|Year : 2018 | Volume
| Issue : 3 | Page : 258-260
Pulmonary arteriovenous malformation in a 2-month-old boy
Ibrahim Aliyu1, Zainab Fumilayo Ibrahim2
1 Department of Paediatrics, Aminu Kano Teaching Hospital, Bayero University, Kano, Nigeria
2 Department of Nursing, Aminu Kano Teaching Hospital, Kano, Nigeria
|Date of Web Publication||29-Jun-2018|
Department of Paediatrics, Aminu Kano Teaching Hospital, Bayero University, Kano
Source of Support: None, Conflict of Interest: None
Pulmonary arteriovenous malformation (PAVM) is a rare vascular anomaly, in which there is direct connection between branches of the pulmonary artery and pulmonary vein, therefore, bypassing the capillaries; this may remain asymptomatic. However, in severe cases, patients may manifest with cyanosis and high-output heart failure. Furthermore, they stand the risk of stroke and cerebral abscess. This remains a diagnostic challenge in childhood because most patients present in adulthood; therefore, it is easily overlooked. Furthermore, limited diagnostic facilities in resource-limited setting make proper evaluation a constraint. Therefore, the case of a 2-month-old boy, who presented with PAVM early in life and was wrongly treated for chest infection, is reported. The diagnosis in the index case was established using contrast-enhanced computerized tomography of the chest.
Keywords: Cyanosis, heart failure, pulmonary arteriovenous malformation
|How to cite this article:|
Aliyu I, Ibrahim ZF. Pulmonary arteriovenous malformation in a 2-month-old boy. Med J DY Patil Vidyapeeth 2018;11:258-60
| Introduction|| |
Pulmonary arteriovenous malformations (PAVMs) are rare vascular malformations; they were first described by Churton in 1897. In PAVMs, the arteries are directly connected with venous channels, bypassing the capillaries. This therefore voids the usual capillary function of substrate exchange and rapidly increases blood flow to the venous system therefore predisposing to blood volume overload in the left ventricle, hence, precipitating heart failure; in the lungs, such bypasses may result in ventilation-perfusion mismatch and severe hypoxemia. They are also prone to intracranial embolism due to loss of the filtration function of the lungs. Furthermore, they may present with thrombocytopenia due to platelet destruction. Therefore, the case of a 2-month-old boy who presented with PAVM which was complicated by heart failure and thrombocytopenia is reported.
| Case Report|| |
A 2-month-old boy presented with central cyanosis and recurrent difficulty in breathing which were characterized by occasional apneic attacks since birth; there were also three episodes of generalized tonic–clonic convulsion each lasting for about 5–10 min before presentation; there was no history of bleeding from the nostrils or gastrointestinal tract. There was no history of choking, but difficulty in breathing was exacerbated by breastfeeding. He was previously admitted and treated in a private hospital as chest infection for the same complaint but without significant improvement. He was delivered at term; the pregnancy and delivery were not adversely eventful; an antenatal scan was done, but it was reported as normal. He was a born of a nonconsanguineous marriage. There was no family history of similar problem. He was centrally cyanosed, but there was no digital clubbing and no evidence of telangiectasia. He was tachypneic with vesicular breath sounds; he had tachycardic with apex beat located at the fifth left intercostal and space lateral to the midclavicle line; a continuous murmur was heard over the anterior chest wall and there was a soft hepatomegaly. Oxygen saturation in room air was between 75% and 80% which increased to 90%–92% in 100% oxygen. Full blood count showed white cell count of 3.6 × 109/L, packed cell volume of 26.7%, and platelet count of 72 × 109/L (thrombocytopenia); blood culture was negative. Chest X-ray showed wedge-shaped homogenous opacity on the right lung field [Figure 1]; he was treated for chest infection without significant improvement, a chest computerized tomography scan with contrast studies verified soft tissue opacity on the posterior right side extending inferiorly. There was increased vascularity extending from the soft tissue mass in the posterior right lung with dilated and tortuous vascular channels also extending below the diaphragm to the liver [Figure 2]. The brain computed tomography (CT), electrocardiogram, and echocardiogram were not remarkable though genetic studies were not conducted due to nonavailability of such facilities. Therefore, the diagnosis of PAVM was made. Due to lack of facilities for definitive treatment within our reach, he was managed conservatively; the heart failure and the thrombocytopenia worsened despite anti-heart failure medications and platelet transfusion and the patient died within 4 days of admission. Autopsy was requested, but the parents declined due to their religious belief.
|Figure 1: Chest X-ray showing a wedge-shaped right-sided homogenous opacity|
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|Figure 2: Chest computed tomography showing vascular tributaries arising from the mass some radiating downward toward the diaphragm|
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| Discussion|| |
Arteriovenous malformations (AVMs) are mostly located in the central nervous system often presenting with seizures, headaches, and intracranial bleeds. However, other organs may also be involved such the liver, kidneys, and spleen, but its occurrences in the lungs are rare with an estimated annual incidence of 3.2 and 4.5 cases/year, as reported in Mayo Clinic reviews of 1972 and 1981, respectively; however, Liu et al. in 2010 reported an incidence of 1:50,000.
The exact cause of PAVM is not completely understood, but they are often congenital in about 80% of cases though acquired cases have been associated with patients with liver cirrhosis and following shunt procedures as in the Fontan surgery. Furthermore, it occurs in about 47%–80% of patients with hereditary hemorrhagic telangiectasia (HHT); however, it is estimated that only 5%–15% of population of those with HHT have PAVM. Therefore, some authors believe it maybe a variant of this syndrome which is linked to mutation in genes located in chromosomes 9q3 that codes for endoglin; this is a transforming growth factor-beta binding protein that found on the endothelial cells. However, HHT is autosomal dominant; therefore, it does not explain all cases of AVMs such as in the index case which lacked any family history of similar disorder; more so the index case did not fulfill the Caero criteria for HHT.
The clinical presentation is variable depending on the size and location, ranging from asymptomatic cases reported in 13%–55% of cases in different publications to those with severe respiratory distress in 31%–67% of cases; our patient had a large mass which almost occupied the whole posterior aspect of the lower right lobe, precipitating heart failure at an early age. Although the index case had convulsions, they were attributed to hypoxia because the contrast computer tomography scan of the brain was essentially normal.
Pulmonary angiography remains the gold standard in diagnosing PAVM; however, this is not readily available in most resource-limited settings. Therefore, chest X-rays and contrast enhanced chest CT are of great relevance. Although the index case did not meet the typical chest X-ray description of PAVM such as round or oval mass of uniform density, ranging in size from 1 to 5 cm in diameter), rather it was massive and could easily had been confused with an extensive lobal consolidation, contrast computerized tomography of the chest effectively delineated its vascular connections.,,, Therefore, chest CT has a significant role in the evaluation of children with persistent difficult with breathing; otherwise, rare lesions such as PAVM may be easily missed. Surgical lobectomy had been the mainstay of treatment in the early 1950s before the introduction of transcatheter embolization. Several devices such as Gianturco coils, Amplatzer vascular plugs, and detachable balloons have been used for occlusion with successes. However, our case did not have the benefit of such treatment options due to a lack of such expertise in our facility.
| Conclusion|| |
PAVM is a rare disease; however, a high index of suspicion should be entertained, especially in a cyanotic child while excluding the possibility of a cyanotic congenital heart disease.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]