Hypotonic baby experiences failure to thrive

Key Points

The Case

A mother in your practice, whose newborn is being treated at a community hospital where you do not have privileges, calls you with a tale of woe. Three weeks previously, the mother had delivered her full-term baby at home after less than 20 minutes of labor. The mother kept the baby wrapped in clean towels until the local EMS arrived. The paramedics found the baby to be acrocyanotic but alert and crying.

The baby's temperature was 95.8°F, pulse was 134 beats per minute and regular, and respiration rate was 40 breaths per minute. The paramedics rushed the baby to the local community hospital, where a rectal temperature was taken; the reading was 93.6°F. The baby was immediately placed under a warmer and on a heating blanket.

While everyone was perplexed and distraught over the baby's burn, it was decided that the heating blanket probably malfunctioned and overheated, and an incident report was filed. The baby's wounds were cleaned, and silver sulfadiazine cream was applied. The baby's vital signs were stable, and she was not in any distress from the burns.

New symptoms

After 4 hours, the baby was fed. She gagged, spat up, and became agitated. The agitation was persistent and was interpreted as irritability. Vitals were stable, but a sepsis workup was performed, including complete blood count (CBC) with differential; chemistries; blood, cerebrospinal fluid, urine, and wound cultures, and chest x-ray. The CBC showed a white blood cell count (WBC) of 21.3K/mm³ , hemoglobin (Hgb) 18.7 g/dL, hematocrit (Hct) 54.2 %, and platelets 183K/mm³ . Differential was neutrophils 53%, basophils 25%, lymphocytes 15%, and monocytes 2%. Chemistries were: sodium 136 meq/L, potassium 3.7 meq/L, chloride 104 meq/L, carbon dioxide 22.1 meq/L, glucose 102 mg/dL, BUN (blood urea nitrogen) 11 mg/dL, creatinine 0.9 mg/dL, and calcium 10.2 mg/dL. The chest x-ray was unremarkable. As the lumbar puncture returned grossly bloody fluid, cerebrospinal fluid (CSF) cell count and protein were not performed. Ampicillin and gentamicin treatment plus intravenous (IV) maintenance fluids were initiated. The baby was designated as NPO status for the next 48 hours.

Blood, urine, and CSF cultures were negative at 48 hours, and the wound cultures grew only rare Staphylococcus epidermidis, so antibiotics were discontinued, and feeding was re-attempted. Over the next few days, the baby slowly but steadily took 0.5 to 1 ounce of formula at each feeding. However, her mother tells you that the baby does not feed normally like her older sister did.

The baby began vomiting and gagging again the next day. Abdominal films were taken, and reported normal, with no signs of obstruction or infection. The baby was switched to soy formula. Again, she did better for a day or 2, although still feeding extremely slowly. Then on the sixth day of life the baby gagged and turned blue during a feeding. Vitals at that time showed a normal temperature, pulse of 170 beats per minute, and normal respirations. A computed tomography (CT) scan of the brain was performed, and the results were unremarkable. TORCH studies were drawn, but the results were negative (toxoplasmosis, negative; rubella, Rubazyme index=1.3, indicating passive immunity and not active infection; cytomegalovirus [CMV] IgG, negative; herpes simplex virus [HSV] 1 and HSV2 antibody, negative). Gastrointestinal (GI) and cardiology consults were requested.

The GI specialist thought that the baby had reflux and therefore recommended small, frequent feeds, as well as elevation to 30° at all times. The cardiologist performed an electrocardiogram (EKG) and an echocardiogram, which were reported as normal.

The baby was now taking 0.5 ounce per feeding every 2 hours, still with gagging. She was losing weight, now weighing 6 pounds 2 ounces at 9 days of age. Then she developed a rectal temperature of 100.6°F. Physical exam revealed healing burns, but the exam was otherwise normal. Once again, a full sepsis workup was performed. The CBC was normal, and cerebrospinal fluid cell count and protein were normal. A full chemistry panel showed normal electrolytes and normal liver and kidney function. Ampicillin and gentamicin were reinitiated, and the baby was again designated as NPO status. The GI specialist requested an upper GI series; the results were normal. After 3 days, cultures were negative, antibiotics were stopped, and feedings were resumed, increasing to Enfamil #24 with 1 teaspoon of MCT oil per 8 ounces of formula. Still, there was no improvement in the feeding pattern, and the baby had not regained her birth weight at 3 weeks of age.