Acute Abdominal Pain – 3

We’ve already discussed new-onset upper belly pain (Acute Abd. Pain – 1), and then pain in the flanks & lower abdomen (Acute Abd. Pain – 2).  Now for Diffuse, Periumbilical, or Generalized Abdominal Pain.

Would not be any of the localized conditions we’ve described so far, unless there’s telltale radiation (e.g. to Right shoulder may suggest Biliary Colic).  See our TABLE for the differential.  We’re either going to diagnose something benign & self-limiting [in which case it doesn’t really matter if we’re wrong], or send to surgery.

PERIUMBILICAL / DIFFUSE ABDOMINAL PAIN

First Step — Rule-out catastrophes, which may be obvious (fever, hard abdomen, doubled-over).  Such patients gain a trip to the E.D., as do those whose pain appears significantly disproportionate to findings on exam.  The rest of this discussion deals with the subtle, early presentations, which are more interesting and difficult.

[ Parenthetic Comment — I’ve always enjoyed dealing with early, subtle conundrums.  Full-blown pathology or Zebras aren’t half as “interesting” as easy-to-miss conditions.  Dermatology texts show slides of fulminant melanomas; I want to see what they look like at 1-2 weeks.  Maybe those patients had gotten sent home (“come back when the spot is more photogenic.”) ]

Back to diffuse abdominal pain.

Consider Bowel Obstruction in patients at risk for adhesions, namely anyone with any sort of prior abdominal surgery or irradiation.  This is when to listen for hyperactive bowel sounds (“tinkles” or “rushes”).  Any such patient with new, unusual abdominal pain, especially if there’s nausea, deserves an abdominal x-ray to detect dilated bowel or air-fluid levels (plain film or “KUB”, both flat & upright — one of the only times that such a study is meaningful).

Strangulated hernias are a form of bowel obstruction.  They’re not subtle — extremely tender, invariably accompanied by nausea/vomiting.  They most commonly occur in the inguinal area, possibly in old incision sites, & rarely in midline or lateral to the umbilicus.  Shouldn’t be a problem diagnostically.

Early Peritonitis is a not-to-miss diagnosis.  The key to diagnosis is finding tenderness despite every effort to distract, absolutely every time you palpate.  That’s hard to ignore, and deserves a CBC and at least some sort of observation.  Tenderness to abdominal percussion is pretty suggestive.  Any degree of fever raises the likelihood.

Suspect in the elderly and other compromised hosts (see below), and especially those with portal hypertension & therefore possible ascites.  Send such patients to an E.D.; they may die before achieving a “board-like abdomen.”

Abdominal pain, with nausea / vomiting & sometimes severe enough to mimic an acute abdomen, frequently accompanies Diabetic Ketoacidosis.  DKA progresses rapidly, invariably within 24-48 hours.  Polydypsia & Polyuria are present, but maybe only if you ask about them.  A urine dipstick suggests the diagnosis (large ketones & glucose).  It’s trickier for undiagnosed occult Type-1 Diabetics; indeed, the disease is usually initially identified during the first episode of DKA.

For generalized (or any) abdominal pain, be sure to consider vascular catastrophes.  Ruptured Abdominal Aortic Aneurysm (AAA) occurs in older patients with atherosclerosis (especially smokers).  Mesenteric Ischemia occurs in the same population, and in those at risk for heart failure or cardiac emboli.  When the latter is due to Thrombosis, it’s usually among patients with portal hypertension or hypercoagulable states.

Don’t forget to seek a family history of hypercoagulable states, which would be highly relevant to the patient at hand.  This is obviously rare, but easily identifiable via a simple question.

These catastrophic vascular events of ten present with pain out of proportion to physical findings, so don’t let the exam guide (i.e. fool) you.  Certainly don’t wait for textbook descriptors of ruptured aneurysm like shock or absent femoral pulses.  Up to 40% of persons with AAA lack a palpable mass.  Send patients to the E.D. based on two simple parameters:

• Risk factors
• Sudden onset of new, severe abdominal pain

And then, there are the “compromised hosts.”  When such patients present with new, generalized abdominal pain, have a high index of suspicion that some horrible intra-abdominal condition catastrophe might be brewing.  Compromised hosts include:

When these patients present with new, unexplained abdominal pain, it always makes me nervous.  Especially if it’s a Friday, & I can’t follow up the next day.  More often than not, I prefer bailing them out to the E.D., to at least get a stat CBC & perhaps an image.  If you decide to manage them with a tentative diagnosis like “dyspepsia,” if that’s what it really sounds like, be sure you can see them back soon if need be.  And give “ER precautions” if they get worse.

The same holds true for the Severely Mentally Ill, who can tolerate inordinate levels of pain.  When they do come in with a complaint, worry.

An otherwise-well 78-year old lady once presented with LLQ pain since the day before.  She looked fine, didn’t seem ill at all.  It might have been uncomplicated diverticulitis, but I was nervous.  So I sent her to the E.D., her CT was negative, they gave her empiric antibiotics anyway, & the next day she returned to me with T-12 Zoster lesions.  I had no regrets whatsoever.

As all the catastrophic conditions mentioned above progress, they eventually cause nausea and then vomiting.  A clinical pearl: when nausea / vomiting precede the pain, it may well be due to gastroenteritis.  But when pain begins first, seek something more serious.

But let’s say, like the vast majority of persons presenting with recent onset of generalized abdominal pain, our patient isn’t a compromised host, & has no risk factors for vascular catastrophes.  We might order a simple dipstick urinalysis, for new-onset diabetes or the rare UTI without dysuria.  But if this is negative, and our exam benign, our diagnosis will also be benign.

• If there’s a bloating sensation, call it Dyspepsia.
• If the abdomen is soft, but you elicit tenderness to palpation especially while the patient is flexing their abs (like doing a partial sit-up, a.k.a. “Carnett’s Sign” [med trivia]), they probably have an abdominal wall Muscle Strain.
• If there’s diarrhea, or nausea/vomiting that preceded the pain, we’re probably dealing with Gastroenteritis.  As we mentioned before, never make this diagnosis casually.  If pain began before the nausea, strongly suspect an alternative etiology.

All these conditions are self-limiting, so it doesn’t really matter if we’re wrong.  Trying to distinguish allows us to recommend / prescribe an appropriate treatment.  But I still like to keep an intellectual sincerity, knowing know that there’s no gold standard for my guesswork.

And, as discussed previously, don’t miss Early Appendicitis, during the first 24 (maybe 48) hours.  The pain is non-descript, diffusely located.  Key symptom is anorexia.  Key sign is mild but persistent RLQ tenderness despite every effort to distract.

That’s it for Acute Abdominal Pain; next time, onward to the longer-lasting version (Chronic Abdominal Pain).