Article: Constipation and its classification - by Dr. Preeti Kachroo Bhagat, Dr. Abhishek Bhagat

Constipation is a condition, where a person faces hard feces and experiences difficulty in passing stools. At times it leads to painful symptoms leading to bowel obstruction, caused by dietary, hormonal or anatomical reasons. Constipation is one of the most common prevalent gastrointestinal symptoms, affecting approximately 14% of the population. There is no single definition of constipation and it can be defined by one or more symptoms: hard stool, infrequent stools (typically fewer than three per week), a sense of incomplete bowel evacuation, and excessive time spent on the toilet or in unsuccessful defecation. 
Causes
Constipation is frequently multifactorial and can result from systemic or neurologic disorders or medications. Constipation may also be caused by conditions such as:
· Primary diseases of the colon (stricture, cancer, anal fissure, proctitis) 
· Metabolic disturbances (hypercalcemia, hypothyroidism, diabetes mellitus) 
· Neurologic disorders (parkinsonism, spinal cord lesions) 
Classification
Constipation can be classified into three broad categories: 
a) normal-transit constipation, 
b )slow-transit constipation, and 
c) disorders of defecatory or rectal evacuation. 
More than one mechanism may contribute to constipation in a patient. “The Rome II criteria” is the widely accepted format for diagnosis of constipation.
"Functional" constipation (or Normal-transit constipation) is the most common form of constipation that clinicians see. In patients with this disorder, stool traverses at a normal rate through the colon and the stool frequency is normal, yet patients believe they are constipated. In this group of patients, constipation is likely to be due to a perceived difficulty with evacuation or the presence of hard stools. The patients may experience bloating and abdominal pain or discomfort, and they may exhibit increased psychosocial distress; some may have increased rectal compliance, reduced rectal sensation, or both.