節を形成する距骨,舟状骨など周囲の骨接合面を含めて
びまん性に高信号域として確認された.これらの範囲に
1 )Jaakkola J, Kehl D: Hematogenous calcaneal osteomyelitis
炎症が波及した場合は,発熱や疼痛,炎症反応上昇など
in children: J Pediatr Orthop, 19( 6 ): 699-704, 1999.
の所見が予想されるが,疼痛や運動・荷重困難を伴う局
2 )M o o n e y M L , H a i d e t K , L i u J , E b r a h e i m N A :
所症状を認めず,血液検査所見では炎症反応上昇も認め
Hematogenous calcaneal osteomyelitis in children: A
なかったことから,臨床的に骨髄炎の再燃は否定的であ
ると考えた.また患児にはバスケットボールの運動習慣
があり,制限解除により荷重のかかる強度の高い運動を
systematic review of the literature. Foot Ankle Spec, 10
( 1 ): 63-68, 2017.
3 )Thakolkaran N, Shetty AK: Acute Hematogenous
再開した時期であり,物理的ストレスによる骨髄の生理
Osteomyelitis in Children. Ochsner J, 19( 2 ): 116 -
的反応である可能性が考えられた.本症例では健側の画
122, 2019.
像評価は未施行であるが,小児では成長期の骨における
骨髄の生理的反応として,両足に左右対称性に同様の
4 )Peltola H, Paakkonen M: Acute Osteomyelitis in Children.
N Engl J Med, 370( 4 ): 352-360, 2014.
MRI 高信号所見が確認されることがあると報告されてい
5 )Lee YJ, Sadigh S, Mankad K, Kapse N, Rajeswaran G: The
る 9 ).小児急性骨髄炎症例に対する治療介入後の MRI 画
imaging of osteomyelitis. Quant Imaging Med Surg, 6
像再評価の際には,運動制限解除後に一過性の骨髄高信
( 2 ): 184-198, 2016.
号所見が確認される場合があり,治療経過と臨床症状を
6 )秋本浩二,西須 孝,柿崎 潤,他:小児の骨髄浮
併せて所見を判断することが重要であると考えられた.
腫疾患の MRI 画像の検討.日本小児整形外科学会雑
誌,25( 2 ):242-246,2016.
Ⅳ.結 語
急性骨髄炎の診断確定と治療効果判定に MRI 検査は有
7 )Helms C, Major N, Anderson M, Kaplan P, Dussault R:
Musculoskeletal MRI, 2 nd Edition. Saunders Elsevier,
92-110, 2009.
用であるが,小児の場合は赤色髄の存在により骨髄内の
8 )Shabshin N, Schweitzer ME, Morrison WB, Carrino JA,
血流が豊富であり,生理的あるいは物理的ストレスによ
Keller MS, Grissom LE: High signal T 2 changes of the
り信号強度の変化が確認されることがある.この様な所
bone marrow of the foot and ankle in children: red
見が確認された際は臨床経過と併せて炎症の再燃や慢性
marrow or traumatic changes? Pediatr Radiol, 36( 7 ):
化について鑑別することが必要である.
670-676, 2006.
9 )Pal CR, Tasker AD, Ostlere SJ, Watson MS: Heterogeneous
本論文の要旨は第51回日本小児感染症学会総会・学術集
signal in bone marrow on MRI of children's feet: a
会で報告した.
normal finding? Skeletal Radiol, 28( 5 ): 274 - 278,
1999.
10)Coutney PM, Flynn JM, Jaramillo D, Horn BD, Calabro
K, Spiegel DA: Clinical Indications for Repeat MRI in
Children With Acute Hematogenous Osteomyelitis. J
Pediatr Orthop, 30( 8 ): 883-887, 2010.
25
金 田 美 緒,他
Abstract
A CASE OF PEDIATRIC ACUTE CALCANEAL OSTEOMYELITIS:
TRANSIENT BONE MARROW HYPERINTENSITY
ON MAGNETIC RESONANCE IMAGING AFTER INFLAMMATION RESOLVED
Mio Kaneta, Takashi Nishizawa, Moe Ito, Shinichiro Ina,
Takako Ehara, Sho Nakayama, Shingo Kobari
Department of Pediatrics, Yokohama Minami Kyosai Hospital
A case of acute calcaneal osteomyelitis followed-up by magnetic resonance imaging (MRI) is presented. An
8-year-old boy visited our hospital with complaints of fever and right heel pain that had persisted for 4 days. MRI
showed bone marrow edema in the right calcaneal bone, and blood culture results identified methicillin-sensitive
Staphylococcus aureus as the cause of bacteremia. The patient was diagnosed as having acute staphylococcal
calcaneal osteomyelitis. Intravenous cefazolin gradually improved the symptoms. On day 20 after admission, the
antibiotic was de-escalated to oral cefalexin, and he was discharged on day 27. On day 42, all of his symptoms
disappeared, and follow-up MRI showed improvement of bone marrow inflammation. Follow-up MRI on day 75
showed hyperintensity in the right calcaneal bone marrow, though there were no symptoms of pain or inflammation.
Given his absence of symptoms, this was not considered indicative of recurrent osteomyelitis, and he was followedup as an outpatient. On MRI on day 167, all findings were improved, and there were no features of bone marrow
edema or osteomyelitis. It has been reported that MRI signal changes can be seen in normal bone marrow of healthy
children. Therefore, MRI findings need to be evaluated in the context of the clinical course and symptoms.
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