Right Lower Abdominal Pain: Appendicitis vs. Kidney Stones

Pain in the lower right side of your abdomen often raises one immediate question: Could this be appendicitis? Appendicitis is an important cause of right lower abdominal pain, but it is not the only one. Kidney stones, bowel problems, ovarian conditions, and pregnancy-related emergencies can cause pain in the same general area.

The location matters, but where the pain started, how it moved, and which other symptoms appeared with it can be just as useful. Severe pain, rapidly worsening pain, or abdominal pain with concerning symptoms should be evaluated promptly rather than diagnosed at home.

How does appendicitis pain usually begin?

Appendicitis does not always start with pain directly over the appendix.

A typical pattern is pain that begins near the belly button and then moves down toward the lower right side of the abdomen. The pain may start suddenly, become worse over several hours, and hurt more with movement, coughing, sneezing, or deep breathing.

Other symptoms can include:

• Loss of appetite
• Nausea or vomiting
• Fever
• Abdominal swelling
• Constipation or diarrhea

Not everyone follows the classic pattern. Children and some other patients may have less typical symptoms, which is one reason symptoms alone cannot confirm appendicitis. NIDDK recommends immediate medical evaluation when appendicitis is suspected because it is considered a medical emergency.

How is kidney stone pain different?

A kidney stone that moves into a ureter—the tube carrying urine from a kidney to the bladder—can also cause severe abdominal pain.

The pain more often begins in the back or side and may spread into the lower abdomen or groin. It may also come and go in waves rather than steadily worsening in one location.

Urinary symptoms make a kidney stone more likely to be considered. These can include:

• Pink, red, or brown urine from blood
• A frequent urge to urinate
• Pain or burning with urination
• Passing only a small amount of urine
• Cloudy or bad-smelling urine

Nausea and vomiting can occur with kidney stones as well, so vomiting does not automatically point toward appendicitis.

The differences below can help you describe your symptoms to a health care professional, but they cannot diagnose the cause by themselves.

What to notice	Appendicitis may look like	Kidney stones may look like
Where pain may begin	Near the belly button	Back or side
Where pain may move	Toward the lower right abdomen	Toward the lower abdomen or groin
Pain pattern	Often worsens over hours	May come and go in waves
Other possible symptoms	Loss of appetite, nausea, vomiting, fever	Blood in urine, urinary urgency, painful urination, nausea or vomiting

Because the patterns can overlap, right lower abdominal pain should not be labeled appendicitis or a kidney stone based only on location.

What other conditions can cause lower right abdominal pain?

The intestines and reproductive organs can also cause pain in this area.

Constipation, diarrhea, intestinal inflammation, or bowel obstruction may cause abdominal pain along with bloating, vomiting, or changes in bowel movements. Persistent or recurring abdominal pain, particularly with rectal bleeding or significant changes in bowel habits, deserves medical evaluation.

For people with ovaries, sudden pelvic or lower abdominal pain can also come from an ovarian problem. An ovarian cyst may become painful if it bleeds, ruptures, or interferes with blood supply to the ovary. Sudden severe pelvic pain with nausea or vomiting can occur with ovarian torsion or a ruptured cyst and needs prompt medical assessment.

Pregnancy possibility also changes how lower abdominal pain should be evaluated. An ectopic pregnancy may cause pelvic or abdominal pain and vaginal bleeding. Abdominal pain accompanied by shoulder pain, vaginal bleeding, dizziness, or fainting during a possible pregnancy requires immediate medical care because internal bleeding can become life-threatening.

What tests are used for right lower abdominal pain?

There is no single test used for every person with right lower abdominal pain.

A clinician will usually start by asking:

• When did the pain begin?
• Where did it begin?
• Has the location changed?
• Is the pain constant or does it come in waves?
• Are you vomiting or running a fever?
• Have your bowel movements changed?
• Do you have blood in your urine or pain with urination?
• Is pregnancy possible?

For possible appendicitis, evaluation may include a physical abdominal exam, blood tests, urinalysis, and imaging. A pregnancy test may also be performed when pregnancy is possible. Ultrasound, MRI, or CT may be selected depending on the patient and suspected cause.

When a kidney stone is suspected, urine testing can look for blood, minerals, white blood cells, or bacteria. Imaging may be used to locate a stone and determine whether it is blocking the urinary tract. CT is one imaging method commonly used to identify a stone’s size and location.

When should right lower abdominal pain be treated as urgent?

Get immediate medical help for sudden, sharp abdominal pain, especially if your abdomen becomes stiff, hard, or very tender. Blood in vomit or stool and an inability to have a bowel movement while vomiting are also reasons to seek immediate care.

Do not delay evaluation if you suspect appendicitis, or if severe pain is accompanied by urinary symptoms that could indicate a kidney stone or urinary blockage.

If pregnancy is possible, abdominal or pelvic pain with vaginal bleeding, shoulder pain, severe dizziness, or fainting requires immediate medical attention.

When you seek care, write down where the pain first started, where it is now, whether it moves or comes in waves, and any urinary, bowel, fever, vomiting, or bleeding symptoms. Those details can help your health care team narrow down the possible cause and choose the appropriate tests.

Sources:
National Institute of Diabetes and Digestive and Kidney Diseases — Symptoms & Causes of Appendicitis
National Institute of Diabetes and Digestive and Kidney Diseases — Diagnosis of Appendicitis
National Institute of Diabetes and Digestive and Kidney Diseases — Symptoms & Causes of Kidney Stones
National Institute of Diabetes and Digestive and Kidney Diseases — Diagnosis of Kidney Stones
MedlinePlus — Ectopic Pregnancy
MedlinePlus Medical Encyclopedia — Ovarian CystsMedlinePlus — Abdominal Pain