A. Types of Pain

1. Focal: organ distension (parietal pain)
2. Diffuse: organ involvement (visceral pain)

B. Character of Pain

1. Burning: Peptic Ulcer, Reflux
2. Cramping: Biliary Colic, Irritable Bowel, Inflammatory Bowel, Mesenteric Ischemia
3. Colicky: appendicitis, impacted feces, cholecystitis, renal stone
4. Aching: appendiceal irritation
5. Knife-like: Pancreatitis, Aortic Dissection / Rupture
6. Gradual Onset: Infection, primary or secondary, retroperitoneal fibrosis
7. Sudden Onset
   1. Peptic ulcer
   2. Pancreatitis
   3. Obstruction
   4. Perforation
   5. Ruptured ectopic pregnancy
8. Opiate treatment may alter physical exam findings but no significant change in management in patients with abdominal pain [1]

C. Epigastric Pain

1. Esophagus
   1. Achalasia
   2. Esophageal Spasm
   3. Tumor
   4. Scleroderma
   5. Esophagitis
   6. Esophageal perforation (usually thoracic pain)
2. Lungs
   1. Lower Lobe Pneumonia
   2. Collapse
   3. Pulmonary Infarction (lower lobes)
3. Heart
   1. Angina / Myocardial Infarction - especially in women, Diabetes
   2. Pericarditis
   3. Aneurysm
4. Gastrointestinal / Dyspepsia
   1. Gastritis and Gastric Ulcer - usually worse with eating
   2. Duodenal Ulcer - usually better with eating
   3. Gastroesphageal Reflux Disease (GERD)
   4. Gastroparesis
   5. Gastric Neoplasm
   6. Gall bladder disease
   7. Malabsorption syndrome
   8. Pancreatitis
   9. Intestinal parasites
   10. Mesenteric Ischemia - usually worse 1/2 to 2 hours after eating

D. Kidney Pain

1. Costovertebral angle (CVA) tenderness
2. Radiation anteriorly, including RUQ pain
3. Infection: urinalysis, culture
4. Renal Stone: often very painful on passing stone
5. Obstruction: rule out with ultrasound
6. Retroperitoneal fibrosis may mimic kidney pain

E. Clinical Evaluation Of Abdominal Pain

1. Women
   1. If premenopausal or <55 years old, consider a pregnancy test (HCG)
   2. If last menstrual period was >30 days ago, perform a pregnancy test
   3. If lower abdominal pain present, perform a urinalysis
   4. If urinalysis is negative for infection, perform a pelvic exam
   5. Pregnant patients with abdominal pain should have ultrasound and gynecologic evaluation
2. Men with lower abdominal pain should have a genital examination
3. All patients with abdominal pain should have a rectal exam and stool guaiac exam
4. Orthostatic vital signs should ALWAYS be performed
5. Blood on Rectal or Stool Guaiac Positive - complete blood count ± reticulocyte count
6. Upper Abdominal Pain
   1. If tenderness is present on palpation, imaging is essential
   2. If no tenderness, then consider an ECG (particularly if cardiac risks present)
7. Lower abdominal pain and/or flank pain should always include a urinalysis
8. Surgical Consultation
   1. Abnormal vital signs or temerature >38°C
   2. Rebound or guarding on examination
   3. White blood cell count >10K/mL

1. Acute
   1. Pain in epigastrium and RUQ
   2. Colicky then steady
   3. Nausea and vomting
   4. Low grade fever
   5. Leukocytosis
   6. Possible mild bilirubinemia
   7. Bilirubinuria after 24 hours
   8. Constipation
   9. Mild Paralytic ileus with air filled jejunal loop
   10. 90% of patients have gallstones
2. Chronic
   1. Chronic crampy RUQ pain
   2. Colicky at times
   3. Low grade Fever
   4. Constipation
   5. Usually chronic gallstones
3. Cholelithiasis with obstruction
   1. Obstruction is the major cause of cholecystitis
   2. Cholesterol stones
   3. Bilirubin stones

B. Ileus

1. Intestinal obstruction
   1. Mechanical: adhesions, tumor
   2. Paralytic: no bowel sounds
2. Symptoms
   1. Abdominal Pain
   2. Distension
   3. Vomiting
   4. Obstipation
3. Etiology
   1. Small bowel adhesions [4]
   2. Incarcerated hernias
   3. Intra-abdominal abscess
   4. Neoplasms
   5. Fecal impaction

C. Appendicitis

1. Classically RLQ pain, but may be mid or RUQ
2. Pain usually begins epigastrium then migrates
3. Fever, leukocytosis
4. Nausea and vomiting

D. Diverticulitis

1. Usually causes acute LLQ pain
2. Sigmoid colon most commonly involved
3. Nausea and vomiting later in course
4. Constipation or Bloody Diarrhea

E. Ulcer Perforation

1. Usually gastric ulcer with perforation
2. Duodenal ulcer much less common
3. Recall gastric ulcers usually better with food
4. Epigastric burning pain
5. Consider Crohn's Disease in perforated ulcers

F. Pancreatitis

1. Knife-like epigastric pain
2. Radiating usu through to back
3. Consider aneurysm, GI ulceration

G. Crampy Abdominal Pain

1. Usually due to organ distension
2. Infection: bacterial, viral, parasitic
3. Inflammatory Bowel Disease
4. Malabsorption Syndrome
5. Small Bowel Bacterial Overgrowth
6. Constipation
7. Porphyria
8. Angioneurotic Edema
9. Familial Mediterranean Fever
10. Adhesions

H. Knife-Like Abdominal Pain

1. Aortic Aneurysm Dissection (Perforation)
2. Pancreatitis
3. Esophageal perforation
4. Severe gastric ulceration
5. Celiac disease (uncommon) [2]

1. Peptic Ulcer
2. Pyloric Obstruction
3. Post-gastrostomy
4. Diaphragmatic Hernia
5. Pancreatitis
6. Gastric CA
7. Non-Ulcer Dyspepsia / Functional Gastritis

B. Hypogastric Pain

1. Cystitis
2. Chronic Prostatitis
3. Pelvic Inflammatory Disease
4. Ovarian Cyst or torsion [6]
5. Uterine fibroids
6. Small Bowel Adhesions
7. Henoch-Schonlein purpura or other vasculitis [5]

C. Right Upper Quadrant (RUQ) Pain [3]

1. Gallstones
2. Chronic Cholecystitis
3. Cholangiocarcinoma (causing obstruction)
4. Hepatitis
5. Hepatic Abscess (amoebic, bacterial)
6. Other Cancers
   1. Hepatic Neoplasm
   2. Gastric Cancer
   3. Metastatic Disease
7. Pancreatitis
8. Pancreatic Duct Obstruction
9. Peptic Ulcer (duodenitis)
10. Right lower lobe Pneumonia
11. Kidney stones (nephrolithiasis)
12. Pyelonephritis
13. Intestinal obstruction
14. Trauma
15. Biliary Tract Obstruction - Tropical Areas [7]
    1. In addition to RUQ pain above
    2. Salmonella associated cholelithiasis
    3. Hepatobiliary parasitosis: ascariasis, liver flukes
    4. Granulomatous disease: tuberculosis, paragonimiasis
    5. External compression: tuberculous periporpal lymphadenitis
    6. Hydatid disease with biliary fistulization or ductal compression

D. Left Upper Quadrant (LUQ) Pain

1. Splenic Ischemia / Infarction
2. Mesenteric Ischemia
3. Left lower lobe Pneumonia
4. Pyelonephritis

E. Right Lower Quadrant (RLQ) Pain

1. Chronic Appendicitis
2. Crohn's Ileitis
3. Meckel's Diverticulitis
4. Ovarian Process [6]
5. Pelvic Inflammatory Disease
6. Pericecal abscess

F. Left Lower Quadrant (LLQ) Pain

1. Diverticulitis
2. Ulcerative Colitis
3. Ovarian Process [6]
4. Pelvic Inflammatory Disease

G. Abdominal Wall Pain

1. Nerve
   1. Radiculitis
   2. Rectus Entrapment
   3. Ischemic Injury
2. Myositis
3. Contusion
4. Hematoma

H. Intestinal Bloating

1. Hypomotility Syndromes
   1. Irritable Bowel
   2. Neural Disease
   3. Scleroderma
2. Enzyme Deficiency
   1. Lactase Deficiency
   2. Celiac Disease
3. Small Intestinal Bacterial Overgrowth
4. Infection
5. Intestinal Obstruction
   1. Ileus
   2. Hernia
   3. Volvulus
   4. Stricture
   5. Compression
   6. Intussusception
6. Small Bowel Adhesions

I. Organ Distension

1. Stomach
2. Spleen
3. Liver
4. Gall Bladder
5. Kidney
6. Urinary Bladder
7. Intestine
8. Uterus
9. Ovary [6]

J. Renal Pain

1. Pyelonephritis
   1. Bacterial
   2. Emphysematous
2. Ischemia
3. Hydronephrosis
   1. Obstructive
   2. Reflux

K. Miscellaneous

1. Trauma
   1. Spleen
   2. Liver
   3. Kidney
   4. Duodenum
2. AIDS Enteropathy
3. Diverticulitis
4. Lymphadenitis
5. Hyperthyroidism
6. Amyloidosis
7. Radiation Enteritis
8. Familial Mediterranean Fever (FMF)
9. Angioneurotic Edema (Angioedema)
10. Porphyria
11. Endometriosis
12. Retroperitoneal Fibrosis

L. Infection

1. Bacterial
   1. E. coli
   2. C. difficile
   3. Salmonella
   4. Shigella
   5. Uncommon: yersinia, campylobacter, others
2. Viral
   1. Adenovirus
   2. Norwalk Agent
   3. Echovirus
   4. Poliovirus
3. Parasitic
   1. Malaria
   2. Amoebiasis
   3. Giardiasis
   4. Cryptosporidiosis
4. AIDS Enteropathy
   1. Cryptospiridiosis
   2. Giardiasis
   3. Amoebiasis
   4. Isospora
   5. Atypical mycobacteria
5. Tropical Sprue (?)
6. Whipple's Disease (Tropherema whippelii)

M. Inflammatory Diseases

1. Crohn's Disease
2. Ulcerative Colitis
3. Eosinophilic Gastroenteritis
4. Retroperitoneal Fibrosis

N. Constipation Syndromes

1. Irritable Bowel Syndrome
2. Intestinal Hypomotility
3. Megacolon / Hirschprung's Syndrome
4. Colon Carcinoma (usually Left sided)
5. Fecal Impaction
6. Medications
   1. Opiates
   2. Calcium Channel Blocking Agents
   3. Iron Salts
   4. Calcium Salts
   5. Aluminum Salts
   6. Anticholinergic Agents
7. Less Common:
   1. Cystic Fibrosis
   2. Hypothyroidism
   3. Hyperparathyroidism (from hypercalcemia)
   4. Rectal Strictures
   5. Parkinson's Disease
   6. Cerebral Infarction (Stroke)
8. Small Bowel Adhesions with Ileus

O. Malabsorption

1. Celiac Disease (Sprue)
2. Tropical Sprue
3. Lactose Intolerance (Lactase Deficiency)
4. Pancreatic Insufficiency
5. Zollinger-Ellison Syndrome

References

1. Ranji SR, Goldman LE, Simel DL, Shojania KG. 2006. JAMA. 296(14):1762
2. Naveb F and Yantiss RK. 2001. NEJM. 344(7):510 (Case Record)
3. Ross AM IV, Anupindi SA, Balis UJ. 2003. NEJM. 348(15):1464 (Case Record)
4. Swank DJ, Swank-Bordewijk SCG, Hop WCJ, et al. 2003. Lancet. 361(9365):1247
5. Kassutto S and Wolf MA. 2003. NEJM. 349(6):597 (Case Discussion)
6. McGee DM, Connolly SA, Young RH. 2003. NEJM. 349(5):486 (Case Record)
7. Hurtado RM, Sahani DV, Kradin RL. 2006. NEJM. 354(12):1295 (Case Record)