API:  http://id.who.int/icd/release/10/2008/O21
{
    "@context": "http://id.who.int/icd/contexts/contextForICD10Entity.json",
    "@id": "http://id.who.int/icd/release/10/2008/O21",
    "parent": [
        "http://id.who.int/icd/release/10/2008/O20-O29"
    ],
    "child": [
        "http://id.who.int/icd/release/10/2008/O21.0",
        "http://id.who.int/icd/release/10/2008/O21.1",
        "http://id.who.int/icd/release/10/2008/O21.2",
        "http://id.who.int/icd/release/10/2008/O21.8",
        "http://id.who.int/icd/release/10/2008/O21.9"
    ],
    "browserUrl": "http://apps.who.int/classifications/icd10/browse/2008/en#/O21",
    "code": "O21",
    "title": {
        "@language": "en",
        "@value": "Excessive vomiting in pregnancy"
    },
    "classKind": "category"
}