August 2026 Research Update

This month added a clearer picture that fatigue in LAM may not be only a lung issue. In a small comparison study, women with LAM had lower muscle strength, power, and endurance and reported more fatigue than matched people without LAM, even though muscle biopsies did not show obvious LAM cell involvement or major muscle fiber changes. This points to muscle function and energy use during exercise as possible contributors to how fatigue feels day to day. [1]

The same study found that people with LAM who had lower muscle endurance also tended to have shorter walking distance and lower peak exercise performance on formal testing. This matters because it connects "how the muscles perform" with "how active someone can be" and "how fatigued they feel" in a measurable way, rather than treating fatigue as a vague symptom. [1]

One specific signal was that reduced fat burning during moderate exercise was linked with worse fatigue scores in the LAM group. In plain language, the study observed that the body may be using fuel differently during exercise in those who feel more fatigued, even without clear structural remodeling of the sampled leg muscle. [1]

For patients, these results mainly add understanding rather than changing care right now. They support the idea that fatigue in LAM can have a "whole-body" component, including muscle performance and how energy is used during activity, and not just breathing limitations. What remains uncertain is whether these muscle findings are a direct effect of LAM biology, an indirect effect of reduced activity over time, medication effects, or other factors, because the study was small and looked at one point in time. [1]

This month included a long follow-up case that highlights how symptoms and lung function can change over time in a very severe form of TSC-LAM (LAM linked to tuberous sclerosis complex). The report described rapid improvement soon after starting sirolimus, a long period of relative stability while continuing it, and noticeable worsening after the medicine was stopped abruptly. Because this is one person, it cannot tell what will happen for most patients, but it shows what long-term ups and downs can look like. [2]

After sirolimus was restarted, the report described that the patient benefited again, but lung function and walking test results did not return fully to the prior level. The case also noted a pneumothorax during the period off treatment, which did not recur after restarting in the time described. This helps illustrate that changes in treatment over time may be linked with meaningful shifts in breathing and activity in some individuals, though the reasons cannot be proven from a single case. [2]

For patients and caregivers, this case mainly matters as a real-world example of long-term disease course in severe TSC-LAM while using sirolimus, including what happened when the drug was stopped and then restarted. It does not establish what is typical or what any individual should expect, because it is one person and details like dosing and other health factors were not fully described in the summary. It may matter most for future research into how treatment interruptions relate to symptoms and lung function over time. [2]