CASE 8924 Published on 07.11.2010

Metastatic pulmonary calcification as complication of haemodialysis

Section

Chest imaging

Case Type

Clinical Cases

Authors

De Keyzer B, Coolen J, Verschakelen JA, De Wever W.
Radiology department, University Hospitals, Leuven, Belgium

Patient

61 years, male

Categories
Area of Interest Lung ; Imaging Technique CT-High Resolution, Digital radiography, Nuclear medicine conventional
Clinical History
A 61 year old man presented with chronic productive cough without haemoptysis or hoarseness. He had a weight loss of 5 kg the last two months. He had a smoking history of 30 pack/year, but had stopped smoking 14-years ago. He had a history of IgA glomerulonefritis and was treated with haemodialysis.
Imaging Findings
A 61 year old man presented with a chronic productive cough.
A chest radiograph, High-Resolution-Computed-Tomography (HRCT) and bone scan were performed.
Chest X-ray was normal. The PA-film demonstrated a moderate decrease of the translucency in the right lower lung, no parenchymal abnormalities on lateral view were visible. Paracardial fat tissue caused the decreased lung-translucency (Fig 1).
HRCT showed multiple nodular ground glass opacities, with a centrilobular distribution pattern bilaterally (Fig 2). Bronchiectasies, consolidations or thickening of the interstitium were not seen.
The bone scan showed diffuse increased tracer uptake at the level of both lungs (Fig 3). There was also an increased tracer uptake at the level of the skull and at the right ankle.
Bronchoscopy with transbronchial biopsies was done. Histology showed the presence of fibrosis and dystrophic calcifications in the interalveolar septa and focally in the walls of the blood vessels. The diagnosis of pulmonary metastatic calcification was made.
Discussion
Metastatic pulmonary calcification, also named alveolar calcinosis, occurs in diseases with calcium-phosphate metabolism disturbance. It is most commonly seen in chronic renal failure, but has also been described in primary and secondary hyperparathyroidism, vitamin D hypervitaminosis, milk-alkali syndrome, diffuse myelomatosis and extensive bone malignancy [1]. Usually, the process is seen in the cases of failed renal transplantation, and during haemodialysis treatment. Postmortem, metastatic pulmonary calcification can be found in 60-75% of haemodialysed patients at autopsy [2]. In extensive pulmonary calcification, a restrictive lung function, a decreased diffusion capacity and hypoxemia can be detected [1].
In chronic renal failure, four conditions predispose to metastatic calcification. First, acidosis leaches calcium and phosphate from the bone. Second, the failing kidneys fail to produce vitamin D, which leads to lesser calcium uptake. There will be increased parathyroid hormone uptake, resulting in an increased calcium and phosphate release from the bone. Third, intermittent alkalosis, which often accompanies haemodialysis, facilitates the precipitation of calcium salts. Finally, the decreased glomerular filtration of phosphate may contribute to an elevated serum calcium-phosphate product. [2, 3]
The extent of the physiologic impairment associated with calcium deposition does not necessarily correlate with the degree of macroscopic calcification deposition [2]. Calcium deposition can be found in every all-parenchymal organs, also the lungs.
Chest radiograph is not very effective for detecting metastatic pulmonary calcification. HRCT scan and 99mTechnetium-methylene diphosphate (99mTc-MDP) bone scintigraphy are more sensitive and specific for the detection of pulmonary calcification [1,4].
Three patterns of pulmonary parenchymal calcification can be seen on HRCT. First, multiple calcified and/or apparently non-calcified nodules distributed diffusely or patchy in the lungs. Second, diffuse or patchy areas of ground glass opacities. Third, relatively dense areas of consolidation [2].
Bone scintigraphy with the bone-avid radiotracer 99mTc-MDP can demonstrate calcium deposition, also in lung tissue and can help in the differential diagnosis of pulmonary lesions [2,4].
Specific treatment is aimed at correction of isolated hyperphosphatemia or elevated calcium-phosphate product, if present [2].
Differential Diagnosis List
Metastatic pulmonary calcification
hypersensitivity pneumonitis
pulmonary hemmorhage
respiratory bronchiolitis interstitial lung disease
infectious disease
Final Diagnosis
Metastatic pulmonary calcification
Case information
URL: https://www.eurorad.org/case/8924
DOI: 10.1594/EURORAD/CASE.8924
ISSN: 1563-4086