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Journal of Postgraduate Medicine, Vol. 55, No. 2, April-June, 2009, pp. 121-123 Case Report Renal amyloidosis secondary to childhood tuberculosis: A report of two cases Krishnamurthy S, Samanta D, Yadav S Department of Pediatrics, Maulana Azad Medical College and Associated Lok Nayak Hospital, New Delhi - 110 002 Date of Submission: 16-Jun-2008 Code Number: jp09032 PMID: 19550057 Abstract Childhood renal amyloidosis is a rare entity and is mostly secondary in nature. We describe two cases of renal amyloidosis in association with childhood tuberculosis. The first case was a 10-year-old girl who presented with abdominal tuberculosis and nephrotic syndrome, while the second case was a 5-year-old boy who presented with disseminated tuberculosis and nephrotic syndrome. They were found to have amyloidosis on renal biopsy. The former was treated with anti-tubercular drugs, while the latter required anti-tubercular drugs and steroids. Both the cases showed clinical improvement with remission of nephrotic syndrome. Successful treatment of tuberculosis can result in remission of nephrotic syndrome due to secondary renal amyloidosis. It is important, especially in developing countries, to be aware that tuberculosis continues to be part of the differential diagnosis of amyloidosis in children.Keywords: Renal amyloidosis, nephrotic syndrome, tuberculosis Tuberculosis continues to thrive in developing countries and is re-emerging in the industrialized world. Childhood renal amyloidosis is a rare entity and is mostly secondary in nature, in contrast to primary tuberculosis, which is encountered in adults. The association of tuberculosis with renal amyloidosis is common in adults; [1] however, to the best of our knowledge, in the last 10 years, only two pediatric cases have been described in English literature. [2],[3] We describe two cases of secondary amyloidosis in association with childhood tuberculosis. Our report serves as a timely reminder that tuberculosis continues to be an important cause of amyloidosis in developing countries. Case Reports Case 1 In view of abdominal tuberculosis with nephrotic syndrome, renal biopsy was done which showed excess extracellular hyaline amorphous material (amyloid) occupying the glomerular mesangium [Figure - 1]. A potassium permanganate stain followed by Congo red staining revealed absence of apple green birefringence on polarized light, suggestive of secondary amyloidosis. [4],[5] Anti-tubercular drugs were prescribed, to which she showed clinical improvement in 6 weeks, with subsidence of proteinuria and increase in serum albumin levels. She continues to be under follow up for the last 1 year. Nephrotic syndrome continues to be in remission. There is no azotemia or proteinuria. Case 2 He is under follow up for the last 14 months during which he has shown clinical improvement. There is no proteinuria. Blood urea and serum creatinine levels are normal. He has no neurological deficits. Power, tone, and reflexes in the lower limbs are normal. Discussion Amyloidosis occurs rarely in children. It is characterized by extracellular deposition of insoluble fibrillar amyloid proteins in various body tissues. The deposits are composed of seemingly homogeneous eosinophilic material that stains pink to orange-red with Congo red dye and in polarized light, demonstrates the pathognomonic apple-green birefringence of amyloid. Primary amyloidosis, characterized by deposition of monoclonal light chain of immunoglobulin (AL type) is the commonest form in adults, but extremely rare in children. Secondary amyloidosis occurs due to deposition of amyloid A protein (AA), an acute phase reactant. This explains the presence of AA amyloid in chronic inflammatory conditions. Only secondary amyloidosis affects children in appreciable numbers. Most cases of secondary amyloidosis described in children are secondary to juvenile rheumatoid arthritis (JRA) and familial meditteranean fever (FMF). [6],[7] JRA has become the most common cause of secondary amyloidosis in children in European countries, [6] while FMF has been reported mostly in Turkish children. [7] Other reported etiologies in children include tuberculosis [2],[3] and Hodgkin Disease. [8] The association of tuberculosis with amyloidosis is fairly common in adults (3.6-50%), [1] but only infrequently reported in children. [2],[3] Tank et al, [3] described a 12-year-old girl with disseminated tuberculosis and amyloidosis who did not respond to anti-tubercular therapy, while Ozkaya et al, [2] have described a 13-year-old girl with Down syndrome who had pulmonary tuberculosis-related renal amyloidosis. Renal amyloidosis is diagnosed by demonstration of amyloid on renal biopsy. In contrast to primary amyloidosis, the apple-green birefringence is abolished in secondary amyloidosis if the specimen is treated with potassium permanganate before Congo red stain. [2] This phenomenon was observed in both the cases described by us. Management of secondary amyloidosis involves treatment of underlying cause, as remission has been reported following treatment of the underlying disorder. [8] The cases described by us had remission of nephrotic syndrome following treatment of tuberculosis. This is in conformity with the observations of some authors. [9],[10] Renal amyloidosis has a relatively poor prognosis with a median survival of 50 months. [3] To conclude, it is important, especially in developing countries, to be aware that tuberculosis continues to be part of the differential diagnosis of amyloidosis in children. Successful treatment of tuberculosis can result in remission of nephrotic syndrome due to secondary renal amyloidosis. References
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