1. Introduction

The benefits of exclusive breast feeding of a baby are well-known [1]. It reduces the incidence of many acute infections and chronic diseases and improved neurodevelopmental outcomes of the baby [2]. Hypernatremia, a frequently encountered electrolytes disorder is defined as a serum sodium level greater than 145 mmol/L. Serum sodium of >160mmol/L is often regarded as severe hypernatremia. In neonate, hypernatremic dehydration may be suspected as a weight loss of more than 10% of birth weight at the end of the first week of life [3]. Hypernatremia was previously thought to be unusual in breastfed babies but recent reports suggested that the incidence of hypernatremia and hypernatremic dehydration is rising [4]. Failure to diagnose neonatal hypernatremia can have serious consequences including cerebral edema, seizures, intracerebral hemorrhage, vascular thrombosis and death [1,5]. In this case report, we describe a case of severe hypernatremia with hypernatremic dehydration in a neonate who is exclusively breastfed with a review of the literature.

2. Case Presentation

A 13 days old term female neonate, weighing 2.1 kg was admitted to the Neonatal Intensive Care Unit (NICU) of North East Medical College Hospital (NEMCH) due to complaints of baby being lethargic, unable to breast feed for 3 days before admission and baby was not urinating adequately for 20 hours before admission but no history of loose motion, vomiting, convulsion and jaundice. Baby was born by caesarean section due to mother’s desire, because mother was concerned about cerebral palsy which she observed in a case of her relative’s vaginal delivery. Mother was 31 years old primigravida healthy, had no history of PIH, GDM and pregnancy was uneventful. Baby’s birth weight was 3.3 kg. After birth, the baby was seen by a paediatric consultant and parents were assured that the baby was well. The neonate was on exclusive breastfeeding. On examination the baby was sick, lethargic, markedly wasted and had clinical evidence of severe dehydration. Her vital signs were: respiratory rate 45 breaths/minute, heart rate 160 b/min, temperature 99°F. Oxygen saturation was 94% without oxygen. Skin was doughy, and the anterior fontanelle was depressed. Examination of heart, lungs were unremarkable and abdomen was scaphoid. Neurologically she was extremely lethargic, with a weak cry and marked hypotonia. Moro reflex was poor and sucking was intermittent. A provisional diagnosis of sepsis with severe dehydration was made. Baby’s birth weight was 3.3 kg and the admission weight was 2.1 kg. Weight loss 36.3%.

Figure 1. During admission at NICU, NEMCH, Sylhet, Bangladesh

On admission laboratory findings showed severe hypernatremia. The initial serum sodium was 175.9mmol/L and potassium was 5.1mmol/L, serum creatinine 1.98mg/dl, random blood sugar was 5mmol/L, serum calcium 9.5mg/dl, and sepsis screen was negative. ABG at the time of admission showed metabolic acidosis. Hemoglobin 18g/dl, TLC- 4700/cumm and platelets count 250000/cumm. Blood was sent for culture and sensitivity. She (patient) was diagnosed as a case of severe hypernatremia with hypernatremic dehydration.

She was given a bolus of isotonic saline 20 ml/kg over 60 minutes, IV antibiotics started with intravenous injection ceftazidime and injection ampicillin. Then sodium excess was managed by gradual and slow correction over 72 hours with baby saline (composed of 0.225% NaCl and 5% dextrose). The baby required 200 ml /kg /day (1.3 times maintenance) of fluids from day 1 to day 3 to correct hydration status. Serum electrolytes were measured 12 hours intervals and serum creatinine daily.

Figure 2. During discharge from the NEMCH, Sylhet

As there was no apparent cause of hypernatremia found, further evaluation was started. At that time mother gave history of taking added salt with food. Then mother’s breast milk was taken into consideration. As it is relatively a rare phenomenon, 2 samples of mother’s breast milk were collected and sent to two different laboratories for breast milk electrolytes test. Mother’s serum electrolytes were also done and results were within normal limits. Breast milk electrolytes results showed sodium 95 mmol/L (normal; 13 mmol/L), potassium 7.1 mmol/L, and chloride 75 mmol/L. Results from both laboratories were almost the same. So, it was quite evident that the breast milk is the source of hypernatremia of the baby.

Under constant supervised management with proper rehydration and maintaining intake output chart. Serum sodium levels and serum creatinine returned to normal at day 4 of admission. Baby’s general condition dramatically improved, urine output became normal, and the baby became more active. Blood culture showed no growth, antibiotics stopped at day 5. Initial twenty-four hours baby was nothing per oral then naso-gastric feeding started with expressed breast milk. Initially parents refused to give breast milk but assuring that this high breast milk sodium decreases as time progresses then they agreed to give breast milk. The baby was on exclusive breastfeeding at 4^th day of admission and discharged at 6^th day of admission. The discharged weight was 2.9 kg. The final diagnosis was severe hypernatremia with hypernatremic dehydration. The cause of hypernatremia was due to breast milk.

3. Discussion

Breast milk hypernatremia in neonates was thought to be unusual until the late 1970s in the USA and western countries but was never in the discussion in countries like Bangladesh. Since 1990 there have been increased reported cases from countries like England, USA, Hong Kong, India [6,7,8]. In those cases, serious complications like seizures, disseminated intravascular coagulation, cerebrovascular accidents and even deaths were reported. It is normal over the 1^st week of life for the neonate to lose as much as 7% of birth weight through normal diuresis. Neonates should start to gain weight thereafter and regain their birth weight by the 10^th day of life. Rapid weight loss or weight loss >7% of birth weight is a cause for concern. The first signs of neonatal dehydration include the failure to have bowel movements or the presence of urate crystals, combined with weight loss [9]. Fortunately, in our case no serious complications were developed before or during treatment. We studied different cases from various journals and found that this baby was an ideal case of neonatal severe hypernatremia on exclusive breast feeding. Hypernatremic dehydration is notoriously difficult to diagnose on clinical examination alone, as skin turgor is preserved; the anterior fontanelle can retain its normal fullness, and urine output, although reduced, is maintained even in the face of severe dehydration [10]. The clinical features are a spectrum, from an alert and hungry child who appears relatively well to a child who is lethargic, irritable and even moribund. [11] Sodium content of breast milk at birth is high and declines rapidly over the subsequent days. In 1949, Macy established mean Na⁺ content of colostrum in first 5 days is 22 mmol/L and transitional milk from day 5 to day 10 is 13 mmol/L and of mature milk after 15 days is 7 mmol/l. [12,13] Hypernatremia may be associated with hyperglycemia and mild hypocalcemia, the mechanism of which is not known. [5] Hyperglycemia was noted in 13 out of 42 reported cases of breastfeeding associated hypernatremia by Van Amerongen et al. [14] In this case has no hyperglycemia or hypocalcemia observed. Hypernatremia in neonates is entirely preventable, If the right steps can be taken quickly and in a timely manner.

4. Conclusions

The study can be safely concluded that breast feeding associated neonatal hypernatremia is not as rare as it is commonly believed. Poor feeding and weight loss could be a reason to suspect neonatal hypernatremia in an otherwise healthy baby. In this particular case we suggest, close monitoring of weight and hydration status of exclusively breast-fed babies and earlier intervention if weight loss exceeds 10% of birth weight reduces the consequences of neonatal hypernatremia. This case had a happy ending if not detected early and intervention delayed outcome may have been entirely different.