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Several body systems are located diffusely or within multiple regions of the body. As a result, the clinician assesses these systems continuously throughout the examination to a greater extent than the more localized systems. Although disease predominately arising in a single body system can present with constitutional symptoms, this is generally more true of the systems discussed here. It is important to keep these systems in mind throughout the examination process. Diseases and syndromes within these systems are exemplars of the need to integrate the findings from all parts of the diagnostic examination into your hypothesis generating process. This concept is reflected in the century-old saying that “he who knows syphilis, knows medicine.” This is analogous to knowing human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) today.

Constitutional symptoms are those that relate to the body or person as a whole, generally excluding psychological symptoms. Many of these symptoms are very nonspecific, but may be clues to serious systemic illness. Because of their nonspecific nature, they must be combined with other physical examination findings and laboratory tests before a specific set of physiologic and diagnostic hypotheses can be generated. It may, however, be possible to posit a class or two of general physiologic processes. For instance, the middle-aged patient who presents with anorexia, weight loss, and night sweats suggests the presence of neoplastic or chronic infectious or inflammatory disease, or possibly Addison disease.

Key Symptom Fatigue

Fatigue is a nonspecific symptom that can result from serious organic disease, neuropsychiatric disease, or deconditioning. Patients describe decreased energy, decreased endurance for normal activities, and a feeling of increased effort in usual tasks. It is important to distinguish fatigue from shortness of breath and excessive sleepiness. Fatigue can complicate any chronic disease or medical condition; especially common causes are anemia, hypothyroidism, and hyperthyroidism, autoimmune and neurologic disorders [Chaudhuri A, Behan PO. Fatigue in neurological disorders. Lancet. 2004;363:978–988 [PubMed: 15043967]. DDX: When a complete history, physical examination, and screening laboratory evaluation do not find a specific explanation consider deconditioning, depression, sleep disorders, and chronic fatigue syndrome.


These are examples only. Congenital muscular dystrophies, mitochondrial myopathy; Endocrine hypothyroidism, hyperthyroidism, Addison disease, hypopituitarism, hypoparathyroidism, hypogonadism; Idiopathic chronic fatigue syndrome, inclusion body myositis; Infectious tuberculosis, infectious mononucleosis, hepatitis, following other viral illnesses, hookworm infestation, HIV infection; Inflammatory/Immune systemic lupus erythematosis (SLE), rheumatoid arthritis (RA), polymyositis, dermatomyositis, vasculitis; Metabolic/Toxic hypokalemia, hypocalcemia, hypomagnesemia, hyponatremia, anemia, uremia, hypoglycemia, congestive heart failure, drugs (e.g., β-blockers, sedatives, anticholinergics), alcohol; Neoplastic acute and chronic leukemia, myelodysplastic syndromes, myeloproliferative syndromes, solid tumors, lymphomas; Neurologic myasthenia gravis, amyotrophic lateral sclerosis, multiple sclerosis, dementia; Psychosocial disordered sleep, depression, deconditioning, overwork and overtraining, chronic anxiety; Vascular claudication, strokes.

Key Syndrome Chronic Fatigue Syndrome

The cause is unknown, but frequently follows a viral infection. This usually is seen in young to middle-aged adults. The case definition requires new onset ...

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