Pediatric emergency medicine trisk 644

TABLE 96.6
EXAMPLES OF HYPOTONIA AND NEUROMUSCULAR DISEASE
Anterior horn cell

Motor and sensory
neuropathies
Neuromuscular junction

Congenital myopathy
Muscular dystrophy

Metabolic and multisystem
disease

Spinal muscular atrophies
Infantile neuronal degeneration
Neurogenic arthrogryposis
Hypomyelinating neuropathy
Charcot–Marie–Tooth disease
Hereditary sensory and autonomic neuropathy
Acquired transient neonatal myasthenia
Congenital myasthenia
Infantile botulism
Magnesium toxicity
Aminoglycoside toxicity
Nemaline myopathy
Myotubular myopathy
Congenital muscular dystrophy
Walker–Warburg syndrome
Muscle–eye–brain disease
Duchenne dystrophy

Mitochondrial disorder
Peroxisomal disorder
Neonatal adrenoleukodystrophy
Cerebrohepatorenal syndrome
Pompe disease
Severe neonatal phosphofructokinase
deficiency
Severe neonatal phosphorylase deficiency

Neonatal Abstinence Syndrome
Goals of Treatment
It is estimated that over 4% of pregnant women abuse one or more substances
during pregnancy—both legal and illicit substances. The goals of treatment are to
distinguish the infant suffering from neonatal abstinence syndrome (NAS) and


acute intoxication, and to assess the safety of the infant’s current home
environment. First-line treatment for infants with abstinence syndrome is
supportive care and decreased stimulation. Available pharmacotherapy is
dependent on the class of drug the infant was exposed to in utero. Infants that
present with seizures respond well to anticonvulsant therapy, however, these
infants should have a broad diagnostic evaluation for seizure etiology, including
infection, metabolic derangements, and CNS hemorrhage.
CLINICAL PEARLS AND PITFALLS
The age of presentation for infants with NAS can vary from several
hours to several weeks after birth, depending on the exposed
substance.
Naloxone administration to chronically opioid-exposed neonates is
contraindicated as it may precipitate severe withdrawal and/or seizures.
Opioids

Infants with opiate withdrawal may present with sleep–wake abnormalities,
feeding difficulties, irritability, or weight loss. In extreme cases, up to 10% of
infants will also present with seizures. Common opioid exposures during
pregnancy may include morphine (and its derivatives), heroin, methadone, and
buprenorphine. Sixty percent to 80% of infants exposed to heroin or methadone
will develop signs of NAS. Higher doses of maternal methadone are more likely
to result in NAS. The onset of withdrawal is most often in the first 2 to 3 days
after birth, although can present as late as 4 weeks of age. Pharmacotherapy for
opioid withdrawal includes opiates (oral or intravenous morphine), barbiturates
(phenobarbital), and benzodiazepines (diazepam). Opiate treatment can decrease
the incidence of seizure, reduce time to regain birth weight, and decrease the
incidence of treatment failure. More recent reports using clonidine have been
promising in the treatment of opioid withdrawal, although larger, more detailed
pharmacokinetic studies are warranted.
Cocaine
Cocaine use in pregnancy increases the risk of intrauterine demise, placental
abruption, hypoxia–ischemia, and growth restriction of the developing fetus.
Early exposure may also be associated with congenital anomalies, though a
distinct syndrome has not been described. These children may have abnormalities
in state regulation, autonomic regulation, and reflexes at 2 to 4 weeks postpartum,


although they do not have typical neonatal withdrawal symptoms. If present, the
intensity and duration of symptoms are much shorter than in opioid-exposed
infants. Most importantly, these infants should be evaluated for additional
substance exposure, as many pregnant women using cocaine may also
demonstrate polysubstance use.
Amphetamines
The effects of amphetamine and methamphetamine use are similar to cocaine,
acting as a CNS stimulant, but with a longer duration of action. There is a

similarly increased risk of miscarriage, prematurity, growth restriction, and
placental abruption. Infants may present with disturbances in state regulation and
sleep, as well as feeding disturbances, hypertonia, and tremors.
Marijuana
The effects of marijuana, and specifically tetrahydrocannabinol (THC) are dose
dependent. Infants with higher intrauterine exposure are more likely to present
with lethargy, hypotonia, and decreased responses to stimuli. Infants may exhibit
increased startle reflexes or tremors. Infants rarely present with typical symptoms
of NAS, although long-term studies are lacking.
Selective Serotonin Reuptake Inhibitors
There has been increased use of antidepressants in pregnancy over the last
decade, particularly the use of selective serotonin reuptake inhibitors. Emerging
literature suggests prenatal SSRI exposure may result in infant withdrawal
symptoms of altered state regulation and autonomic reactivity. There have been
reports of more serious reactions, such as tachycardia and cyanosis. Symptoms
appear to be self-limited, and current therapy is largely supportive, although longterm studies regarding the safety of SSRI use in pregnancy are still warranted.

Abnormal Tone
Hypotonia in the neonate can interfere with adequate oral intake, and in
progressive or severe forms, may impede normal respiratory function. These
infants may present with failure to thrive, respiratory distress and impending
respiratory failure, aspiration pneumonia, apnea, including sleep apnea, or
apparent life-threatening events (ALTEs). The goals of treatment are to stabilize
the infant with supportive care, including intubation and assisted ventilation when
appropriate, and then initiating the diagnostic evaluation for the low tone (see
Table 96.5 ). The differential for hypotonia is quite broad and extends beyond
neurologic disorders. Systemic illness, including infections, endocrine disorders,


such as congenital hypothyroidism, and genetic disorders, such as Prader–Willi,

all may present with hypotonia. The hypotonic infant can be identified by low
resting tone—the classic “froglike” position with abnormal extension of the limbs
—as well as exaggerated head lag when pulled to sit. Central hypotonia can be
identified when there is excessive “slip-through” at the shoulder girdle when the
infant is held in vertical suspension, or when the limbs and head hang low on
horizontal suspension. While the hypertonic infant is an abnormal neurologic
finding and should be referred to a specialist, it rarely presents as an emergency.
Exceptions include neonatal tetanus and advanced staged kernicterus, with
hypertonic extension of the extremities, retrocollis, and opisthotonus.

NEONATAL INFECTIONS
Goals of Treatment
Neonatal infection and neonatal sepsis are among the most common diagnoses
encountered in the emergency room. The immature immune system makes
newborns very susceptible to infection resulting in more severe manifestations
than older children or adults. Neonatal infections often have nonspecific
presentations. Neonatal sepsis should be included in any differential diagnosis in
a symptomatic neonate. Rapid evaluation and management of acute deterioration
is the initial goal of therapy. Obtaining the necessary cultures and diagnostic
testing and coverage with broad-spectrum antibiotics is the main priority.
Symptomatic neonates should be admitted for close observation due to the
likelihood of progression. Treatment is then tailored to the specific pathogen once
it has been identified. Treatment in the ED is aimed at cardiorespiratory
stabilization and rapid initiation of antibiotic therapy to prevent acute
deterioration.
KEY POINTS