Sigmoidoscopy of the rectum and colon duration and what is examined

Many people suffer from annoying symptoms such as rectal bleeding, abdominal pain, or bowel disturbances, and these symptoms may lead a doctor to request a sigmoidoscopy. Sigmoidoscopy is an important medical test that helps diagnose rectal and lower colon diseases accurately and quickly, without the need for complex procedures or full anesthesia in most cases. In this article from Dali Medical, we will take a detailed look at what sigmoidoscopy is, how long it takes, what it examines inside the colon, and the most important information a patient needs before undergoing this test.

What is a Sigmoidoscopy?
A sigmoidoscopy is a diagnostic medical procedure used to examine the rectum and the lower part of the colon (sigmoid colon) using a small, flexible tube equipped with a camera and light. This test helps in the early detection of causes of rectal bleeding, colonic inflammation, polyps, and tumors in their early stages.
What is the difference between a Sigmoidoscopy and a Full Colonoscopy?
- Sigmoidoscopy:
  Examines only the rectum and sigmoid colon, and is a quicker, simpler procedure that generally doesn't require complex preparation.
- Full Colonoscopy:
  Examines the entire colon and is used in cases requiring a more comprehensive examination or removal of large polyps.
Is Sigmoidoscopy painful?
In most cases, a sigmoidoscopy is not painful, and the patient may only feel mild discomfort or light pressure in the abdomen during the procedure. A local anesthetic or mild sedative can be used to reduce any discomfort.
How to prepare for Sigmoidoscopy before the test?
To ensure accurate results, the following steps are recommended:
- Partial bowel cleansing using an enema or mild laxative before the procedure.
- Avoid high-fiber foods for one or two days prior to the test.
- Inform the doctor about all medications being used, especially blood thinners and diabetes medications.
How long does Sigmoidoscopy take?
- Flexible Sigmoidoscopy: Typically takes 10 to 20 minutes.
- Rigid Sigmoidoscopy: Usually takes about 5 to 10 minutes.
Can biopsies or polyp removal be done during a Sigmoidoscopy?
Yes, a sigmoidoscopy allows the doctor to:
- Take tissue samples (biopsies) for laboratory analysis.
- Remove small polyps, helping prevent the development of colon cancer.
What are the normal symptoms after a Sigmoidoscopy?
After the test, temporary symptoms such as the following may appear:
- Mild bloating or gas.
- Light abdominal cramping.
- Slight bleeding, especially if biopsies or polyps were removed, which usually resolves quickly.
When should I contact the doctor after Sigmoidoscopy?
You should contact your doctor immediately if any of the following occur:
- Severe or ongoing rectal bleeding.
- Severe abdominal pain that does not improve with time or basic painkillers.
- Fever or chills.
- Severe abdominal bloating or difficulty passing gas with pain.
Do I need to stay in the hospital after Sigmoidoscopy?
In most cases, the patient does not need to stay in the hospital and can go home after a short observation period. If sedation was used, driving or engaging in activities requiring concentration is prohibited until the sedative effects wear off completely.
What should I eat after Sigmoidoscopy?
It is recommended to consume light meals and warm liquids during the first 24 hours post-procedure. Avoid heavy foods or high-fiber foods if experiencing bloating or cramping.
Is there a difference between Flexible and Rigid Sigmoidoscopy?

Flexible Sigmoidoscopy:
More comfortable for the patient, allows the doctor to examine a larger portion of the colon, and permits biopsy and removal of polyps.
Duration: About 10 to 20 minutes.
Rigid Sigmoidoscopy:
A shorter, rigid tube used only for examining the lower rectum. It is quicker but less comfortable.
Duration: Typically 5-10 minutes.

Is Sigmoidoscopy safe for older adults?
Yes, sigmoidoscopy is generally safe for most older adults. The doctor will assess the patient's overall health and any chronic conditions to minimize potential risks.
Can Sigmoidoscopy be done during pregnancy?
It is recommended to postpone sigmoidoscopy during pregnancy unless absolutely necessary, especially in the early months. If the test is required, it is performed with great caution, using minimal air and safe sedatives under strict medical supervision.
How long does it take to recover after Sigmoidoscopy?
Most patients fully recover within 24 hours. Bloating and gas typically disappear within a few hours. Any minor bleeding after biopsies is normal and usually resolves quickly.
Can Sigmoidoscopy detect colon cancer?
Yes, sigmoidoscopy helps detect early changes and polyps in the colon and rectum, contributing to the prevention of colon cancer. However, since it does not examine the entire colon, a full colonoscopy may be recommended in some cases.
Can I return to work immediately after Sigmoidoscopy?
You can return to daily activities right away if no sedative was used. If sedation was used, you must wait until its effects completely wear off before driving or operating machinery.
Is Sigmoidoscopy painful for children?
Sigmoidoscopy is rarely performed on children except in necessary cases. Mild or full anesthesia is usually used depending on the child's age and health condition.
Does Sigmoidoscopy prevent bleeding?
Sigmoidoscopy does not prevent bleeding, but it helps identify the source of bleeding such as hemorrhoids, infections, or polyps. The doctor may address the cause during the procedure.

Types of Sigmoidoscopy

1️⃣ Flexible Sigmoidoscopy:

Scope: Long, flexible tube with a camera and light.
Area Examined: Rectum and sigmoid colon (lower part of the colon).
Preparation: Partial bowel cleansing with an enema or mild laxative.
Benefits: More comfortable than rigid sigmoidoscopy, allows biopsies and polyp removal.
Duration: 10 to 20 minutes.

2️⃣ Rigid Sigmoidoscopy:

Scope: Short, rigid tube.
Area Examined: Only the lower rectum, does not reach the sigmoid colon.
Preparation: Rectal cleansing with an enema only.
Benefits: Quick procedure (5–10 minutes).
Drawbacks: Less comfortable, does not examine the entire sigmoid colon.

3️⃣ Sigmoidoscopy with Biopsy or Polyp Removal:

This is not a separate type, but an additional procedure that can be performed during any type of sigmoidoscopy.
Allows the doctor to remove small polyps and take tissue samples for examination.

Indications for Sigmoidoscopy

1️⃣ Diagnosis of Colon and Rectum Issues:
Sigmoidoscopy is used to examine the lower colon and rectum for abnormalities, helping diagnose causes of rectal bleeding or bowel disorders.

2️⃣ Diagnosis of Rectal Bleeding or Blood in Stool:
Blood in the stool may be caused by:

Hemorrhoids
Anal fissures
Benign or malignant tumors
Sigmoidoscopy helps pinpoint the source of bleeding.

3️⃣ Diagnosis of Lower Gastrointestinal Diseases:

Colonic inflammations (e.g., ulcerative colitis).
Crohn’s disease, if the lower colon is affected.
Evaluation of certain irritable bowel syndrome cases after excluding organic causes.

4️⃣ Detection of Benign and Malignant Tumors:
Sigmoidoscopy helps detect early-stage colon and rectal cancers. It also allows for the removal of small polyps during the procedure, reducing the risk of cancer.

5️⃣ Follow-up for Previous Medical Conditions
Sigmoidoscopy is used as a routine examination for individuals with a medical history of:

Colonic polyps
Colon cancer
Chronic colitis

6️⃣ Evaluation of Chronic Bowel Changes
It helps in assessing chronic conditions like constipation, diarrhea, or sudden changes in stool shape or color.

7️⃣ Preparation for Some Therapeutic Procedures
Such as:

Removal of small polyps
Taking biopsies for tissue examination

How is Sigmoidoscopy performed?

Steps for Flexible Sigmoidoscopy

Preparation: Partial bowel cleansing using an enema or mild laxative before the test.
Patient Position: Lying on the left side with knees bent (Sim's position).
Inserting the scope: The doctor gently inserts the scope through the anus, and the image is displayed on a screen.
Examination: The doctor looks for signs of inflammation, bleeding, polyps, or tumors and may take biopsies if needed.
Procedure Duration: Typically 10 to 20 minutes, usually without full anesthesia.

Steps for Rigid Sigmoidoscopy

Preparation: Cleansing only the rectum.
Inserting the scope: The rigid scope is gently inserted.
Examination: Only the lower rectum is examined.
Procedure Duration: Usually 5 to 10 minutes.

Common and Temporary Side Effects After Sigmoidoscopy

Bloating and gas: Caused by air introduced into the colon for clearer visualization.
Mild abdominal cramps: A temporary sensation of mild discomfort.
Slight bleeding: Especially if biopsies are taken or polyps are removed, usually resolving quickly.

Rare Complications

Severe or persistent bleeding: Rare, usually after removal of large polyps or deep biopsies.
Perforation (tear) in the bowel: Very rare, and much less common than with a full colonoscopy.
Reaction to sedatives: If sedatives were used, dizziness, low blood pressure, or rare difficulty breathing may occur.

If you experience severe pain, heavy bleeding, fever, or severe bloating that doesn’t improve, you should contact your doctor immediately.

Common and Temporary Side Effects After Sigmoidoscopy (Continued)

These are common symptoms and generally disappear within hours or a day:

Bloating and gas: Caused by the air injected into the colon to aid visibility. It improves with light movement or passing gas.
Mild abdominal cramps: A normal sensation of mild cramping or temporary tightness, which fades shortly after the test.
Very slight bleeding: If biopsies were taken or small polyps removed, you may see light bleeding that stops within a few hours.
Mild discomfort around the anus: Caused by the insertion of the scope. A soothing ointment may be used if needed.

Rare and Serious Complications

While sigmoidoscopy is generally very safe, rare complications can occur:

Severe bleeding: Extremely rare, mostly after the removal of large polyps or deep biopsies. If the bleeding continues or is heavy, immediate medical attention is necessary.
Bowel perforation (tear): Very rare, less common than with a full colonoscopy. Symptoms include:
- Severe abdominal pain
- Extreme bloating
- Fever
- Nausea or vomiting
  This is an emergency situation that may require surgical intervention.
Sedative reactions: If a mild sedative was used, you may experience:
- Dizziness
- Low blood pressure
- Difficulty breathing (very rare)
  These reactions are generally managed under medical supervision during and after the test.

Important Tips After Sigmoidoscopy

Drink warm liquids to help reduce bloating.
Eat light meals after the test unless advised otherwise by your doctor.
Light movement helps expel gas.
Monitor for any increased bleeding or severe pain and contact your doctor immediately.

What Happens During Sigmoidoscopy?

1️⃣ Arrival at the Exam Site:
You enter the clinic or hospital where the test will be performed.
The doctor or nurse will ask about your medical history, medications, and any allergies.

2️⃣ Preparation in the Exam Room:
You will wear a gown specifically for the test and lie on your left side with knees bent towards your chest (Sim’s position).
In most cases, full anesthesia isn’t needed, but a mild sedative may be used if you're anxious.

3️⃣ Inserting the Scope:
The doctor gently inserts the scope through the anus, and the camera will show the images on a screen.

4️⃣ Examining the Rectum and Sigmoid Colon:
The doctor will check for inflammation, bleeding, polyps, or tumors. A biopsy may be taken, or small polyps can be removed if necessary.

5️⃣ Using Air During the Exam:
A small amount of air or CO₂ is introduced to expand the colon for better visualization. This is why you may feel bloated or have the urge to pass gas.

6️⃣ End of the Exam:
The scope is carefully withdrawn.

Duration: Flexible sigmoidoscopy takes about 10–20 minutes; rigid sigmoidoscopy is slightly shorter.

7️⃣ Immediately After the Exam:
You may feel some bloating or mild cramping.

If biopsies were taken, you may have slight bleeding.
If sedatives were used, do not drive and arrange for someone to take you home.

Contraindications for Sigmoidoscopy

In some cases, sigmoidoscopy should not be performed or may be postponed until the condition is treated, depending on the patient's health situation.

1️⃣ Absolute Contraindications:
These conditions completely prohibit sigmoidoscopy due to a high risk of complications:

Bowel perforation (tear): A prior or current tear in the colon or rectum. Inserting the scope may worsen the tear and cause serious complications.
Acute bowel obstruction: Such as a complete colon obstruction. It prevents the scope from passing and increases the risk of bowel perforation.
Acute abdominal infections: Such as appendicitis or peritonitis. Performing the test could spread the infection or cause a tear.
Severe, unstable rectal bleeding: Heavy bleeding can obscure the view and worsen during the procedure.

2️⃣ Relative Contraindications:
These conditions require caution or treatment of the underlying problem before proceeding:

Severe heart or lung disease: Especially if sedatives or mild anesthesia are needed. A thorough health assessment is required before proceeding.
Active infections in the rectum or colon: Such as bacterial colitis or viral infections. It’s best to treat the infection first before performing the exam.
Pregnancy (especially in later stages): It is advised to postpone the test unless absolutely necessary. If it’s essential, it is done with utmost caution under strict medical supervision.
Blood clotting disorders or use of blood-thinning medications: Increases the risk of bleeding, especially when taking biopsies or removing polyps.

3️⃣ Contraindications Related to Exam Preparation:

Inadequate bowel cleansing: This reduces the accuracy of the test and increases the risk of complications.
Heavy foods or supplements that cause gas before the test: These can obstruct visibility and reduce the effectiveness of the sigmoidoscopy.

Expected Recovery Timeline After Sigmoidoscopy

Time Stage	Normal Symptoms	Tips and Advice	When to Contact a Doctor?
During the exam (10–20 minutes)	Light pressure, mild bloating, cramps	Breathe deeply and relax	—
Immediately after (0–1 hour)	Gas, abdominal fullness, mild discomfort	Rest, drink water, light movement	—
After a few hours (1–4 hours)	Mild bloating, light cramping	Light meal, warm liquids, walking	Severe pain, heavy bleeding, persistent vomiting
Within 24 hours	Gradual improvement, slight bleeding if biopsies were taken	Avoid heavy meals, monitor symptoms	Fever, severe pain, abnormal bloating
After 24 hours	Near complete recovery	Return to daily activities	Persistent or worsening symptoms