Acute Abdomen – Overview
Abdomen pain is a condition that needs to be treated and attended to right away. An infection, inflammation, vascular blockage, or obstruction are all potential causes of acute abdomen. Usually, the patient will experience an abrupt onset of stomach pain along with accompanying nausea or vomiting. With an emphasis on the inter-professional team’s role in patient care, this exercise discusses assessing and managing patients with acute abdomen.
An acute abdomen necessitates prompt diagnosis and treatment. Acute abdominal pain may result from an infection, inflammation, vascular blockage, or occlusion. The patient frequently complains of rapid-onset stomach pain and any accompanying nausea or vomiting. Most people who have an acute abdomen seem sick.
A comprehensive history and physical exam should be performed on a patient who has an acute abdomen.  Since it could indicate a localized process, the location of the discomfort is crucial. However, patients with free air may experience diffuse abdomen pain as a symptom. Auscultation may indicate peritonitis when bowel sounds are lacking, and palpation may show rebound discomfort and guard. Bowel ischemia,
appendicitis, perforated peptic ulcer, acute pancreatitis, ruptured sigmoid diverticulum, ovarian torsion, volvulus, ruptured aortic aneurysm, lacerated spleen or liver, and ischemic bowel are among the conditions that can cause an acute abdomen. [2,3,4]
There are no specific figures, however, between 7% and 10% of visits to emergency rooms are for abdominal pain. Abdominal discomfort was the primary complaint for 11.5% of patients who attended the emergency room in 2008, according to the Centers for Disease Control and Prevention (CDC), which used data from the 1999–2008 National Hospital Ambulatory Medical Care Survey. Patients with abdominal pain are diagnosed with non-specific abdominal pain in about one-third of cases. Another 30% suffer from severe renal colic. 
The scope of this review does not include the pathophysiology of each disease condition. Infection (appendicitis, diverticulitis) and blockage are some of the causes (appendicitis, cholecystitis). Malrotation of the intestine is one example of anatomic anomalies. Some diseases are correlated with age; older individuals are more prone to present with vascular crises, diverticulitis, and cholecystitis.
The dual innervation of the abdomen, both visceral and somatic, is largely responsible for the classic presentations of appendicitis, cholecystitis, pancreatitis, and diverticulitis. The autonomic nervous system includes visceral nerves, which innervate the viscera. These nerves are susceptible to colic-related smooth muscle contractions, ischemia, inflammation, and mechanical distension. The pain is frequently dull, deep, poorly localized, and midline. Epigastric pain originates from embryonic foregut organs like the gallbladder, pancreas, liver, and stomach. The hindgut, large bowel, and rectum origin of pain are located in the lower abdomen. The midgut-originated pain, small bowel, and appendix are located in the periumbilical region. The parietal peritoneum receives feeling through somatic sensory nerves. Somatic pain is more acute and more precisely focused. Somatic discomfort may indicate peritoneal inflammation. An illustration of this is pain over McBurney’s point caused by the parietal peritoneum being irritated by an inflamed or burst appendix. Visceral pain can be perceived as referred pain from a somatic distribution because spinal cord segments shared by visceral and somatic afferent nerve fibers exist. This explains the right scapula-radiating cholecystitis pain. 
Acute appendicitis, acute cholecystitis, hollow organ perforation, mechanical intestinal blockage, an intra-abdominal abscess that could not be treated with needles, ischemic bowel illness, pancreatitis, diverticulitis, inflammatory bowel diseases like Crohn’s disease or malignancy and gluten allergy or intolerance are common causes of abdominal disease. Urological causes involving ureteral colic and pyelonephritis, perinephric abscess, and urethral stones can also present as acute abdominal pain. Moreover, there are gynecological and obstetric issues, including ruptured ectopic pregnancy, ovarian torsion, and ovarian cysts. Furthermore, in vascular settings, ruptured abdominal aortic aneurysm and mesenteric ischemia are common causes of acute abdominal pain. The findings of a CT-based study showed that 90.7% of patients, which included ischemic bowel disease (55.6%), acute appendicitis (89.3%), intra-abdominal abscess (100%), acute cholecystitis (89.7%), hollow organ perforation (97.3%), bowel obstruction (100%) require surgical management. 
Common Reasons for Acute Abdomen
Acute appendicitis is primarily diagnosed clinically, and many patients have a typical medical history and physical examination results. Although the exact origin of acute appendicitis is unknown, luminal blockage, nutritional variables, and hereditary factors are all thought to play a part. The preferred course of treatment is an appendectomy, which is increasingly carried out laparoscopically. This page examines the symptoms, research, care, and side effects of acute appendicitis and appendicectomy. 
Signs and Symptoms
An initial widespread or periumbilical abdominal pain that centers in the right lower quadrant are how appendicitis typically manifests. Initial stimulation of the visceral afferent nerve fibers at T8 through T10 results in nebulous concentrated pain. The right lower quadrant of the body is where the pain is most intense as the appendix becomes more inflamed and the nearby parietal peritoneum is irritated. Any of the following symptoms may or may not be present in addition to pain, Anorexia, Nausea/vomiting, fever affecting 40% of patients, diarrhea, malaise, and urgency or regularity of urination. 
Uncommon Presentation: Patients occasionally show unusual characteristics. The agony in these patients may have jolted them out of their slumber. The individuals may also experience pain when coughing or walking.
The psoas sign is pain with passive extension of the right leg with the patient in the left lateral decubitus posture. An infected retrocecal appendix might irritate the psoas major muscle, which is stretched during this exercise. In order to shorten the psoas major muscle and reduce pain, patients frequently flex their hips. 
Physical Examination: In early appendicitis, specifically, findings are frequently inconspicuous. Peritoneal inflammation symptoms appear when the inflammation worsens. Symptoms include:
- Tenderness over McBurney’s point, which is 1.5 to 2 inches from the anterior superior iliac spine (ASIS) to the umbilicus in the right lower quadrant during guarding and rebounding.
- The Rovsing sign (right lower quadrant pain elicited by palpation of the left lower quadrant).
- The Dunphy sign (increased abdominal pain with coughing).
The psoas sign, which is pain on external rotation or passive extension of the right hip and suggests appendicitis of the retrocecum, and the obturator sign, which is pain on internal rotation of the right hip and suggests appendicitis of the pelvis, are uncommon additional related findings. Although the symptoms might manifest over a variety of time periods, they commonly proceed from early appendicitis at 12 to 24 hours to rupture at more than 48 hours. Seventy-five percent of people show up within 24 hours of the start of their symptoms. The likelihood of rupture varies, but it is approximately 2% at 36 hours and rises by approximately 5% every 12 hours after that.
In order to speed up the diagnosis of acute appendicitis, a number of practical scores have been developed. These scores are primarily based on the history and physical examination and are supplemented by laboratory testing, imaging techniques, and abdominal ultrasound. Accordingly, Alvarado criteria have been routinely used since 1986 to evaluate individuals with suspicious signs and symptoms that could be indicative of acute appendicitis. The right iliac fossa soreness and leukocytosis receive the highest Alvarado criteria scores, while the other anticipated symptoms—migratory right iliac fossa pain, nausea and/or vomiting, and anorexia—all receive one point. Additionally, a score of one would be assigned if positive results were found for the remaining physical examination indicators, such as fever and rebound soreness in the right iliac fossa. 
- Elevated white blood cells count, however, up to one-third of patients present with normal leukocytes.
- Elevation of C-Reactive Protein (CRP). A combination of normal results of CRP and WBCs have up to 98% probability for the exclusion of acute appendicitis. Moreover, the CRP and WBCs values have a positive predive value of whether the appendix is inflamed and complicated or not.
- Urine analysis may show ketone bodies in the urine. 
Imaging and Scan
Appendicitis is typically diagnosed clinically. However, a variety of imaging techniques, such as an abdominal CT scan, ultrasonography, and MRI, are employed to move forward with the diagnostic procedures. An abdominal CT scan can diagnose appendicitis with higher than 95% accuracy. Appendiceal wall thickness greater than 2 mm, peri-appendiceal fat stranding, appendiceal wall enhancement, and the presence of an appendicolith (seen in roughly 25% of patients) are all CT criteria for appendicitis. 
In the emergency room, the patient must be maintained Nil per Os (NPO), so the patient gets hydrated intravenously with crystalloid and is treated with intravenous antibiotics. The surgeon in charge is responsible for obtaining the patient consent. An appendectomy is the gold-standard treatment for acute appendicitis. 
The term “acute cholecystitis” describes gallbladder inflammation. Blockage of the cystic duct is the pathophysiologic mechanism of acute cholecystitis. Surgery is the preferred treatment for cholecystitis, but less invasive measures can be taken if necessary. This disorder can be categorized as acute or chronic and can be present with or without gallstones. Although it can occur in both men and women, it might be more common in some communities. Additionally, it could exhibit a few well-known symptoms and indicators. Additionally, various conditions like peptic ulcer disease, irritable bowel syndrome, and heart disease might be mistaken for acute cholecystitis. Acute and chronic pancreatitis can both seem like gallbladder disease. [15,16]
Physical examination and patient presentation
Chronic cholecystitis cases are characterized by right upper quadrant abdominal pain that worsens over time, along with bloating, food intolerances (particularly to oily and spicy foods), increased gas, nausea, and vomiting. There may also be shoulder or midback pain. Years may pass before this discomfort is diagnosed. The symptoms of acute cholecystitis are similar but more severe. Symptoms are frequently misdiagnosed as heart problems. The Murphy sign, which manifests as right upper abdomen pain with deep palpation, is typically a hallmark symptom of this condition. Frequently, a particular eating incident causes an acute attack, e.g., ” I ate a burger and fried potato last night.”
- White Blood cell count elevated.
- Liver Function Tests may be elevated.
- High bilirubin above level 2 detects the presence of common bile duct stones.
- Amylase and lipase must be evaluated to rule out pancreatitis.
Keep this in mind! In the case of chronic cholecystitis, these findings might be normal, also, in some acute patients, the lab values represent normal results.
Imaging and CT scan
Gallbladder ultrasonography (US) is the most reliable test in the primary evaluation of gallbladder and cholecystitis. However, in the emergency department, a CT scan is required. In acute cholecystitis, a hepatobiliary (HIDA) scan is recommended. This scan can identify cystic duct obstruction or gallbladder function. When there are no gallstones, the addition of cholecystokinin (CCK) may be used to diagnose acalculous cholecystitis. An ejection fraction of less than 35% suggests this.
Laparoscopic cholecystectomy is the most suitable treatment for cholecystitis. Low rates of morbidity and mortality are present, and recovery times are short. In situations where the patient is not a good candidate for laparoscopic surgery, this can alternatively be done using an open approach. A temporary percutaneous gallbladder draining procedure may be used to treat patients who are critically unwell and are not candidates for surgery. Low-fat and low-spice diets may be used to treat people with milder instances of chronic cholecystitis who are not regarded as good surgical candidates. This treatment has a range of outcomes. Ursodiol has been used medically to treat gallstones with varying degrees of success. 
Other Differential Diagnosis is as follows
- Abdominal aortic aneurysm (AAA) defines a condition in which the abdominal aorta weakens and dilates, most frequently affecting the infrarenal portion. Since AAA rarely presents with symptoms unless complications do, it is commonly discovered through imaging procedures used to investigate unrelated abdominal complaints or through ultrasound screening programs for AAA that are implemented in some developed nations. Most patients are asymptomatic, but some signs and symptoms like back or flank pain, abdominal palpitation without tenderness, pulsatile abdominal mass, GI, and renal manifestations. Sings of shock present ruptured AAA. 
- Acute diverticulitis is an inflammation caused by a diverticulum’s micro-perforation. A sac-like protrusion of the colon wall is referred to as a diverticulum. 10% to 25% of patients with diverticulosis may also have diverticulitis. Diverticulitis diagnosis can be straightforward or difficult. Diverticulitis that isn’t complex doesn’t have any related complications. Abscess, fistula, bowel blockage, or outright perforation are all symptoms of complicated diverticulitis. Diverticulitis has traditionally been understood and treated as an essentially surgical disease; however, even at its most acute stage, this condition is currently managed medically. Abdominal pain with constipation (50%) or diarrhea (35%), abdominal tenderness, nausea and vomiting, and hypoactive bowel sound are signs and symptoms of diverticulitis as well as the part of inflamed bowel contact with the bladder, which is usually called sympathetic cystitis consisting of urinary urgency, may take place. 
- Acute Intestinal ischemia occurs when there is at least a 75% reduction in the blood supply to the bowels and can be classified into mesenteric ischemia, which affects the small intestine, and colonic ischemia, which affects the large intestine. Bowel ischemia is associated with a high mortality rate when being discovered late. 
- Acute peptic ulcer (APU) is a discontinuity in the GI tract’s inner lining brought on by excessive pepsin and gastric acid release. The common causes of APU are H. pylori infection and medications, especially NSAIDs. Nausea and vomiting, abdominal fullness, epigastric pain, melena, weight gain or loss, and hematemesis are the symptoms of APU.
- Acute pancreatitis is an inflammation of the pancreas. The patient commonly presents complaining of severe epigastric pain with nausea and anorexia. Smoking and alcohol intake are strong risk factors for pancreatitis. 
- Acute peritonitis is a life-threatening surgical emergency characterized by inflammation of the peritoneum. 
- Acute pyelonephritis is a bacterial infection. Pyelonephritis is the most common kidney disorder and results due to an coli bacterial infection. Signs and symptoms are fever, flank pain, and nausea or vomiting. 
- Acute ureteric colic is a frequent emergency medical issue that results in obstruction of the urinary tract due to calculi formation. Pain is the most common patient presentation in addition to fever, chills, nausea, and vomiting, fool-smelling urine, and urinary tract infection. 
- Adrenal crisis. is a life-threatening condition involving adrenal and corticosteroid deficiency associated with a high mortality rate. Adrenal crisis is precipitated by internal or external processes. In some cases, its cause is unknown. However, the gastrointestinal illness seems to be the major precipitating factor for the adrenal crisis. Other causes may be due to infections, emotional stress, strenuous activity, dehydration, alcoholic intoxication, and thyrotoxicosis. 
- Biliary colic is an acute pain due to an obstructive stone in the biliary tree (common bile duct or cystic duct). Classical manifestations are fatigue, weight loss, and weakness with decreased appetite. 
- Bowel volvulus is a twisting of the intestine around itself, causing intestinal obstruction. Constipation, abdominal distention, vomiting, and bloody stool are common clinical presentations. 
- Carcinoid syndrome is most frequently brought on by midgut neuroendocrine tumors that spread to the liver. Rarely, foregut and hindgut neuroendocrine tumors can also lead to carcinoid syndrome. About 70% of neuroendocrine tumors develop in the GI system, with the respiratory tract accounting for the remaining 25%. Rarely, neuroendocrine tumors can develop in other organs such as kidneys, testicles, or ovaries. 
- Ectopic pregnancy with tubal rupture. The term “ectopic pregnancy” refers to conceptions that develop outside of the uterine endometrium. The fallopian tube (95.5%) is the most typical implantation site, followed by the ovary (3.2%) and the abdominal (1.3%) sites. The sites of tubal implantation are the ampulla (73.3%), isthmus (12.5%), fimbrial (11.6%), and interstitial (2.6%) in decreasing order of frequency.  A case study report has shown that nausea, vomiting, and shortness of breath with substernal and pleuritic chest pain (rare) are clinical manifestations of the ruptured tube in ectopic pregnancy.
- Familial Mediterranean fever (FMF). The autoinflammatory genetic disorder Reimann syndrome, also known as “periodic peritonitis,” “familial paroxysmal polyserositis,” “Siegal-Cattan-Mamou disease,” “Wolff periodic disease,” or “periodic disease,” is characterized by recurrent fevers and severe pain from inflammation of the abdomen, lungs, and joints. 
- is intra-abdominal bleeding caused by traumatic or iatrogenic reasons. Distended abdomen, clammy, cold and pale skin, sweating, tachycardia, rapid breathing, and confusion are signs and symptoms of intraperitoneal hemorrhage.
- Ruptured spleen. A hematopoietic organ that is encapsulated and is in the left upper quadrant of the peritoneal cavity is friable when traumatized, especially if its diameter is augmented. Splenic rupture may be due to traumatic or non-traumatic reasons, but trauma is the most common cause that leads to splenic rupture. Hypovolemic shock manifestations such as hypotension, reflex tachycardia, and pallor represent the syndrome of a ruptured spleen. [33, 34]
- Sickle cell anemia
Acute abdominal pain is typically a sign of a surgical issue, and in the past, the patient was brought right to the operating room when this happened. Unfortunately, some medical conditions can also cause severe abdominal pain and the need for medical treatment. Some of these illnesses include acute pancreatitis, sickle cell anemia, diabetic ketoacidosis, adrenal crisis, and pyelonephritis. Today, it is common practice to use ultrasound and/or CT scans to identify the underlying etiology of the acute abdomen so that the surgeon is prepared for surgical management if necessary. Additionally, it prevents needless surgery in patients with acute abdominal conditions. Every person who has an acute abdomen has to see a surgeon. Imaging tests may be obtained if the patient is stable. [35,36]
Sepsis, fistula, and necrosis of the intestine are the most common consequences of acute abdominal pain. Therefore, consultation with an infectious disease specialist, Obstetrician, Gynecologist, Urologist, Vascular surgeon, General surgeon, and Radiologist is crucial and important for a precise and concise diagnosis and management.
General Considerations for Treatment
Tachycardia and hypotension indicate sepsis, hypovolemia, or blood loss and call for swift, vigorous fluid resuscitation with suitable large-bore IV access. When sepsis, peritoneal soiling, or infection are possibilities, broad-spectrum antibiotics that cover gram-negative enteric pathogens should be given promptly. Patients who are ill need constant vital sign monitoring and resuscitation. Opioids are a standard of care for providing adequate pain relief. Anti-emetics are also crucial to utilize. Urgent consultation with a surgeon should be made if it is believed that there is a surgical emergency as a result of the presentation or physical findings. Before performing possibly time-consuming diagnostics, the surgeon must be contacted.
In conclusion, the acute abdomen is made up of several intrabdominal processes that demand quick action for both diagnosis and treatment. The symptoms of an acute abdomen might be overt or covert, but they must always be detected. Resuscitative therapy must be administered together with prompt, suitable testing. Early consultation with a specialist is also required if the problem might perhaps require surgery.
The author does not report any conflict of interest.
This information is for educational purposes and is not intended to treat disease or supplant medical professional judgment. Physicians should follow local policy regarding the diagnosis and management of medical conditions.
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