Acute Abdomen

Erin Burrell ACNP-BCVanderbilt University Medical Center

Surgical Intensive Care Unit

Objectives

• Define an acute abdomen

• Obtain adequate history and physical

• Order the appropriate labs and imaging

• Recognize appropriate differential diagnoses

• Recognize surgical emergencies

“Signs and symptoms of abdominal pain or

tenderness, a clinical presentation which

often requires surgical intervention”

Acute abdomen = Peritonitis

Definition of the Acute Abdomen

Definition of Pain• Visceral pain – autonomic nerve fibers responding to sensations of

distention and muscular contraction – Typically vague, dull, and nauseating– Poorly localized and tends to be referred to areas corresponding to the embryonic

origin of the affected structure– Upper abdominal pain - stomach, duodenum, liver, and pancreas– Periumbilical pain - small bowel, proximal colon, and appendix– Lower abdominal pain - distal colon and GU tract

• Somatic pain – comes from parietal peritoneum

– Sharp and well localized

• Referred pain - perceived pain distant from its source and results from convergence of nerve fibers at the spinal cord• Peritonitis - inflammation of the peritoneal cavity

History

• Onset and location of pain • Associated symptoms:– Nausea & Vomiting (include character of vomit)– GERD – Constipation/Diarrhea – Obstipation (failure to pass stools or gas)– Hematochezia/Melena – Hematuria– Weight Loss

Past Medical History• Previous illnesses or diagnoses? • Medication Usage?– Narcotics – NSAIDS – Steroids – Immunosuppressants– Anticoagulants– EtOH abuse– Recreational drugs

Physical Exam• General appearance of the patient• Abdominal examination

– Inspection• Note any surgical scars

– Auscultation– Palpation

• Begin gently, away from the area of greatest pain• Note areas of particular tenderness as well as guarding, rigidity, rebound tenderness, and

masses• Surgical scars examined for hernia

– Percussion– Make sure to include the groin in your exam

• Rectal and pelvic examination should be performed– Lower abdominal pain only – search for evidence of colonic impaction, tumor, GIB, retrocecal appendicitis, fallopian tube

infection, ovarian mass

**Remember- Steroids and morbid obesity make physical exam more unreliable!**

Labs

• CBC• BMP• ABG, Lactate, Ionized calcium• Blood cultures x2, UA/Urine culture, Sputum

cultures• LFT’s • Amylase/Lipase• Pregnancy test

ImagingCXR/KUB

Abdominal Ultrasound

CT Scan

• Rarely diagnostic• May be helpful in identifying air or stool in rectum• CXR can identify subdiaphragmatic air

• Wide availability in the ED• Lower cost• Absence of radiation exposure • Useful in viewing the liver and gallbladder• Excellent for detecting pelvic processes in women (ectopic pregnancy)

• Study of choice – IV and PO contrast preferred • Enteral contrast is required to distinguish bowel from other gas or fluid-filled

structures like abscesses • IV contrast only if unable to tolerate PO contrast

Causes of the Acute Abdomen

ObstructionIschemic

PerforatedInfectious

Hemorrhagic

What is wrong with this picture?

Obstruction• Occurs when normal flow of intraluminal contents is

interrupted (functional vs mechanical)• Risk factors: Prior abdominal or pelvic surgery, abdominal

wall or groin hernia, neoplasm, prior irradiation, foreign body ingestion – Adhesions, incarcerated hernias and malignancy cause 75% of cases

• Four types of obstruction:– Small bowel obstruction– Large bowel obstruction– Volvulus– Intussusception

Small Bowel Obstruction• S&S: – Colicky, crampy, intermittent abdominal pain– N&V– Obstipation with complete obstruction– Decreased bowel function but still present with partial

obstruction– Severe, steady pain suggests strangulation

• Physical exam:– Hyperactive, high-pitched bowel sounds early– Hypoactive bowel sounds late– Dilated loops of bowel may be palpable

Small Bowel Obstruction• Imaging:

– Flat/upright KUB – multiple air fluid levels with distal evacuation of colon and rectum

– UGI with small bowel followthrough – CT scan – can identifity transition point

• Treatment:– NGT to LIWS– Hydration with IVF– Electrolyte repletion– Surgical intervention

Colonic Obstruction• S&S:– Similar symptoms as an SBO – more urgent intervention

needed– Increasing constipation which leads to obstipation and

ABD distention– Vomiting not common (only 50%)

• Physical Exam:– Typically shows a distended abdomen with loud

borborygmi – No tenderness– Empty rectum

Colonic Obstruction

• Imaging:– “Comma sign” or “kidney bean” appearance– Mechanical obstruction has “cutoff” sign at level of obstruction with

air in the proximal colon and small bowel and a gasless distal colon. – An acute increase of cecal diameter >10cm, perforation of the colon

may be imminent

• Treatment:– NGT to LIWS– Hydration with IVF– Replete electrolytes– Surgical intervention

Volvulus• Refers to a twisting of a segment of the intestinal

tract around a fixed point – Leads to ischemia and necrosis of the bowel

• Most common sites of volvulus are the cecum and sigmoid colon – Small bowel volvulus is less common in adults– Sigmoid volvulus are common in bedridden, institutionalized patients

• S&S:– Abrupt onset in continuous pain with superimposed colicky pain

during peristalsis– N&V (1-3 days after onset of pain)– Abdominal distention– Constipation

Volvulus

• ABD Exam:– Tympany upon auscultation– Distended, tender abdomen

• Imaging:– CT scan – “whirl pattern” or “bird beak” appearance, absence of rectal

gas, split wall sign and two crossing sigmoid transition points projecting from a single location ; may see bowel necrosis

– KUB – U-shaped distended sigmoid colon extending from pelvis to RUQ as high as diapraghm• Points LLQ for sigmoid and RLQ for cecal

Sigmoid volvulus

Volvulus

Treatment:– Sigmoid volvulus• Can attempt endoscopy first – successful in 75-95% of

patients• Surgery if endoscopy is unsuccessful• 40-50% will not have recurrence

– Cecal volvulus • Resection and anastomosis of involved segment

Intussusception

• Intenstines slide or “telescope” into an adjacent part of the intestine– Cause of only 1-5% of bowel obstructions

• S&S:– Intermittent abdominal pain– N&V– Melena– Constipation

Intussusception• ABD Exam:

– Distended, tender abdomen

• Imaging:– KUB – may show distal small bowel obstruction– CT scan is diagnostic – distended loop of bowel is thickened

because it represents two layers– “Target sign”

• Treatment:– Surgical resection– NGT to LIWS– IV hydration– ABX if perforated

“Pseudo-obstruction”Ogilvie syndrome

• S&S of bowel obstruction present without mechanical cause

• Associated with:– Bedridden patients– Electrolyte abnormalities– Opiate administration– Critical illness– Spinal cord injury– Recent surgery– Trauma– Infection

Ogilvie’s syndrome• Imaging:

– KUB – dilated colon often from cecum to splenic flexure and occasionally to the rectum

– CT scan – confirms diagnosis and excludes mechanical obstruction

• Treatment:– Normalize electrolytes– Minimize narcotics– NGT to LIWS– Anti-cholinergic agents (Neostigmine or Methylnaltrexone)– Colonic decompression - scope

Ischemic Acute Abdomen

• Ischemia due to a reduction in blood flow due to acute arterial occlusion, venous thrombosis, or hypoperfusion– Risk factors: abdominal surgery, cardiac bypass surgery, MI, atrial

fibrillation, hemodialysis

• Two main types:1. Colonic ischemia

• Most common form of intestinal ischemia• Most often affects patients 60yo and older • Approximately 15 percent of patients with colonic ischemia develop

gangrene

2. Mesenteric ischemia• Mortality is 70%

Ischemic Acute Abdomen• ABD exam:

Acute mesenteric ischemia – rapid onset periumbilical pain out of proportion to exam, N&VIschemic colitis – rapid onset of mild abdominal pain over affected bowel, typically the left side, hematochezia within 24H of pain

**Septic shock may be the presenting symptom if perforation or infarction has occurred **

• Imaging:–CT scan of Abdomen/pelvis with IV contrast – thickening of the bowel wall, air in portal vein, or focal bowel dilitation however CT is not always accurate

Mesenteric Ischemia• Treatment

– IVF resuscitation– Correction of electrolyte

abnormalities– Cultures– Empiric abdominal sepsis

antibiotic coverage– Anticoagulate if emboliccause for ischemia– Immediate surgical

intervention for peritoneal signs and diagnostic findings of intestinal perforation or infarction

**Strangulating obstruction can progress to infarction and gangrene in as little as SIX

hours.**

Perforated Acute Abdomen• Associated with h/o colonic obstruction, PUD, UC,

Crohn’s dx, diverticulitis, and trauma • S&S

– N&V– Quiet to absent bowel sounds– Anorexia

• ABD exam: depends on location of perforation– Esophageal, gastric, duodenal perf – abrupt onset of severe

generalized pain and peritonitis– Other GI site perf – usually gradually developing, localized pain that

has worsened

Perforated Acute Abdomen

• Imaging:– KUB – subdiaphragmatic air– Abdominal CT is highly sensitive showing free

intraperitoneal air not contained within any visible bowel wall

Perforated Acute Abdomen

• Treatment: – Fluid resuscitation– Broad spectrum ABX to cover intraabdominal flora– Immediate surgical intervention

Infectious Acute Abdomen• S&S:– N&V, anorexia– Location and onset of pain help determine cause

of infectious process

• Causes: appendicitis, pancreatitis, intraabdominal abscesses, diverticulitis, cholecystitis, SBP, c. difficile colitis

Infectious Acute Abdomen• ABD Exam - depends on cause of infectious process

– Appendicitis – periumbilical or epigastric pain that shifts to RLQ – increased pain with passive extension of the right hip

– Pancreatitis – upper ABD pain with radiation to the back– Intraabdominal abscesses – related to recent abdominal surgery or

inflammatory disease processes– Diverticulitis – LLQ pain with rebound and guarding– Cholecystitis – right subcostal pain worsened by inspiration upon

palpation– SBP – associated with hepatic dysfunction

Infectious Acute Abdomen• Imaging:– CT with IV contrast is preferred

• Treatment:– Broad spectrum ABX coverage for intraabdominal flora– Pan cultures– IVF resuscitation– Supportive care– May need surgical intervention to obtain source control

Hemorrhagic Acute Abdomen• S&S:

– Hematemesis– Hematochezia vs melena– Easy bleeding or bruising– Weakness– Fatigue– Dizziness– Syncope

• Physical Exam:– Tachycardia– Hypotension– Pallor– Diaphoresis– Abdominal discomfort

Hemorrhagic Acute Abdomen• Causes:– GI bleed

• Associated with liver disease, NSAID abuse, PUD, aortoenteric fistula, diverticulosis, CA

– Abdominal aortic aneurysm• Associated with tender, pulsatile mass and back pain

– Ruptured ectopic pregnancy• Associated with amenorrhea and/or vaginal bleeding• Ruled out with negative pregnancy test

– Recent abdominal surgery– Trauma

**If patient has orthostatic hypotension, this indicates a >/= 15% blood loss**

Hemorrhagic Acute Abdomen

• Imaging: – CT with IV contrast to evaluate active extrav – Do not halt surgical intervention to obtain imaging

• Treatment:– Supportive care– NGT – Resuscitate and correct coagulopathy– Serial labs– Scope vs IR vs Operating Room

Things to Remember

The most rapidly lethal condition compatible with the presentation should be considered first, particularly in

patients with overt abdominal signs and shock

Shock associated with acute abdomen is usually attributable to vascular disruption with intra-abdominal

hemorrhage or severe sepsis

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management. Retrieved from www.uptodate.com.• Kendall, J. et al. (2014). Evaluation of the adult in the emergency department with

acute abdominal pain. Retrieved from www.uptodate.com• Maloney, N. (2005) Acute Intestinal Pseudo-Obstruction (Ogilvie's Syndrome). Clinics

in Colon and Rectal Surgery, 18 (2), 96-101.• Penner, R. et al. (2014). Diagnostic approach to abdominal pain in adults. Retrieved

from www.uptodate.com.• Tendler, D et al. (2014). Acute Mesenteric Ischemia. Retrieved from

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