- Carpopedal spasm (see also Tetany) 781.7
- Carpoptosis 736.05
- Carrier (suspected) of
- Carrión's disease (Bartonellosis) 088.0
- Carter's
- Cartilage - see condition
- Caruncle (inflamed)
- Cascade stomach 537.6
- Caseation lymphatic gland (see also Tuberculosis) 017.2
- Caseous
- Cassidy (-Scholte) syndrome (malignant carcinoid) 259.2
- Castellani's bronchitis 104.8
- Castleman's tumor or lymphoma (mediastinal lymph node hyperplasia) 785.6
- Castration, traumatic 878.2
- Casts in urine 791.7
- Cat's ear 744.29
- Cat-scratch - see also Injury, superficial
- Catalepsy 300.11
- Cataphasia 307.0
- Cataplexy (idiopathic) see also Narcolepsy
- Cataract (anterior cortical) (anterior polar) (black) (capsular) (central) (cortical) (hypermature) (immature) (incipient) (mature) 366.9
- Cataracta 366.10