Cause |
Common Features* |
Tests |
Birth defects of the anus |
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Abnormal position of the anus |
Opening of the anus that appears closer than normal to the genitals |
Measurements to determine the exact location of the anus’s opening |
Anal stenosis (a narrowed anus) |
Delayed passage of the first BM (called meconium) during the first 24–48 hours of life Explosive and painful BMs A swollen abdomen Abnormal appearance or position of the anus |
A doctor's examination |
Blockage of the opening of the anus (anorectal malformations) |
A swollen abdomen No BMs A blockage of the anus detected during a doctor's examination |
A doctor's examination done soon after birth |
Spinal cord problems |
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Meningomyelocele (the most severe form of spina bifida) |
A raw, red area on the back where the spinal cord protrudes, seen at birth A decrease in reflexes of the legs or in muscle tone Absence of the normal reflex of the anus (a tightening when lightly touched, called anal wink) |
Plain x-rays of the lower spine MRI of the spine |
Occult spina bifida (incomplete formation of the bones of the spine) |
Possibly a tuft of hair or dimpling on the skin over the defect, seen at birth |
MRI of the spine |
A tethered spinal cord (during fetal development, the spinal cord is stuck at the lower end of the spinal column and cannot move up to its normal position) |
Problems with walking, pain or weakness in the legs, and back pain Urinary incontinence |
MRI of the spine |
A tumor near the tailbone (sacral teratoma) or other spinal cord tumor |
Back pain, problems with walking, and pain or weakness in the legs Urinary incontinence |
MRI of the spine |
Infection of the spine or spinal cord |
Back pain, problems with walking, and pain or weakness in the legs Fever Urinary incontinence |
MRI of the spine |
Hormonal, metabolic, or electrolyte disorders |
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Diabetes insipidus (due to problems with antidiuretic hormone, which helps regulate the amount of water in the body) |
Excessive thirst and excessive crying that is quieted by giving children water Excessive urination of dilute urine Weight loss and vomiting |
Urine and blood tests to measure how dilute urine and blood are (osmolality) Blood tests to measure antidiuretic hormone levels |
Hypercalcemia (an abnormally high calcium level in the blood) |
Nausea and vomiting, loss of appetite, weight loss, muscle weakness, and abdominal pain Excessive thirst and excessive urination |
Blood tests to measure the calcium level |
Hypokalemia (an abnormally low potassium level in the blood) |
Muscular weakness Excessive urination and dehydration Not growing as expected (failure to thrive) Possibly use of diuretics or certain antibiotics |
Blood tests to measure levels of electrolytes |
Hypothyroidism (an underactive thyroid gland) |
Poor feeding A slow heart rate In newborns, large soft spots (fontanelles) between the skull bones and slack muscle tone Dry skin, intolerance of cold, fatigue, and jaundice |
Blood tests to measure thyroid hormone levels |
Intestinal disorders |
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Delayed passage of the first BM Poor weight gain or failure to thrive Frequent bouts of pneumonia |
A sweat test Possibly genetic testing to confirm the diagnosis |
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Delayed passage of the first BM A swollen abdomen Green or yellow vomit, indicating that it contains bile A narrowed anus detected during a doctor's examination |
X-rays of the lower digestive tract after barium is inserted in the rectum (barium enema) Measurement of pressure inside the anus and rectum (manometry) Biopsy of the rectum |
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Vomiting Poor feeding Weight loss, poor growth, or both Blood in stools |
Stool tests Symptoms that lessen when the formula is changed Possibly endoscopy, colonoscopy, or both |
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Abdominal pain Bloating Weight loss Fatigue |
Blood tests Endoscopy |
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Long-standing (chronic) abdominal pain Diarrhea and constipation that come and go A feeling of incomplete emptying after a BM |
Evaluation of BM patterns and the timing and characteristics of pain Exclusion of other disorders by history, physical examination, and possibly blood tests, stool tests, imaging, or colonoscopy |
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Pseudo-obstruction (which causes symptoms of a blockage but no blockage is detected) |
Nausea and vomiting Abdominal pain and a swollen abdomen |
X-ray of the abdomen Tests to assess how well the bowel functions (bowel motility studies) |
A tumor in the abdomen |
Weight loss, night sweats, and fever Abdominal swelling or pain An abdominal mass detected during a doctor's examination |
MRI |
Drug side effects |
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Use of drugs with anticholinergic effects(such as antihistamines), antidepressants, chemotherapy drugs, or opioids |
Use of drugs that can cause constipation |
A doctor's examination |
Toxins |
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A sudden reduction in the ability to suck Loss of muscle tone Sometimes consumption of honey before age 12 months |
A test for botulinum toxin in stool |
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Usually no symptoms Possibly abdominal pain, fatigue, and irritability Regression in development |
Blood tests to measure the lead level |
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* Features include symptoms and results of the doctor's examination. Features mentioned are typical but not always present. |
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BM = bowel movement; MRI = magnetic resonance imaging. |