Hypokalemia and metabolic alkalosis in an Egyptian boy with Pendred syndrome Kotb Abbass Metwalley, Hekma Saad Farghaly, Mohamed Kotb Abbass Metwalley1 Department of Pediatrics, Faculty of Medicine, Assiut University, Assiut, 1 Undergraduate Medical Student, Armed Forces College of Medicine, Cairo, Egypt

1. Hypokalemia and metabolic
alkalosis in an Egyptian boy
with Pendred syndrome
Case Report
Kotb Abbass Metwalley
Professor of Pediatric Endocrinology& Diabetes -
Faculty of Medicine -Assiut University-Egypt

3. Introduction
Pendred syndrome is an autosomal recessive disorder
that is classically defined by the combination of
mild-to-severe sensorineural deafness/hearing
impairment, goiter, and an abnormal organification of
iodide with or without hypothyroidism . It is due to
mutations in pendrin gene which is important for
normal functions of the inner ear and thyroid.

4. Case presentation
A 14 year old boy known to have Pendred
syndrome ( goiter and deafness ) was referred
for the evaluation generalized weakness
associated with polyuria of 5-month duration.
Apart from thyroxine treatment for mild
hypothyroidism, he was not receiving any other
medication. There was no history of vomiting or
gastrointestinal disease

5. Examination
Physical examination revealed a height of 155 cm
(50th percentile), weight of 33.5 kg (25th
percentile), and blood pressure of 110/60 mmHg,
with the rest of the general and systemic
examinations being within normal limits .

6. Examination
He had a big goiter with
multiple palpable
nodules Neither the
goiter was tender, nor
bruit was found on
auscultation. Ultrasound
examination confirmed
multinodularty

7. Laboratory investigations
Laboratory tests showed a free thyroxine level of 13
pmol/l (normal value: 9–20 pmol/l) and a
thyroid-stimulating hormone level of 2.5 mU/l
(normal value: 0.15–5.0 mU/l). His fasting blood
sugar and renal function are within normal range.
He had hypokalemia (2.2 mEq/l) and hypocalcemia
(8.1 mg/dl)

8. Blood gas analysis
Blood gas analysis indicated severe metabolic
alkalosis : pH : 7.52,pO2 : 10 .55 kPa, pCO2 : 6.48
kPa, bicarbonate (HCO3) :43 mmol/l, and base
excess + 14 (normal ranges: 7.36–7.44; 9.3–13.3
kPa; 4.5–6.0 kPa; 22–26 mmol/l; and −2 to +2,
respectively).

9. Treatment
Based on the above mentioned findings, a
diagnosis of Pendred with metabolic alkalosis
was made. He was treated with oral KCl and
spironolactone to maintain his electrolytes in or
near normal range.

10. Pendrin is localized in the connecting tubule and
in the collecting duct of the kidney cortex, and
in particular, at the apical membrane of a
subpopulation of intercalated cells (type B and
non-A non-B) These cells carryout a fine
regulation of acid–base excretion through
bicarbonate-transport processes. Pendrin does
play a part in maintaining acid–base
homeostasis, its absence lead to failure of renal
bicarbonate excretion, leading to metabolic
alkalosis, hypokalemia, and hypomagnesemia.