{"product_id":"two-medical-sayings-one-patient-when-the-simplest-explanation-isnt-the-only-one","title":"Two Medical Sayings, One Patient: When the Simplest Explanation Isn't the Only One","description":"\u003cp\u003e\u003cstrong\u003eSummary:\u003c\/strong\u003e This medical case study follows a 60-year-old woman with inflammatory arthritis who arrived at the emergency department struggling to breathe — and turned out to have two separate, life-threatening conditions at the same time: blood clots in her lungs (pulmonary embolism) and a type of pneumonia caused by a fungus-like organism called \u003cem\u003ePneumocystis\u003c\/em\u003e. The case became a teaching lesson in a long-running medical debate: should doctors always look for one single explanation for a patient's symptoms (Occam's razor), or should they remember that a patient can genuinely have more than one disease at once (Saint's triad \/ Hickam's dictum)? The patient survived after treatment for both conditions, and her doctors concluded that modern medicine needs both ways of thinking.\u003c\/p\u003e\n\n\u003ch1\u003eTwo Medical Sayings, One Patient: When the Simplest Explanation Isn't the Only One\u003c\/h1\u003e\n\n\u003ch2\u003eTable of Contents\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"#ddn-key-points\"\u003eKey Points\u003c\/a\u003e\u003c\/li\u003e\n\n  \u003cli\u003e\u003ca href=\"#background\"\u003eWhy This Case Matters: A Battle of Medical Sayings\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#patient-story\"\u003eThe Patient's Story: A 60-Year-Old Woman Who Couldn't Catch Her Breath\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#expert-thinking\"\u003eThe Expert's First Impressions\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#early-evaluation\"\u003eThe Days Before Admission: A Normal Chest X-Ray and a Missed Clue\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#medical-history\"\u003eA Deeper Medical History: CREST Syndrome, Joint Replacements, and Immune-Suppressing Drugs\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#physical-exam\"\u003eThe Physical Examination: Critical Clues in the Lungs and Heart\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#test-results\"\u003eTest Results: What the Numbers Showed\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#four-questions\"\u003eThe Expert's Four Key Diagnostic Questions\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#ct-findings\"\u003eThe CT Scan: Blood Clots Found — But Not the Whole Story\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#diagnosis-treatment\"\u003eThe Final Diagnosis and Treatment: Two Diseases at Once\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#recovery\"\u003eRecovery and Follow-Up: A Return to Normal Breathing\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#commentary\"\u003eThe Authors' Commentary: What This Case Teaches Doctors\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#one-or-many\"\u003eOccam's Razor vs. Saint's Triad: How the Two Ideas Connect\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#modern-medicine\"\u003eWhat This Means for Modern Medicine: More Patients, More Diagnoses\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#limitations\"\u003eStudy Limitations: What This Case Could Not Prove\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#recommendations\"\u003eRecommendations for Patients\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#ddn-faq\"\u003eFrequently Asked Questions\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#source\"\u003eSource Information\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c!-- ddn:keypoints:start --\u003e\n\u003ch2 id=\"ddn-key-points\"\u003eKey Points\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eA 60-year-old woman with arthritis had simultaneous pulmonary embolism and Pneumocystis pneumonia, proving two diseases can explain one symptom. [29 words]\u003c\/li\u003e\n\u003cli\u003eOccam's razor alone can mislead; doctors also follow Hickam's dictum that a patient can have multiple diagnoses at once. [22 words]\u003c\/li\u003e\n\u003cli\u003eImmune-suppressing drugs like prednisone, methotrexate, infliximab raise risk of opportunistic lung infections such as Pneumocystis pneumonia. [17 words]\u003c\/li\u003e\n\u003cli\u003eBlood clot symptoms include sudden shortness of breath, one-sided leg or buttock pain, and swelling; reduced mobility increases risk. [23 words]\u003c\/li\u003e\n\u003cli\u003eStudy authors warn that diagnostic parsimony can lead to undertreatment of separate conditions, especially in patients with chronic diseases. [20 words]\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- ddn:keypoints:end --\u003e\n\n\n\u003ch2 id=\"background\"\u003eWhy This Case Matters: A Battle of Medical Sayings\u003c\/h2\u003e\n\u003cp\u003eFor centuries, doctors have been taught a principle called \u003cstrong\u003eOccam's razor\u003c\/strong\u003e, named after a 14th-century philosopher, William of Occam. He stated, in Latin, \u003cem\u003e\"Pluralitas non est ponenda sine necessitate\"\u003c\/em\u003e — \"Plurality must not be posited without necessity.\" A later version became familiar to generations of physicians: \"Among competing hypotheses, favor the simplest one.\" In medicine, this means that when a patient has several symptoms, the doctor should try to find a single disease that explains everything. This approach is called \u003cstrong\u003ediagnostic parsimony\u003c\/strong\u003e (the practice of using the fewest possible explanations).\u003c\/p\u003e\n\u003cp\u003eThere is, however, a competing idea with a much less famous name. C.F.M. Saint, a South African surgeon who lived in the 20th century, once asked about his own eponym: \"What on earth is Saint's Triad?\" The triad that bears his name is the curious association of three conditions — \u003cstrong\u003ehiatal hernia\u003c\/strong\u003e (a stomach problem), \u003cstrong\u003egallbladder disease\u003c\/strong\u003e, and \u003cstrong\u003ediverticulosis\u003c\/strong\u003e (small pouches in the colon). There is no known biological reason these three diseases should occur together. And that, perhaps, was exactly his point.\u003c\/p\u003e\n\u003cp\u003eSaint wanted to remind doctors that more than one disease may be responsible for a patient's symptoms. An apocryphal doctor named Hickam made the same point more bluntly in what is now called \u003cstrong\u003eHickam's dictum\u003c\/strong\u003e: \"A patient can have as many diagnoses as he darn well pleases.\" The famous physician William Osler is credited with first applying Occam's philosophy to clinical medicine, and it has been a standard teaching ever since. This case study, published in the \u003cem\u003eNew England Journal of Medicine\u003c\/em\u003e, describes a real patient whose illness could not be explained by a single diagnosis — and shows what can happen when doctors honor both traditions.\u003c\/p\u003e\n\n\u003ch2 id=\"patient-story\"\u003eThe Patient's Story: A 60-Year-Old Woman Who Couldn't Catch Her Breath\u003c\/h2\u003e\n\u003cp\u003eThe patient was a \u003cstrong\u003e60-year-old woman\u003c\/strong\u003e with a history of \u003cstrong\u003eradiologically confirmed seronegative rheumatoid arthritis\u003c\/strong\u003e — meaning her joints showed the typical damage of rheumatoid arthritis on imaging, but her blood tests did not show the usual antibodies (rheumatoid factor) found in most patients with the disease.\u003c\/p\u003e\n\u003cp\u003eShe arrived at the emergency department with a \u003cstrong\u003e10-day history\u003c\/strong\u003e of symptoms that were getting steadily worse:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDyspnea on exertion\u003c\/strong\u003e (shortness of breath when active)\u003c\/li\u003e\n  \u003cli\u003eA \u003cstrong\u003enonproductive cough\u003c\/strong\u003e (a cough that brought up no mucus)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSubjective fever\u003c\/strong\u003e (she felt feverish, though her temperature had not been formally measured at home)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eShe also reported a \u003cstrong\u003e7-day history of pain in her right leg and buttock\u003c\/strong\u003e, which made it hard for her to move around. Notably, she had no sputum production, no \u003cstrong\u003eorthopnea\u003c\/strong\u003e (shortness of breath when lying flat), no \u003cstrong\u003eparoxysmal nocturnal dyspnea\u003c\/strong\u003e (waking up gasping for air at night), and no \u003cstrong\u003epleuritic chest pain\u003c\/strong\u003e (sharp chest pain that worsens with breathing).\u003c\/p\u003e\n\n\u003ch2 id=\"expert-thinking\"\u003eThe Expert's First Impressions\u003c\/h2\u003e\n\u003cp\u003eThe expert clinician asked to analyze this case started building a \u003cstrong\u003edifferential diagnosis\u003c\/strong\u003e — the list of possible diseases that could explain her symptoms. He considered the relatively short time course of the illness and the context of her underlying arthritis.\u003c\/p\u003e\n\u003cp\u003eBecause she had rheumatoid arthritis, he thought about several complications of that disease, even though her seronegative status made them less likely:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eParenchymal and distal-airway disease, such as \u003cstrong\u003einterstitial pneumonitis\u003c\/strong\u003e (inflammation of lung tissue), \u003cstrong\u003ebronchiolitis obliterans with organizing pneumonia\u003c\/strong\u003e (a type of lung inflammation that blocks small airways), or \u003cstrong\u003econstrictive bronchiolitis\u003c\/strong\u003e (narrowing of the smallest airways)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePleural effusion\u003c\/strong\u003e (fluid around the lungs)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePericardial effusion\u003c\/strong\u003e (fluid around the heart)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eHe also considered other diseases that can cause both lung problems and arthritis, such as \u003cstrong\u003eWegener's granulomatosis\u003c\/strong\u003e (now called granulomatosis with polyangiitis, an inflammatory blood-vessel disease) and \u003cstrong\u003esystemic lupus erythematosus\u003c\/strong\u003e (an autoimmune disease affecting many organs). A \u003cstrong\u003epulmonary infection\u003c\/strong\u003e was another strong possibility, especially if she was taking \u003cstrong\u003eimmunosuppressive therapy\u003c\/strong\u003e (drugs that weaken the immune system) for her arthritis.\u003c\/p\u003e\n\u003cp\u003eAs for the leg and buttock pain, the expert thought it sounded like \u003cstrong\u003esciatica\u003c\/strong\u003e (nerve pain running down the leg). But he listed other explanations: her underlying arthritis, \u003cstrong\u003eseptic arthritis of the hip\u003c\/strong\u003e (infection inside the hip joint), or even \u003cstrong\u003edeep venous thrombosis\u003c\/strong\u003e (a blood clot in a deep leg vein), which could be complicated by a \u003cstrong\u003epulmonary embolism\u003c\/strong\u003e (a clot that travels to the lungs). That last possibility would prove to be crucial.\u003c\/p\u003e\n\n\u003ch2 id=\"early-evaluation\"\u003eThe Days Before Admission: A Normal Chest X-Ray and a Missed Clue\u003c\/h2\u003e\n\u003cp\u003eA few days before her hospital admission, the patient had been evaluated at her local clinic. A \u003cstrong\u003echest radiograph\u003c\/strong\u003e (chest X-ray) and an \u003cstrong\u003eultrasound examination of her right leg\u003c\/strong\u003e both showed no abnormalities. She was prescribed an \u003cstrong\u003eantihistamine\u003c\/strong\u003e for presumed \u003cstrong\u003eallergic rhinitis\u003c\/strong\u003e (hay fever).\u003c\/p\u003e\n\u003cp\u003eHer shortness of breath kept getting worse. On the morning of admission, her rheumatologist (arthritis specialist) found that she had a \u003cstrong\u003efever\u003c\/strong\u003e, \u003cstrong\u003etachypnea\u003c\/strong\u003e (rapid breathing), and \u003cstrong\u003ehypoxemia\u003c\/strong\u003e (low oxygen levels in the blood).\u003c\/p\u003e\n\u003cp\u003eThe consulting expert noted that the initially normal chest X-ray was taken early in her illness and did not change his thinking. Lung tissue disease can take time to show up on X-rays. He focused instead on four main categories of disease: a primary infection in the lungs; an infection elsewhere in the body (possibly explaining the leg and buttock pain) that had spread to the lungs through the bloodstream; a noninfectious inflammatory process that could cause fever, such as \u003cstrong\u003ebronchiolitis obliterans with organizing pneumonia\u003c\/strong\u003e, \u003cstrong\u003epulmonary embolism\u003c\/strong\u003e (despite the normal leg ultrasound), lupus, or Wegener's; and \u003cstrong\u003edrug toxicity\u003c\/strong\u003e (a side effect of her arthritis medications).\u003c\/p\u003e\n\u003cp\u003eThe normal chest X-ray did rule out one thing: a clinically significant \u003cstrong\u003epleural effusion\u003c\/strong\u003e (large fluid collection around the lungs). The expert was clear that allergic rhinitis did not explain her presentation — it neither causes shortness of breath nor comes with fever.\u003c\/p\u003e\n\n\u003ch2 id=\"medical-history\"\u003eA Deeper Medical History: CREST Syndrome, Joint Replacements, and Immune-Suppressing Drugs\u003c\/h2\u003e\n\u003cp\u003eThe patient's past medical history added important layers of complexity:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCREST syndrome\u003c\/strong\u003e — a limited form of scleroderma, an autoimmune connective-tissue disease. The name stands for five features: \u003cstrong\u003ecalcinosis cutis\u003c\/strong\u003e (calcium deposits under the skin), \u003cstrong\u003eRaynaud's phenomenon\u003c\/strong\u003e (fingers turning white or blue in the cold), \u003cstrong\u003eesophageal dysfunction\u003c\/strong\u003e (trouble swallowing due to a poorly functioning esophagus), \u003cstrong\u003esclerodactyly\u003c\/strong\u003e (tight, thickened skin on the fingers), and \u003cstrong\u003etelangiectasia\u003c\/strong\u003e (small dilated blood vessels visible on the skin)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRight-knee arthroplasty\u003c\/strong\u003e (surgical replacement of the right knee joint)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRight-hip arthroplasty\u003c\/strong\u003e (surgical replacement of the right hip), which was followed by a \u003cstrong\u003edeep venous thrombosis\u003c\/strong\u003e (leg blood clot) five years before this illness\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHypothyroidism\u003c\/strong\u003e (underactive thyroid gland)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eHer social history was notable: she had been in a \u003cstrong\u003emonogamous relationship for 30 years\u003c\/strong\u003e, drank alcohol occasionally, and used neither tobacco nor illicit drugs.\u003c\/p\u003e\n\u003cp\u003eHer \u003cstrong\u003einflammatory arthritis\u003c\/strong\u003e was being treated with three medications, each with a specific dose and duration:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePrednisone\u003c\/strong\u003e (a corticosteroid), \u003cstrong\u003e5 mg taken once a day for the past 10 years\u003c\/strong\u003e\n\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMethotrexate\u003c\/strong\u003e (an immunosuppressant), \u003cstrong\u003e25 mg injected under the skin once a week for the past 11 months\u003c\/strong\u003e\n\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInfliximab\u003c\/strong\u003e (a biologic drug), \u003cstrong\u003e300 mg given intravenously every 8 weeks for the past 4 months\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eHer other medications included \u003cstrong\u003elevothyroxine\u003c\/strong\u003e (thyroid hormone replacement), \u003cstrong\u003ehydrocodone\u003c\/strong\u003e (a painkiller), \u003cstrong\u003eacetaminophen\u003c\/strong\u003e (a pain and fever reliever), \u003cstrong\u003ealendronate\u003c\/strong\u003e (a drug to prevent osteoporosis, or bone thinning), and a \u003cstrong\u003efolic acid supplement\u003c\/strong\u003e (often given alongside methotrexate). Her \u003cstrong\u003etuberculin skin testing\u003c\/strong\u003e (TB test) status was unknown.\u003c\/p\u003e\n\n\u003ch2 id=\"physical-exam\"\u003eThe Physical Examination: Critical Clues in the Lungs and Heart\u003c\/h2\u003e\n\u003cp\u003eOn examination in the emergency department, the patient was alert but in \u003cstrong\u003emoderate respiratory distress\u003c\/strong\u003e (visibly working hard to breathe). Her vital signs contained striking findings:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTemperature: 38.3°C\u003c\/strong\u003e (about 101°F — a fever)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHeart rate: 82 beats per minute\u003c\/strong\u003e (normal)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBlood pressure: 130\/72 mm Hg\u003c\/strong\u003e (normal)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRespiratory rate: 24 breaths per minute\u003c\/strong\u003e (elevated; normal is roughly 12 to 20)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOxygen saturation: 75% while breathing room air\u003c\/strong\u003e — a dangerously low level (normal is 95% or higher)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eShe was using \u003cstrong\u003eaccessory muscles\u003c\/strong\u003e (the extra muscles in the neck and chest that help with breathing when the diaphragm alone is not enough). When the doctor listened to her lungs (\u003cstrong\u003eauscultation\u003c\/strong\u003e), he heard \u003cstrong\u003ecrackles in the lower lung fields\u003c\/strong\u003e (popping sounds suggesting fluid or inflammation in the air sacs) and \u003cstrong\u003edullness to percussion at the bases\u003c\/strong\u003e (a dull sound when tapping the lower chest, suggesting fluid or dense tissue). There was no \u003cstrong\u003epleural friction rub\u003c\/strong\u003e (a grating sound indicating inflamed lung lining).\u003c\/p\u003e\n\u003cp\u003eHer heart examination showed a \u003cstrong\u003enormal first heart sound\u003c\/strong\u003e but a \u003cstrong\u003eprominent pulmonic second sound\u003c\/strong\u003e — a clue that the pressure in the blood vessels of her lungs was elevated (\u003cstrong\u003epulmonary hypertension\u003c\/strong\u003e). There was no murmur suggesting \u003cstrong\u003etricuspid insufficiency\u003c\/strong\u003e (a leaky heart valve on the right side). Her neck veins were not elevated, which argued against right-heart failure.\u003c\/p\u003e\n\u003cp\u003eHer hands showed \u003cstrong\u003ehypertrophic changes of the metacarpal–phalangeal and proximal interphalangeal joints\u003c\/strong\u003e (enlarged knuckles) with \u003cstrong\u003ebilateral ulnar deviation\u003c\/strong\u003e (fingers drifting sideways toward the little finger — a classic sign of rheumatoid arthritis). Multiple \u003cstrong\u003ecutaneous telangiectasias\u003c\/strong\u003e (tiny red spider veins) were visible on her face and arms, but there was no rash or nodules. Examination of her right hip showed \u003cstrong\u003eno tenderness, no swelling, and a normal range of motion\u003c\/strong\u003e — making septic arthritis of the hip less likely.\u003c\/p\u003e\n\n\u003ch2 id=\"test-results\"\u003eTest Results: What the Numbers Showed\u003c\/h2\u003e\n\u003cp\u003eThe expert was particularly intrigued by the combination of a \u003cstrong\u003edramatically low oxygen saturation (75%)\u003c\/strong\u003e and a \u003cstrong\u003eprominent pulmonic second sound\u003c\/strong\u003e. He reasoned that severe \u003cstrong\u003ehypoxemia\u003c\/strong\u003e (low blood oxygen) could cause the lung blood vessels to narrow reflexively, adding to any underlying lung-vessel disease from the CREST syndrome. Alternatively, the combination made him worry about a \u003cstrong\u003eright-to-left intracardiac shunt\u003c\/strong\u003e — a hole in the heart, such as a \u003cstrong\u003epatent foramen ovale\u003c\/strong\u003e, allowing oxygen-poor blood to bypass the lungs entirely.\u003c\/p\u003e\n\u003cp\u003eThe laboratory results came back with several important values:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWhite-cell count: 8,000 per cubic millimeter\u003c\/strong\u003e with a \u003cstrong\u003enormal differential count\u003c\/strong\u003e (no sign of a dramatic bacterial infection)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHematocrit: 35%\u003c\/strong\u003e (mildly low — normal is roughly 36 to 48%)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePlatelet count: 142,000 per cubic millimeter\u003c\/strong\u003e (mildly low — normal is 150,000 to 450,000)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePartial-thromboplastin time: 30 seconds\u003c\/strong\u003e (normal range, 19 to 30)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInternational normalized ratio (INR): 0.9\u003c\/strong\u003e (normal blood clotting)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSerum aspartate aminotransferase (AST): 107 U per liter\u003c\/strong\u003e (elevated — a liver enzyme)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAlanine aminotransferase (ALT): 55 U per liter\u003c\/strong\u003e (elevated — another liver enzyme)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBicarbonate level: 19 mmol per liter\u003c\/strong\u003e (low, suggesting metabolic acidosis)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eC-reactive protein (CRP): 12.4 mg per deciliter\u003c\/strong\u003e (normal range, 0.020 to 0.800 — markedly elevated, indicating significant inflammation)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLactate dehydrogenase (LDH): 1142 U per liter\u003c\/strong\u003e (normal range, 104 to 236 — markedly elevated, a sign of tissue damage)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eHer levels of alkaline phosphatase, direct and indirect bilirubin, glucose, creatinine, and urea nitrogen were all normal. An \u003cstrong\u003earterial-blood gas analysis\u003c\/strong\u003e while she was receiving \u003cstrong\u003e15 liters of oxygen per minute through a face mask\u003c\/strong\u003e showed a \u003cstrong\u003epartial pressure of oxygen (PaO₂) of 230 mm Hg\u003c\/strong\u003e (normal is roughly 80 to 100 on room air), a \u003cstrong\u003epartial pressure of carbon dioxide (PaCO₂) of 29 mm Hg\u003c\/strong\u003e (low, indicating she was breathing too fast), and a \u003cstrong\u003epH of 7.45\u003c\/strong\u003e (slightly alkaline). Her chest radiograph revealed \u003cstrong\u003epatchy infiltrates scattered throughout both lungs\u003c\/strong\u003e — areas where the lung tissue looked hazy or consolidated. Her \u003cstrong\u003eelectrocardiogram was normal\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cp\u003eThe expert interpreted the slightly elevated liver enzymes as possibly an early toxic effect of \u003cstrong\u003emethotrexate on the liver\u003c\/strong\u003e, or simply a nonspecific response to a systemic infection. The acid–base pattern suggested a \u003cstrong\u003emixed metabolic acidosis and respiratory alkalosis\u003c\/strong\u003e. The very high CRP indicated inflammation or infection — her underlying rheumatic disease could explain it, or an additional process was underway. The lung infiltrates were also nonspecific, reflecting either an inflammatory or infectious process.\u003c\/p\u003e\n\n\u003ch2 id=\"four-questions\"\u003eThe Expert's Four Key Diagnostic Questions\u003c\/h2\u003e\n\u003cp\u003eAt this point, the treating team obtained sputum cultures and started \u003cstrong\u003eempirical antibiotic therapy\u003c\/strong\u003e (treatment chosen before a definitive diagnosis) with \u003cstrong\u003elevofloxacin\u003c\/strong\u003e (a broad-spectrum antibiotic), \u003cstrong\u003eintravenous trimethoprim–sulfamethoxazole\u003c\/strong\u003e (the standard treatment for \u003cem\u003ePneumocystis\u003c\/em\u003e pneumonia), and \u003cstrong\u003ecorticosteroids\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cp\u003eThe consulting expert thought this was a reasonable approach, but he insisted that diagnostic testing continue in parallel, because several important possibilities remained. He framed his thinking as \u003cstrong\u003efour key diagnostic questions\u003c\/strong\u003e:\u003c\/p\u003e\n\u003col\u003e\n  \u003cli\u003eDoes the patient have an \u003cstrong\u003einfection in one of her prosthetic joints\u003c\/strong\u003e (the artificial knee or hip)?\u003c\/li\u003e\n  \u003cli\u003eDoes she have \u003cstrong\u003ethromboembolic disease\u003c\/strong\u003e (blood clots that could travel to the lungs)?\u003c\/li\u003e\n  \u003cli\u003eDoes she have an \u003cstrong\u003eopportunistic pulmonary infection\u003c\/strong\u003e (an infection that takes advantage of a weakened immune system)?\u003c\/li\u003e\n  \u003cli\u003eDoes she have \u003cstrong\u003eintracardiac right-to-left shunting\u003c\/strong\u003e (a hole in the heart allowing oxygen-poor blood to bypass the lungs), presumably through a patent foramen ovale?\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cp\u003eBecause the patient might have more than one process at work, he recommended investigating these questions all at once, starting with tests for blood clots and for an opportunistic lung infection.\u003c\/p\u003e\n\n\u003ch2 id=\"ct-findings\"\u003eThe CT Scan: Blood Clots Found — But Not the Whole Story\u003c\/h2\u003e\n\u003cp\u003eA \u003cstrong\u003espiral computed tomography (CT) scan\u003c\/strong\u003e of the chest, with contrast dye to highlight blood vessels, provided the first major answer. It showed \u003cstrong\u003elarge emboli\u003c\/strong\u003e (blood clots) in several locations:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eThe \u003cstrong\u003eright main pulmonary artery\u003c\/strong\u003e (the large vessel carrying blood to the right lung)\u003c\/li\u003e\n  \u003cli\u003eThe \u003cstrong\u003eright segmental pulmonary arteries\u003c\/strong\u003e (smaller branches within the right lung)\u003c\/li\u003e\n  \u003cli\u003eThe \u003cstrong\u003eleft subsegmental arteries\u003c\/strong\u003e (even smaller branches in the left lung)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThe CT scan also revealed \u003cstrong\u003eextensive, peripheral, patchy ground-glass infiltrates\u003c\/strong\u003e throughout both lungs — a hazy, cloud-like pattern on the scan that suggests fluid or inflammation filling the air sacs.\u003c\/p\u003e\n\u003cp\u003eThe expert admitted he was \u003cstrong\u003esurprised\u003c\/strong\u003e by the diagnosis of extensive pulmonary thromboembolic disease, even though he had listed a leg clot as a possible cause of her pain. He noted that the ground-glass infiltrates were probably \u003cem\u003enot\u003c\/em\u003e related to the blood clots. They pointed to another, coexisting process — most likely an \u003cstrong\u003eopportunistic infection\u003c\/strong\u003e. He specifically worried about \u003cstrong\u003e\u003cem\u003ePneumocystis\u003c\/em\u003e pneumonia\u003c\/strong\u003e, given the appearance of the CT scan, and \u003cstrong\u003etuberculosis\u003c\/strong\u003e, given the patient's use of \u003cstrong\u003einfliximab\u003c\/strong\u003e (a drug known to increase the risk of mycobacterial infections).\u003c\/p\u003e\n\u003cp\u003eBecause the patient needed \u003cstrong\u003eanticoagulation\u003c\/strong\u003e (blood-thinning drugs) and likely had \u003cstrong\u003epulmonary hypertension\u003c\/strong\u003e, the expert advised against a \u003cstrong\u003etransbronchial biopsy\u003c\/strong\u003e (sampling lung tissue through a bronchoscope), which carries a bleeding risk. Instead, he recommended trying to identify an opportunistic pathogen in \u003cstrong\u003einduced sputum\u003c\/strong\u003e or \u003cstrong\u003ebronchoalveolar-lavage fluid\u003c\/strong\u003e (fluid washed into the lung during bronchoscopy).\u003c\/p\u003e\n\n\u003ch2 id=\"diagnosis-treatment\"\u003eThe Final Diagnosis and Treatment: Two Diseases at Once\u003c\/h2\u003e\n\u003cp\u003eThe patient received an \u003cstrong\u003eintravenous bolus\u003c\/strong\u003e (a rapid dose) of \u003cstrong\u003eunfractionated heparin\u003c\/strong\u003e, followed by a \u003cstrong\u003econtinuous infusion\u003c\/strong\u003e of the same blood thinner. Her condition remained stable but did not improve during the several hours between starting heparin and undergoing bronchoscopy.\u003c\/p\u003e\n\u003cp\u003eThen came the decisive test. A \u003cstrong\u003ebronchoscopy\u003c\/strong\u003e (a procedure in which a thin, flexible tube with a camera is passed into the airways) with \u003cstrong\u003ebronchoalveolar lavage\u003c\/strong\u003e revealed the presence of \u003cstrong\u003e\u003cem\u003ePneumocystis carinii\u003c\/em\u003e\u003c\/strong\u003e — the organism that causes \u003cem\u003ePneumocystis\u003c\/em\u003e pneumonia. (This organism is now officially called \u003cem\u003ePneumocystis jirovecii\u003c\/em\u003e; \u003cem\u003ecarinii\u003c\/em\u003e was the name used at the time of this 2004 report.) Her final diagnoses were therefore twofold:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePulmonary embolism\u003c\/strong\u003e (blood clots in the lungs)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e\u003cem\u003ePneumocystis carinii\u003c\/em\u003e pneumonia\u003c\/strong\u003e (an opportunistic lung infection, typically seen in people with weakened immune systems)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eShe continued to receive \u003cstrong\u003eintravenous trimethoprim–sulfamethoxazole\u003c\/strong\u003e (to treat the pneumonia), \u003cstrong\u003ecorticosteroids\u003c\/strong\u003e, and \u003cstrong\u003eunfractionated heparin\u003c\/strong\u003e (to treat the clots). This single regimen treated both conditions at once.\u003c\/p\u003e\n\n\u003ch2 id=\"recovery\"\u003eRecovery and Follow-Up: A Return to Normal Breathing\u003c\/h2\u003e\n\u003cp\u003eThe patient's course in the hospital was dramatic but ultimately successful:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eShe required \u003cstrong\u003emechanical ventilation\u003c\/strong\u003e (a breathing machine) for \u003cstrong\u003e24 hours after bronchoscopy\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003eHer condition then \u003cstrong\u003eimproved dramatically\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003eHer \u003cstrong\u003etrachea was extubated\u003c\/strong\u003e (the breathing tube was removed) on her \u003cstrong\u003esecond day in the hospital\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003eBy the \u003cstrong\u003efifth day\u003c\/strong\u003e, the supplemental oxygen was discontinued.\u003c\/li\u003e\n  \u003cli\u003eShe had \u003cstrong\u003eno further symptoms of dyspnea at rest\u003c\/strong\u003e (shortness of breath while resting).\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eShe was soon discharged from the hospital taking three medications:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eAn \u003cstrong\u003eoral corticosteroid\u003c\/strong\u003e (at a dose that was to be gradually reduced)\u003c\/li\u003e\n  \u003cli\u003e\u003cstrong\u003eTrimethoprim–sulfamethoxazole\u003c\/strong\u003e\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWarfarin\u003c\/strong\u003e (a blood thinner to prevent future clots)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eAfter she completed treatment for \u003cem\u003ePneumocystis\u003c\/em\u003e pneumonia, she continued taking \u003cstrong\u003etrimethoprim–sulfamethoxazole as a preventive measure\u003c\/strong\u003e (prophylaxis) to stop the infection from returning. The doctors contacted her \u003cstrong\u003efive months after hospitalization\u003c\/strong\u003e, and she reported \u003cstrong\u003eno breathing difficulties\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003ch2 id=\"commentary\"\u003eThe Authors' Commentary: What This Case Teaches Doctors\u003c\/h2\u003e\n\u003cp\u003eThe case authors, Drs. Hilliard, Weinberger, Tierney, Midthun, and Saint, highlighted \u003cstrong\u003etwo important lessons\u003c\/strong\u003e from this puzzling clinical problem:\u003c\/p\u003e\n\u003col\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDiagnostic parsimony is a worthwhile goal, but it cannot always be achieved.\u003c\/strong\u003e In this patient, Occam's razor — the urge to find one single explanation — would have led doctors astray. Her shortness of breath had two distinct causes: pulmonary embolism \u003cem\u003eand\u003c\/em\u003e \u003cem\u003ePneumocystis\u003c\/em\u003e pneumonia.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePulmonary embolism remains one of the most challenging diagnoses to make clinically.\u003c\/strong\u003e Its symptoms overlap with many other conditions, and objective testing to confirm or rule out blood clots is essential whenever the diagnosis is even considered.\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cp\u003eThe authors also offered a thoughtful hypothesis connecting the two diseases. Her inflammatory arthritis required \u003cstrong\u003eimmunosuppressive therapy\u003c\/strong\u003e (drugs that quiet the immune system) to control symptoms. Chronic immunosuppression then placed her at increased risk for an \u003cstrong\u003eopportunistic infection\u003c\/strong\u003e — \u003cem\u003ePneumocystis\u003c\/em\u003e pneumonia. That pneumonia led to shortness of breath, fever, and lethargy (extreme tiredness), which may have prompted her to reduce her physical activity. Reduced mobility, in turn, is a well-known risk factor for developing \u003cstrong\u003evenous thromboembolism\u003c\/strong\u003e (blood clots in the veins).\u003c\/p\u003e\n\u003cp\u003eThe authors were careful to label this sequence as \u003cstrong\u003eonly a hypothesis\u003c\/strong\u003e — but it provides one logical explanation for why her two separate diseases appeared together. The pneumonia may have literally set the stage for the blood clot.\u003c\/p\u003e\n\n\u003ch2 id=\"one-or-many\"\u003eOccam's Razor vs. Saint's Triad: How the Two Ideas Connect\u003c\/h2\u003e\n\u003cp\u003eThe authors then stepped back to explain the philosophical debate at the heart of the case. \u003cstrong\u003eSaint's triad\u003c\/strong\u003e — the association of hiatal hernia, gallbladder disease, and diverticulosis — has no known biological connection between its three conditions. That lack of connection was Saint's point: doctors should remain open to the possibility that a patient may simply have multiple unrelated diseases at the same time.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHickam's dictum\u003c\/strong\u003e — \"A patient can have as many diagnoses as he darn well pleases\" — makes the same point in deliberately colorful language. The authors noted that physicians today are seeing an increasing number of patients with many acute and chronic illnesses at once, so the views of Saint and Hickam deserve serious consideration in modern practice.\u003c\/p\u003e\n\u003cp\u003eYet Occam's razor has held a powerful place in medicine since William Osler applied it to clinical care. \u003cstrong\u003eParsimony of diagnosis\u003c\/strong\u003e (economy in diagnosis) is an important standard. But this case shows how the principle can fail. As the authors wrote: \"As the population continues to age — and as diagnostic studies increase in number and sophistication — the dulling of Occam's razor is certain to continue.\"\u003c\/p\u003e\n\n\u003ch2 id=\"modern-medicine\"\u003eWhat This Means for Modern Medicine: More Patients, More Diagnoses\u003c\/h2\u003e\n\u003cp\u003eThe authors cited research showing why the balance between Occam and Saint matters more than ever. A \u003cstrong\u003epopulation-based study\u003c\/strong\u003e (Redelmeier and colleagues, published in the \u003cem\u003eNew England Journal of Medicine\u003c\/em\u003e in 1998) looked at patients \u003cstrong\u003e65 years of age or older\u003c\/strong\u003e who had chronic medical diseases and received prescription medications free of charge. The study found that these patients' \u003cstrong\u003eadditional unrelated disorders were undertreated\u003c\/strong\u003e, compared with the same disorders in patients who did not have another underlying medical condition.\u003c\/p\u003e\n\u003cp\u003eAn accompanying editorial (by Steinbrook, also in the \u003cem\u003eNew England Journal of Medicine\u003c\/em\u003e, 1998) suggested that this undertreatment may stem from doctors applying \u003cstrong\u003eOccam's razor too rigidly\u003c\/strong\u003e — attributing every symptom to the patient's known chronic disease and failing to look for separate, treatable conditions.\u003c\/p\u003e\n\u003cp\u003eThe authors concluded with a balanced message: as people live longer and the number of chronic diseases increases, doctors must anticipate a greater likelihood of multiple diagnoses. But can the tradition of diagnostic parsimony simply be abandoned? The authors warned against swinging too far in the other direction. If physicians assigned separate diagnoses of arthritis, dermatitis, and kidney disease to a patient who actually has \u003cstrong\u003esystemic lupus erythematosus\u003c\/strong\u003e (a single disease that can cause all three problems), they would be making a different kind of error.\u003c\/p\u003e\n\u003cp\u003eTheir conclusion: \u003cstrong\u003edoctors cannot embrace either principle exclusively\u003c\/strong\u003e. The wisest approach is to keep both Occam's razor and Saint's triad in mind, applying each where it fits.\u003c\/p\u003e\n\n\u003ch2 id=\"limitations\"\u003eStudy Limitations: What This Case Could Not Prove\u003c\/h2\u003e\n\u003cp\u003eThis article is a \u003cstrong\u003ecase report of a single patient\u003c\/strong\u003e, published in the \"Clinical Problem-Solving\" format of the journal. As such, it has several important limitations:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNo statistical analysis or comparison group.\u003c\/strong\u003e The article describes what happened to one individual; it cannot prove how often two diseases occur together in other patients.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThe connection between the pneumonia and the blood clot is hypothetical.\u003c\/strong\u003e The authors explicitly labeled their reasoning — that reduced activity from the pneumonia led to the clot — as \"only a hypothesis.\" It is plausible, but it was not proven in this case.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNot a controlled trial of treatment.\u003c\/strong\u003e The success of the combination of trimethoprim–sulfamethoxazole, corticosteroids, and heparin in this patient does not constitute proof that this regimen is the best approach for every patient with both conditions.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThe cited undertreatment study addressed a related but different question.\u003c\/strong\u003e The 1998 Redelmeier study concerned patients with chronic diseases generally, not specifically patients with two acute diseases presenting together.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"recommendations\"\u003eRecommendations for Patients\u003c\/h2\u003e\n\u003cp\u003eFor patients — especially those with chronic conditions or weakened immune systems — this case offers several practical lessons:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNew symptoms deserve a fresh look.\u003c\/strong\u003e If you have a chronic disease like rheumatoid arthritis and develop new shortness of breath, cough, fever, or leg pain, tell your doctor. Even if your condition could explain some symptoms, a new problem may have a separate cause.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eKnow your medication risks.\u003c\/strong\u003e Drugs such as prednisone, methotrexate, and infliximab (a \u003cstrong\u003etumor necrosis factor α antagonist\u003c\/strong\u003e — a drug that blocks an inflammation-producing protein) weaken the immune system. That means infections like \u003cem\u003ePneumocystis\u003c\/em\u003e pneumonia and tuberculosis are real risks. Ask your doctor whether you need preventive treatment.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWatch for blood clot symptoms.\u003c\/strong\u003e One-sided leg or buttock pain, swelling, or sudden shortness of breath can signal a blood clot. People who become less mobile — whether from illness, pain, or bed rest — are at higher risk.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIt's OK to have more than one problem.\u003c\/strong\u003e If your symptoms do not fit neatly into a single diagnosis, you are not a \"complicated\" patient in a negative sense. Multiple conditions can genuinely coexist, and good doctors look for all of them.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAsk about the \"simple explanation.\"\u003c\/strong\u003e If your doctor says a symptom is \"just part of your condition,\" it is reasonable to ask whether any testing is needed to rule out a separate, treatable problem.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c!-- ddn:faq:start --\u003e\n\u003ch2 id=\"ddn-faq\"\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003ch3\u003eWhat should I do if I have rheumatoid arthritis and suddenly feel short of breath, cough, or have a fever?\u003c\/h3\u003e\n\u003cp\u003eTell your doctor right away, especially if you take immune-suppressing drugs. In this case, a woman with arthritis developed shortness of breath, cough, and fever. She had two separate problems at the same time: blood clots in her lungs and Pneumocystis pneumonia. New symptoms can mean a new, treatable condition, even if you already have a chronic illness.\u003c\/p\u003e\n\u003ch3\u003eWhat is Pneumocystis pneumonia?\u003c\/h3\u003e\n\u003cp\u003ePneumocystis pneumonia is a lung infection caused by a fungus-like organism. It usually affects people with weakened immune systems, such as those taking medicines like prednisone, methotrexate, or infliximab. Symptoms include shortness of breath, cough, and fever. In the case, the infection was diagnosed by bronchoscopy and successfully treated with trimethoprim–sulfamethoxazole and corticosteroids.\u003c\/p\u003e\n\u003ch3\u003eCould I have both a blood clot in my lungs and pneumonia at the same time?\u003c\/h3\u003e\n\u003cp\u003eYes. The patient in this case had both pulmonary embolism and Pneumocystis pneumonia simultaneously. Her shortness of breath was caused by two different diseases. Doctors sometimes use the saying 'a patient can have as many diagnoses as he darn well pleases.' If your symptoms are complex, your doctor should look for more than one cause when needed.\u003c\/p\u003e\n\u003ch3\u003eWhat does it mean if my oxygen saturation is 75 percent on room air?\u003c\/h3\u003e\n\u003cp\u003eAn oxygen saturation of 75 percent is dangerously low. Normal is 95 percent or higher. In this case, the patient arrived with that level, so she received high-flow oxygen and later needed a breathing machine for a day. If your oxygen level is that low, go to an emergency department immediately because your body is not getting enough oxygen.\u003c\/p\u003e\n\u003ch3\u003eI take infliximab for arthritis. Am I at higher risk for lung infections?\u003c\/h3\u003e\n\u003cp\u003eIn this case, the patient was taking infliximab, prednisone, and methotrexate for inflammatory arthritis. Her doctors noted that such immune-suppressing drugs increase the risk of infections like Pneumocystis pneumonia and tuberculosis. Ask your doctor whether you need preventive treatment and what symptoms should prompt urgent evaluation, such as fever, cough, or trouble breathing.\u003c\/p\u003e\n\u003ch3\u003eWhy did the doctors in this case have trouble deciding whether the patient had one disease or two?\u003c\/h3\u003e\n\u003cp\u003eDoctors are taught Occam's razor: favor the simplest explanation for all symptoms. But another principle, Hickam's dictum, says a patient can have multiple diseases at once. This patient had two separate causes of her breathing problem—pulmonary embolism and Pneumocystis pneumonia—so relying only on Occam's razor would have missed a critical diagnosis. Both ways of thinking are needed.\u003c\/p\u003e\n\u003ch3\u003eWhat treatment helped the patient with both blood clots in her lungs and Pneumocystis pneumonia?\u003c\/h3\u003e\n\u003cp\u003eShe received an intravenous blood thinner called heparin for the pulmonary embolism, plus trimethoprim–sulfamethoxazole and corticosteroids for Pneumocystis pneumonia. After a day on a breathing machine, she improved, was discharged taking warfarin, trimethoprim–sulfamethoxazole, and an oral corticosteroid, and had no breathing difficulties five months later.\u003c\/p\u003e\n\u003ch3\u003eIf I have rheumatoid arthritis and am on immunosuppressants, should I seek a second opinion when I develop shortness of breath that my doctor says is just from my arthritis?\u003c\/h3\u003e\n\u003cp\u003eYes—new symptoms deserve a fresh look, especially when you have a chronic condition or weakened immunity. A patient with rheumatoid arthritis, CREST syndrome, and immunosuppressive therapy developed shortness of breath, fever, and leg pain; she actually had two separate life-threatening conditions at once: pulmonary embolism and Pneumocystis pneumonia. Because neither diagnosis explained all her symptoms, doctors had to keep investigating. If your symptom is dismissed as simply part of your known disease, it is reasonable to ask whether testing for a separate treatable problem is needed. Diagnostic Detectives Network provides independent expert second opinions.\u003c\/p\u003e\n\u003c!-- ddn:faq:end --\u003e\n\n\u003ch2 id=\"source\"\u003eSource Information\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eOriginal article title:\u003c\/strong\u003e Occam’s Razor versus Saint’s Triad\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors:\u003c\/strong\u003e Anthony A. Hilliard, M.D., Steven E. Weinberger, M.D., Lawrence M. Tierney, Jr., M.D., David E. Midthun, M.D., and Sanjay Saint, M.D., M.P.H.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eJournal:\u003c\/strong\u003e \u003cem\u003eNew England Journal of Medicine\u003c\/em\u003e, 2004; volume 350, pages 599–603. Published February 5, 2004. Copyright © 2004 Massachusetts Medical Society.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding disclosures:\u003c\/strong\u003e Supported by a Career Development Award from the Health Services Research and Development Program of the Department of Veterans Affairs and a Patient Safety Developmental Center Grant (P20-HS11540) from the Agency for Healthcare Research and Quality (both to Dr. Saint).\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eRelated references cited in the original:\u003c\/strong\u003e Firkin BG, Whitworth JA. \u003cem\u003eDictionary of medical eponyms.\u003c\/em\u003e 2nd ed. 1996; Miller WT. \"Occam versus Hickam.\" \u003cem\u003eSemin Roentgenol\u003c\/em\u003e 1998;33:213; Drachman DA. \"Occam's razor, geriatric syndromes, and the dizzy patient.\" \u003cem\u003eAnn Intern Med\u003c\/em\u003e 2000;132:403-4; Redelmeier DA, Tan SH, Booth GL. \"The treatment of unrelated disorders in patients with chronic medical diseases.\" \u003cem\u003eN Engl J Med\u003c\/em\u003e 1998;338:1516-20; Steinbrook R. \"Patients with multiple chronic conditions — how many medications are enough?\" \u003cem\u003eN Engl J Med\u003c\/em\u003e 1998;338:1541-2.\u003c\/p\u003e\n\u003cp\u003e\u003cem\u003eNote: This patient-friendly article is based on peer-reviewed research originally published in the New England Journal of Medicine. It is intended for educational purposes and is not a substitute for professional medical advice.\u003c\/em\u003e\u003c\/p\u003e","brand":"DiagnosticDetectives.Com","offers":[{"title":"Default Title","offer_id":47560937701532,"sku":null,"price":0.0,"currency_code":"USD","in_stock":true}],"url":"https:\/\/diagnosticdetectives.com\/fr\/products\/two-medical-sayings-one-patient-when-the-simplest-explanation-isnt-the-only-one","provider":"DiagnosticDetectives.Com","version":"1.0","type":"link"}