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Introduction – Moving Targets and Humbling Presentations
The abdomen presents a particular diagnostic dilemma as the pain can be of three different types: (1) the vague visceral pain, (2) the more precise somatic pain, (3) or the tricky referred pain. An example of this is the gallbladder: it may cause pain in the epigastric area (visceral), right upper quadrant (somatic), or shoulder (referred). There are also many humbling presentations for the abdomen. For instance, a patient may complain of epigastric discomfort because they are not eating but on palpation they have right lower quadrant tenderness and are found to have appendicitis.
History Hints
While obtaining the usual history take special note of whether the pain was sudden and whether the pain precedes vomiting. These two factors can suggest a surgical cause (examples: mesenteric ischemia, testicular or ovarian torsion, and intestinal perforation). Infections conversely, tend to be of gradual onset (examples: appendicitis and diverticulitis).
Often Overlooked
With lower abdominal pain always ask about sexual activity, abnormal discharge, and testicular pain. With generalized pain, ask about previous surgeries.
Physical Exam Hints
If you are thinking the patient’s pain could be muscular then apply the Carnett’s test by having the patient partially sit up (crunch) and palpating again. If it worsens, then it becomes more likely you are correct. If it improves, then think again.
Often Overlooked
Make sure you look for hernias in older patients, particularly for generalized abdominal pain and possible small bowel obstruction (including self-described “constipation”).
Can’t Miss Differential
Emergent:
- Ruptured AAA
- Ruptured ectopic pregnancy
Urgent
- Perforated viscous
- Obstruction
- Mesenteric ischemia
- Pancreatitis
- Torsions (testicle/ovary)
- Tubo-ovarian abscess
- Incarcerated hernia
- Ascending cholangitis
- Appendicitis
- Cholecystitis
- Choledocholithiasis
- Diverticulitis
Work-Up
Labs
- CBC – Lack of leukocytosis is often false reassuring (particularly in the elderly)
- CMP – Only a couple of dollars more than BMP
- Lipase
- Urine HCG
- UA – Leukocytes may be seen in appendicitis, AAA, tumor, TOA
- Lactate – Severe generalized pain in older patient (helps to pick up mesenteric ischemia)
Imaging
- US – RUQ, pelvis/testicle, possible appendicitis in young or pregnant
- CT Abdomen and Pelvis – When you are concerned about an emergent or urgent diagnosis. Have a lower threshold for elderly patients.
When is oral contrast needed?
Thin (low BMI), pediatric, bowel altering surgery and/or inflammatory bowel disease history (crohn’s, ulcerative colitis).
When is IV contrast suggested?
If you are not convinced it is a ureteral stone, they have no allergy to contrast, and they have good renal function.
Diagnosis – Humbling Surprises
Case
72 year-old female presents with generalized abdominal pain and vomiting. Exam shows generalized tenderness. No fever, hypoxia and slight tachycardia. CT abdomen and pelvis reveals bilateral basal pulmonary emboli. CTA chest reveals large bilateral clot burden. Note: similar presentations occur for lower lobe pneumonia.
Cautions
- Be careful when diagnosing an ovarian cyst, as often this is incidental and other pathology exists (examples: appendicitis, cholecystitis, diverticulitis).
- Remember the appendix is not necessarily in the RLQ during pregnancy and be careful blaming biliary disease.
- Exercise caution above the age of 60: ~50% surgical cases, 5% die within 2 weeks of presentation, and often no fever or peritoneal signs (thin abdominal wall musculature). CT is often recommended unless US may be better or another overt cause such as shingles is present.
Negative Work-Up – Now What?
Up to 30% of patients will be discharged without a specific diagnosis. In these cases use the following four-step process:
- Consider things you may have missed (examples: pelvic exam, lower lobe pneumonia).
- Discuss how even CT and labs are not 100% for cases of conditions such as early appendicitis.
- If the pain is chronic refer to a gastrointestinal specialist and have a conversation about causes that are not traditionally picked up by CT scan*.
- Don’t forget to specify acute vs. chronic and location in ICD-10.
*Acute intermittent porphyria, angioedema, abdominal vasculitis, abdominal migraine, gastroparesis, cyclic vomiting syndrome, and opioid withdrawal.
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