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 Table of Contents 
Year : 2019  |  Volume : 8  |  Issue : 2  |  Page : 763-765  

Uncommon cause of persistent hypoxia in a patient with obstructive sleep apnea

1 Department of Medicine, PGIMER, Dr. RML Hospital, New Delhi, India
2 Department of Medicine, Smt. Sucheta Kriplani Hospital and LHMC, New Delhi, India

Date of Web Publication28-Feb-2019

Correspondence Address:
Dr. Subodh Kumar Mahto
Department of Medicine, OPD Block, PGIMER, Dr. RML Hospital, New Delhi - 110 001
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jfmpc.jfmpc_3_19

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We report a case of hypothyroidism, obstructive sleep apnea (OSA) with persistent daytime hypoxemia. Cause of hypoxemia was two arteriovenous (AV) malformations in the lower lobe of the lung. We must be alert to other causes of hypoxemia in patients of OSA with persistent daytime hypoxemia.

Keywords: Hypoxemia, obstructive sleep apnoea, pulmonary AV malformations

How to cite this article:
Mahto SK, Gupta PK, Majumdar P, War GA, Mittal V, Goel A. Uncommon cause of persistent hypoxia in a patient with obstructive sleep apnea. J Family Med Prim Care 2019;8:763-5

How to cite this URL:
Mahto SK, Gupta PK, Majumdar P, War GA, Mittal V, Goel A. Uncommon cause of persistent hypoxia in a patient with obstructive sleep apnea. J Family Med Prim Care [serial online] 2019 [cited 2021 Sep 28];8:763-5. Available from: https://www.jfmpc.com/text.asp?2019/8/2/763/252994

  Introduction Top

Congenital pulmonary AV malformation (PAVM) is a rare disease and the incidence of PAVMs is about 2.5 in 100,000.[1] Most patients are asymptomatic (60%), although signs of right to left shunt such as exertional dyspnea, cyanosis, and clubbing may be seen in severe cases.[2] So absence of symptoms does not preclude the diagnosis of PAVM.

  Case Report Top

A 47-year-old male presented with complaints of heavy snoring and excessive daytime sleepiness for 9 years. Patient also complained of breathlessness on exertion for 6 years. He was a nonsmoker with no history of occupational exposure to dust or fumes. He was a case of hypothyroidism with bipolar mood disorder for 10 years, and was compliant with a treatment of thyroxin, sodium valproate, and resperidone.

On physical examination, he had a BMI of 38.8 kg/m2 and mild central cyanosis. Pulse rate was 80 beats per minute, regular and blood pressure was 120/70 mmHg in right arm, supine position.

Rest of the general physical and systemic examination did not reveal any abnormality. Pulse oximetry revealed saturation of 86–90% on room air, with higher values on supine position. ABG revealed persistent hypoxemia with hypocarbia.

Laboratory investigations revealed hemoglobin of 12.6 g%, total leukocyte count of 7100/mm3, and a normal platelet count of 1.6 lakh. Liver function tests, lipid profile, thyroid profile, and renal function tests were all within normal limits. His chest X-ray showed no abnormality.

ECG and 2D-echocardiography were normal. Pulmonary function test revealed mild restrictive deficit. Contrast-enhanced computed tomography (CECT) of the chest suggested possibility of a pulmonary arteriovenous malformation (PAVM) in the left lower lobe [Figure 1], which was confirmed on CT angiogram [Figure 2]. An overnight polysomnography revealed severe OSA (AHI-22.5; RDI-25.4 Desaturation index-16). The patient has undergone successful embolization of the feeding artery. The patient had no clinical evidence of hereditary hemorrhagic telangiectasia (HHT).
Figure 1: Contrast-enhanced computed tomography (CECT) of the chest showed pulmonary arteriovenous malformation (PAVM) in the left lower lobe

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Figure 2: CT angiogram showed pulmonary arteriovenous malformation (PAVM) in the left lower lobe

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  Discussion Top

The association of obesity, hypothyroidism, and OSA is well established.[3] However, it is not common to have persistent daytime hypoxemia in OSA, especially in absence of symptoms. Prevalence and determinants of daytime hypoxemia in patients with OSA are not well established. However, it has been observed that patients with OSA, who spend an increased time in hypoxemia during sleep, are likely to have lower daytime PaO2, as adjusted for age.[4] Congenital PAVM are uncommon. In one of the largest series of 15,000 consecutive autopsies, only 3 cases of PAVM were detected. However, very small PAVMs may be missed in routine autopsies. PAVMs have been reported to be twice as often in women than men.[5] Approximately 80% of PAVMs are associated with HHT.[1] Our case was a 46-year-old male who had no evidence of HHT. In the present case, there was breathlessness and cyanosis with persistent daytime hypoxemia, and the two contributing disorders were obstructive sleep apnea and congenital AV malformations. Persistent hypoxemia, even in the night time can result in pulmonary hypertension, which will not manifest in a patient with congenital PAVM, which acts as a low pressure sink.

Currently, management option of PAVM is percutaneous embolization.[6] The feeding artery may be occluded with coils. If multiple feeding arteries are present, they must all be occluded individually for successful resolution to occur.[7] Embolectomy is advisable in all PAVMs with a feeding artery diameter of over 3 mm, which should include 88% of all PAVMs, as described in Velthuis et al.[8] All these cases treated by embolectomy had a shunt grade of II or III.

  Conclusion Top

Daytime hypoxemia is the hallmark clinical presentation of congenital PAVM but other disease like emphysema or interstitial lung disease should also be considered in differential diagnosis. Early differentiation from other diseases is necessary to prevent lethal complications and to institute early treatment and allow prompt recovery.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Sladden D, Casha A, Azzopardi C, Manche' A. A large pulmonary arteriovenous malformation causing cerebrovascular accidents. BMJ Case Rep 2015;4:2014-20.  Back to cited text no. 1
Velthuis S, Vorselaars VMM, van Gent MWF, Westermann CJJ, Snijder RJ, Mager JJ. Role of transthoracic echocardiography in the clinical diagnosis of hereditary haemorrhagic telangiectasia. Chest 2013;144:1876-82.  Back to cited text no. 2
Resta O, Pannacciulli N, Di Gioia G, Stefàno A, Barbaro MP, De Pergola G. High prevalence of previously unknown subclinical hypothyroidism in obese patients referred to a sleep clinic for sleep disordered breathing. Nutr Metab Cardiovasc Dis 2004;14:248-53.  Back to cited text no. 3
Fanfulla F, Grassi M, Taurino AE, D'Artavilla Lupo N, Trentin R. The relationship of daytime hypoxemia and nocturnal hypoxia in obstructive sleep apnoea syndrome. Sleep 2008;31:249-55.  Back to cited text no. 4
Gossage JR, Kanj G. Pulmonary arteriovenous malformations – A state of the art review. Am J Respir Crit Care Med 1998;158:643-61.  Back to cited text no. 5
Kraemer N, Krombach GA. Images in clinical medicine. Pulmonary arteriovenous fistulae. N Engl J Med 2009;360:1769.  Back to cited text no. 6
Oliveira GH, Seward JB, Stanson AW, Swanson JW. Paradoxical cerebrovascular embolism associated with pulmonary arteriovenous fistula: Contrast transoesophageal echocardiographic diagnosis. Eur J Echocardiogr 2001;2:207-11.  Back to cited text no. 7
Velthuis S, Buscarini E, Mager JJ, Vorselaars VM, van Gent MW, Gazzaniga P, et al. Predicting the size of pulmonary arteriovenous malformations on chest computed tomography: A role for transthoracic contrast echocardiography. Eur Respir J 2014;44:150-9.  Back to cited text no. 8


  [Figure 1], [Figure 2]


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