敗血症
敗血症是早產兒面對的主要挑戰之一。嬰兒出生的週數愈早，出生體重愈輕，患上此病的風險就愈高。[1] 雖然身體不同的部位如肺部、腸道、腦部都可能遭到感染，但敗血症是一種更嚴重的疾病，因為細菌有機會從血液中擴散至全身。
敗血症的原因有很多，發病的時間亦會因而不同。如胎水或產道內存有細菌，嬰兒可能會在出生的過程中已受到感染，並在出生後首數天病發。[2] 至於出生後，嬰兒亦有機會從周圍的環境中受到感染。由於早產兒的免疫系統未成熟，加上他們較常需要使用具侵入性的設備，如：使用血管內導管、呼吸導管等，這些都會增加他們受到感染的風險。[3]
患有敗血症的嬰兒或會出現餵食不耐、煩躁不安、活動能力下降等徵狀。他們的維生指數如體溫、心跳、血氧飽和度和血壓亦會較為不穩定。嬰兒的情況能急速轉差，因此，具有以上特徵的嬰兒需要立即接受診斷和治療。根據臨床的情況，醫生會抽取嬰兒的血液、尿液、脊髓液等樣本來進行病原體培植，這能為日後的治療提供重要的資訊。醫生也會透過胸部和腹部的X光片來找出受感染的地方。
所有患上敗血症的嬰兒應及時接受抗生素治療。病情較重的嬰兒可能需要額外的器官支援，例如使用呼吸機來協助呼吸、使用強心藥來支援心藏等。雖然有些患者的治療效果理想並能順利康復，但敗血症仍然是能威脅早產嬰兒性命的重要疾病之一。
-撰寫自劉凱盈醫生
威爾斯親王醫院兒科
駐院醫生
Septicaemia
Septicaemia is one of the major challenges that preterm babies have to face, the risk increases with a decreasing gestational age and body weight.[1] While infection could happen in different parts of the body e.g., lung, gut, brain; septicaemia describes an even more serious condition where the bacteria enters into the bloodstream and spreads throughout the body.
Babies could develop septicaemia at different time periods depending on the underlying cause. Babies who acquire an infection related to the delivery process, e.g., due to contaminated amniotic fluid or the presence of bacteria in the birth canal, will usually present within the first few days of life.[2] For those who acquire the infection after birth, are more likely to have acquired the pathogens from the environment. The risk of infection is higher in preterm babies because of their relatively immature immune systems and the increased need for more invasive devices e.g., use of intravascular catheters, breathing tubes.[3]
Babies with septicaemia may present with non-specific features like poor feeding, irritability, decreased activeness. Vital signs like temperature, heart rate, oximetry and blood pressure may be unstable. Septicaemia could progress quickly, so babies with any of the above features should be investigated and treated promptly. Depending on the clinical suspicion, samples like blood, urine, fluid surrounding the spinal cord may be taken for culture of pathogens, this would provide essential information for subsequent adjustments of treatment. Radiographs of the chest and abdomen are also commonly done to locate the site of infection.
All babies with septicaemia should be treated promptly with anti-microbial agents. For those with severe conditions, extra support is commonly provided, e.g., ventilatory support from respiratory devices and cardiovascular support with medications such as inotropes. While some may respond well to treatment with a good recovery, septicaemia remains a potentially life-threatening condition in preterm babies.
Written by Dr. Sharon Lau
Resident, Department of Paediatrics
Prince of Wales Hospital
Reference
[1] Stoll BJ, Hansen N. Infections in VLBW infants: studies from the NICHD Neonatal Research Network. Semin Perinatol 2003; 27:293.
[2] Stoll BJ, Hansen NI, Higgins RD, et al. Very low birth weight preterm infants with early onset neonatal sepsis: the predominance of gram-negative infections continues in the National Institute of Child Health and Human Development Neonatal Research Network, 2002-2003. Pediatr Infect Dis J 2005; 24:635.
[3] Stoll BJ, Hansen N, Fanaroff AA, et al. Late-onset sepsis in very low birth weight neonates: the experience of the NICHD Neonatal Research Network. Pediatrics 2002; 110:285.