- Hydrocele (calcified) (chylous) (idiopathic) (infantile) (inguinal canal) (recurrent) (senile) (spermatic cord) (testis) (tunica vaginalis) 603.9
- Hydrocephalic fetus
- Hydrocephalus (acquired) (external) (internal) (malignant) (noncommunicating) (obstructive) (recurrent) 331.4
- Hydrocolpos (congenital) 623.8
- Hydrocystoma (M8404/0) - see Neoplasm, skin, benign
- Hydroencephalocele (congenital) 742.0
- Hydroencephalomeningocele (congenital) 742.0
- Hydrohematopneumothorax (see also Hemothorax) 511.8
- Hydromeningitis - see Meningitis
- Hydromeningocele (spinal) (see also Spina bifida) 741.9
- Hydrometra 621.8
- Hydrometrocolpos 623.8
- Hydromicrocephaly 742.1
- Hydromphalus (congenital) (since birth) 757.39
- Hydromyelia 742.53
- Hydromyelocele (see also Spina bifida) 741.9
- Hydronephrosis 591
- Hydropericarditis (see also Pericarditis) 423.9
- Hydropericardium (see also Pericarditis) 423.9
- Hydroperitoneum 789.5
- Hydrophobia 071
- Hydrophthalmos (see also Buphthalmia) 743.20
