Original Article
Clinical profile and outcome of renal tubular disorders in children: A single center experience B. Vijay Kiran, H. Barman1, A. Iyengar2 Department of Nephrology, King George Hospital/Andhra Medical College, Visakhapatnam, Andhra Pradesh, 1Department of Paediatrics, NEIGRIHMS, Shillong, Meghalaya, 2Department of Paediatric Nephrology, St. John’s Medical College Hospital, Bengaluru, Karnataka, India
ABSTRACT Tubular disorders form a significant proportion of pediatric kidney diseases and are an important differential diagnosis of failure to thrive (FTT) in children. Data regarding their outcome is scarce from India. We evaluated the clinical profile of these children and studied the outcome in terms of their growth and renal failure. This is a retrospective longitudinal study of all children with renal tubular disorders attending a tertiary care pediatric nephrology center from 2005 to 2010. Growth and renal outcomes were assessed by Z scores and estimated glomerular filtration rate at diagnosis and. The common disorders encountered were distal renal tubular acidosis (d‑RTA) (44%), Bartter‑like (Bartter’s and Gitelman) syndromes (22%) followed by hereditary Fanconi syndrome (cystinosis and idiopathic Fanconi syndrome) (13%) and few cases of nephrogenic diabetes insipidus, hypophosphatemic rickets and idiopathic hypercalciuria. Male: female ratio was 1.22. The median age at diagnosis was 1.5 (range 0.13-11) years. Growth failure was the presenting feature in 86% of children followed by polyuria (60%) and bone deformities (47%). In 60% of children with hereditary Fanconi syndrome, nephropathic cystinosis was diagnosed, all of whom progressed to stage III chronic kidney disease (CKD) within 3.41 ± 1.42 years. With appropriate therapy, catch‑up growth was noted in d‑RTA and Bartter syndrome. Renal tubular disorders usually present with FTT. d‑RTA is the most common etiology followed by Bartter‑like syndrome. Renal function is preserved in all these disorders except for nephropathic cystinosis, who ultimately progressed to CKD. With appropriate and inexpensive therapy, these children do grow well. Key words: Chronic kidney disease, distal renal tubular acidosis, estimated glomerular filtration rate, nephrogenic diabetes insipidus
Introduction Renal tubules play an important role in fluid, electrolyte, and acid‑base homeostasis. Defect of these functions can give rise to a host of disorders.[1,2] These disorders can be inherited or acquired. In India, the data is especially scarce with regard to prevalence and clinical course of these disorders. Early diagnosis and prompt therapeutic
interventions can improve the overall clinical outcome of these children. Moreover, with improved management strategies, many of these children are reaching adulthood. Therefore knowledge about their natural history and long‑term outcome is of particular importance. We describe the clinical profile of various tubular disorders followed‑up in our center ans outcome in terms of growth and progression to renal failure.
Subjects and Methods Address for correspondence: Dr. Banigallapati Vijay Kiran, S1, Senior Resident Hostel, Andhra Medical College/King George Hospital, Vishakhapatnam, Andhra Pradesh, India. E‑mail: [email protected] Access this article online Quick Response Code:
Website:
A retrospective longitudinal study of all children with renal tubular disorders attending our center for 5 years (2005-2010) was done. Children with tubular disorders secondary to drugs and transient in nature were excluded. Furthermore, children with no follow‑up in last 5 years were excluded.
www.indianjnephrol.org DOI: 10.4103/0971-4065.133002
362
Nov 2014 / Vol 24 / Issue 6
Growth assessment was done by serial record of height and weight. The height standards of the Indian academy of pediatrics growth charts were used to calculate age‑related standard deviation scores (SDS) for height.[3] Indian Journal of Nephrology
Kiran, et al.: Clinical outcome of renal tubular disorders in children
Growth was analyzed as Z scores for the age and sex and compared. The glomerular function was assessed by estimated glomerular filtration rate (eGFR) calculated using Schwartz formula.[4] Chronic kidney disease (CKD) was defined in the presence of a permanent reduction in GFR (e‑GFR;
Clinical profile and outcome of renal tubular disorders in children: A single center experience B. Vijay Kiran, H. Barman1, A. Iyengar2 Department of Nephrology, King George Hospital/Andhra Medical College, Visakhapatnam, Andhra Pradesh, 1Department of Paediatrics, NEIGRIHMS, Shillong, Meghalaya, 2Department of Paediatric Nephrology, St. John’s Medical College Hospital, Bengaluru, Karnataka, India
ABSTRACT Tubular disorders form a significant proportion of pediatric kidney diseases and are an important differential diagnosis of failure to thrive (FTT) in children. Data regarding their outcome is scarce from India. We evaluated the clinical profile of these children and studied the outcome in terms of their growth and renal failure. This is a retrospective longitudinal study of all children with renal tubular disorders attending a tertiary care pediatric nephrology center from 2005 to 2010. Growth and renal outcomes were assessed by Z scores and estimated glomerular filtration rate at diagnosis and. The common disorders encountered were distal renal tubular acidosis (d‑RTA) (44%), Bartter‑like (Bartter’s and Gitelman) syndromes (22%) followed by hereditary Fanconi syndrome (cystinosis and idiopathic Fanconi syndrome) (13%) and few cases of nephrogenic diabetes insipidus, hypophosphatemic rickets and idiopathic hypercalciuria. Male: female ratio was 1.22. The median age at diagnosis was 1.5 (range 0.13-11) years. Growth failure was the presenting feature in 86% of children followed by polyuria (60%) and bone deformities (47%). In 60% of children with hereditary Fanconi syndrome, nephropathic cystinosis was diagnosed, all of whom progressed to stage III chronic kidney disease (CKD) within 3.41 ± 1.42 years. With appropriate therapy, catch‑up growth was noted in d‑RTA and Bartter syndrome. Renal tubular disorders usually present with FTT. d‑RTA is the most common etiology followed by Bartter‑like syndrome. Renal function is preserved in all these disorders except for nephropathic cystinosis, who ultimately progressed to CKD. With appropriate and inexpensive therapy, these children do grow well. Key words: Chronic kidney disease, distal renal tubular acidosis, estimated glomerular filtration rate, nephrogenic diabetes insipidus
Introduction Renal tubules play an important role in fluid, electrolyte, and acid‑base homeostasis. Defect of these functions can give rise to a host of disorders.[1,2] These disorders can be inherited or acquired. In India, the data is especially scarce with regard to prevalence and clinical course of these disorders. Early diagnosis and prompt therapeutic
interventions can improve the overall clinical outcome of these children. Moreover, with improved management strategies, many of these children are reaching adulthood. Therefore knowledge about their natural history and long‑term outcome is of particular importance. We describe the clinical profile of various tubular disorders followed‑up in our center ans outcome in terms of growth and progression to renal failure.
Subjects and Methods Address for correspondence: Dr. Banigallapati Vijay Kiran, S1, Senior Resident Hostel, Andhra Medical College/King George Hospital, Vishakhapatnam, Andhra Pradesh, India. E‑mail: [email protected] Access this article online Quick Response Code:
Website:
A retrospective longitudinal study of all children with renal tubular disorders attending our center for 5 years (2005-2010) was done. Children with tubular disorders secondary to drugs and transient in nature were excluded. Furthermore, children with no follow‑up in last 5 years were excluded.
www.indianjnephrol.org DOI: 10.4103/0971-4065.133002
362
Nov 2014 / Vol 24 / Issue 6
Growth assessment was done by serial record of height and weight. The height standards of the Indian academy of pediatrics growth charts were used to calculate age‑related standard deviation scores (SDS) for height.[3] Indian Journal of Nephrology
Kiran, et al.: Clinical outcome of renal tubular disorders in children
Growth was analyzed as Z scores for the age and sex and compared. The glomerular function was assessed by estimated glomerular filtration rate (eGFR) calculated using Schwartz formula.[4] Chronic kidney disease (CKD) was defined in the presence of a permanent reduction in GFR (e‑GFR;
