic vasoconstriction of pulmonary arterioles can lead to remodeling, resistance and pulmonary hypertension [ 1 ]. Diagnosis of UAPA is challenging, particularly in asymptomatic patients who may not have developed clinically significant complications. In addition to a thorough medical history and physical examination, a high index of suspicion is required to confirm the diagnosis with appropriate investigations, especially imaging studies. Electrocardiogram may show right ventricular dominance (as was the case in our patient) and chest xray may reveal asymmetric lung fields. These findings are non-specific and better imaging studies are required to make the diagnosis. Definitive diagnosis can be made using a CT scan, echocardiography, magnetic resonance imaging (MRI) or a combination of these [ 1 ]. This approach has also been described in other case reports and case series [ 6 ]. In addition to confirming the absence of the pulmonary artery, a CT scan may also show collateral circulation and mosaic parenchymal changes and bronchiectasis secondary to recurrent infections [ 1 ]. Echocardiography will assist in excluding other congenital cardiac anomalies and detect associated pulmonary hypertension. In one case report, the diagnosis of UAPA was made after a patient developed unilateral left pulmonary fibrosis, thought to be secondary to the absent right pulmonary artery [ 7 ]. Due to the rarity of the disease and the non-specific presentation, the diagnosis in our patient was made incidentally when she developed difficulty in breathing after surgery. Similar instances of incidental diagnosis have been described in literature [ 8 , 9 ]. To date, there is no consensus regarding the treatment of UAPA. Management is largely directed towards symptomatic relief and correction of associated cardiac anomalies and treatment of pulmonary hypertension [ 1 ]. Treatment is usually reserved for those with hemoptysis, lower respiratory tract infections and pulmonary hypertension. Treatment options include total or partial pneumonectomy, closure of selected collateral blood vessels not solely responsible for blood supply or a primary versus staged pulmonary artery anastomosis [ 1 , [10] , [11] , [12] ].Selective embolization of the affected vessel is a feasible option in patients who present with massive hemoptysis [ 4 , 5 ]. Some experts advocate for pneumonectomy, particularly in patients with recurrent hemoptysis. If surgery is not an option due to lack of expertise or unsuitability of the patient then pharmacotherapy for pulmonary hypertension is indicated [ 1 , 9 ].Endothelin receptor antagonists such as bosentan is usually preferred. However, other options including sildenafil has been associated with variable response. Our patient was prescribed sildenafil and diuretics with good response and was discharged to follow up at the pulmonology out-patient clinic. Interestingly, our patient was found to be positive for ANA, Anti-RPP antibodies and Anti-Ku antibodies, suggesting the presence of an underlying autoimmune disease like systemic lupus erythematosus. To the best of our knowledge, no association has been found between UAPA and underlying autoimmune disease. She has been referred to the rheumatology clinic for further evaluation.

Isolated unilateral absence of pulmonary artery (UAPA) is a rare entity, which is usually associated with congenital cardiac anomalies. A high index of suspicion is required to make an early diagnosis which can be crucial to avoid complications of recurrent pulmonary infections and hemoptysis. We describe a case of a 34-year old female who was diagnosed incidentally to have isolated UAPA. The diagnosis, complications and management options for UAPA are discussed.

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.