Test Description
The barium enema is the fluoroscopic examination of the large intestine after instil- lation of barium sulfate into the rectum. If a “double contrast” or “air contrast”
study is being used, air is also instilled. During this procedure, a fluoroscopic screen is positioned over the intestines. These structures are then projected onto the fluoroscopic screen. The image remains on the monitor for continuous obser- vation; therefore, as the barium is instilled, the flow of barium can be monitored on the screen. The patient’s position is changed throughout the exam to allow visualiza- tion of the structures and their function, including peristalsis. This test is especially
THE EVIDENCE FOR PRACTICE
According to the American Cancer Society, if colonoscopy is unavailable, not feasible, or not desired by the patient, double contrast barium enema (DCBE) alone, or the combina- tion of flexible sigmoidoscopy and DCBE are acceptable alternatives. Adding flexible sig- moidoscopy to DCBE may provide a more comprehensive diagnostic evaluation than DCBE alone in finding significant lesions. These procedures should be done every 5 years.
Normal Values
Normal size, shape, position, and functioning of the large intestine Possible Meanings of Abnormal Values
Appendicitis Carcinoma Crohn’s disease Diverticulitis Diverticulosis Fistulas Gastroenteritis Granulomatous colitis Hirschsprung’s disease Intussusception
Irritable bowel syndrome Perforation of the colon Polyps
Sigmoid torsion Sigmoid volvulus Telescoping of the bowel Tumors
Ulcerative colitis
Contributing Factors to Abnormal Values
• Under- or overexposure of the film may alter film quality.
• When patients are unable to hold still, due to pain or mental status, the quality of the film may be affected.
• Barium retained from other exams and inadequate bowel preparation will interfere with the procedure.
Interventions/Implications Pretest
• Explain to the patient the purpose of the test and the benefits and risks associated with the test. Provide any written teaching materials available on the subject. Explain to the
useful in the evaluation of patients experiencing lower abdominal pain, changes in their bowel habits, or the passage of stools containing blood or mucus, and for visu- alizing polyps, diverticula, and tumors. Videotaping of the fluoroscopic procedure enables the movements to be studied at later times.
BARIUM ENEMA 85
B
B
patient that instillation of the barium and/or air may cause cramping and the urge to defe- cate. Reassure the patient that there is a balloon on the tube which will prevent leakage of the barium from the rectum.
• Explain to the patient the importance of all aspects of the preparation to ensure complete emptying of the intestinal tract. If fecal material has been retained, the test must be repeated at another time.
• Preparation of the patient includes:
• a liquid diet with no dairy products for 24 hours prior to the exam
• intake of at least 1200 cc of fluids the day prior to the exam
• stool softeners, laxatives, and enemas as per institutional policy the evening before and the morning of the exam (Note: Enemas may occasionally be ordered “until clear”.
This means that enemas are given until the solution returned is clear and colorless.)
• being NPO (nothing by mouth) after midnight before the exam
• The patient should be monitored throughout the bowel preparation for fatigue and fluid and electrolyte imbalance.
• Instruct the patient to remove all objects containing metal, such as jewelry or undergar- ments, as these will show on the film.
Procedure
• The patient is first assisted to a supine position on the exam table, and a preliminary film is taken. This provides verification that no stool remains in the large intestine. If prepa- ration is adequate, the test may continue.
• The patient is then turned to the side (Sims’ position) and a lubricated rectal tube is inserted.
• The barium is allowed to flow slowly into the intestine until the entire intestine up to the ileocecal valve is filled. During this time, the flow of barium is observed on the fluoro- scopic screen and periodic films are taken.
• Once the intestine is filled, the rectal tube is removed. The patient is assisted to the rest- room, or provided a bedpan, and is instructed to expel as much barium as possible.
• After expulsion of the barium, an additional film is taken of the intestine.
• If a double-contrast barium enema has been ordered, air is then instilled in the intestine and additional films taken.
• The procedure takes 45 minutes to 1 1/4 hours.
Posttest
• Resume the patient’s diet and medications as taken prior to the test. Encourage fluid intake.
• Instruct the patient on the need to evacuate all of the barium. Administer a cathartic or enema as ordered. Check all stools for presence of barium, explaining to the patient that the stools will be white initially and return to normal color following passage of all of the barium.
• Instruct the patient to report any abdominal pain, fever, or weakness.
• Notify the primary care provider if the barium is not expelled within 2 to 3 days.
• Report abnormal findings to the primary care provider.
RClinical Alerts
• If a barium swallow or an upper gastrointestinal and small-bowel series test is ordered, these should be completed after the barium enema is performed.
Otherwise the barium sulfate ingested during the other exams may obscure the films made during the barium enema.
B
THE EVIDENCE FOR PRACTICE
Abnormalities of the mid or distal esophagus or even the uppermost part of the stomach may cause referred dysphagia to the upper chest or pharynx, whereas abnormalities of the pharynx rarely cause referred dysphagia to the lower chest. The esophagus and upper stom- ach should therefore be evaluated in patients with pharyngeal symptoms, particularly if no abnormalities are found in the pharynx to explain these symptoms.
Normal Values
Normal size, shape, position, and functioning of the esophagus
• If an intestinal perforation is suspected, a water-soluble contrast medium (Gastrografin) is used. No bowel preparation is performed.
• Possible complications include: perforation of the colon, fluid and electrolyte imbalance, and fecal impaction due to retention of barium.
C O N T R A I N D I C AT I O N S !
• Pregnant women
• Caution: A woman in her childbearing years should undergo radiography only during her menses or 12 to 14 days after its onset to avoid any exposure to a fetus.
• Patients with tachycardia.
• Patients with severe active ulcerative colitis accompanied by systemic toxicity and megacolon.
• Patients with suspected intestinal perforation.
• Patients who are unable to cooperate in retaining the barium due to age, mental status, pain, or other factors.
Barium Swallow (Esophageal Radiography, Esophagography)
Test Description
The barium swallow, which is usually included as a part of the upper gastrointesti- nal series, is the fluoroscopic examination of the pharynx and the esophagus after ingestion of barium sulfate mixtures. During this procedure, a fluoroscopic screen is positioned over the heart, lungs, and abdomen. These structures are then pro- jected on the fluoroscopic screen. The image remains on the monitor for continu- ous observation; therefore, as the patient swallows barium, the flow of barium can be monitored on the screen. The patient’s position is changed throughout the exam to allow visualization of the entire esophagus and to assess for such problems as gastric reflux. This test is especially useful in the evaluation of patients experienc- ing dysphagia and regurgitation. Videotaping of the fluoroscopic procedure enables the movements to be studied at later times.
BARIUM SWALLOW 87
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Possible Meanings of Abnormal Values Achalasia
Cancer of the esophagus
Cancer of the stomach invading the esophagus Chalasia
Congenital abnormalities Diverticula
Esophageal motility disorders, such as spasms Esophageal ulcers
Esophageal varices Esophagitis Hiatal hernia
Perforation of the esophagus Polyps
Strictures
Contributing Factors to Abnormal Values
• Under- or overexposure of the film may alter film quality.
• When patients are unable to hold still, due to pain or mental status, the quality of the film may be affected.
Interventions/Implications Pretest
• Explain to the patient the purpose of the test and the benefits and risks associated with the test. Provide any written teaching materials available on the subject. Note that no dis- comfort is associated with this procedure. The barium, although in a milkshake-type solu- tion, may taste chalky.
• Fasting for 8 hours is required prior to the test.
• Instruct the patient to remove all objects containing metal, such as jewelry or undergar- ments, as these will show on the film.
Procedure
• The patient is placed in an upright position for the first part of the procedure.
• The fluoroscopic screen is placed in front of the patient and the heart, lungs, and abdomen are viewed.
• The patient is instructed to take one swallow of a thick barium mixture while the video- tape is made of the pharyngeal action.
• As the patient then continues to drink the barium mixture, in addition to the fluoroscopic viewing, spot films are made of the esophageal area from a variety of angles.
• The patient is then placed in different positions and instructed to drink more of the bar- ium. This allows for evaluation of the patient for such problems as gastric reflux.
• The test takes approximately 30 minutes to 1 hour.
Posttest
• Resume the patient’s diet and medications as taken prior to the test. Encourage fluid intake.
• Instruct the patient on the need to evacuate all of the barium. Administer a cathartic as ordered. Check all stools for the presence of barium, explaining to the patient that the stools will be white initially and will return to normal color following passage of all of the barium.
B
• Notify the primary care provider if the barium is not expelled within 2 to 3 days.
• Report abnormal findings to the primary care provider.
RClinical Alerts
• If cholangiography and/or a barium enema test are ordered, these should be com- pleted before the barium swallow is performed. Otherwise the barium sulfate ingested during the barium swallow may obscure the films made during the other exams.
• Possible complication of procedure: fecal impaction due to retention of barium.
C O N T R A I N D I C AT I O N S !
• Pregnant women.
• Caution: A woman in her childbearing years should undergo radiography only during her menses or 12 to 14 days after its onset to avoid any exposure to a fetus.
• Patients with intestinal obstruction.
• Patients with a perforated esophagus. (Gastrografin, a water-soluble contrast medium, would be used in place of barium.)
• Patients who are unable to cooperate due to age, mental status, pain, or other factors.
• Patients with unstable vital signs.
Normal Values
Absence of Bence Jones protein in the urine
Bence Jones Protein (Immunoglobulin Light Chains)
Test Description
Individuals with such conditions as multiple myeloma and amyloidosis often have an increased production of a single homogeneous immunoglobulin or immunoglob- ulin fragment (i.e., kappa or lambda light chains). These immunoglobulin light chains, called Bence Jones proteins, are small and easily cleared by the kidney.
Hence, they will be present in the urine and are usually absent in the plasma.
Historically, the detection of light chains in urine was based on their unique solu- bility characteristics related to temperature. On heating a urine sample, these pro- teins will precipitate out of solution when at 40°C to 60°C, redissolve at 100°C, and reappear on cooling. This “heat precipitation test” is insensitive and nonspecific.
Today, sensitive and specific detection of Bence Jones protein is obtained using the immunoelectrophoresis process.
BENCE JONES PROTEIN 89
B
Possible Meanings of Abnormal Values
Increased
Adult Fanconi’s syndrome Amyloidosis
Benign monoclonal gammopathy Chronic lymphocytic leukemia Chronic renal insufficiency Cryoglobulinemia Hyperparathyroidism Lymphoma
Metastases Multiple myeloma Rheumatoid arthritis Systemic lupus erythematosus Waldenstrửm’s macroglobulinemia
Contributing Factors to Abnormal Values
• False-negativetest results may occur with dilute urine or in the presence of severe urinary tract infection.
Interventions/Implications Pretest
• Explain the procedure to the patient, stressing the importance of not contaminating the specimen.
• No fasting is required before the test.
Procedure
• A minimum of 50 mL of urine is needed for the test. Collection of an early morning spec- imen is best.
• Use of clean-catch midstream technique is recommended to prevent contamination of the specimen.
• A clean-catch kit containing cleansing materials and a sterile specimen container is given to the patient.
• Male patients should cleanse the urinary meatus with the materials provided or with soap and water, void a small amount into the toilet, and then void directly into the specimen container.
• Female patients should cleanse the labia minora and urinary meatus, cleansing from front to back. While keeping the labia separated, the female should void a small amount into the toilet and then void directly into the specimen container.
• Instruct patients to avoid touching the inside of the specimen container and lid.
• A 24-hour urine collection may be needed to detect trace amounts of protein. If so, refrig- erate specimen throughout the collection.
• Gloves are worn by the health-care worker when dealing with the specimen.
Posttest
• Label the specimen. The specimen must be transported to the laboratory immediately or refrigerated to prevent bacterial growth that can lead to a breakdown of proteins.
• Report abnormal findings to the primary care provider.
THE EVIDENCE FOR PRACTICE
Initial evaluations should determine whether the elevated serum bilirubin is conjugated (direct) or unconjugated (indirect). Asymptomatic adult patients with an isolated, mild unconjugated hyperbilirubinemia should be evaluated for Gilbert’s syndrome, hemolysis, and medication-induced hyperbilirubinemia. If conjugated hyperbilirubinemia is present, the presence of concomitant alkaline phosphatase elevations must be assessed and biliary obstruction should be excluded. (AGAI guidelines at http://www.gastrojournal.org/article/
PIIS0016508502002408/fulltext)
Normal Values
Total bilirubin: 0.3–1.0 mg/dL (5–17 àmol/L SI units)
Direct (conjugated) bilirubin: 0.0–0.4 mg/dL (0–7 àmol/L SI units) Indirect (unconjugated) bilirubin: 0.1–1.0 mg/dL (1–17 àmol/L SI units)
Possible Meanings of Abnormal Values
Increased Direct (Conjugated) Bilirubin Biliary obstruction
Cancer of the head of the pancreas
BILIRUBIN, BLOOD 91
B
Bilirubin, Blood (Direct, Indirect, Total)
Test Description
Bilirubin, which is one of the components of bile, is formed in the liver, spleen, and bone marrow. It is also formed as a result of hemoglobin breakdown, as in the destruc- tion of red blood cells. There are three types of bilirubin: total, direct (conjugated), and indirect (unconjugated). Total bilirubinis composed of the direct bilirubin plus the indirect bilirubin. The total bilirubin level increases with any type of jaundice.
Normally, directorconjugated, bilirubinis excreted by the gastrointestinal (GI) tract, with only minimal amounts entering the bloodstream. It was originally named
“direct” bilirubin because this water-soluble type of bilirubin reacts directly with the reagents added to the blood sample. Its level rises in the blood when obstructive jaundice (as from gallstones) or hepatic jaundice occurs, because the bilirubin is unable to reach the intestines for excretion and instead, enter the bloodstream for excretion by the kidneys. Direct bilirubin is the only type of bilirubin able to cross the glomerular filter; thus it is the only type of bilirubin that can be found in the urine.
Indirect bilirubin, also known asfree or unconjugated bilirubin, is normally found in the bloodstream. Its name comes from the fact that this non-water-soluble bilirubin does not directly react with reagents added to a blood sample. Alcohol must be added for the reaction to occur. Indirect bilirubin rises in cases of hemolytic jaundice, in which the breakdown of hemoglobin results in a higher than normal level of indirect bilirubin being present in the bloodstream. This is the type of bilirubin elevated in cases of hepatocellular dysfunction, such as hepatitis.
Typically, only the total bilirubin is reported. If the total bilirubin is abnormal, further testing is done to differentiate the level of direct and indirect bilirubin.
Choledocholithiasis Cirrhosis
Dubin-Johnson syndrome Hepatitis
Obstructive jaundice Pregnancy
Increased Indirect (Unconjugated) Bilirubin Autoimmune hemolysis
Cirrhosis
Crigler-Najjer syndrome Erythroblastosis fetalis Gilbert’s syndrome
Hemolytic transfusion reaction Hepatitis
Malaria
Myocardial infarction Pernicious anemia Septicemia Sickle cell disease Tissue hemorrhage
Contributing Factors to Abnormal Values
• Hemolysis of the blood sample will alter test results.
• Exposure of the blood sample to sunlight or artificial light for 1 hour or more will decrease the bilirubin content of the sample.
• Testing with contrast media within 24 hours will alter test results.
• Drugs that may increasetotal bilirubin: allopurinal, anabolic steroids, antimalarials, ascorbic acid, azathioprine, chlorpropamide, cholinergics, codeine, dextran, diuret- ics, epinephrine, isoproterenol, levodopa, MAO inhibitors, meperidine, methyldopa, methotrexate, morphine, oral contraceptives, phenazopyridine, phenothiazines, quinidine, rifampin, streptomycin, theophylline, tyrosine, vitamin A.
• Drugs that may decreasetotal bilirubin: barbiturates, caffeine, chlorine, citrate, cor- ticosteroids, ethanol, penicillin, protein, salicylates, sulfonamides, urea.
Interventions/Implications Pretest
• Explain to the patient the purpose of the test and the need for a blood sample to be drawn.
• Fasting for 4 to 8 hours is required before the test. Water is permitted.
Procedure
• A 7-mL blood sample is drawn in a lavender-top collection tube.
• Gloves are worn throughout the procedure.
Posttest
• Apply pressure at venipuncture site. Apply dressing, periodically assessing for continued bleeding.
• Protect the specimen from bright light by wrapping the sample tube in foil or placing in a refrigerator.
• Label the specimen and transport it to the laboratory.
• Report abnormal findings to the primary care provider.
B
Anthrax
Anthrax is caused by Bacillus anthracis, a bacterium that forms spores. People can become infected through handling or breathing in the anthrax spores, or from ingest- ing undercooked meat from infected animals. There are three types of anthrax: cuta- neous, gastrointestinal (GI), and inhalation. The cutaneous form begins with a papule resembling an insect bite, which then progresses to development of a central vesicle.
This vesicle becomes a painless, necrotic ulcer. Lesions may be solitary or multiple and are accompanied by regional lymphadenopathy, fatigue, fever, and/or chills. Even without treatment, 80% of people with cutaneous anthrax survive. GI anthrax is more serious, with 25% to 50% mortality. Symptoms include nausea, loss of appetite, bloody diarrhea, fever, and abdominal pain. The most serious form is inhalation anthrax. It first appears with cold or flu-like symptoms which progress to more severe respiratory difficulty. Death can occur in 50% of the cases. Treatment involves antibiotic therapy (ciprofloxacin or doxycycline) for 60 days. Survival depends on the type of anthrax and how soon treatment is initiated.
Diagnostic Testing:Testing method depends on the type of anthrax suspected.
Cutaneous anthrax:
• Swabs of lesion for Gram stain, culture, and polymerase chain reaction (PCR)
• Biopsies for PCR
• Blood testing: acute and convalescent titers, blood culture
BIOTERRORISM INFECTIOUS AGENTS TESTING 93
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Bioterrorism Infectious Agents Testing (Anthrax, Botulism, Plague, Smallpox, Tularemia, Viral Hemorrhagic Fevers [VHFs])
Test Description
Among the health protection goals of the Centers for Disease Control and Prevention (CDC) is to prepare people for emerging health threats, including those of bioter- rorism. The CDC website (http://www.bt.cdc.gov/bioterrorism/) provides access to information on many biological agents. Biological agents are classified according to three priority levels. The highest priority is Category A. According to the CDC, higher priority agents include organisms that pose a risk to national security because they:
• can be easily disseminated or transmitted from person to person;
• result in high mortality rates and have the potential for major public health impact;
• might cause public panic and social disruption; and
• require special action for public health preparedness.
Currently, the agents classified as Category A include:
• Anthrax(Bacillus anthracis)
• Botulism(Clostridium botulinumtoxin)
• Plague(Yersinia pestis)
• Smallpox(variola major)
• Tularemia(Francisella tularensis)
• Viral hemorrhagic fevers (filoviruses [e.g., Ebola, Marburg] and arenaviruses [e.g., Lassa, Machupo])
Following is a compilation of information on the Category A agents, including a description of the agent and how it is diagnosed.