Convert to ICD-10-CM: 
543.9 converts approximately to:
- 2015/16 ICD-10-CM K38.1 Appendicular concretions
Or:
 - 2015/16 ICD-10-CM K38.2 Diverticulum of appendix
Or:
 - 2015/16 ICD-10-CM K38.3 Fistula of appendix
Or:
 - 2015/16 ICD-10-CM K38.8 Other specified diseases of appendix
Or:
 - 2015/16 ICD-10-CM K38.9 Disease of appendix, unspecified
 
 ICD-9-CM Volume 2 Index entries containing back-references to 
543.9:
- Adhesion(s), adhesive (postinfectional) (postoperative)
appendix 543.9
 - Appendiclausis 543.9
 - Appendicolithiasis 543.9
 - Atrophy, atrophic
appendix 543.9
 - Calculus, calculi, calculous 592.9

appendix 543.9
 - Colic (recurrent) 789.7

appendicular 543.9
appendix 543.9
vermicular 543.9
 - Concretion - see also Calculus
appendicular 543.9
 - Cyst (mucus) (retention) (serous) (simple)
appendix 543.9
 - Dilatation
appendix (cystic) 543.9
 - Disease, diseased - see also Syndrome
appendix 543.9
 - Diverticula, diverticulosis, diverticulum (acute) (multiple) (perforated) (ruptured) 562.10

appendix (noninflammatory) 543.9
 - Fecalith (impaction) 560.32

appendix 543.9
 - Fibrosis, fibrotic
appendix, appendiceal, noninflammatory 543.9
periappendiceal 543.9
 - Fistula (sinus) 686.9

appendix, appendicular 543.9
 - Granuloma NEC 686.1

appendix 543.9
 - Intussusception (colon) (enteric) (intestine) (rectum) 560.0

appendix 543.9
 - Kink, kinking
appendix 543.9
 - Mucocele
appendix 543.9
 - Obliteration
appendix (lumen) 543.9
 - Sloughing (multiple) (skin) 686.9

appendix 543.9
 - Stercolith (see also Fecalith) 560.32

appendix 543.9
 - Strangulation, strangulated 994.7

appendix 543.9