Chronic Abdominal Pain

This one is short and easy.  Defined as pain lasting more than several weeks, though often for months or years, chronic abdominal pai is almost always functional:

  • Irritable Bowel Syndrome (IBS)
  • Dyspepsia
  • Abdominal Wall Muscle Strain.

So our job is to try as hard as possible to prove that it’s something else.  If we can’t convince ourselves, we can feel secure in our diagnosis.  And we don’t image or refer to GI unless truly necessary.

First we seek Red Flags not compatible with a benign condition:

  • Fevers or night sweats
  • Blood in stool / melena
  • Regular nausea or vomiting
  • Weight Loss
  • Pedal edema (objective), which masks weight loss
  • Age >50 y.o. at onset of symptoms
  • Heavy alcohol history

A few comments about the Red Flags:

  • Fever should be documented >100.8° F (38.0° C).  Have the patient buy a thermometer & keep a record if they think they have intermittent fevers.
  • “Night Sweats” are drenching, defined as “soak the sheets or pajamas such that sweat drips out upon wringing.”  Sometimes I pantomime “wringing.”
  • Vomiting episodes are more objective than nausea, but persistent nausea is also significant.  However, persistent nausea with no weight loss at follow-up is less concerning.
  • “Blood in Stool” (hematochezia) is more impressive if it’s noted in the toilet, not just on toilet paper.
  • “Melena” means truly black stools, not just dark.  It also means no concurrent Pepto-Bismol or Iron (the latter possibly mixed in with a multivitamin preparation)
  • “Weight Loss” should be quantified in terms of clothing becoming looser, best measured if belt notches have changed for the tighter.  Follow-up weights will ultimately rule.

We take a careful history to delineate duration and chronology of illness, and to ascertain that symptoms are intermittent.  The longer they’ve been present, the more relaxed we are, and the more worried the patient often is.  Past episodes are especially important.  Three months of pain this year, and 6 months of the same symptoms last year, rules out cancer, “because cancer doesn’t come and go.”  I’ve had many patients smile reassured by that simple explanation alone.

Of course, we ask about diarrhea & constipation.  Are stools loose or frankly watery?  For constipation, are stools hard?  Most important, however, is quantifying chronology of stool dysfunction —

  • Diarrhea:  How many times per day, days in a row, diarrhea-free days in a row.
  • Constipation:  How many days in a row without defecation, days-in-a-row of normal stools.

Then get a gestalt in terms of weeks or months.

All this helps us paint a picture for ourselves of exactly what the patient is experiencing.  It also reassures the patient that we take them seriously, which is especially important if we ultimately wind up making a functional diagnosis.

We perform a decent physical exam looking for oral lesions, thyromegaly, lymphadenopathy, lung & heart abnormalities, and pedal edema.  And of course a thorough abdominal exam.  Rectal exams have virtually no yield unless you suspect a fecal impaction, or a mass in patients >50.  Pelvic and prostate exams are useful for Chronic Pelvic Pain and chronic Lower Urinary Tract Symptoms, which are not the topic at hand.

And as mentioned in a previous posting, NEVER perform a stool for occult blood in the office.  The only time I ever do is if the patient mentions “black stools” & I want to see if there’s melena.  True melena makes the specimen turn blue in ≤1 second; if negative then, I quickly toss the card.

IF THERE ARE ANY RED FLAGS

Order basic lab tests:

  • CBC.  Persistent abnormalities generate work-ups.
  • Sed Rate.  If elevated, think Inflammatory Bowel Disease (IBD, not IBS) or cancer.
  • Chemistry panel, including electrolytes, calcium, total protein, plus renal & liver function.
  • Ferriten.  If low, suspect blood loss from a lesion or Celiac Disease.
  • Tissue-Transglutaminase (TTG), IgA Antibody.  Very sensitive & specific for Celiac Disease.
  • Lipase, for chronic pancreatitis.
  • If constipation is prominent, a TSH for Hypothyroidism.

Have the patient return in 3 weeks for results.  Weigh them again.  If significant abnormalities found, begin a more extensive work-up:

Refer to G.I. for Endoscopy / Colonoscopy:

  • Anemia
  • Low Ferriten (= iron deficiency)
  • History of Melena / Hematochezia (frank blood in stool)
  • TTG elevated (= Celiac Disease).  Since it requires a difficult lifetime dietary change, it’s nice to have a biopsy-proven diagnosis, as recommended by the American College of Gastroenterology.  However, biopsies can be false-negative; the serum TTG may be more sensitive & equally specific.
  • Elevated Sed Rate (especially if diarrhea is a symptom)  —  looking for IBD.
  • Weight Loss
  • Age >50 (they’d need some sort of colon cancer screening anyway; as long as they’re symptomatic of something abdominal, why not do a scope?)

Order an Abdominal CT with Contrast (if normal renal function)

  • Significantly abnormal WBC count
  • Elevated Sed Rate
  • Elevated Lipase
  • Weight Loss documented (or let GI order it)

IF THERE ARE NO RED FLAGS

 I postpone the lab tests and institute a “Therapeutic Trial” based on best-guess working Diagnosis what emerged from the history [assuming physical exam was normal].  Options include:

**  For Dyspepsia —

  • A Proton-Pump Inhibitor (PPI);…..PLUS
  • Liquid Antacids used p.r.n.;…..PLUS
  • Instructions to avoid eating 2-3 hours before bedtime.

As mentioned in past postings, I start with high-dose, e.g. Omeprazole 20-40 mg B.I.D.  High-dose is important, because we’re aiming for a Diagnosis [hence title of our Blog].  If we give a low starting dose & it doesn’t help, we wouldn’t know if it had been wrong Dx or wrong Dose.  If high-dose helps, lower it on follow-up.

** If Constipation is a prominent associated symptom  —

  • Psyllium Fiber (e.g. Metamucil®) in powder form T.I.D. (mixed in 8 oz water, with another 8 oz water as a chaser, thus gaining adequate fluid intake);…..PLUS
  • Stool Softener, T.I.D.;…..PLUS
  • Increase fiber, fluids, & exercise

** If Diarrhea is a prominent associated symptom —

  • Psyllium Fiber as above;….PLUS
  • Kaolin-Pectin preparation;…..PLUS
  • Loperamide used p.r.n.

** If there are No Prominent Associated Symptoms —

  • I tentatively diagnose and treat for Dyspepsia as above.  That’s because PPIs work more rapidly & better for dyspepsia than anything works for IBS.

If all this seems like overkill, it’s because our focus at first is always diagnostic.  Have the patient back in 3-4 weeks.  Weigh them, & see how they’re doing.

If lots better, problem solved [duh].  Reduce therapeutic intensity, like substituting a once-daily H2-Receptor Blocker (famotidine / ranitidine) for the PPI (telling them they can always increase dose as needed).

If NONE BETTER, discontinue whatever regimen you’d given.

  • Try a different Therapeutic Trial if it seems logical
  • Order labs as above
  • Begin asking about “stress,” lest symptoms be a manifestation of a mood disorder
  • See them back in 3 weeks and weigh them again

If you document weight loss, you’ve got a Red Flag & can proceed as above.

If no weight loss, no red Flags, no laboratory abnormalities, and no improvement — well, that’s IBS:

Rome III Diagnostic Criteria* for Irritable Bowel Syndrome (esp. for research purposes):

Recurrent abdominal pain / discomfort for at least 3 days per month, over the last 3 months, associated with 2 or more of the following:

  • Improvement with defecation
  • Onset associated with change in frequency of stool
  • Onset associated with change in form (appearance) of stool

* Criteria must have been fulfilled for the last 3 months, but Symptom Onset required at least 6 months prior to diagnosis

Diagnosis isn’t hard.  Treatment is.

Refer to GI?????  Only if you need to therapeutically, after going through a variety of treatment options.  Not that GI will necessarily have more to offer, but some patients require that level of reassurance.  Besides, it’ll be nice to read in the report how GI reinforced to the patient that you’ve been doing all the right things all along.

We’re done with the belly.  See also Acute Abdominal Pain -1, -2, and -3: Upper Abd., Flanks & Lower Abd., and diffuse or Generalized Abd. Pain.

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2 responses to “Chronic Abdominal Pain

  1. Man, what a great layout. So logical! I’m still in the process of becoming an RN, so my diagnosis days are a ways away, but I did want to ask about the lab tests, specifically the ESR to detect inflammation in order to point yourself toward cancer or IBD. Why not a CRP? I only ask because I was googling the ESR and the page I stumbled upon said that it was largely being supplanted by the CRP.

    • Can use CRP as well; might be technically easier for the lab, tho I’m not sure. Neither test is at all specific, nor even sensitive. Both should be interpreted cautiously. If elevated, they simply alert you to the possibility of an underlying inflammatory condition. Those of us in practice for a while are more used to the ESR, esp. when it’s *very high*(approaching 100 mm) & raises suspicion for a limited number of conditions. Nobody has a sense as to the equivalent level for CRP.

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