|Year : 2017 | Volume
| Issue : 3 | Page : 189-191
Mitral bones in mitral stenosis: A rare presentation
Onteddu Joji Reddy1, Polysetty Obuleswar Prasad2, Jamkhana Abdul Gafoor1, Munirajulu Rajanikanth2
1 Department of Radiology, Government General Hospital, Kurnool, Andhra Pradesh, India
2 Department of Radiodiagnosis, Government General Hospital, Kurnool, Andhra Pradesh, India
|Date of Web Publication||25-Sep-2017|
Onteddu Joji Reddy
Department of Radiology, Government General Hospital, Bhudhawarapeta, Kurnool, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Pulmonary ossification is described as mature bone formation with or without marrow elements in alveolar or interstitial spaces. Pulmonary ossification is a rare late sequelae that is virtually pathognomonic of mitral stenosis. Mitral bone is nothing but pulmonary ossification that can be seen in cases of severe Mitral stenosis. In olden days, these pulmonary ossific nodules were not infrequent, but nowadays pulmonary ossific nodules in mitral stenosis (mitral Bones) are very rare to see in chest radiographs in view of early diagnosis of rheumatic heart disease and recent rapid developments in medical diagnosis and surgical treatments for mitral stenosis, such as mitral valvotomy and mitral valve replacement. We report here a case of mitral bones in mitral stenosis in a middle aged man who is suffering from chronic mitral stenosis since childhood.
Keywords: Interstitial lung disease, mitral stenosis, pulmonary ossification
|How to cite this article:|
Reddy OJ, Prasad PO, Gafoor JA, Rajanikanth M. Mitral bones in mitral stenosis: A rare presentation. J NTR Univ Health Sci 2017;6:189-91
| Introduction|| |
The common chest radio graph findings are consequence of left atrial enlargement, mitral calcification, pulmonary hypertension and congestive cardiac failure changes. When clinicians encounter multiple nodular calcifications in pateints with mitral stenosis, they think of infective pathologies like Tuberculosis or Hsitoplasmosis as differential diagnosis. Disseminated ossification in lungs associated with mitral stenosis has been recognized for many years. Pulmonary ossification in mitral stenosis is seen only in patients who were suffering from long standing stenosis from younger age. Due to rapid development of medicine and changing treatment guidelines of mitral stenosis leads to decreased incidence of ossific nodules in Mitral stenosis nowadays.
| Case Report|| |
A 30-year-old male patient who was suffering from rheumatic heart disease since childhood presented with the chief complaints of shortness of breath since childhood and palpitations since 1 month. Palpitations were irregularly irregular and even present at rest. He had no history of working in high-risk occupations prone to interstitial lung diseases. The patient was on irregular treatment for rheumatic heart disease (RHD). There was no history of tuberculosis contact in the past. On examination, pulse rate was irregularly irregular, jugular venous pressure (JVP) was raised, and pedal edema was present. On auscultation of chest bilateral basal crepitations, mid diastolic murmur in mitral area was present. Electrocardiography (ECG) showed absent P wave and irregularly irregular heart rate suggestive of atrial fibrillation. Two-dimensional echocardiogram (ECHO) was done that showed critical mitral stenosis (valve area less than 0.8 cm2) with mitral valve calcifications. Purified protein derivative (PPD) (tuberculin) testing was negative. X-ray chest PA view was taken that showed typical features of mitral stenosis such as cardiomegaly, elevated left main stem bronchus, straightening of left heart border, prominent interstitial markings, cephalization of vessels, and dilated main pulmonary artery. Round-to-oval calcified nodules were noted in both lung bases more on right mid and lower zones [Figure 1]a and [Figure 1]b. Biochemical investigations showed mild increase in serum creatinine. Serum calcium, phosphorous, and parathyroid hormone levels were within normal range. Plain CT scan of the chest was done that showed densely calcified mitral valve, ground glass attenuation of both lung fields due to interstitial, and alveolar edema and calcified nodular lesions sized about 2-8 mm in both lung bases more on right side with Hounsfield units more than 1000 (HF Units more than 1000 suggestive of bone) [Figure 2]a,[Figure 2]b,[Figure 2]c. Based on the clinical history and imaging findings, a provisional diagnosis of mitral bones in severe mitral stenosis was put forth. Open lung biopsy of the ossific nodules was not done, which is the confirmatory test for demonstration of ossification in lung parenchyma.
|Figure 1: (a) Chest x-ray PA view showing cardiomegaly, prominent interstitial markings, and round-to-oval calcified nodules (arrow) in basal areas of lung fields (b) Chest x-ray clearly showing calcified nodules (arrows) that are more prominent in right basal area|
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|Figure 2: (a-c) CT chest showing calcified nodules with Hounsfield units above 1000 indicating ossification in lung parenchyma|
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| Discussion|| |
Pulmonary ossification is a rare late sequelae of mitral stenosis. Its incidence is 3-13% in patients suffering from mitral stenosis and it is more common in men (20-40 years). Pulmonary ossification is associated with mitral stenosis, pulmonary venous hypertension, and with mitral valve calcification. Radiographically mitral bones appear as dense calcified nodules in size about 2-8 mm. Nodules predominantly involve right mid and lower zones of lung with a tendency to confluence and occasional presence of bony trabeculae.
Bone formation with or without marrow components occurring in the interstitial and alveolar compartments is unusual. Pulmonary ossification can be idiopathic or be associated with a variety of underlying pulmonary, cardiac, and systemic disorders. Pulmonary ossification also occurs with metastatic or dystrophic calcification. Thus, ossification could represent a continuation of either process in the lung.
The pathogenesis of pulmonary ossification is unknown. Serum calcium, phosphorus, and alkaline phosphatase levels are usually normal. In cases associated with pulmonary venous congestion, chronic intraalveolar hemorrhage has been implicated as a predisposing factor for subsequent fibrosis and ossification. Shear stress in noncompliant lung tissue due to chronic venous hypertension, intra alveolar hemorrhage, and fibrosis in chronic mitral stenosis patients may induce the conversion of fibroblasts to osteoblasts and ultimately bone formation in the alveoli. Growth factors, such as beta transforming growth factor, bone morphogenetic protein, and Interleukin-1 and4, play main role in bone formation in lungs.
Pulmonary ossification can be localized or widely distributed throughout the pulmonary parenchyma. Two histological types of pulmonary ossification have been described:
- Nodular circumscribed form, and
- Dendriform type.
The nodular form is characterized by lamellar deposits of calcified osteoid material situated within the alveolar spaces often without marrow elements. The nodular form is typically associated with preexisting cardiac disorders that result in chronic pulmonary venous congestion such as mitral stenosis, chronic left ventricular failure, and idiopathic hypertrophic subaortic stenosis. In contrast, dendriform ossification refers to interstitial branching spicules of bone and marrow elements that may protrude into the alveoli. The dendriform type is found in idiopathic pulmonary ossification and interstitial fibrosis.
Diffusely scattered small calcified lesions in the lung fields may occur due to a variety of disorders. Calcified miliary tuberculosis, hemosiderosis, histoplasmosis, and coccidioidomycosis are usually more diffused than ossific nodules and affect all lung zones. Pulmonary alveolar Microlithiasis produces a fairly typical radiological picture. Most of these lesions are in fact much less sharply defined than ossific nodules and in the presence of mitral valve disease there is rarely any difficulty in diagnosis. The nodules were normally most conspicuous in the lower zones and particularly at the right base. Occasionally, they were diffusely distributed throughout the lung fields but tended to thin out toward the apices, which were only rarely affected.
Pulmonary venous hypertension usually appears relatively late in the natural course of mitral regurgitation and occurs often due to left ventricular failure. Its duration is therefore less prolonged than in dominant mitral stenosis. This may be the main reason for the very few reported cases of ossific nodules associated with mitral regurgitation. Left ventricular failure, due to disorders such as hypertension, coronary artery disease, or aortic valve disease, is usually of short duration and even with modern treatment it is not likely to persist for more than 2-3 years. This time is probably too short for ossific nodules to develop. There is no correlation among symptomatology, cardiac rhythm, heart size, pulmonary arterial pressure, hemosiderosis, and mitral valve calcifications.
The authors are thankful to Dr. P. Chandra Shekha, MD.DM (Cardiology), Professor, Department of Cardiology, Dr. B. Suresh MDRD, Associate Professor, Department of RADIOLOGY, Government General Hospital, Kurnool, for expert opinion on this case.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]