Abdominal Pain: Essential Diagnosis and Management in Acute Medicine

Abdominal pain (AP) is by far among the most common complaints in healthcare institutions. Approximately every tenth patient in the acute setting is estimated to present with AP. Although cultural, geographical and sociodemographic variations exist, it is an outstanding complaint in all patient groups, independent of age and gender. Although it can be a manifestation of an intraabdominal pathology itself, a serious systemic or extraabdominal condition can be revealed following a thorough investigation of AP. Therefore, it is vital to evaluate the patient systemically, a focused but elaborate history, and extensive physical examination not confined to the abdomen in order to establish important diagnoses. Inspection, auscultation, percussion, superficial and deep palpation are important elements of the examination methods for the abdomen. Each positive or negative finding on examination should be interpreted cautiously for the individual patient. After history and evaluation narrow the list of differential diagnoses (DD), ancillary investigations including laboratory tests and radiological modalities can be ordered.

Abdominal pain (AP) is a very common complaint that renders it elusive to diagnose in most instances. After history and evaluation narrow the list of differential diagnoses (DD), ancillary investigations including laboratory tests and radiological modalities are ordered. Of note, these adjuncts will only help the clinician who bears a presumptive diagnosis on the mind. Non-invasive, repeatable and cost-efficient options such as ultrasound are preferred initially, although, in most instances, more specific and definitive information warrants advanced imaging techniques including computed tomography and contrast studies. Laboratory work-up needs to be tailored to the individual based on findings on evaluation. ECG, complete blood count and blood chemistry can provide inappreciable clues for specific diagnoses while none will be sufficient per se. Urinalysis and specific cultures including stool studies will expedite recognition of urinary tract infection, amebiasis and other infections when indicated. B-hCG level can prevent unwanted exposure to radiation and drug effects on an unrecognized pregnant woman. Thus, all these adjunctive investigations should be included in the management plan individualized to the patient, based on the history and evaluation findings. 

 International Association for the Study of Pain defines pain as an unpleasant subjective sensation that includes the past experiences of the person with or without tissue damage. Acute pain, generally lasting for hours to days, is the primary complaint at a rate of up to 70-80% at first admission. Headache, myalgia, arthralgia, back pain, local pain induced by minor trauma (such as sprains), thoracoabdominal pain, ear, facial pain, etc. are the most common types of presentations in the acute setting related to pain. Analgesia, on the other hand, is the relief of the perception of pain without causing sedation or any change in vital signs. It is one of the few areas a physician can make a difference to implement more efficient patient care. The subjective and multidimensional nature of the pain experience make pain assessment really challenging. Patients’ evaluation of pain should be the main reference for decision-making to provide analgesics or not. Implementation of dimensional recording of pain in clinical practice include the addition of pain as the “fifth” vital sign to be noted during initial assessment; the use of pain intensity ratings; and posting of a statement on pain management in all patient care area. Our motto should be “pain cannot be treated if it cannot be assessed”. The most important principle is that clinicians should somehow assess their patients' pain levels, independent of the specific method or scale to achieve this. Although all pain-rating scales are valid, reliable and appropriate for use, the VAS has somehow appeared more difficult than the others. Pain reassessment should be guided by pain severity reported by the patients themselves. 

Acute abdominal conditions which frequently necessitate emergency interventions and/or surgery include visceral perforations i.e., gastric and duodenal ulcer, bleeding and rarely, ingested foreign bodies causing tissue damage, e.g., button batteries. However, the differential diagnosis (DD) of patients presenting with acute abdominal pain is much broader than this, including many benign conditions as well. Acute gastroenteritis, acute gastritis and peptic ulcer disease are benign and mostly temporary diseases which may be relieved with simple treatments and follow-up. Gastrointestinal bleeding (with or without esophageal varices) may cause hemorrhagic shock unless expedient management is pursued. Ingested foreign bodies can constitute emergency conditions with tissue damage, especially when lodged in a specific site. The most important thing about button batteries is the prevention of their ingestion. Complications increase in direct proportion to time wasted.

 Acute appendicitis, visceral perforations, diverticulitis (including bleeding and abscesses) acute calculous cholecystitis, acute ischemic bowel, mesenteric artery ischemia and infarction can cause acute abdominal conditions which prompt emergency interventions. Inflammatory bowel diseases (ulcerative colitis and Crohn’s disease) may be followed up in some time without remarkable complications, although at some point with abscesses, hemorrhagic diarrhea and acute abdominal syndromes. However, the differential diagnosis (DD) of patients presenting with acute abdominal pain is much broader than this, including many benign conditions as well. Some etiologies of abdominal pain such as cholangitis strangulated hernias, colonic diverticulitis, perianal/ perirectal abscesses and fistulas may progress and turn into lifethreatening conditions like abdominal sepsis without proper management. 

 Hepatobiliary and pancreatic diseases are among common illnesses which cause major morbidity and mortality in the middle-aged and elderly patients and some specific subpopulations. Some geographic predispositions also exist for some diseases. For example, pain, fever, jaundice, and hepatomegaly can be noted in hydatic cyst disease which may cause allergic reaction and portal hypertension in the Southeast Europe and the Middle East. Of note, hepatobiliary and pancreatic diseases are commonly confused with each other, which may complicate diagnostic and therapeutic processes. A patient with biliary stones may be asymptomatic or suffer from acute or chronic cholecystitis, biliary colic, obstructive jaundice, cholangitis, mucocele, empyema, acute pancreatitis, gallstone ileus, and carcinoma. Cholecystitis and cholangitis are among diseases with high morbidity especially in the elderly and thus need to be ruled out in any patient with abdominal pain evaluated in acute and primary care setting. Some diagnostic clues are extremely helpful, such as Charcot triad which suggest severe cholecystitis (right upper quadrant AP, jaundice and fever) or cholangitis when complicated by altered mental status and hemodynamic instability. Acute pancreatitis refers to acute response to injury of the pancreas is referred to. Chronic pancreatitis, on the contrary, results from permanent damage to the endocrine and exocrine functions of the gland. Ultrasound, computed tomography and magnetic resonance imaging are among invaluable tools in diagnosing these diseases, together with specific laboratory adjuncts such as serum lipase for pancreatitis and bilirubin for obstructive jaundice. Definitive treatment encompasses surgical procedures, mostly in patients with acute abdomen due to gallstones or pancreatic necrosis.

Urinary tract infections (UTIs) and genital tract diseases (GTD) are among the most common infectious diseases with female predominance. On the other hand, acute epididymitis and orchitis are the most common GTDs which cause scrotal pain in adult males. Testicular torsion is a true medical emergency with vascular compromise and mandates immediate intervention to beware of serious complications. Although a majority are self-limiting diseases which can be treated easily, rapid diagnosis and management of certain UTIs and GTDs are a must to prevent grave outcomes. The infections may inflict the lower and/or the upper parts of urinary tract which also determines the severity of the disease. The urinary stone disease generally presents with ureteral colicky pain, blunt flank pain, nausea/vomiting, and hematuria with a male predominance. Most patients are managed easily in the acute setting but some are prone to deterioration with protracted urinary obstruction and resultant renal damage. The utilization of reliable, easy-to-use diagnostic tools with high accuracy is the key to expedient detection, identification and treatment. Ultrasound provides invaluable information in point-of-care diagnosis of most urinary tract diseases in both sexes. Management should be individualized in accord with the patients’ signs and symptoms, general status and outcome estimations.

Chronic abdominal pain is a very common condition all over the world. Although not expected to present emergently, acute exacerbations of chronic pain or the slightest change that worsens the patient's condition (e.g, acute-onset diarrhea, vomiting, or loss of appetite) will trigger admissions to ED. Functional bowel diseases include irritable bowel syndrome (IBS, a.k.a. spastic colon), functional bloating, functional constipation, functional diarrhea, and unspecified functional bowel disorders. Epidemiologic, pathophysiologic and therapeutic studies of functional bowel diseases, employed the Rome Criteria with universal validity. Patients with malignancy can experience different types of cancer-related pain at any time during the disease process, perceived by the organs or systems involved.

 Specific patient groups have inherent characteristics when they suffer from diseases, including those of the digestive system and other causes of abdominal pain. Both diagnostic features and treatment measures differ regarding the patient’s age, sex, previous medical / surgical history, and comorbid diseases. Pregnancy has its unique features in both anatomy and physiology of the woman which result in substantial variation in physical examination finding, radiological and laboratory adjuncts (e.g., the location of the appendix is shifted away from its usual site and computed tomography is hardly ever used to diagnose etiologies of abdominal pain in pregnant women). Likewise, children have many differences in presentation, examination findings, work up and treatment principles, complicating the management process. In addition, the pandemic disease has caused a paradigm shift in the evaluation of almost all diseases, including those with abdominal pain. Many data suggest a close relationship between COVID-19 and the digestive system. Patients with COVID-19 carry a high risk of digestive symptomatology including abdominal pain, nausea and vomiting, diarrhea and others. HIV (+) patients exhibit various GI symptoms such as diarrhea, abdominal pain and proctitis. Healthcare providers should have robust knowledge of various forms of presentations and characteristics of special subgroups with abdominal pain in this regard, to prevent misdiagnoses and treatment errors in those patients. 

Diabetes mellitus (DM), chronic renal failure (CRF), amyloidosis, sickle cell anemia (SCA) and acute intermittent porphyria are among diseases that can be associated with abdominal pain (AP) at some point in the course of the pathological process. Diabetic ketoacidosis (DKA) is a severe life-threatening syndrome characterized by fluid loss, electrolyte changes, hyperosmolarity and acidosis. These pathophysiologic factors can explain AP in patients with DKA. Vomiting and AP can also be initial manifestations of DKA even in euglycemic patients. SCA is one of the most common autosomal recessive diseases classified in hemoglobinopathies. The disease is first recognized by history, then by peripheral smear and hemoglobin electrophoresis, and advanced studies. Splenic sequestration crisis is a severe complication of SCA that prompts emergent treatment, Opiate analgesia and hydration is the main treatment. Patients with chronic renal failure (CRF) and end-stage renal disease are also prone to severe AP due to peritonitis which is triggered by continuous ambulatory peritoneal dialysis in vulnerable patients. Amyloidosis is mostly recognized with typical attacks i.e., febrile episodes, exanthema, AP, myalgias and arthralgias. Acute intermittent porphyria is an autosomal dominant disorder characterized by severe neurovisceral attacks of AP, nausea, vomiting, tachycardia, and hypertension in the absence of signs compatible with peritonitis. Management of mild attacks comprises symptomatic treatment, optimized calorie intake, and fluid replacement to beware dehydration.

Trauma is the most common cause of death in the young population, predominantly males. Abdominal trauma is a leading source of occult bleeding which is the second cause of early-phase deaths following major head injury. Uncontrollable bleeding constitutes the most common cause of preventable deaths especially if the management of shock is delayed. Penetrating trauma leads to significant morbidity and mortality, nonetheless, diagnosed more easily with its remarkable presentation. The main goal in the evaluation of the abdomen in the acute setting is to uncover (i.e., not to overlook) the injuries requiring surgery without delay, rather than to diagnose specific injuries in detail. Signs and symptoms of progressing shock states vary from patient to patient, and sometimes very subtle changes can herald impending doom. The clinician should be proactive in detecting the injuries, using both evaluation findings and bedside ultrasound together with other advanced imaging techniques when necessary, keeping in mind that occult injuries can evolve in time insidiously. Ongoing intraabdominal bleeding is an ominous finding which precedes advanced hemorrhagic shock and needs to be sought for carefully in patients with trauma.

Provision of airway patency, effective breathing and gas exchange and circulatory functions producing adequate perfusion (ABC) are vital elements in all emergent and critical patients. Initial resuscitation should begin with control in a primary survey both in the field and in the hospital in the management of the patients with abdominal pain. In a patient whose respiratory patency is under threat, evaluation and management of the inflammatory process in the abdomen should not be considered before this is resolved. Differential diagnosis and proper management of abdominal pain follow the primary survey, resuscitation and resolution of vital threats. IV fluid therapy and pain management are commenced as prompted by the general condition. Prehospital providers should operate in communication with the command control center in this context. “Tubes or fingers for all orifices” can be accepted as a general approach for the moribund patient to monitor the clinical course. In the hospital, the emergency physician should relieve the pain expediently after evaluating and recording the initial vital signs and findings on systemic examination. Antiemetic therapy and other symptomatic measures should be individualized for the given patient.