The most mysterious element of this triad (Cachexia, Anorexia, and Asthenia) for me is asthenia (lack of energy). Asthenia and its opposite, vigor, are familiar to all of us. Everyday, we hope, we start the day refreshed. By the end of the day we are tired, asthenic, and ready to sleep. Even catching a cold can dramatically influence our energy levels. We become weak and tired for no reason identifiable on a blood test. This is a part of our everyday experience. If a cold or a busy day at work can do that, think what a life-threatening chronic illness and dying can do. Clinicians, despite being very aware of their own periodic asthenia, have largely ignored asthenia in their patients. Where does this weakness come from? In cancer and in many other conditions such as advanced dementia and very old age (>95), asthenia appears to be a major cause of death. This is quite remarkable. Arguably, in chronic illnesses that do not directly destroy vital organs (such as heart, lung, kidney, brain, or liver), asthenia (or the "dwindles" in common vernacular) is the leading cause of death, yet we have paid very little attention to it. Most cancers do not metastasize to vital organs such as the heart, and if they do death occurs long before organ failure occurs. They seem to kill in some very poorly understood way by weakening the body such that it succumbs to degenerative processes. In cancer asthenia correlates poorly with tumor mass. I have seen some patients with prostate cancer whose bone scans have shown their entire axial skeleton replaced by tumor yet who maintain good energy levels. Other cancer patients with overtly small tumor burdens take to their beds and inexorably die in a matter of days or weeks. Much of this asthenic effect may relate to tumor-related cytokines, as previously described. Perhaps one day physicians will focus on helping people live with their cancers by interfering with these mediators when tumors cannot be eradicated.
Even if we do come up with a cure for cancer, this will inevitably result in more patients who live to very old ages. Many geriatric patients of very advanced age appear to "melt," developing severe cachexia, anorexia, and profound asthenia in the months or years prior to death. We do not understand this pathophysiology well at all.
There are some correctable causes of asthenia that are familiar to most clinicians. Hypothyroidism, anemia, and depression can result in reversible asthenia and should be diagnosed and corrected when possible. Untreated pain, other metabolic abnormalities such as adrenal insufficiency, hypokalemia, and steroid-related myopathy may also manifest as asthenia.
A special note needs to be made about treating anemia as a cause of asthenia. Many patients with anemia respond well to either transfusions or stimulation of red cell production with erythropoietin, both of which increase energy and functional status.88 However, a point usually comes when patients no longer get the same "bounce" out transfusions that they once did, especially if they are dying of some chronic illness. Their asthenia becomes refractory to such interventions. Patients, families, and even clinicians may have trouble recognizing or acknowledging this change. Getting transfusions then becomes a ritual in which caring is shown. Suggesting that transfusions may no longer be useful for the desired purpose (when treating asthenia) may be hard to accept and may result in grief reactions that must be addressed.
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Palliative Care Perspectives
James L. Hallenbeck, M.D.
Copyright © 2003 by Oxford University Press, Inc.
The online version of this book is used with permission of the publisher and author on web sites affiliated with the Inter-Institutional Collaborating Network on End-of-life Care (IICN), sponsored by Growth House, Inc.