Chapter 1: Certain Infectious and Parasitic Diseases (A00-B99) – Coding Cases with Answers and Rationales

1.

1. N39.0 Infection, infected, infective (opportunistic), urinary (tract)
2. B96.20 Infection, infected, infective (opportunistic), bacterial NOS, as cause of disease classified elsewhere, Escherichia coli [E. coli] -see also Escherichia coli

Rationale: The symptoms associated with the UTI should not be coded. The “use addition-al code” note under N39.0 instructs the coder to an additional code (B95-B97) to identify the infectious agent.

2.

1. A07.0 Balantidiasis, balantidiosis
2. Z16.29 Resistance, resistant (to), to, drug, antibiotic(s), specified NEC

Rationale: ICD-10-CM provides a code to identify resistance to antimicrobial drugs (Z16.-). This category includes the code Z16.29, Resistance to specified antibiotic, which includes Flagyl.

3.

1. M62.562 Atrophy, atrophic (of), muscle, muscular (diffuse) (general) (idiopathic) (primary), lower leg
2. B91 Late effect(s) – see Sequelae, Sequelae (of), poliomyelitis (acute)

Rationale: In ICD-10-CM, late effect conditions are classified to “sequelae.” In Chapter 1, Sequelae of Infectious and Parasitic Diseases are classified to categories B90-B94.

The condition resulting from the sequela is sequenced first.

4.

1. A02.9 Poisoning (acute), food NEC, bacterial – see Intoxication, foodborne, by agent, Intoxication, foodborne, due to Salmonella OR

Infection, Salmonella, due to food (poisoning)

Rationale: Food poisoning is classified to Chapter 1, Certain infectious and parasitic diseases (A00-B99). If gastroenteritis was documented, the code would be A02.0. Quite frequently there is more than one index path for a diagnosis as seen here using either main term Poisoning or Infection.

5.

1. A56.11 Disease, diseased, sexually transmitted, chlamydial infection – see Chlamyd-ia, female, pelvic inflammatory disease

Rationale: With documentation of a sexually transmitted condition, the correct diagnosiscode is found beginning with Disease, sexually transmitted.

6.

1. B20 AIDS (related complex)
2. B59 Pneumonia, Pneumocystis (carinii) (jiroveci)

Rationale: Per the Official Coding Guidelines (I.C.1.a.2), if a patient is admitted for an HIV-related condition, the principal diagnosis should be B20, Human immunodeficiency virus [HIV] disease, followed by additional diagnosis codes for all reported HIV-related conditions.

7.

1. A41.51 Sepsis (generalized), Escherichia coli (E. Coli). Review Tabular for complete code assignment.

Rationale: Without documentation of severe sepsis or an associated organ dysfunction, only one code from category A41 is necessary for correct code assignment.

8.

1. A41.50 Sepsis (generalized), gram-negative (organism). Review Tabular for complete code assignment.
2. R65.20 Sepsis, with, organ dysfunction (acute) (multiple)
3. J96.00 Failure, failed, respiration, respiratory, acute

Rationale: Under the R65.2 subcategory, there is a “code first underlying infection” note; therefore, A41.50 should be listed as the principal diagnosis followed by R65.20 as a secondary diagnosis. Coding Guideline C.1.d.1.b provides sequencing guidance for severe sepsis: “the coding of severe sepsis requires a minimum of two codes: first a code for the underlying systemic infection, followed by a code from subcategory R65.2, Severe sepsis.” Code J96.00 is used to identify the acute respiratory failure.

9.

1. A39.2 Sepsis (generalized), meningococcal, acute
2. R65.21 Shock, septic (due to severe sepsis)

Rationale: The combination code of severe sepsis with septic shock is assigned as a secondary diagnosis although severe sepsis is not documented. The underlying infection, meningococcal sepsis is sequenced first.

10.

1. B18.1 Hepatitis, viral, virus, chronic, type B

Rationale: In ICD-10-CM chronic (viral) hepatitis B without delta-agent is coded B18.1. Delta agent is a type of virus called hepatitis D that causes symptoms only in people who have hepatitis B infection. Because of this, there are no other hepatitis D codes (in the Index or Tabular List). It is a combination code available for use with hepatitis B codes. The delta-agent can be shown with or without hepatic coma by individual codes.