As discussed in Chapter 24, Diagnostic Reasoning in Physical Diagnosis, most of the time, the diagnosis is not clear-cut; the history is often not that of a 70-year-old man with a history of hypertension and hypercholesterolemia who presents with crushing chest pain, or that of a 43-year-old obese woman who presents with severe right upper quadrant pain radiating to her right shoulder and nausea. In most cases, there exists uncertainty as to the diagnosis, and the health-care provider must assess the relative chance that the patient is or is not suffering from a particular medical problem. There are elements of uncertainty in almost every case you will see.

Despite the technology of the twenty-first century, physicians still must use their judgment when making clinical decisions. The hard part of practicing medicine lies in knowing when it is acceptable to be cost conscious with the use of further testing and when this technology must be used. Codifying the way in which health care providers logically approach medical problems and deal with uncertainty is a difficult task. Good medicine is playing the odds after having obtained the important data. The focused history starts with uncovering the major details of the current medical problem or the reason the patient has sought medical attention at this time.

In documenting a focused history and performing a focused physical examination, you need to explore the chief complaint, the history of the present illness, the past medical history, medications and allergies, the family history and social history, the occupational history, and the sexual history that are relevant to that specific patient. It is important to recognize that focused does not mean making one diagnosis and skipping the differential diagnosis. In the focused physical examination, you need to examine specifically the body part or system directly involved with the medical problem when there is no time to perform a head-to-toe examination. Remember, however, that other organ systems may need to be evaluated as well. A patient with chest pain requires a full cardiac examination, in addition to examination of the legs for peripheral pulses and edema, carotid artery auscultation and palpation, evaluation of liver size, and evaluation of the retina for related vascular changes.

After your clinical evaluation, tests should be obtained only to corroborate your clinical impression or if the result will in some way affect your decision-making. Remember that common things are common. Uncommon symptoms are more likely to represent an uncommon manifestation associated with a common condition than with a totally uncommon illness.

Illustrative Case

Diagnostic Evaluation

In speaking with Mr. Stern, there appear to be several important diagnoses. Inflammatory bowel disease (IBD), irritable bowel syndrome, traveler’s diarrhea, pseudomembranous colitis, celiac disease, and giardiasis are certainly in the differential diagnosis. The history of iritis and low back pain makes the diagnosis of IBD a strong possibility. IBD, consisting of Crohn’s disease and ulcerative colitis, is very common, with an annual incidence in the United States of approximately 3 to 10 new cases per 100,000 people. Extraintestinal inflammatory manifestations are common. Ocular manifestations occur in 5% of patients with IBD, and ankylosing spondylitis, in 5% to 10%. The most common extraintestinal manifestation is a peripheral, large-joint, asymmetric, nondeforming arthritis; this occurs in 20% of patients with IBD. Mr. Stern does not have a history of this type of arthritis. Genetic disorders seem unlikely, inasmuch as the appearance of this patient’s problem started at age 27 or 28. Viral or bacterial gastroenteritis also seems unlikely, because of the apparent chronicity of the problem despite the travel history 15 months ago to Central America. Salmonella, Shigella, and Campylobacter enterocolitis are generally associated also with fever and are short-lived infections, lasting from 3 to 6 days, although Campylobacter infection may cause a more protracted diarrheal illness. Antibiotic-associated colitis (pseudomembranous colitis) is unlikely, inasmuch as most of the symptoms antedated the use of the recently prescribed antibiotics. Colorectal carcinoma is unlikely because of the history and this patient’s age. Giardiasis is still a possibility, but it is low on the list of differential diagnoses: Most patients with giardiasis exhibit a malabsorptive diarrhea, and lactase deficiency occurs frequently, in 20% to 24% of patients; Mr. Stern denies milk intolerance. The regular use of condoms by a man who has sex only with women makes the diarrheal illness less likely to be related to acquired immune deficiency syndrome (AIDS). Diarrheal illnesses and malabsorptive syndromes can occur in as many at 50% of AIDS patients. Malabsorption syndromes are common. They are characterized by defective adsorption of fats, fat-soluble and other vitamins, carbohydrates, electrolytes, minerals, and water. Although chronic diarrhea and flatulence are common in malabsorption syndromes, the hallmark of malabsorption is excessive fecal fat content, or steatorrhea. Mr. Stern denies floating stools, a symptom of steatorrhea. Celiac disease is a chronic disease, but this patient’s lack of sensitivity to gluten makes this diagnosis less likely. Vascular disorders are unlikely because of the age of the patient and the lack of other medical conditions.