Thin tremor, sweating and high-pitched crying in the newborn

Specialty: Pediatrics.

• Suspected neonatal abstinence syndrome
• symptomatic neonatal hypoglycemia or hypocalcemia

Why it occurs

• Neonatal Abstinence Syndrome or NAS (sudden interruption of the transplacental transfer of psychoactive substances or drugs taken by the mother during pregnancy, mainly opiates, methadone, benzodiazepines or selective serotonin reuptake inhibitors)
• Symptomatic neonatal hypoglycemia (critical drop in blood glucose levels that generates an intense sympathetic autonomic response with tremor, diaphoresis and tachycardia)
• Symptomatic neonatal hypocalcemia (ionic calcium levels less than 4.4 mg/dl that increase neuromuscular excitability causing tremors, myoclonus and hyperreflexia)
• Early neonatal sepsis or hypoxic-ischemic encephalopathy in the hyperexcitability phase (infection or brain damage that alters autonomic and neuromuscular regulation).

Initial workup

Immediate determination of capillary blood glucose and ionic calcium levels in the blood. Complete general analysis with complete blood count, CRP, procalcitonin, blood culture, serum electrolytes (sodium, potassium, chlorine, magnesium), capillary blood gas analysis and renal/hepatic profile. Determination of toxins in urine and meconium (meconium provides a much wider exposure window than urine when maternal substance abuse is suspected). Serial application of the modified Finnegan scale (to quantify the severity of neonatal abstinence syndrome symptoms).

Standard management

• Treatment initially focuses on non-pharmacological support measures — quiet environment, dim light, wrapping the newborn in a firm swaddle, non-nutritive sucker and frequent high-calorie feedings). Oral morphine (first-line drug for moderate-severe opioid withdrawal syndrome with a Finnegan scale persistently greater than or equal to 8; initial dose of 0.04 to 0.2 mg/kg/day divided every 4-6 hours orally, individually adjusted and tapered very gradually
• Phenobarbital — drug of choice for non-opioid withdrawal syndrome or as an adjuvant; 20 mg/kg IV loading dose followed by maintenance
• 10% Calcium Gluconate (specific treatment for symptomatic hypocalcemia; dose of 100 to 200 mg/kg slow IV under strict electrocardiographic monitoring to avoid bradycardia).