Flank Pain: Causes, Symptoms and When to Worry

It starts with a twinge. Maybe a dull ache after a long day or a sudden, sharp stab takes your breath away. Whatever the sensation, flank pain the discomfort felt on either side of your body between the lower ribs and hips is something you shouldn’t ignore. It can be as harmless as a strained muscle or as serious as a kidney infection.

In this guide, we’ll walk you through the flank pain causes, common flank pain symptoms, and when you should consider seeing a doctor. Whether you’re dealing with left, right, or flank pain on both sides, this blog is your go-to resource.

What Is Flank Pain?

Pain on one’s side is referred to as flank pain, often between the ribs and the hip. This area houses vital organs like the kidneys and is closely related to structures in the back, digestive system, and reproductive system.

The pain may be subtle or intense, continuous or sporadic, and may radiate to the abdomen or lower back. While flank pain on one side is more common, experiencing flank pain on both sides can point to more systemic or bilateral issues.

Flank Pain Symptoms

Understanding how flank pain symptoms present can help identify what’s causing the discomfort. Common symptoms include:

• Sharp pain on one or both sides, or a vague discomfort
• Pain that worsens with movement
• Radiating pain to the groin or lower abdomen
• Fever and chills (possible infection)
• Nausea or vomiting
• Blood in urine
• Burning sensation while urinating
• Muscle stiffness or spasms

If your pain is persistent, severe, or associated with any of the above symptoms, you should seek medical evaluation immediately.

Causes of Flank Pain

Several conditions can cause flank pain, ranging from mild to life-threatening. Here are some of the most common culprits:

1. Kidney-Related Issues

The kidneys are one of the most frequent sources of flank pain, particularly if you’re experiencing right flank pain or left flank pain.

• Kidney Stones: These hard deposits can block urine flow and cause sharp, excruciating pain that may radiate to the groin.
• Kidney Infections (Pyelonephritis): Infection can lead to flank pain, fever, chills, and a burning sensation during urination.
• Polycystic Kidney Disease: A genetic condition where fluid-filled cysts form on the kidneys, often leading to chronic flank pain on both sides.
• Hydronephrosis: swelling of one or both kidneys as a result of a urinary tract blockage.

2. Musculoskeletal Causes

If you’ve recently lifted something heavy or twisted your body awkwardly, your flank pain could be muscular in origin.

• Muscle Strain: A common cause, especially if you’ve had recent physical activity or poor posture.
• Herniated Disc or Spinal Problems: Issues in the lower spine can compress nerves, causing flank pain that radiates down the leg.

3. Urinary Tract Infections (UTIS)

Though UTIS typically cause pelvic discomfort, a severe or untreated infection can ascend to the kidneys and lead to left flank pain, right flank pain, or flank pain on both sides.

4. Gastrointestinal Issues

Your digestive system can also be a hidden source of flank pain.

• Constipation: Severe constipation can cause bloating and pain in the flanks.
• Diverticulitis: Inflammation in the colon that can cause left-sided flank pain.
• Irritable Bowel Syndrome (IBS): While IBS more commonly causes abdominal pain, some patients experience discomfort in the flanks.

5. Reproductive System Conditions

For women, gynecological conditions can sometimes mimic or contribute to flank pain:

• Ovarian Cysts: Huge cysts can cause right or left flank pain.
• Endometriosis: This condition can lead to referred pain in the flank, especially during menstruation.
• Ectopic Pregnancy: A case where a fertilized egg implants outside of the uterus and causes medical emergency, sometimes presenting with sharp flank pain.

Men may also experience referred flank pain from testicular conditions, like torsion or infection.

6. Shingles (Herpes Zoster)

Before the rash appears, shingles can cause a burning or tingling sensation in one flank. This pain is usually one-sided and very intense.

Flank Pain: When to Worry

While some causes of flank pain are benign and resolve on their own, others require urgent medical attention. Here’s when you should be concerned:

Sudden, Severe Pain

Could indicate kidney stones or a ruptured ovarian cyst.

Pain with Fever or Chills

May point to a kidney infection or systemic infection.

Blood in Urine

Never normal. It could signal kidney stones, infections, or, in rare cases, tumours.

Pain Lasting More Than a Few Days

Chronic or worsening pain should always be evaluated to rule out more serious conditions.

Flank Pain Both Sides

Simultaneous pain on both flanks may be a sign of a systemic condition, such as polycystic kidney disease or dehydration affecting both kidneys.

Diagnosing Flank Pain: What to Expect

When you visit a healthcare provider with flank pain, here’s what they might do:

• Medical History & Physical Exam: Helps narrow down the possible causes.
• Urine Tests: Check for blood, infection, or abnormal substances.
• Blood Tests: To assess kidney function or look for signs of infection.
• Imaging: Ultrasound or CT scans often detect stones, cysts, or structural abnormalities.
• MRI or X-ray: Used if musculoskeletal issues are suspected.

For insurance and documentation, flank pain ICD 10 codes, such as R10.9 (Unspecified abdominal pain) or more specific ones, are used for diagnosis and billing purposes.

Treatment Options for Flank Pain

Treatment depends entirely on the underlying cause:

• Kidney Stones: Smaller stones may pass naturally. Larger ones might require medical intervention like lithotripsy or surgery.
• Infections: UTIS or kidney infections require antibiotics and increased fluid intake.
• Muscle Strain: Rest, ice, gentle stretching, and anti-inflammatory medications can relieve symptoms.
• Chronic Diseases: Conditions like polycystic kidney disease or endometriosis require ongoing management and specialist care.

Always follow your doctor’s advice and avoid self-diagnosing or self-medicating, especially with something as variable as flank pain.

Preventing Flank Pain

While you can’t prevent every type of flank pain, some lifestyle changes can reduce your risk:

• Stay Hydrated: Especially important for kidney health and preventing stones.
• Exercise Safely: Strengthen your core and back muscles while avoiding strain.
• Practice Good Posture: Reduces the risk of musculoskeletal pain.
• Manage Chronic Conditions: Check blood sugar, blood pressure, and hormonal health.
• Seek Early Treatment: Don’t ignore back discomfort or urine signs.

Conclusion:

Your body uses flanking as a warning sign when anything is wrong. Paying attention is always crucial, whether you have a minor muscle pain or a more complicated problem with your kidneys or reproductive organs. If you are aware of the symptoms and possible causes of flank pain, you can make better decisions about when to seek assistance.

While many causes are minor, others can be dangerous if left untreated. If you’re experiencing persistent left flank pain, right flank pain, or flank pain on both sides, don’t wait. Contact a healthcare provider for timely evaluation and treatment.