Fatigue

Contents

Foreword xiTeofilo Lee-Chiong Jr

Preface xiiiMaxHirshkowitz and Amir Sharafkhaneh

Fatigue, Sleepiness, and Safety: Definitions, Assessment, Methodology 183MaxHirshkowitz

In normal physiology, fatigue may be weakness (or weariness) from repeated exer-tion or a decreased response of cells, tissues, or organs after excessive stimulationor activity. Sleepiness plays a major role in nonpathological forms of mental fatigue.A thorough sleep history is an essential part of any fatigue risk-management pro-gram. Increasingly sophisticated computerized detection, monitoring, and surveil-lance systems provide the opportunity to help engineer new solutions to oldproblems.

Fatigue in Neurologic Disorders 191Sushanth Bhat and Sudhansu Chokroverty

Neurologists and primary care practitioners treating patients with neurologic dis-eases are often called on to address complaints of fatigue. This symptom often limitspatients’ independence and quality of life out of proportion to the degree of theirneurologic impairment, and is a major cause of disability. Determining the causeand best treatment strategies for patients with this difficult symptom may be chal-lenging. This review summarizes the mechanisms underlying central and peripheralfatigue, provides an overview of the nature of fatigue in common neurologic condi-tions, and discusses recent advances and recommendations in the treatment offatigue affecting patients with neurologic disorders.

Psychiatric Disorders and Fatigue 213John Herman

Because obstructive sleep apnea disrupts sleep and causes multiple awakenings,some patients with obstructive sleep apnea report insomnia. However, it alsocauses daytime sleepiness, and many patients describe excessive sleepiness.This model is similar to how fatigue presents in psychiatric disorders. Some patientscomplain of depression, mood swings, anxiety, irritability, or panic attacks and seektherapy or medications for these symptoms. However, each of these symptoms isstrongly associated with fatigue. This article describes sleepiness and fatigue com-monly seen in psychiatric disorders.

Fatigue in Cardiorespiratory Conditions 221Amir Sharafkhaneh, JoseMelendez, FarahAkhtar, and Charlie Lan

Fatigue is frequently reported in patients with chronic cardiorespiratory conditions.Change in muscle structure and function, deteriorated nutritional status, sleep dep-rivation, hypoxia (awake, exertional, and nocturnal), adverse effects of medications,

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and comorbid conditions are among many pathophysiologic mechanisms that maypromote fatigue in patients. Comprehensive assessment of all the promoting causesis required for better understanding and management of fatigue in these patients.

Cancer-Related Fatigue and Sleep Disorders 229Diwakar D. Balachandran, Saadia Faiz, Lara Bashoura, and EllenManzullo

Cancer-related fatigue (CRF) continues to be a major concern of patients andproviders of cancer care. The symptoms are debilitating and can persist formany years after the cancer diagnosis and therapy. Further research is requiredto address the mechanisms of illness, including a better understanding of thecomplex interplay between the sleep system, circadian rhythms, inflammation,and the hypothalamic-pituitary axis. Genetic analysis and genomic studies needto be done to better understand which patients may be prone to CRF and whichtherapies may exacerbate these symptoms. Attention must be focused on under-standing which comorbidities contribute to CRF.

Sleep Disorders and Fatigue 235Sheila C. Tsai and Teofilo Lee-ChiongJr

Fatigue is defined by a lack of energy or a sensation of tiredness that may improvewith rest. It is a prominent symptom in numerous disorders. Many individuals withcardiovascular, endocrine, psychiatric (anxiety and depression), and neurologic(multiple sclerosis) disorders experience significant, sometimes debilitating, fatigue.Fatigue can also factor prominently in some sleep disorders. A thorough sleep his-tory, including sleep quality, sleep quantity, work schedule, and perceptions regard-ing sleep, is crucial for the evaluation of fatigue. Identifying and managing underlyingsleep disorders may improve sleep and attenuate fatigue.

Fatigue in Other Medical Disorders 241HashirMajid, Munira Shabbir-Moosajee, and Sarah Nadeem

Fatigue is a highly subjective and nonspecific symptom. It can have a significantimpact on an individual’s quality of life. A variety of conditions can be associatedwith fatigue. This review focuses on fatigue related to renal disease and endocrineand hematological disorders. Special attention is paid to fatigue in the setting ofchronic kidney disease, anemia, and parathyroid and other endocrine disorders.The pathophysiology of fatigue and its treatment options are described in connec-tion with these disorders.

Universal Fatigue Management Strategies 255Mary Rose andNilgunGiray

Fatigue (rather than sleepiness) generated in the work placemay be caused primarilyby overwork, related to factors such as repetitive non-novel tasks monotony, andnoise sleepiness, however, is the direct result of sleep loss caused by eithera loss of total sleep time or a misalignment of circadian rhythm. Type of fatigue orsleepiness is the first categorization needed before a management strategy canbe designed. Inadequate total sleep time and misalignment of circadian rhythmare the most significant contributors to disastrous human error in the work place.Pharmacologic and nonpharmacologic interventions to modify fatigue and sleepi-ness suggest some overall improvement in alertness and performance with a varietyof agents.

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Medical Management of Fatigue 265Amir Sharafkhaneh, Suryakanta Velamuri, JoseMelendez, FarahAkhtar, andMax Hirshkowitz

Fatigue is frequently reported in chronic medical conditions. Improvement of the pri-mary condition positively affects health-related quality of life and fatigue. Interven-tions to achieve exercise rehabilitation robustly affect the fatigue in these patients.Improving sleep may improve the quality of life and fatigue. In some cases, medicalmanagement may use wake-promoting medications. The risks and benefits must becarefully weighed. When insomnia is contributing significantly to the overall fatigue,pharmacotherapy may be appropriate. The clinical picture is often complicated bypotential interactions with other medications and contraindications. It is importantfor the physician to be aware of any self-medication.

Index 277