Sarcoidosis and Fatigue: Influence of successive cardiopulmonary exercise testing on fatigue, ACE, cytokine response and acitivity pattern

Fatigue is an often reported complaint by patients suffering from sarcoidosis,
especially during the onset and the active phase of this multi-systemic
granulomatous disorder. However, when sarcoidosis patients are tested for
cardiovascular, pulmonary, and aerobic capacity by means of exercise tests, the
results of these tests are usually within normal limits. Nonetheless a lot of
these patients state that after completing the exercise test they are totally
exhausted. Their complaints are so severe that they cannot do their daily work
the same and the next day(s).
This study examines if excessive complaints of fatigue in sarcoidosis patients
after exercise can be objectified. It hypothesizes that the recuperative
capacity in sarcoidosis is decreased, probably due to an increase in levels of
ACE and cytokines in blood, as result of the disease. Until now this particular
phenomenon of exhaustion after exercise has never been studied before in
sarcoidosis patients.

This study will investigate fatigue after exercise in sarcoidosis patients. It
will determine the severity of their fatigue, the recuperative capacity after
maximal exertion (bicycle ergometer) and the levels of ACE and cytokines
(before and after exercise) in these patients. Results in sarcoidosis patients
will be compared to results of a control group of healthy volunteers.
Our secondary objective is to find associations with sleep behaviour and
activity pattern.

This study is a pilotstudy to instigate a prospective observational study.

Nature and extent of the burden and risks associated with participation,
benefit and group relatedness: Participants will visit the hospital on 3 days:
2 times successively to complete the exercise test and a 3rd time to collect a
last blood sample. In addition they are asked to keep a sleep- and activity
diary, and to wear an actometer during a period of 14 days.
The aerobic capacity during the exercise test is registered by means of a
combined sensor for CO2 en SaO2 measurement (TOSCA 500 Monitoring System),
which is applied to the ear lobe. This has a tremendous benefit because it is
obviously not invasive (there is no arterial line needed). The only risks of
the study comprises a haematoma as result of venous bloodsampling.
This study could give insight in pathways of fatigue during a systemic disease.
Fatigued sarcoidosis patients might benefit from this study if physical factors
can be found that can explain their exhaustion after exercise. This information
is not only helpful in their private life, but can also clarify their
incapacity to work. In this respect it could be used in labour disputes in
which a lot of these sarcoidosis patients are involved. If a relationship
between fatigue and cytokine levels can be established, in the future patients
may benefit from anticytokine therapy.