Pencil Thin Stools
What are pencil thin stools?
Changes in the stool can be related to changes in the diet or may be indications of a condition of the digestive tract. Narrowing of the stool may be due to a mass in the colon or rectum that limits the size of the stool that can pass through it. Conditions that cause diarrhea can also cause pencil thin stools.
Persistent pencil thin stool, which may be solid or loose, is one of the symptoms of colorectal polyps or cancer. As the size of the polyp or cancer increases, it can decrease the internal diameter of the colon or rectum so that only thin stool can pass through. Other symptoms can include blood in the stool, abdominal discomfort, and unintended weight loss, particularly in the case of advanced colorectal cancer. Colorectal cancers are diagnosed in about 140,000 people in the United States per year.
Narrowing of the rectum or anus can be caused by enlargement of the prostate in men or may be a complication of anal fissures (tears or cracks), rectal ulcers, Crohn’s disease or ulcerative colitis (inflammatory bowel diseases), or anorectal trauma or surgery.
The loosely formed stools of diarrhea may have a narrow, sometimes ribbon-like appearance. Diarrhea can have a variety of causes; it may go away on its own or become chronic. Diarrhea that is persistent or accompanied by other symptoms may require treatment.
Pencil thin stools that do not resolve within a couple of days or that are associated with other symptoms can be associated with serious conditions. Seek immediate medical care (call 911) if you have bloody stool, black or tarry stool, stool with pus, severe abdominal pain or cramping, high fever (higher than 101 degrees Fahrenheit), or if you suddenly stop passing stool. If you are having diarrhea, it increases your risk of dehydration, which can have significant complications. Symptoms of dehydration, such as decreased urination, excessive thirst, fatigue, and light-headedness, also require immediate medical care.
If your pencil thin stools are persistent or cause you concern, seek prompt medical care
What other symptoms might occur with pencil thin stools?
Pencil thin stools may accompany other symptoms, which vary depending on the underlying disease, disorder or condition. Conditions that affect the digestive tract may also involve other body systems.
Digestive tract symptoms that may occur along with pencil thin stools
Pencil thin stools may accompany other symptoms affecting the digestive system including:
Abdominal pain or cramping
Abdominal swelling, distension or bloating
Abnormally foul-smelling stools
Bloody stool (blood may be red, black or tarry in texture)
Fecal incontinence (inability to control stools)
Mucus or undigested food in feces
Painful bowel movements
Urgent need to pass stool
Other symptoms that may occur along with pencil thin stools
Pencil thin stools may accompany symptoms related to other body systems including:
Bloody or pink-colored urine (hematuria)
General ill feeling
Serious symptoms that might indicate a life-threatening condition
In some cases, pencil thin stools may be a symptom of a life-threatening condition that should be immediately evaluated in an emergency setting. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:
Bloody stool (blood may be red, black or tarry in texture)
Change in level of consciousness or alertness, such as passing out or unresponsiveness
High fever (higher than 101 degrees Fahrenheit)
Inability to pass stool
Not producing any urine, or an infant who does not produce the usual amount of wet diapers
Severe abdominal or rectal pain
What causes pencil thin stools?
Pencil thin stools can be caused by a narrowing in the colon, rectum or anus, or may occur as a result of diarrhea.
Causes of pencil thin stools related to narrowing of the colon, rectum or anus
Causes of colonic or anorectal narrowing include:
Anorectal stenosis (narrowing of the anus or rectum, which can be due to scarring from inflammatory conditions, fissures, ulcers, trauma, or surgery)
Polyps in the colon
Diarrhea-related causes of pencil thin stools
Pencil thin stools can also be due to conditions that cause diarrhea including:
Bacterial, parasitic or viral infection of the gastrointestinal tract
Diverticulitis (inflammation of an abnormal pocket in the colon)
Fecal impaction (hard stool that is difficult to pass)
Inflammatory bowel disease (including Crohn’s disease and ulcerative colitis)
Irritable bowel syndrome (IBS; digestive discomfort that does not cause intestinal damage or serious disease)
Serious or life-threatening causes of pencil thin stools
In some cases, pencil thin stools may be a symptom of a serious or life-threatening condition that should be immediately evaluated in an emergency setting. These include:
Colonic volvulus (twisting of the colon)
Intussusception (telescoping of the intestines into themselves, which can reduce blood supply, cause obstruction, and tissue death)
Questions for diagnosing the cause of pencil thin stools
To diagnose your condition, your doctor or licensed health care practitioner will ask you several questions related to your pencil thin stools including:
When did you first notice pencil thin stools?
Have you noticed any other changes in your stool or bowel habits?
Are you having pain or discomfort anywhere?
Do you have any other symptoms?
Have you experienced any anorectal trauma or had anorectal surgery?
Have you had these symptoms before?
Do you have a family history of colorectal or other types of cancer?
What medications are you taking?
Because pencil thin stools can be due to serious diseases, failure to seek treatment can result in serious complications and permanent damage. Once the underlying cause is diagnosed, it is important for you to follow the treatment plan that you and your health care professional design specifically for you to reduce the risk of potential complications including:
Anemia (low red blood cell count)
Bowel obstruction, perforation or infarction (severe injury to an area of the bowel due to decreased blood supply)
Dehydration and electrolyte imbalance due to long-term diarrhea
Poor nutrition due to vomiting, diarrhea, or a decreased desire to eat
Peritonitis (infection of the lining that surrounds the abdomen)
Spread of cancer
Spread of infection
Surgery to remove parts of the digestive tract due to obstruction, rupture, serious infection, or malignant condition