• Antithromboplastinogenemia (see also Circulating anticoagulants) 286.59
  • Antitoxin complication or reaction - see Complications, vaccination
  • Anton (-Babinski) syndrome (hemiasomatognosia) 307.9
  • Antritis (chronic) 473.0
  • Antrum, antral - see condition
  • Anuria 788.5
  • Anus, anal - see also condition
  • Anusitis 569.49
  • Anxiety (neurosis) (reaction) (state) 300.00
  • Aorta, aortic - see condition
  • Aortectasia (see also Ectasia, aortic) 447.70
  • Aortitis (nonsyphilitic) 447.6
  • Apathetic 799.25
  • Apathy 799.25
  • Apepsia 536.8
  • Aperistalsis, esophagus 530.0
  • Apert's syndrome (acrocephalosyndactyly) 755.55
  • Apert-Gallais syndrome (adrenogenital) 255.2
  • Apertognathia 524.20
  • Aphagia 787.20
  • Aphakia (acquired) (bilateral) (postoperative) (unilateral) 379.31
  • Aphalangia (congenital) 755.4