Q&A: ICD-10-CM code selection for clinical consequences of measles and rubella
Q: How do the clinical consequences of measles and rubella influence ICD-10-CM code selection, particularly when coding specific complications, congenital rubella syndrome, and infections documented without complications?
A: Measles and rubella are distinct viral infections with different clinical presentations, potential complications, and ICD-10-CM coding requirements. Both infections can produce widespread rashes and discomfort, but measles is associated with more severe complications, including pneumonia, encephalitis, and other conditions affecting multiple organ systems. Measles can also cause meningitis, otitis media, intestinal complications, keratitis, and keratoconjunctivitis. These complications demonstrate that the effects of measles may extend beyond the initial illness and involve the respiratory, neurological, gastrointestinal, auditory, and visual systems. On the other hand, rubella, historically known as German measles, is generally milder than measles; however, it poses significant risks during pregnancy because of its potential effects on the developing fetus.
The ICD-10-CM category B05.- (measles) identifies measles and includes codes that distinguish uncomplicated infections from those associated with specific complications. Rather than representing measles with a single code in every circumstance, the classification provides additional specificity for documented complications and distinguishes certain conditions that occur following measles, including circumstances in which complications persist after the acute infection has resolved. For example, code B05.0 identifies measles complicated by encephalitis and lists post-measles encephalitis as a clarifying term. The precise code assignment must be based on the documented clinical circumstances and applicable instructional notes.
Rubella is classified under ICD-10-CM category B06.- (rubella [German measles]). As with measles, the category distinguishes uncomplicated infection from infection associated with specified complications. Codes address neurological complications, including encephalitis, meningoencephalitis, and meningitis, as well as other complications such as pneumonia and arthritis. The distinction between rubella acquired outside the congenital setting and congenital rubella syndrome is particularly important, as an Excludes1 note directs the classification of congenital rubella syndrome to code P35.0 rather than the B06.- category.
Congenital rubella syndrome occurs when maternal rubella infection results in fetal infection and associated birth defects. The condition may affect multiple organ systems and can result in cataracts and other ocular abnormalities, congenital heart disease, hearing loss, intellectual disability, and congenital pneumonia. These outcomes illustrate why rubella requires particular attention in pregnant patients. Although the maternal illness may be relatively mild, infection during pregnancy can have serious and lasting consequences for the developing fetus. Accurate identification of congenital rubella syndrome with code P35.0 is essential to distinguish it from rubella classified under category B06.- and to capture the clinical picture.
Accurate code assignment also requires distinguishing other specified complications from infections documented without complications. Codes ending in .89 generally identify other specified complications that do not have a more specific code within the applicable category. Consequently, the assignment of codes for other complications must be supported by documentation that identifies the condition being reported. Additional documentation or a provider query may be necessary when the medical record does not contain sufficient information to support the code. Otherwise, an unspecified code may be used when the available documentation does not establish the necessary detail. For measles and rubella, there is no designated unspecified code. Instead, code B05.9 identifies measles without complications, and code B06.9 identifies rubella without complications.
Editor’s note: This question and answer were originally published in JustCoding, which adapted them from the HCPro webinar, “Spotting the Correct Code for Measles,” presented by Shelley C. Safian, PhD, RHIA, CCS-P, COC, CPC-I.