April 1, 2024

We see a lot of questions (and confusion) over what constitutes an “acute illness with systemic symptoms.” In fact, according to the American Academy of Pediatrics, “Of the three elements that make up medical decision-making (MDM), the number and complexity of problems addressed at the encounter seems to be the hardest for coders to determine.”1

So, we’ll try to make this all a little less complex for coders and providers. Let’s start with definitions from the Current Procedural Terminology 2023 (CPT) E/M guidelines, from the CPT® Professional edition:

Acute, uncomplicated illness Acute illness with systemic symptoms
A recent or new short-term problem with low risk of morbidity for which treatment is considered. There is little to no risk of mortality with treatment, and full recovery without functional impairment is expected. A problem that is normally self-limited or minor, but is not resolving consistent with a definite and prescribed course, is an acute uncomplicated illness. 
An illness that causes systemic symptoms and has a high risk of morbidity without treatment. For systemic general symptoms such as fever, body aches, or fatigue in a minor illness that may be treated to alleviate symptoms, shorten the course of illness, or prevent complications, see the definitions for “self-limited or minor” or “acute, uncomplicated.” Systemic symptoms may not be general, but may be single system. 
From CPT®: Examples may include cystitis, allergic rhinitis, or a simple sprain.  
From CPT®: Examples may include pyelonephritis, pneumonitis, or colitis.  
Little to no risk of mortality  
High risk of morbidity without treatment  
Full recovery without functional impairment  
If treating systemic general symptoms such as fever, body aches or fatigue, see: “self-limited or minor” or “acute uncomplicated.”  
Oher examples: Otitis, URI, UTI, diarrhea.  
Patient has symptoms in other body areas/organ systems than condition. 
Fever, body aches, fatigue in the conditions listed above do not constitute an acute illness with systemic symptoms.  
SOB, cough, fatigue, loss of appetite, unintended weight loss in a patient with pneumonitis is an example of acute illness with systemic symptoms.2

1 “What Constitutes ‘Acute Illness with Systemic Symptoms?’” AAP News, March 1, 2023

2Acute, uncomplicated vs. acute with systemic symptoms (codingintel.com)

Acute illness with systemic symptoms is listed under moderate MDM for problems addressed. Based on the definitions, the distinction between an acute, uncomplicated illness and an acute illness with systemic symptoms hinges on mortality risk. So, we need to turn next to CPT’s definition of morbidity: “a state of illness or functional impairment that is expected to be of substantial duration during which function is limited, quality of life is impaired, or there is organ damage that may not be transient despite treatment.”

It also makes sense to look at CPT’s definitions of “self-limited or minor”: A problem that runs a definite and prescribed course, is transient in nature, and is not likely to permanently alter health status OR has a good prognosis with management/compliance.”

When you apply these definitions, a case of flu combined with fever and body aches would not rise to the level of an acute illness with systemic symptoms. So if you’re a coder and reviewing a provider’s note, you’ll do well to apply a couple of basic litmus tests: (1) If there is a high risk of morbidity without treatment, then the case is more likely to involve systemic symptoms; (2) If there is little risk of mortality, and the patient’s acuity is similar to the examples (cystitis, rhinitis) in the CPT definition for an uncomplicated illness, then you should incline in that direction.

Definitions, however, can take you only so far. That’s why it’s important to examine the context as well. Here’s a good example offered by Linda Parsi, M.D., who chairs the AAP Committee on Coding and Nomenclature Editorial Advisory Board. Does RSV (Respiratory Syncytial Virus) with fever qualify as an acute illness with systemic symptoms? Answer: It depends. In a 5-year-old patient, the answer could be no. If the patient is a 2-week-old infant, it’s more likely to be yes.3 For accurate code assignment, you’ll need clear documentation of the patient’s state during the visit.

For physicians and other qualified health professionals, one way to sidestep the questions over “uncomplicated” vs. “systemic symptoms” is to code by time. Visits can be time-intensive for some patient populations (for example, children or older adults who need to be accompanied by an independent historian). Coding by time gives you the option to report prolonged service codes that allow you to capture additional time spent on the patient’s care before or on the date of the in-person visit, including such activities as reviewing tests, reviewing a separately obtained history, and counseling and educating the patient, family, or caregiver. If the physician documents both total time and MDM, coders can assign the appropriate code based on whichever results in a higher level of service.

3“What Constitutes ‘Acute Illness with Systemic Symptoms?’” AAP News, March 1, 2023

Got a question about E/M coding? We’d love to hear from you. Submit your questions by emailing us at coders@calmwatersai.com


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Michelle Sergei-Casiano
Michelle Sergei-Casiano
Michelle Sergei-Casiano
Senior Manager, Regulatory and Coding Compliance