The Prevalence of Neonatal Abstinence Syndrome - Essay Example

?SUMMARY NAS is a complex of varied behavioral and physiologic signs and symptoms resulting from prenatal and maternal substance use that cause withdrawal symptoms. This is an important public health issue, since (3% of 4.1 million) women of child-bearing age still use drugs during pregnancy. These substances and by-products tend to accumulate in the fetus because of the immature renal function and hepatic metabolism (Hamdan, 2012). In addition, depression, which is managed by anti-depressive medications such as SSRIs, is aggravated by stressful conditions such as pregnancy (Levinson-Castiel et al., 2006). Its prevalence and long-term adverse effects all make the studies on this syndrome an important endeavor. INTRODUCTION Symptoms Manifestation of symptoms may occur between 24 hours to two weeks, depending on the half-life of the substance used. Low birth weight, prematurity, and intrauterine growth retardation are common. Those exposed to cocaine show hyperactive Moro reflex, jittering, and excessive sucking. Exposure to caffeine and subsequent accumulation of blood methylxanthine impairs neonatal habituation, orientation, autonomic regulation, exaggerated startle reflex and tremor, as well as auditory orientation. Marijuana exposure leads to hypoglycemia, hypocalcemia, sepsis, hypoxic encephalopathy, intracranial hemorrhage, tachycardia, poor perfusion, irritability, and poor feeding. SSRIs during the last trimester may manifest as irritability, agitation, tremors, tachypnea, nasal congestion, emesis, or diarrhea. These symptoms disappear by two weeks. Other symptoms that may support the diagnosis of NAS are microcephaly, congenital infection, congenital malformations, high-pitched cry, sleep duration less than 1-3 hours after feeding, tremors, hypertonia, myoclonic jerks, generalized convulsions, sweating, fever, mottling, frequent yawning, sneezing, nasal flaring, respiratory rate of greater than 60 breaths per minute, apnea, poor feeding, hyperphagia, regurgitation, and loose stools (Hamdan, 2012). Diagnosis The Finnegan Scoring System is developed based on opiate withdrawal, and thus may not be appropriate for infants exposed to other drugs. It is the most widely used scoring system, attributable to its relative ease of use and reliability once conducted by a trained stuff. Despite this, it is still prone for bias and subjectivity. Aside from diagnosis, it can assess the effectiveness of treatment. If NAS is suspected, radioimmunoassays, enzyme immunoassays, blood tests, urine toxicology assays, meconium analysis or hair analysis may be conducted to confirm substance use by the pregnant mother (Hamdan, 2012). Causes The syndrome can be caused by abrupt discontinuation of opioid, more commonly fentanyl, especially after prolonged drug use. Aside from opioids, barbiturates, caffeine, cocaine, selective serotonin reuptake inhibitors (SSRIs), antihistamines, ethanol, marijuana, nicotine, phencyclidine, meprobamate, glutethimide, ethchlorvynol, and benzodiazepines are noted to cause NAS. Tolerance and physical dependence are seen more rapidly among users of shorter acting drugs and continuous infusion, usually after 5 or more days of continuous infusion of fentanyl. Maternal substance abuse is the leading preventable cause of mental, physical, and psychological problems in infant and children. Certain drugs, such as cocaine and amphetamines, stimulate the release and block the reuptake of dopamine, epinephrine, norepinephrine, and serotonin. Such activity is similar to the activity of SSRIs (Hamdan). Serotoninergic hyperstimulation causes stimulation such as jitterness, tachypnea, hypertonicity, temperature instability, and diarrhea. These symptoms should manifest shortly after birth, since drug exposure, which is a vital factor for symptom presentation, does not continue after birth (Levinson-Castiel et al., 2006). Pathophysiology The drugs noted above cause tolerance and addiction to the infant because of their ability to pass through the placental barrier. For example, psychiatric drugs are usually highly lipophilic, and have relatively low molecular weight (Hamdan, 2012). Withdrawal is dependent on the drug’s half-life, such that the longer the half-life, the later the onset of symptoms. It is also associated with a decreased likelihood of development of NAS in infant. Heroin withdrawal, because of its short half-life, may manifest as early as 24 hours after birth, peaking within 48-72 hours in more than half of infants of heroin users (Hamdan, 2012). Treatment Since the late 1960s, methadone has been used as therapy for opiate-addicted women. Its effects include decrease in illicit behaviors as well as improvement of prenatal care and obstetric outcomes. However, certain studies have found that methadone increases the risk of preterm birth, smaller infants and longer hospital admissions. Non-pharmacologic management includes reduced ambient light exposure, pacifiers, oscillating cribs, minimizing excessive noise, minimizing unnecessary handling, providing swaddling, and giving hypercaloric formula. This is frequent small feedings containing 150 – 250 kcal/kg for 24 hours (Hamdan, 2012). AIMS, DATA COLLECTION AND ANALYSIS METHODS Because of the variation in manifestation and causes, Levinson-Castiel et al. (2006) conducted a cohort study at Rabin Medical Center in Israel, a tertiary care center, to compare the prevalence and clinical characteristics of NAS, as assessed by Finnegan scoring system, in neonates exposed (n = 60) and not exposed (n = 60) to SSRIs in utero. FINDINGS 30% of those exposed to SSRIs manifest with severe (13%) or mild symptoms (17%) of NAS, while unexposed NAS had a normal Finnegan score. Average peak manifestation was recorded within two to four days after birth. As such, the observed symptoms were unlikely caused by serotoninergic hyperstimulation. In addition, symptoms more frequently observed in the newborns from SSRI users were tremor, gastrointestinal or sleep disturbance, hypertonicity, and high-pitched cry. Although tachypnea was noted in previous studies, it was less noted in this study, because preterm infants were excluded. DISCUSSION AND RECOMMENDATIONS Despite the importance of studies on NAS, there are problems encountered in conducting them. History is an important component of establishing NAS, because ensuring substance exposure is an important component of NAS diagnosis. Levinson-Castiel et al., (2006) reported that since mothers may choose not to report SSRI use, the study may not have captured the total exposed population. In addition, a number of psychiatric patients also take multiple medications, and thus the determination of the effects of specific drugs is less possible. A valid assessment of long-term effects of in utero exposure to SSRIs also needs a similarly long-term study. Levinson-Castiel et al., (2006) suggests that information dissemination to both physicians and mothers are necessary to curtail the prevalence of NAS. For mothers suffering from depression, a risk-benefit ratio of continuing SSRI should be assessed. Use of minimum effective dosage, polytherapy, and close monitoring after birth are necessary steps to prevent and to manage possible NAS. REFERENCES Hamdan, A. H. (2012). Neonatal abstinence syndrome. Retrieved from http://emedicine.medscape.com/article/978763-overview Levinson-Castiel, R., Merlob, P., Linder, N., Sirota, L., & Klinger, G. (2006). Neonatal abstinence syndrome after in utero exposure to selective serotonin reuptake inhibitors in term infants. Arch. Pediatr. Adolesc. Med., 160, 173-176. Read More