From the Research
The ICD-10 code for brain fog resulting from chemotherapy is G31.84 (Mild cognitive impairment, so stated). This code is used to document cognitive impairment symptoms like memory problems, difficulty concentrating, and mental cloudiness that occur as a side effect of cancer treatment, as supported by the study published in 2025 1. You should also code the underlying cancer diagnosis and use the additional code Y43.3 (Adverse effect of other antineoplastic drugs) to indicate that the cognitive symptoms are due to chemotherapy.
When documenting this condition, be specific about the cognitive symptoms the patient is experiencing, their severity, and how they impact daily functioning. Brain fog from chemotherapy, also known as "chemo brain," is believed to result from neurotoxic effects of chemotherapy agents on brain tissue, inflammation, oxidative stress, and hormonal changes, as discussed in the study published in 2021 2. Management typically includes cognitive rehabilitation exercises, adequate rest, physical activity, and potentially medications like methylphenidate or modafinil in severe cases, though these should be prescribed by a specialist familiar with chemotherapy-related cognitive impairment.
Some key points to consider when managing brain fog from chemotherapy include:
- The importance of early recognition and documentation of cognitive impairment symptoms
- The need for a comprehensive assessment of the patient's cognitive function and quality of life
- The potential benefits of cognitive rehabilitation exercises and other non-pharmacological interventions
- The role of medications like methylphenidate or modafinil in severe cases, as supported by the study published in 2018 3.
It is also important to note that the long-term development of chemotherapy-induced cognitive impairment has been studied, and the results suggest that cognitive performance and quality of life may recover after 2-3 years, as shown in the study published in 2025 1. However, further research is needed to fully understand the mechanisms and consequences of chemotherapy-related cognitive impairment.