Patterns of Renal Tubular Disorders in Egyptian Children: a Single Center Study
Conditions: Renal Tubular Disorders in Children
Sponsor: Sohag University



Sohag University
Faculty of Medicine
Department of Pediatrics
Patterns of renal tubular disorders in Egyptian
children: a single center study
Thesis
Submitted for Partial Fulfillment of the Master Degree in Pediatrics
Presented by
Mohamed Ashraf Mohamed Osman
M.B.B.Ch.E.
Resident in Pediatric Department
Sohag University Hospital
Under Supervision of
prof. Mostafa Mohamed Abosdera
Professor and head of Pediatric department
Faculty of Medicine, Sohag University
Dr. Mohamed Ahmed Kassem
Lecturer of Pediatrics
Faculty of Medicine, Sohag university
Sohag university
2020 – 2021
1

Patterns of renal tubular disorders in Egyptian
children: a single center study
Introduction
Fluids, electrolytes, and acid-base regulations are the main functions of renal tubules(1).
Defects of these functions  give rise to several disorders(2). In Egypt, little data is available.
Many of these cases are diagnosed late, therefore Early suspicion for diagnosis can improve the
overall clinical outcome of these children. Starting management early will help those children
have a better life. Therefore, awareness about these disorders and long-term outcome is
important(3). We present the clinical characterizations of many tubular disorders and the follow
up in our center with emphasis on growth and renal functions outcomes.
Aim of the work
The aim of this study is to reveal the different clinical presentations and the main lab features of
renal tubular disorders in children to promote early recognition and management in addition to
monitoring growth and glomerular filtration rate.
Patients and methods
-Place of the study:
Sohag University Hospital, Pediatric Department, Nephrology Unit.
-Type of the study: Retrospective and prospective study.
-Study period: 6-12 months after protocol acceptance.
-Patients: -
This study will include all children who have renal tubular disorders (inpatient and outpatient) in
the Pediatric Department, Sohag University Hospital.
- Inclusion criteria: -
All children aged from one month to 18 years who have renal tubular disorders.
Exclusion criteria:
Children who have renal tubular disorders secondary to drugs, intoxication, obstructive
uropathy or transient in nature.
-Methods:
Records of all children who have renal tubular disorders in the nephrology center from 2015 to
2020 and the children following up from April 2021 to December 2021 will be subjected to:
2

1-History taking with emphasis on age, age at diagnosis, sex, family history, Failure to thrive,
polyuria, polydipsia, consanguinity, dehydration episodes, lack of appetite, vomiting, seizures,
weakness, photophobia, and deafness.
2-Complete physical examination with emphasis on general condition, signs of rickets, polyuria
(>4 ml/kg/hour), bone deformities and developmental milestones.
3-Growth assessment was done by recording height and weight according to the WHO growth
charts and z scores. (Failure to thrive means weight and height below the 3rd centiles).
4-Investigations done for children included:
a- Blood gases and anion gap estimation
b- Electrolytes: serum sodium, potassium, calcium, chloride, and phosphorus
c- Urine analysis and urinary calcium creatinine ratio
d- Estimation of GFR
e- Renal ultrasound
f-
Complete blood count
g- Others may be needed e.g., bone radiograph, serum magnesium, and urinary chloride.
Metabolic acidosis means decreased serum HCO3 concentration and pH below 7.35.
Metabolic alkalosis means elevated serum HCO3 concentration and pH above 7.45.
The glomerular function was assessed by estimated glomerular filtration rate (eGFR) calculated
using Schwartz formula.[5]
Statistical analysis:
We expressed the data as percentage, median with range. Data was analyzed using Wilcoxon test
to compare the diverse groups of renal tubular disorder. Qualitative data was presented as
number and percentage and compared using Chi square test.  P value < 0.05 was considered
significant. Serial weight and height were measured and z scores and percentiles were calculated.
GFR was estimated and monitored using Schwartz formula(4).
-Ethical consideration: -
The protocol will be submitted to Medical Research Ethical Committee for approval.
Written informed consent will be taken from all participating patients or their families.
3

Results:
58 children with renal tubular disorders were candidates. Duration of follow up
ranges from (6-132) month with median 12 month. In our study, there were 33
males and 25 females.
Patterns of renal tubular disorders:
Various renal tubular disorders were noticed. DRTA and Barter S were the most
common encountered tubulopathies.
Diagnosis:
The median age at diagnosis was 17 month (ranges from 3-84 month). The age at
diagnosis was less or equal 12 month in 44.83% of cases, (13-36) months in
36.21%, (37-72) month in 15.52% and 73 month or more in 3.45%. Clinical
manifestations were present several months prior to definitive diagnosis was made.
Table: patterns of encountered renal tubular disorders
Renal tubular
disorder
Total number
N= 58
Male/Female
Median age at
diagnosis in
month
Median follow
up duration in
month
DRTA
27
15/12
12(3-84)
12(6-24)
Barter S
16
10/6
12(6-60)
12(7-36)
Gitleman S
1
1/0
60
18
Fanconi S
6
3/3
17.5(3-60)
12(9-13)
NDI
3
2/1
60(29-84)
12(7-12)
PRTA
4
2/2
36(26-42)
12(12-18)
RTA4
1
0/1
5
7
4

DRTA=distal renal tubular acidosis, NDI=nephrogenic diabetes insipidus,
PRTA=proximal renal tubular acidosis, RTA4=renal tubular acidosis type 4
Clinical presentation:
Failure to thrive was the most common presenting feature (91.4% of cases)
followed by polydipsia(81%), delayed motor development(75.9%), dehydration
episodes(72.4%), polyurea(70.72%), vomiting(65.5%), signs of rickets either
clinically or radiologically or both(63.8%), weakness(56.9%),
nephrocalcinosis(34.5%), seizures(24.1%), bone deformities with or without
pathological fractures(17.2%). Deafness and photophobia were the least
encountered (one case of DRTA had deafness and the case of cystinosis had
photophobia).
Table: The main presenting features of renal tubular disorders
Renal tubular
disorder
Failure to
thrive
Polyurea
Dehydration
episodes
Nephrocalcinosis
DRTA (n=28)
25
19
21
13
Barter S (n=16)
14
10
10
7
Gitleman S (n=1)
1
1
0
0
Fanconi S (n=6)
6
4
5
0
PRTA (n=4)
4
3
3
0
NDI (n=3)
2
3
2
0
RTA4 (n=1)
1
1
1
0
DRTA=distal renal tubular acidosis, NDI=nephrogenic diabetes insipidus,
PRTA=proximal renal tubular acidosis, RTA4=renal tubular acidosis type 4
Consanguinity was noticed in 72.4% of cases (p value .001). 60% of cases have
similar condition in their families. 29.3% of cases had low birth weight (birth
5

weight < 2.5 kg). Prematurity was noticed in 34.48% of cases. 60.34% of these
children reported similar conditions among their relatives. 34.48% of cases had
preterm labour (born before 37 weeks of gestation). 41.38% of cases needed
neonatal intensive care admission for variety of reasons. Some of them were
admitted due to persistent vomiting and dehydration episodes.
Height outcome:
In patients with DRTA, a significant improvement in height was noticed (P
value=0.005) thanks to proper management and follow up. Patients with Barter
syndrome showed clinical improvement in height, but it was statistically not
significant (P value=0.053). As regard patients with Fanconi syndrome, there was
no height improvement. Patients with nephrogenic diabetes insipidus had clinical
improvement in height, but not statistically significant (P value=0.109).Patients
with proximal renal tubular acidosis showed no height improvement. In addition,
there was a single case of Gitleman syndrome and another one of renal tubular
acidosis type 4. They both showed height increase.
Table: Height outcome assessment
Renal tubular
disorder
Median Z score
height at diagnosis
Median Z score
height at follow up
P value
DRTA
-3.3 (-8 : 0.6)
-2 (-7.6 : 2.7)
.005
Barter S
-2.3 (-5 : -0.9)
-2.15 (-3.8: 1.9)
.053
Gitleman S
-2.4
-2.3
----------
Fanconi S
-4.6 (-7.5: -3.1)
-4.8 (-5.5 : -4.4)
.599
NDI
-4 (-6.3 : 0)
-3.2 (-4.3 : 0.9)
.109
PRTA
-3.9 (-4.5 : -3.7)
-4.15 (-4.4 : -2.8)
1
RTA4
-4.2
-3.2
----------
DRTA=distal renal tubular acidosis, NDI=nephrogenic diabetes insipidus,
PRTA=proximal renal tubular acidosis, RTA4=renal tubular acidosis type 4
6

Weight outcome:
Marked improvement in weight was noticed in patients with DRTA and barter
syndrome (statistically and clinically significant). There was no weight
improvement in patients with Fanconi syndrome. As regard to children with
nephrogenic diabetes insipidus, clinical improvement in weight was noticed, but
not statistically significant. Mild weight improvement was observed in children
with PRTA. Catch up growth was seen in the child with Gitleman syndrome and
the child with type 4 renal tubular acidosis.
Renal tubular
disorder
Median Z score
weight at
diagnosis
Median Z score
weight at follow
up
P value
DRTA
-4 (-6.6: -0.2)
-1.3 (-5.9: 3.3)
.000
Barter S
-3.95 (-5.8: -1.9)
-0.7 (-3.4: -1.5)
.001
Gitleman S
-4.8
-3.5
------
Fanconi S
-4.9 (-5.8: -3.3)
-4.9 (-5.5: -3.7)
.674
NDI
-1.9 (-3.6: 4.7)
1.4 (-.8: 4.5)
.285
PRTA
-3.9 (-5.6: -3.3)
-3.45 (-5.3: -1.9)
.197
RTA4
-6.4
-3.3
------
DRTA=distal renal tubular acidosis, NDI=nephrogenic diabetes insipidus,
PRTA=proximal renal tubular acidosis, RTA4=renal tubular acidosis type 4
Renal function outcome:
Only one case of Fanconi syndrome developed chronic renal failure and started
renal replacement therapy. No significant change in glomerular filtration rate was
noticed in all children.
Renal tubular
disorder
Median GFR at
diagnosis
Median GFR at
follow up
P value
7

DRTA
65.7 (50-111)
75.09
(43.21-122.31)
.075
Barter S
69.39
(42.57-118.74)
74.72
(50.25-132.59)
.148
Gitleman S
68
94.16
-----
Fanconi S
77.9 (54.14-118)
89.28
(12.39-111.51)
.6
NDI
92.51
(67.23-113.58)
79.16
(65.01-109.03)
.109
PRTA
60.73 (50.83-82.6)
56.24 (51.63-80.1)
.465
RTA4
58.85
66.87
-----
GFR: glomerular filtration rate, DRTA=distal renal tubular acidosis,
NDI=nephrogenic diabetes insipidus, PRTA=proximal renal tubular acidosis,
RTA4=renal tubular acidosis type 4.
References:
 1.
Bagga A, Bajpai A, Menon S. Approach to renal tubular disorders. In: Indian Journal of
Pediatrics. The Indian Journal of Pediatrics; 2005. p. 771–6.
2.
Chadha V, Alon US. Hereditary Renal Tubular Disorders. Semin Nephrol [Internet].
2009;29(4):399–411. Available from:
http://dx.doi.org/10.1016/j.semnephrol.2009.03.013
3.
Barman H, Sciences M. Clinical profile and outcome of renal tubular disorders in
children : A single center experience. 2014;(August).
4.
Schwartz GJ, Muñoz A, Schneider MF, Mak RH, Kaskel F, Warady BA, et al. New equations
to estimate GFR in children with CKD. J Am Soc Nephrol. 2009;20(3):629–37.
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