Acute Abdominal Pain refers to pain going on 1-2 weeks, oftentimes just a few days. The term “Acute” can also mean very serious and needing surgery, like appendicitis, but that’s not how we’re using the word here.
Also, various conditions may cause some pain, but primarily cause other more prominent symptoms like vomiting or diarrhea that lead a patient to seek care. Those aren’t addressed here; we’re now dealing with the patient whose main concern is new-onset pain in the lower part of their belly. See also our Summary Approach to this topic, and definition of “Lower” in the introductory post for Abdominal Pain.
Causes of Acute Lower Abdominal / Pelvic Pain
|xRight Lower Quadrant (RLQ)|
• Kidney Stone ?
• Muscle Strain
• Tubal Infection (PID) *
• Ectopic Pregnancy *
• Miscarriage *
• Mittelschmerz / xxxDysmenorrhea (menstrual xxxxxxxpains) *
• Ovarian Disease *
• Testicular Disease ? **
• Herpes Zoster (Shingles)
? = usually in Flank, but also sometimes here
• Bladder Infection (UTI)
• Uterine Infection xxxx(endometritis) *
• Muscle Strain
• Mittelschmerz /
xxxDysmenorrhea (menstrual xxxxxxxpains) *x*****
xxxx* Women only
xxxx** Men only
|xxLeft Lower Quadrant (LLQ)|
• All conditions that cause xxxxxxRLQ pain
NOTE: Some patients we may send right to ER for tests / exam by a surgeon:
- Severe tenderness (the abdomen is as hard as a board)
- Fever (unless we diagnose urinary tract infection by symptoms & urinalysis)
- Elderly or Immunocompromised (poor immunity due to other diseases), because they’re more likely to have serious illness with minimal or atypical symptoms.
- Also maybe the severely mentally ill (with psychosis), who tolerate enormous degrees of pain, and only seek care if they sense something’s really wrong but don’t express it.
The following discussion assumes that a patient doesn’t appear very ill. We consider each possibility one-by-one.
Acute Right Lower Quadrant (RLQ) Pain — regardless of one’s sex
Appendicitis — This usually begins as a vague discomfort that gets progressively worse and settles in the RLQ. Initial loss-of-appetite turns into nausea, then vomiting (fever is worst).
However, there are lots of variations & exceptions. So for me, the bottom line in diagnosing Appendicitis is recent onset (1-2 days) of mid- or lower-abdominal pain which:
- Keeps gradually getting worse; AND
- With palpation, it hurts to press on the RLQ more than anywhere else
Note that sometimes the appendix points backwards, so there isn’t real tenderness in the RLQ. If other symptoms make us think of appendicitis, we perform a rectal exam to see if the right side there is very tender. There are also some leg maneuvers we can do.
If a person isn’t very ill, I might order a same-day complete blood count (CBC), looking for elevated white blood cells (WBCs), or for lots of immature WBCs called “bands.” If that’s normal, I warn the patient that even though they probably don’t have appendicitis, if symptoms worsen, they should go to an ER [& if they decide to go, don’t eat anything).
A CT scan is very good at ruling-in or ruling-out Appendicitis, but it’s not perfect. In children, we order an ultrasound instead, to avoid radiation (ultrasounds aren’t accurate in larger people). The most important part of diagnosis is the overall opinion of a surgeon, who’s seen so many cases that they’ve got a better feeling than anyone as to who needs an operation.
Hernia — A hernia is a segment of bowel that slips out of the abdomen. These aren’t exactly in the RLQ, but down in the inguinal area (groin). Men may have hernias that protrude into the scrotum. Anybody can have hernia right above the groin crease. Older women may tend to have hernias right below the groin crease.
Hernias come and go. When they protrude, there’s a lump that can be felt. The lump can sometimes be brought out by coughing (exam should be done with patient standing).
Ongoing pain from a hernia is usually mild & dull, occurring more often after prolonged standing, or after heavy lifting. But if the hernia gets trapped (“incarcerated”), cutting off its blood supply, acute moderate-to-severe pain occurs, usually with nausea and then vomiting. Fever is even worse. If the bowel segment dies (“strangulation,”), the person might also. These complications are uncommon, and are not subtle — patients look quite ill.
Muscle Strain (of Abdominal Wall muscles) — This is a commonly-missed cause of abdominal pain; it tricks us because we’re worrying about brewing catastrophes inside the abdomen, whereas our muscles are on the outside. Sometimes we elicit a history of new physical activity (“just joined a gym,” etc.), but oftentimes not, since the pain of a muscle strain can begin 1-2 days after the injury.
We don’t diagnose this until we are sure there’s nothing more serious going on. Then we suspect a Strain by noting tenderness at a specific point while palpating as the patient lies relaxed on the exam table. Then we ask the patient to begin a sit-up (flexing the abs), & we palpate again. If the latter causes more tenderness than the former, we’re sure that it’s due to a muscle (diseases inside the abdomen would be less tender then).
The maneuver is called “Carnett’s Sign.” Few if any clinicians will have heard of it; I’d been performing it for years before I found out there was a name. But still, it’s there to Google if you want.
Kidney Stone — Pain usually runs from the flank to the groin, but occasionally it might mainly be felt in the lower abdomen or pelvic area. We’d suspect it by asking if there’s also some flank pain. Pain comes in waves, patients might appear restless, usually there’s nausea / vomiting. Key finding on exam — the abdomen isn’t tender. Usually there’s blood in the Urinalysis. See topic Flank Pain.
Urinary Tract Infection (“UTI”) [bladder or prostate] — This usually includes prominent urinary symptoms, especially painful urination, or an urge to urinate frequently, in small amounts. Diagnosis is made by finding white blood cells (WBCs) in the urine (see discussion of Urinalysis). However, an Ectopic Pregnancy can also cause these symptoms (see below), and can also cause WBCs in the urine.
Herpes Zoster (Shingles) — This is the recurrence of Varicella virus; initial Varicella is called “chickenpox”. Chickenpox lasts a week & goes away, but latent virus remains hidden in a nerve, and often reactivates many years later. When it reactivates, it causes pain along the nerve pathway, & clusters of blisters which merge into crusts.
Zoster can occur on either side of the abdomen (upper, lower, or flan area). Diagnosis may be tricky at first, if not impossible, since pain may precede skin lesions by 1-2 days. Search the skin for even the tiniest splotches of redness or blisters, anywhere from spine to mid-abdomen. Don’t freak out about the name; Zoster is just in the same family as the STD Herpes simplex (there’s no STD of the belly).
If we diagnose Zoster for sure in a patient younger than 50, we suggest an HIV test. It’ll probably be negative, but almost everyone with HIV gets Zoster at some point, due to even very subtle immune deficiency. Not that you can’t get HIV over 50, but age by itself is enough to cause Zoster reactivation. When it comes to Zoster, 50 is “elderly” (that’s when I began to get AARP mailings. Hemlock & Neptune Societies too!!!).
WOMEN with Acute RLQ Pain
Women are more complicated than men, because a variety of gynecological conditions may be responsible. The pain from these is usually felt below the uppermost crest of the pelvic bone, whereas appendicitis is felt above it, closer to the belly-button, but unfortunately the human body doesn’t obey such hard-and-fast rules.
If there’s any chance at all a woman might be pregnant, we get a pregnancy test. Contraception (even having had a tubal ligation) can fail. Don’t miss the “Moral” at the end of this sub-section.
Ectopic Pregnancy — A pregnancy that gets stuck in the fallopian tube instead of the uterus will grow and eventually rupture the tube (potentially fatally). Pain doesn’t occur until at least 4 weeks after conception (6 weeks after last normal menstrual period if the periods are monthly and regular). A significant number of women, especially those with irregular periods, are not aware that they are pregnant. The urine pregnancy test should always be positive, so an accurate negative pregnancy test means no Ectopic (click link to read about possible inaccuracies).
If an Ectopic Pregnancy has ruptured, not only is the pain severe, but the woman is quite ill, will be bleeding (often all internally), or even in shock. Pelvic exam is very tender. The difficult case, however, is when pain is caused by a slowly-enlarging intact ectopic. Physical examination is usually normal. Timely diagnosis is necessary to prevent rupture, preserving the tube & often saving a life.
The following women are at higher risk of Ectopics, so low abdominal pain should be taken very seriously:
- Previous Ectopic Pregnancy
- Previous tubal surgery
- Current IUD (much less chance of pregnancy, but if pregnant, more chance of Ectopic
- Previous STDs
- Multiple sex partners
New-onset lower abdominal pain, with a positive pregnancy test, should be managed in an ER, where they’ll perform a transvaginal ultrasound (TVUS) [uses a vaginal probe to see better], and measure the blood level of human chorionic gonadotropin (hCG) [the hormone that naturally rises in pregnancy].
- If the TVUS shows a mass in the tube, there’s an ectopic. Unfortunately, Ectopics can’t usually be seen
- If the TVUS shows a fetus in the uterus, then there’s no ectopic (except in the rare of case of an ectopic twin, which isn’t so rare with in vitro fertilization)
- If the TVUS shows no fetus at all, it might be an ectopic, or might be simply too early to see one in the uterus
In the last case above, when the initial TVUS shows nothing, hCG gets measured every 2-3 days. Depending on the week of pregnancy, there are protocols showing how much it should rise if the pregnancy is normal. If less, it suggests an Ectopic. Tests should all be done by the same laboratory.
At a certain point, the TVUS gets repeated too. Diagnosis may be tricky, but gynecologists know how to keep checking until finally deciding, so as to treat before an ectopic might rupture, but not inadvertently terminate a normal pregnancy.
MORAL — Every woman with new-onset of RLQ, LLQ, or pelvic pain should get a urine pregnancy test. Even women using birth control, which can fail (especially it’s an IUD, which is wonderful contraception but can predispose to ectopics). Even women who’ve had their tubes tied (though not, of course, if they had a hysterectomy).
- What about 10-year-old girls? A good idea, just to be safe. We tell parents, “This is extremely unlikely, but I’m obligated,” and most understand.
- What about a woman who 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 pregnancy test in along with the regular urinalysis. We see all sorts of denial in our profession. I don’t charge for it (that might be impossible in other settings).
Miscarriage — This is also called “spontaneous abortion (SAB),” distinguishing it from an intentional “therapeutic abortion (TAB).” Most women with painful miscarriages already know that they are pregnant, since a miscarriage very early on causes more bleeding than pain. But some may not.
Once a positive pregnancy test has been identified, the two main conditions to distinguish from a miscarriage are an Ectopic Pregnancy and a “Threatened Abortion,” which means that a possible miscarriage seems to be happening, but the pregnancy may also wind up continuing normally. The Transvaginal Ultrasound and repeated testing for hCG (the hormone of pregnancy) will establish the differences. OB-GYN specialists are adept at this.
Another type of miscarriage is “Septic Abortion,” in which the dead fetus becomes infected. Pain is moderate-to-severe, pelvic exam is very tender, pus may be noted in the vagina (coming from the uterus), and fever is often present. This is uncommon during spontaneous miscarriages, but can occur. It can kill the mother.
Pelvic Inflammatory Disease (PID) (Tubal Infection) — The medical term is “salpingitis,” meaning infection in a fallopian tube. The infection is usually caused by gonorrhea or chlamydia, both sexually transmitted diseases (STDs). But it can also be due to non-STD germs, especially if the woman has an IUD, or had a pelvic procedure done recently. In the case of the STDs, sometimes the germ has already been present inside for a long time (especially chlamydia), so you can’t always blame a recent partner.
PID is serious because, 1) in rare cases it can spread to the blood and be fatal; and 2) the longer an infection is present, the more scars can form that can cause infertility. So early diagnosis & treatment are essential. Urine tests are done for the STDs, but results take a few days to come back.
We diagnose PID during pelvic examination, by finding “cervical motion tenderness” (“CMT” in Gynecology jargon). Wiggling the cervix (the tip of the uterus) is very tender. The maneuver can’t be felt by a woman without any pelvic disease.
Antibiotics cure the infection, but treatment may be complicated because of all the possible germs. Since permanent infertility is a possible complication, some women get admitted for IV administration. Rarely, PID results in an abscess that requires surgery.
Mittelschmerz — German for “midcycle,” this is normal pain that occurs each month as the egg is released from the ovary. In many women it’s mild or not even felt, but it can be moderate-to-severe. It lasts a few hours to 2 days. Mittelschmerz occurs 14 days before the onset of the next menstrual period, which is hard to determine if you’re irregular.
Dysmenorrhea (same link as above) — Greek for “painful menstruation,” it means menstrual pain, which by definition occurs during menstruation. However, painful bleeding can also occur with a miscarriage, or an ectopic pregnancy. If cycles are irregular, it can be hard to know.
Most women know when they have menstrual cramps (& thus never even seek care for them). In an unusual case, a pregnancy test can rule out those more serious conditions. Painful bleeding can also occur with PID, in which case the pregnancy test is negative, but the pain is out of proportion. A pelvic exam can distinguish. Endometriosis can also cause severe menstrual cramps, but that’s hard to suspect until they become more chronic after several cycles. See symptom topic Abnormal Vaginal (Uterine) Bleeding.
Ovarian Disease — Several conditions of the ovary can cause acute abdominal or pelvic pain. Before menopause, normal cysts form each month as the egg is released from the ovary. Usually these disappear; sometimes they continue to grow, and may rupture, which causes acute pain. Such cysts can be distinguished from ectopic pregnancy (by negative pregnancy test) and from PID (no CMT on pelvic exam). Pain can be controlled by simple medications, and rarely lasts more than a few days.
Worse is Ovarian Torsion, i.e. a twisted ovary. The pain is much worse than with ruptured cysts; nausea & vomiting are common. Ultrasound can distinguish between torsion & cyst. Torsion requires immediate surgery to save the ovary; gynecologists try to avoid surgery for cysts & other non-cancerous tumors, since any pelvic procedure might affect fertility.
Ovarian cancer doesn’t cause acute symptoms; we address it under “Chronic Abdominal Pain.”
MEN with RLQ Pain
Nothing much extra to say here. Men with Testicular Diseases, like infections or torsion (twisting) can point to the testicle as opposed to the abdomen, except for the very rare case in which the pain & vomiting are too severe to communicate. There are old rumors of surgeons having operated for “appendicitis” without examining the testicles. I doubt there’s much risk of that happening these days.
Acute Left Lower Quadrant (LLQ) Pain
The possible diagnoses here are similar to the RLQ, although appendicitis is not an issue (except for the very rare and unfortunate person with unsuspected reversal of internal organs, called “situs inversus”). However , some conditions are unique to the LLQ.
Constipation is possible cause of LLQ pain, but it has to be very recent or extreme to cause acute LLQ pain. I’d only suspect it if it began the same time as the pain. Constipation more commonly causes chronic low-grade abdominal discomfort in the LLQ.
The elderly, debilitated, and those paralyzed or who have other serious diseases of the spinal cord, can have a “fecal impaction.” This is when stool slowly builds up in the rectum, so much that it can’t be defecated out. The pain eventually begins, and may feel uncomfortable enough rather abruptly, that it seems “acute”. Sometimes the person says they also have “diarrhea,” which is really just loose stool leaking out around the impaction.
See our symptom topic Constipation for a systematic approach to work-up. [ADD sentence LATER when topic is written]
Diverticulitis — Infection & inflammation in a diverticulum, a tiny pocket of bowel in the large intestine (colon). Almost everybody over 50 has some diverticula, which are otherwise harmless unless they get inflamed or bleed. The condition is now occurring a bit 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 begins a little more subtly than appendicitis. Pain may evolve over 3-4 days. Up to 50% of patients may report prior similar episodes. Diagnosis is made by CT scan, which is worth obtaining, since these are patients who are usually older [often >60] with risks for other diseases. The CT will also show if there are serious complications like bowel perforation or abscess formation.
For a relatively younger (50’s) and otherwise healthy patient, some clinicians may simply prescribe antibiotics instead of ordering a CT, & see if the illness resolves. However, even with CT-proven diverticulitis, studies are equivocal as to whether antibiotics help, since inflammation may get better on its own.
Other abdominal diseases also cause LLQ pain, like ulcerative colitis and proctitis (rectal inflammation / infection). But they also cause other more prominent symptoms, like diarrhea, rectal bleeding, rectal discharge, or severe pain with defecation (tenesmus). These latter symptoms overshadow pain.
It’s rare for pain to be occur only in the Suprapubic area. Usually either the RLQ or LLQ is also prominently painful. But for persons with only suprapubic pain, we’d wonder about all of the conditions of the RLQ & LLQ (although not so much appendicitis or diverticulitis), but would mainly consider the following (copied from our initial Table above):
- Urinary Tract Infection (bladder or prostate) (women or men)
- Uterine Infection (Endometritis)
- Dysmenorrhea (menstrual pains) [same link as above]
- Muscle Strain
- Ectopic Pregnancy
- Degeneration of Uterine Fibroid
Bladder infection practically always includes other specific symptoms like painful urination or frequent urge to urinate small quantities. We rule it out by a simple urinalysis. See our topic Urinary Problems.
Women With Suprapubic Pain
- We rule out Ectopic Pregnancy and Miscarriage by a pregnancy test.
- Dysmenorrhea (menstrual pains) occur during menstruation (duh)
- Mittelschmerz occurs at midcycle (14 days before the next period)
- Uterine infection usually only occurs right after childbirth, though it can be a part of tubal infections (PID). If a woman’s lower abdomen is tender, a pelvic exam will make the diagnosis. See our discussion above of women with RLQ pain.
- Uterine fibroids cause chronic, not acute, pain (except in the rare case of acute degeneration, which is severe enough that we’d worry about something else and refer to an ER, where an ultrasound or CT scan will make the diagnosis).
For both Women and Men — That leaves Muscle Strain as a very common cause of pure Suprapubic Pain. See the discussion of other diagnoses under RLQ pain above.
See Lower Abdominal Pain for the clinician’s condensed thought-process when face-to-face with a patient.