Investigation on Gastrointestinal Tract: A Review

Amrish Kumar1*, Vrish Dhwaj Ashwlayan1, Mansi Verma1, Vipin Kumar Garg1, Anurag Chaudhary1, Anjana Sharma1, Sameksha Koul1, Avnesh Kumar Singh1, Anoop Kumar1, Garima Garg1, Shobhit Kumar1, Sachin kumar1, Nishant Kumar1, Satish Kumar Gupta1, Anuj Kumar2, Nitin Sharma3 and Lubhan Singh4 1Department of Pharmaceutical Technology Meerut Institute of Engineering and Technology, N.H. 58, Delhi-Roorkee Highway, Baghpat Bypass Road Crossing, Meerut, Uttar Pradesh, India 2Scientist at Indian Herbs. Specialities Pvt Ltd. Saharanpur, Uttar Pradesh, India 3Institute of Nuclear Medicine and Allied Sciences, Defence Research & Development Organisation, Brig. S.K. Mazumdar Marg, Delhi, 110054 4Kharvel Subharti College of Pharmacy, Subhartipuram, NH-58, Delho-Haridwar Byepass Road, Meerut, Uttar Pradesh Received: August 30, 2018; Published: September 10, 2018 *Corresponding author: (Research Scholar) Amrish Kumar, Department of Pharmaceutical Technology, Meerut institute of engineering and technology, Meerut, N.H. 58, Delhi-Roorkee Highway, Baghpat road crossing, Meerut, Uttar Pradesh 250005, India Lupine Online Journal of Medical Sciences          UPINE PUBLISHERS Open Access L


Patient history
A comprehensive patient history is the cornerstone in the evaluation of a patient with digestive complaints. A clear, detailed, chronologic account of the patient's problems should be ascertained.
This account should include the onset of the problem, the setting in which it developed, and its manifestations. The onset of the problem often provides important information that helps to confirm diagnosis. For example, biliary pain, such as that encountered with symptomatic gallstone disease, typically evolves over minutes and lasts for hours, but pain caused by pancreatitis evolves over hours and lasts for days. The setting is always relevant as it provides clues to the possible origin of the disorder. For example, is the patient an alcoholic (liver disease, esophageal varices, or pancreatitis)? Does the patient have severe atherosclerosis (mesenteric ischemia)? Is the patient immunosuppressed (opportunistic infection)? Also aiding in the differential diagnosis is identification of factors that alleviate or exacerbate the principal symptom. For instance, ingesting a meal often relieves the pain of duodenal ulcer, but worsens that of gastric ulcer. The health care professional should ask questions that address the potential etiologic possibilities, including motility disorders, structural diseases, malignancies, infections, psychosocial factors, dietary factors, and travelassociated diseases [1,2]. Questions concerning past medical and family history detailing illnesses, surgeries, injuries, and habits are extremely valuable. Because many drugs have been reported to cause GI injury, a patient's medication history is also vital. Table 1 revealed, those drugs which cause gastrointestinal injury.

Physical Examination
Because the organ systems of the body interact and may provide important data needed for diagnosis, it is necessary to perform a thorough physical examination.3 A global evaluation of the patient should be performed with notable attention to appearances and vital signs because they may suggest clues to the patient's overall condition and stability. Careful examination of the abdomen is also an essential part of the work-up. Examination of the abdomen is classically approached by inspection, auscultation, percussion, and palpation. Inspection of the abdomen may reveal scars, hernias, bulges, or peristalsis. Auscultation is mainly focused on analysis of bowel sounds and identification of bruits. Percussion of the abdomen allows for detection of tympany, measurement of visceral organs, and detection of ascites. Palpation may allow the clinician to identify tenderness, rigidity, masses, and hernias. A digital rectal examination is used to detect masses, tenderness, and assess muscle tone. Stool on the examiner's glove obtained during rectal examination is often subjected to hemoccult testing for the indirect detection of occult blood [3].

Laboratory and Microbiologic Tests
Laboratory and microbiologic tests may be used to (a) assess organ function, (b) screen for certain GI disorders, and (c) evaluate the effectiveness of therapy. To achieve an accurate diagnosis and provide the best care, it is important to assess the patient's fluid and electrolyte status, nutritional status, and abdominal organ function. A serum chemistry panel provides clinicians with valuable information. For example, serum creatinine (SCr) and blood urea nitrogen (BUN) are often used as a measure of hydration status, as well as serving as indicators for renal function. Elevations in SCr and BUN may be indicative of renal dysfunction or dehydration, and bleeding from the GI tract may lead to elevations in BUN. Albumin levels can be used to assess the patient's nutritional and hydration status and provide information concerning hepatic and renal function. Specifically, low albumin may be indicative of malnutrition, hepatic dysfunction, nephrotic syndromes, or protein-losing enteropathies such as Crohn's disease and ulcerative colitis. Serum measurements of sodium, chloride, and potassium are useful to determine electrolyte abnormalities associated with diarrheal illnesses. A complete blood count (CBC) helps to provide information concerning infection, malignancy, bone marrow suppression, anemia, and blood loss [4] Specific Helicobacter pylori is a significant factor associated with peptic ulcer disease and gastritis, identification of this organism is critical in evaluating patients experiencing dyspepsia

Diagnosis
The patient history, physical examination, and routine laboratory tests are extremely useful in establishing a diagnosis, but frequently a more specific study is required to confirm or

Radiology
Radiologic procedures rely on the differential absorption of radiation of adjacent tissues to highlight anatomy and pathology.
Radiologic procedures important in evaluating the GI tract include plain radiography, upper GI series, lower GI series, and enteroclysis [6,7].

Plain Radiography of The GI System
Radiographic evaluation of the GI tract often starts with plain films of the abdomen, which are straightforward, uncontrasted radiographs. Specific abdominal structures that may be identified

Contrast Agents
Many different types of contrast agents are available. Two types of contrast agents commonly used to enhance visualization of the GI tract are barium sulfate and aqueous iodinated compounds. Barium sulfate is the contrast agent of choice for studying the esophagus, stomach, and intestine, except in special clinical situations.7 Barium sulfate is not generally absorbed, and constipation is the most frequent adverse effect reported with its use. Two widely used iodinated contrast agents for visualizing the GI tract are diatrizoate, meglumine and diatrizoate sodium. Unlike barium, these agents are relatively nontoxic if inadvertently introduced into the peritoneal cavity; therefore the main indication for use of iodinated agents in GI radiography is for suspected bowel perforation. Because iodinated contrast agents are hyperosmolar, they possess the potential to cause severe diarrhea, dehydration, and electrolyte imbalances. Nephrotoxicity associated with iodinated contrast agents may occur and is generally self-limited [8]. Allergies and hypersensitivity reactions such as rashes associated with contrast agents are possible and should be monitored and treated Accordingly.

Upper GI Series
The upper GI series refers to the radiographic visualization of the esophagus, stomach, and small intestine. Patient preparation for an upper GI usually consists of instructing patients to refrain from eating or drinking 8 to 12 hours prior to testing, thereby allowing the upper GI tract to empty. A contrast agent such as barium sulfate is administered to the patient at the beginning of the study. The observed swallowing of the contrast agent permits visualization and monitoring of esophageal structural and motor functions. This phase of the procedure is most often referred to as a barium swallow. As the contrast medium flows into the stomach and small intestine, several regional radiographic films are taken in order to inspect these areas. This tracking of contrast agents through the small intestine is referred to as the small bowel follow-

Lower GI Series
The lower GI series is used to examine the colon and rectum.
Patients complaining of lower abdominal pain, constipation, or diarrhea are often referred for a lower GI series. Before the procedure the colon is prepared by instructing the patient to refrain from eating or drinking 8 to 12 hours before the procedure, and by administering bowel cleansing agents such as bisacodyl, magnesium citrate, magnesium hydroxide, or polyethylene glycolelectrolyte solution. During a lower GI series, a barium sulfate enema is given to contrast the terminal large intestine and rectum.
The lower GI series is useful to detect and evaluate enterocolitis, obstructions, volvulus, and mucosal and structural lesions. The lower GI series is commonly used to diagnose Crohn's disease, ulcerative colitis, colon cancers, and diverticulitis. 58 bowel follow-through [9]. Methylcellulose is used to enhance the detail of the small intestine in enteroclysis, thereby improving visualization. Patient preparation for this procedure involves instructing patients to refrain from eating or drinking 8 to 12 hours before testing and administering bowel-cleansing agents. The most frequent disorder evaluated by enteroclysis is obscure GI bleeding.

Radionuclide Imaging
Radionuclide imaging involves intravenous injections of a radiopharmaceutical imaging agent and the use of a computerized detection camera to gather images. Although the choice of a radiopharmaceutical agent depends on the specific organ or function being studied, the most commonly used agent is technetium (Tc-99m) tagged to a carrier molecule. Radiographic imaging is useful to visualize the liver and spleen (liver-spleen scan), bile ducts, gallbladder (HIDA [hepatoiminodiacetic acid] scan), and gut (bleeding scan). Cysts, abscesses, tumors, and obstructions are detected and displayed as areas of differential uptake of radioactivity (Figure 4). Radionuclide bleeding scans may detect hemorrhages and may assist in localization.

Computed tomography
Computed tomography (CT) or computed axial tomography (CAT) scans provide detailed images of the GI system in which transverse planes of tissue are swept by a radiographic beam and a computer analysis of the variance in absorption produces a precise reconstructed image of that area. Contrast agents may be added in a CT procedure to illuminate specific hollow structures and vascularity of the GI tract. The abdominal CT displays organs from the diaphragm down to the pelvic brim, and is especially valuable for detecting GI diseases of the liver, pancreas, spleen, and colon. Patient preparation for CT includes refraining from eating or drinking for a minimum of 4 hours before the test. The remarkable detail that CT offers in imaging organs and tissues adds to its popularity for evaluation of the GI system. CT is useful in the identification of liver cancer, pancreatitis, pancreatic cancer, intraabdominal abscesses, and cysts ( Figure 5). Unlike ultrasonography, patient body size or the presence of gas does not limit the quality of imaging with CT.

Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) places the patient in close proximity to a high-strength magnetic field through which pulses of radiofrequency radiation are projected, thereby exciting the nuclei of hydrogen, phosphorus, oxygen, and other elements.
The radiofrequency signals are manipulated and recorded by a computer, and a two-dimensional image representing a section of the patient is produced. MRI has greater sensitivity to identify liver tumors than ultrasonography, CT, or radionuclide imaging. Although currently MRI is not as popular as other imaging techniques because of limited availability, expense, and problems associated with the use of powerful magnetic fields, its use is predicted to increase in the future.

Endoscopy
Refinement in optical engineering and fiber optics has

Sigmoidoscopy
Sigmoidoscopy is used to evaluate the sigmoid colon and rectum (Figure 7). Flexible sigmoidoscopy has virtually replaced rigid sigmoidoscopy because of increased patient comfort and superior performance. The major indication for this examination is to evaluate symptoms related to the colon or rectum, and to conduct screening of asymptomatic patients for colon polyps or

Endoscopic Retrograde Cholangiopancreatography (ERCP)
ERCP is an important procedure that is used to evaluate and treat diseases of the biliary tree and pancreas. By injecting contrast agents through a catheter swallowed and acts as an endoscope.
While the video capsule travels naturally through the digestive tract, images are transmitted to a recording device. Patients return the recording device to the practitioner so that the images can be downloaded to a computer and evaluated. Eventually, the camera is naturally excreted and not retrieved [14].

Conclusion
Evaluation of the GI tract begins with a careful history and comprehensive physical examination. It then proceeds in a deliberate and thoughtful manner to establish the correct diagnosis and appropriate management. Laboratory and microbiologic tests, radiography, ultrasonography, computed tomography, radionuclide scanning, magnetic resonance imaging, arteriography, endoscopy, esophageal manometry, pH monitoring, endoscopic ultrasonography, and laparoscopy have definite roles in diagnosing and evaluating GI disorders.