Acute Abdominal Pain – 2

Once again, “Acute” means recent onset, less than a week, and not “severe” or “surgical.”  We discussed Upper Abdominal Pain last posting; now let’s move on down to the Flanks and then the Lower Abdomen.  We’ll save Acute Periumbilical or Generalized Abdominal Pain for the subsequent posting.

FLANK PAIN

The Flanks are those soft areas on our sides between the lower rib margins & the iliac crest of the pelvis (tender meat for cannibals).  Pain localized to the flanks suggests renal disease; our job is to separate out infection from stone, even though most cases of flank pain wind up being benign muscle strains.

TABLE  —  CAUSES OF FLANK PAIN

The presentations of both acute Renal Colic and Pyelonephritis include broad continuums.  We picture the pyelo patient diaphoretic, febrile, wincing as they clutch their side, but a fair number may be virtually asymptomatic, or anything in between.  Similarly with renal colic — the classic restless patient diagnosed from across the room is the exception rather than the rule.

When presentation isn’t classic for one or the other, distinguish them by other parameters:

  • Renal colic usually begins abruptly (when stone gets stuck), Pyelo less so.
  • Fever points to Pyelo, unless symptoms have continued long enough for a stone to become infected.
  • Wave-like episodes of pain, lasting around 20 minutes, point to a Stone.
  • Also think Stone for pain that radiates to groin, testicle, or labia.
  • Pyelonephritis almost always causes flank or CVA tenderness; renal colic is non-tender.
  • Recurrent episodes suggest renal colic.  Both may cause nausea or vomiting.

Then you obtain a urinalysis, more for its negatives than positives.  Absence of WBCs (leukocyte esterase on a dipstick) rules out pyelo.  Absence of blood strongly speaks against stones (but not completely).  Presence of either could be either, or neither.  And a high pH (>7.0) suggests Proteus or Klebsiella infection, with possibly enormous struvite staghorn calculi.

Renal infarcts are rare; suspect them in patients at risk for emboli, such as those with atrial fibrillation or prosthetic valves, especially if the blood pressure is elevated.  Send to the E.D.  A high serum LDH clinches the diagnosis, along with normal non-contrast CT to R/O stone.

Don’t forget the elusive Ruptured Aortic Aneurysm, which may present with Flank Pain.  We’ll discuss this next posting.

Of course, the majority of patients with flank pain usually wind up with normal U/A’s and a diagnosis of Muscle Strain.  Identify this by reproducing the pain with muscle palpation, or a specific range of motion of torso, such as lateral bending or rotation, perhaps against resistance.

Moving on downward (saving periumbilical / generalized abdominal pain for last)…

LOWER ABDOMINAL PAIN

Clearly below the belly-button, not periumbilical or generalized pain.

RLQ

Suprapubic

 

LLQ

 

Acute RLQ Pain is Appendicitis until proven otherwise, even though it usually isn’t, and you don’t want the E.D. to perform CT scans on everyone you send.

But beware — I’ve seen appys [appies ?] present in an enormous variety of ways.  Some were classic: low-grade non-specific abdominal discomfort with anorexia, pain migrates to the RLQ in <1-2 days, with nausea, then vomiting, and eventual fever.  But I’ve also seen abrupt onset with diarrhea, or normal appetite.  And there are case reports of appy patients misdiagnosed with pancreatitis because of a high amylase (at least one of whom died).

Rebound tenderness is only helpful for detecting imminent or actual rupture, not the early case.  Obdurator & Psoas signs help the surgeon localize the cause of established peritonitis.

The bottom line in terms of Appendicitis — in a patient with very recent onset abdominal pain (1-2 days):

  • Is there any degree of focal RLQ tenderness?
  • Are symptoms progressive?

I distract as much as possible, palpate the entire abdomen gently, slightly deeper, & if I consistently elicit a wince when returning to the RLQ, they go to the ER.  Perhaps there’s a patient who’d been lifting weights, with no anorexia or nausea or malaise, and no history of progressive worsening of pain, with RLQ tenderness that’s maximal while doing a sit-up (“Carnett’s Sign” for muscle strain).  I might draw a CBC (WBC <10,000 with normal differential speaks well against an appy), give them “ER Precautions,” & see them back in a day.  That patient’s pretty uncommon.

Of course, there’s always the case of a retrocecal appendix, tender only on rectal exam.  Despite the textbooks, I freely confess that I don’t perform rectals on all my patients with abdominal pain.  But I do if history makes me think of an appy, and the RLQ is non-tender.

I’ve never ordered my own CT to R/O an appy.  Neither sensitivity nor specificity is 100%.  If my level of suspicion is high enough to irradiate, I want a surgeon’s gestalt on the overall clinical picture.

Most Hernias are inguinal, not truly RLQ.  If that seems to be where symptoms are located, examine the patient standing up.  Palpate during cough or strain (have hem turn their head away from you before you request, “Cough”):

  • Indirect Hernias: in the scrotal sac (men) / above the inguinal ligament (women)
  • Direct Hernias: above the inguinal ligament
  • Femoral Hernias (especially in older women): below the inguinal ligament & medial to femoral pulse

Women with Acute RLQ Pain are more complicated.  Consistent tenderness at McBurney’s point points to an appy, but if it’s primarily below the iliac crest, we’re really dealing with the pelvis.  Ectopic Pregnancy is the worst case not to miss, easily ruled out by a urine pregnancy test.  Threatened Abortion of intrauterine pregnancy is much more common.

Question  —   do you order pregnancy tests on women who’ve had tubal ligations?  What about 10-year-old girls?  You should — most patients & parents understand, “This is extremely unlikely, but I’m obligated.”  What about a woman who swears she hasn’t had sex for a year?  I usually don’t, but confess rare cases when I’ve felt uncomfortable about a patient’s honesty for one reason or another, & have sneaked a UCG in along with the U/A.  Didn’t charge for it.

Do we do a pelvic exam on every woman with acute RLQ or LLQ pain?  Certainly if she looks ill, is febrile, describes an unusual vaginal discharge, or seems very straight-forward and concerned about new and unabating symptoms.  Even if the timing is right for Mittelschmerz, other more ominous possibilities such as Pelvic Inflammatory Disease (PID) or Ovarian Torsion require a definite rule-out.

But these latter two conditions are not subtle.  If there’s no tenderness on deep external palpation in the pelvis during abdominal exam, and the pain in not persistent, I may forgo a pelvic.  Especially if I have reason to suspect a muscle strain, such as tenderness in the inguinal crease, or with abdominal or hip flexion.  But just be sure there’s no hernia either.

BEWARE of diagnosing “PID.”  I’ve seen way too many clinicians, fearful of missing a possible salpingitis, over-prescribe doxycycline based on a perceived assessment of cervical motion tenderness.  Please adopt strict criteria for declaring “CMT.”  I repeat the maneuver several times, 5-10 seconds apart, while conversing to distract, & expect to see discomfort each time.  I also avoid simultaneous pressure with the external hand, which is necessary to size a uterus, but can easily confound suprapubic tenderness for CMT.  Other meanings for “PID” include “Provider In Doubt,” or “Pretty Inadequate Diagnosis.”

In men, RLQ / LLQ pain can result from testicular conditions.  Most patients can describe their pain as testicular, and not abdominal, but some patients with testicular torsion may feel too ill to care.  A classic error has been to operate for an appy without examining the testes.

Acute LLQ Pain –The differential is similar to the RLQ, except appendicitis is not an issue (except in the very unfortunate person with unsuspected situs inversus).  Some conditions are unique to the LLQ.

Constipation is possible, but I doubt its relevance when a patient presents with a chief complaint of LLQ pain, & I elicit this in a review of systems.  Always wonder why a chronically constipated person has developed acute pain now.  In other words, if the onset of pain doesn’t match the chronology of constipation, the latter may be a red herring.

Diverticulitis is infection & inflammation in a diverticulum; the latter always used to be a condition occurring over 50 years old.  Incidence is now increasing among 20-40 year-olds, perhaps due societal changes in fiber intake & physical activity [specifically, the lack thereof].  In the US over 95% of diverticula occur in the left colon, as opposed to Asia, where most are on the right.  Still, Asians with acute RLQ pain usually have appendicitis, not diverticulitis.

Diverticulitis presents a little more insidiously than an appy; pain may evolve over 3-4 days.  Constipation and diarrhea are not helpful parameters.  Up to 50% of patients may report prior similar episodes.  A CT scan makes the diagnosis; worth doing, since we’re dealing with older patients [often >60] with risks for other pathology, also for perforation or abscess formation.

Note that conditions like ulcerative colitis and proctitis are not included in this differential.  They certainly may cause LLQ pain, but commonly present with a different chief complaint, such as diarrhea, rectal bleeding, discharge, or tenesmus.  The latter symptoms overshadow pain.

Suprapubic Pain might result from all the conditions that cause RLQ or LLQ symptoms, but usually doesn’t.  Or, if there is a suprapubic component, one or both LQs is also painful or tender.  If a U/A is normal, and palpation or gender don’t suggest uterine infection, pure isolated suprapubic pain is usually due to a muscle strain.  You can confirm this with the maneuvers described above.

Next Posting — Generalized Abdominal Pain.

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