Int J Clin Pediatr

International Journal of Clinical Pediatrics, ISSN 1927-1255 print, 1927-1263 online, Open Access

Article copyright, the authors; Journal compilation copyright, Int J Clin Pediatr and Elmer Press Inc

Journal website https://www.theijcp.org

Case Report

Volume 12, Number 2, September 2023, pages 45-50

Severe Unexpected Hyponatremia in an Infant With Cystic Fibrosis Carriership

**Table 1.** Laboratory Results at Presentation
Laboratory investigation	Results
CRP: C-reactive protein; TSH: thyroid-stimulating hormone.
Serum
Sodium	115 mmol/L
Potassium	3.0 mmol/L
Calcium	2.81 mmol/L
Phosphate	1.80 mmol/L
Chloride	77 mmol/L
Urea	2.50 mmol/L
Creatinin	14 µmol/L
Osmolality	254 mOsmol/kg
Blood gas capillary
pH	7.48
pCO₂	6.0 kPa
Bicarbonate	33.2 mmol/L
Base excess	8.6 mmol/L
Sodium	122 mmol/L
Potassium	2.82 mmol/L
Chloride	76 mmol/L
Glucose	5.4 mmol/L
Hemoglobin	8.2 mmol/L
Trombocytes	6.7 × 10⁹/L
Leucocytes	6.7 × 10⁹/L
TSH	3.45 mU/L
T4, free	23.8 pmol/L
Cortisol	1,221.9 nmol/L
Albumin	42 g/L
CRP	< 4 mg/L
Urine
Creatinin	1.9 mmol/L
Sodium	< 10 mmol/L
Specific gravity	1.006 kg/L
pH	6.0
Protein	Negative
Glucose	Negative
Ketones	Negative
Nitrite	Negative
Blood	Negative
Leukocytes esterase	Negative

Table 1. Laboratory Results at Presentation

Laboratory investigation

Results

CRP: C-reactive protein; TSH: thyroid-stimulating hormone.

Serum

Sodium

115 mmol/L

Potassium

3.0 mmol/L

Calcium

2.81 mmol/L

Phosphate

1.80 mmol/L

Chloride

77 mmol/L

Urea

2.50 mmol/L

Creatinin

14 µmol/L

Osmolality

254 mOsmol/kg

Blood gas capillary

7.48

pCO₂

6.0 kPa

Bicarbonate

33.2 mmol/L

Base excess

8.6 mmol/L

Sodium

122 mmol/L

Potassium

2.82 mmol/L

Chloride

76 mmol/L

Glucose

5.4 mmol/L

Hemoglobin

8.2 mmol/L

Trombocytes

6.7 × 10⁹/L

Leucocytes

6.7 × 10⁹/L

TSH

3.45 mU/L

T4, free

23.8 pmol/L

Cortisol

1,221.9 nmol/L

Albumin

42 g/L

CRP

< 4 mg/L

Urine

Creatinin

1.9 mmol/L

Sodium

< 10 mmol/L

Specific gravity

1.006 kg/L

6.0

Protein

Negative

Glucose

Negative

Ketones

Negative

Nitrite

Negative

Blood

Negative

Leukocytes esterase

Negative

**Table 2.** Sodium, Potassium and Chloride Levels During Admission
	14-07-2022 (3 PM)	15-07-2022 (4 AM)	15-07-2022 (11 AM)	15-07-2022 (8 PM)	16-07-2022 (8 AM)	17-7-2022 (8 AM)	18-7-2022 (8 AM)	27-7-2022*
*Two days after discontinuing suppletion.
Sodium (mmol/L)	115	122	121	124	128	131	135	138
Potassium (mmol/L)	3.0	2.82	4.03	3.42	3.31	4.2	5.64	4.79
Chloride (mmol/L)	77	76	78	81	84	99	104	105

Table 2. Sodium, Potassium and Chloride Levels During Admission

14-07-2022 (3 PM)

15-07-2022 (4 AM)

15-07-2022 (11 AM)

15-07-2022 (8 PM)

16-07-2022 (8 AM)

17-7-2022 (8 AM)

18-7-2022 (8 AM)

27-7-2022*

*Two days after discontinuing suppletion.

Sodium (mmol/L)

115

122

121

124

128

131

135

138

Potassium (mmol/L)

3.0

2.82

4.03

3.42

3.31

4.2

5.64

4.79

Chloride (mmol/L)

104

105

**Table 3.** Sodium and Chloride Content in Breast Milk of Mother of Infant in This Case, Two Healthy Controls and in Literature Reported Ranges
	Sodium (mmol/L)	Chloride (mmol/L)
Case shows sodium and chloride levels in breast milk of patient’s mother, measured in three different samples. Control 1 shows sodium and chloride levels in breast milk of a 2-month-old baby, fully breastfed, measured in two different samples. Control 2 shows sodium and chloride levels in breast milk of an 8-month-old baby, measured in one sample. Literature shows sodium and chloride levels in breast milk in Stallings et al [4] and Turck et al [7]. CI: confidence interval.
Case
Sample 1	3.4	3.7
Sample 2	4.2	3.6
Sample 3	5.2	4
Control 1
Sample 1	6.1	5.4
Sample 2	6.4	4.8
Control 2
Sample 1	8.6	7.1
Stallings et al [4]
0 - 6 months	6.0 mmol/L (95% CI 5.1 - 6.8)
7 - 12 months	4.8 mmol/L (95% CI 3.5 - 6.2)
Turck et al [7]		11.3

Table 3. Sodium and Chloride Content in Breast Milk of Mother of Infant in This Case, Two Healthy Controls and in Literature Reported Ranges

Sodium (mmol/L)

Chloride (mmol/L)

Case shows sodium and chloride levels in breast milk of patient’s mother, measured in three different samples. Control 1 shows sodium and chloride levels in breast milk of a 2-month-old baby, fully breastfed, measured in two different samples. Control 2 shows sodium and chloride levels in breast milk of an 8-month-old baby, measured in one sample. Literature shows sodium and chloride levels in breast milk in Stallings et al [4] and Turck et al [7]. CI: confidence interval.

Case

Sample 1

3.4

3.7

Sample 2

4.2

3.6

Sample 3

5.2

Control 1

Sample 1

6.1

5.4

Sample 2

6.4

4.8

Control 2

Sample 1

8.6

7.1

Stallings et al [4]

0 - 6 months

6.0 mmol/L (95% CI 5.1 - 6.8)

7 - 12 months

4.8 mmol/L (95% CI 3.5 - 6.2)

Turck et al [7]

11.3