【文献Abstract】おへその問題

〈要点〉

●新生児では、臍ドレナージの最も一般的な原因は臍肉芽腫です。臍帯ドレナージの他の原因には、臍炎および臍帯腸管および尿膜管異常などの臍帯異常が含まれます。 

●臍ヘルニアは一般的に子供に見られ、一般的に簡単に軽減でき、通常、生後5年間は介入なしで消失。ヘルニアが嵌頓しているまれな患者では、外科的修復が必要。サイズが縮小しない、または症候性（グレード2C）の大きな欠陥（直径> 1.5cm）の患者には外科的修復が推奨される。

●臍肉芽腫は、新生児で最も一般的な臍の腫瘤。通常、臍帯分離後に検出される。局所硝酸銀は、この病変を治療するために最も一般的に使用される。 

●omphalomesentericductの発生学的閉鎖の失敗は、尿膜管開存、臍帯ポリープ、メッケル憩室、尿膜管嚢胞、または腹腔内線維帯を含む一連の異常をもたらす。 

●尿膜管の発生学的閉鎖に失敗すると、尿膜管の開存、臍帯ポリープ、膀胱憩室、尿膜管嚢腫など、さまざまな異常が発生する。 

●臍炎とその周辺組織の多菌感染症は、主に新生児に発生する。合併症には、敗血症や壊死性筋膜炎などがあり、死亡率が高くなっている。 

●臍炎の抗生物質治療が必要であり、グラム陽性菌とグラム陰性菌を対象としている。重篤な合併症のリスクを軽減するために、臍炎の乳児には、局所または経口抗生物質療法ではなく、抗ブドウ球菌およびアミノグリコシド剤の最初の非経口投与が推奨される（グレード2C）。MRSAの有病率が高い地域では、抗ブドウ球菌ペニシリンではなくバンコマイシンを投与することが推奨される（グレード2C）。 

〈雑感〉

・先日成人で臍肉芽腫＋感染と思われる方を見たのでUpToDateで再確認。
・自分の兄弟も臍をいじりすぎて尿膜管の感染をきたし緊急手術をしたのを思い出した。おへそはいじりすぎないようにしよう。

〈文献〉

Care of the umbilicus and management of umbilical disorders
Authors:Debra L Palazzi, MD, MEdMary L Brandt, MDSection Editors:Teresa K Duryea, MDRichard Martin, MDDeputy Editor:Melanie S Kim, MD
Literature review current through: Dec 2020. | This topic last updated: Dec 17, 2020.

SUMMARY AND RECOMMENDATIONS

●At delivery, the clamped umbilical cord is inspected to detect any alterations of the normal characteristics (thickness, length, and coiling) of the cord, which can be associated with an increased risk of significant pathology in the newborn infant. (See 'Umbilical cord' above.)

●In the newborn, the most common cause of umbilical drainage is umbilical granuloma. Other causes of umbilical drainage include omphalitis and umbilical anomalies, such as omphalomesenteric duct and urachal abnormalities. (See 'Newborn examination' above and 'Umbilical granuloma' above and 'Other abnormalities' above and 'Omphalitis' above.)

●A single umbilical artery (SUA) is seen in 0.2 to 0.6 percent of live births, of whom 20 to 30 percent will have other major structural anomalies. Although infants with an isolated finding of SUA have an increased risk of occult renal anomalies, these are generally not clinically significant. As a result, in patients with isolated SUA, we suggest not to perform a screening renal ultrasonography (Grade 2C). (See 'Single umbilical artery' above.)

●In the neonate, umbilical cord care is directed toward reducing the risk of umbilical infection and is dependent upon the quality of care at delivery and postnatally. In developing countries where there is an increased risk for omphalitis, we recommend antiseptic topical cord care (eg, chlorhexidine) (Grade 1B). (See 'Cord care' above.)

●Umbilical cord separation usually occurs within the first week of life. Delayed cord separation is associated with underlying immunodeficiency, infection, or urachal anomaly. (See 'Cord separation' above.)

●Umbilical hernias are commonly found in children, generally easily reducible, and usually resolve without intervention over the first five years of life. Surgical repair is required in the rare patient with an incarcerated hernia. We suggest surgical repair for patients with large defects (>1.5 cm in diameter) that fail to decrease in size or are symptomatic (Grade 2C).

●Umbilical granuloma is the most common umbilical mass in neonates. It is usually detected after cord separation because of persistent drainage. Topical silver nitrate is most commonly used to treat this lesion. (See 'Umbilical granuloma' above.)

●Failed embryologic closure of the omphalomesenteric duct results in a range of anomalies including completely patent duct, umbilical polyp, Meckel's diverticulum, omphalomesenteric duct cyst, or intraabdominal fibrous band. (See 'Embryology' above and 'Omphalomesenteric duct anomalies' above.)

●Failed embryologic closure of the urachus results in a range of anomalies including patent urachus, umbilical polyp, bladder diverticulum, or urachal cyst. (See 'Embryology' above and 'Urachal anomalies' above and 'Umbilical polyp' above.)

●Omphalitis, a polymicrobial infection of the umbilicus and surrounding tissue, occurs predominantly in the neonate. Complications include sepsis and necrotizing fasciitis, which has a high mortality rate. (See 'Omphalitis' above and 'Necrotizing fasciitis' above.)

●Antibiotic treatment of omphalitis is required and is directed against Gram-positive and Gram-negative organisms. We suggest initial parenteral administration of antistaphylococcal and aminoglycoside agents rather than topical or oral antibiotic therapy, in infants with omphalitis to reduce the risk of severe complications (Grade 2C). In communities with a high prevalence of methicillin-resistant Staphylococcus aureus, we suggest vancomycin be administered rather than an antistaphylococcal penicillin (Grade 2C). (See 'Omphalitis' above.)