Diarrhea
Synonyms and keywords: Loose stools

# Overview
Diarrhea is defined as the passage of unformed or abnormally liquid stools at an increased frequency. Diarrhea can be classified as acute or chronic. Acute diarrhea has a duration of less than 2 weeks and may be classified on the basis of etiology and presentation. On the basis of etiology, acute diarrhea may be classified into infectious and non-infectious subtypes. Subacute diarrhea is defined as a diarrhea lasting for two to four weeks. Although chronic diarrhea has multiple definitions, a current working definition is the production of loose stools for longer than 4 weeks. Frequent defecation with normal consistency is termed psuedo-diarrhea. There are 3 basic categories of chronic diarrhea: watery, fatty (malabsorption), and inflammatory (with blood and pus). The diagnosis is based on duration of symptoms, signs, microscopic stool examination and culture, stool osmolarity, and in some rare instances colonoscopy. The treatment is mainly based on severity of symptoms, etiology and availability of medications. Prevention is based on proper maintaining the filtration systems at water plants, hand wash, and effectively use of alcohol-based hand sanitizers. Vaccination for some viruses, such as Rotavirus is a part of preventive measures.

# Classification
Diarrhea can be classified as acute or chronic depending on the duration of onset of symptoms. Acute and chronic diarrhea can be further classified as follows:

## Classification of Acute Diarrhea

## Classification of Chronic Diarrhea

# Differential Diagnosis of Diarrhea of other diseases
To review the differential diagnosis of diarrhea, click here.
To review the differential diagnosis of acute diarrhea, click here.
To review the differential diagnosis of chronic diarrhea, click here.
To review the differential diagnosis of traveler's diarrhea, click here.
To review the differential diagnosis of acute watery diarrhea, click here.
To review the differential diagnosis of acute bloody diarrhea, click here.
To review the differential diagnosis of acute fatty diarrhea, click here.
To review the differential diagnosis of chronic watery diarrhea, click here.
To review the differential diagnosis of chronic bloody diarrhea, click here.
To review the differential diagnosis of chronic fatty diarrhea, click here.
To review the differential diagnosis of acute diarrhea and fever, click here.
To review the differential diagnosis of chronic diarrhea and fever, click here.
To review the differential diagnosis of acute diarrhea and abdominal pain, click here.
To review the differential diagnosis of chronic diarrhea and abdominal pain, click here.
To review the differential diagnosis of acute diarrhea and weight loss, click here.
To review the differential diagnosis of chronic diarrhea and weight loss, click here.
To review the differential diagnosis of acute diarrhea, fever, and abdominal pain, click here.
To review the differential diagnosis of chronic diarrhea, fever, and abdominal pain, click here.
To review the differential diagnosis of acute diarrhea, abdominal pain, and weight loss, click here.
To review the differential diagnosis of chronic diarrhea, abdominal pain, and weight loss, click here.

## Diarrhea
The following table outlines the major differential diagnoses of diarrhea.
Abbreviations: GI: Gastrointestinal, CBC: Complete blood count, WBC: White blood cell, RBC: Red blood cell, Plt: Platelet, Hgb: Hemoglobin, ESR: Erythrocyte sedimentation rate, CRP: Creactive protein, IgE: Immunoglobulin E, IgA: Immunoglobulin A, ETEC: Escherichia coli enteritis, EPEC: Enteropathogenic Escherichia coli, EIEC: Enteroinvasive Escherichia coli, EHEC: Enterohemorrhagic Escherichia coli, EAEC: Enteroaggregative Escherichia coli, Nl: Normal, ASCA: Anti saccharomyces cerevisiae antibodies, ANCA: Antineutrophil cytoplasmic antibody, DNA: Deoxyribonucleic acid, CFTR: Cystic fibrosis transmembrane conductance regulator, SLC10A2: Solute carrier family 10 member 2, SeHCAT: Selenium homocholic acid taurine or tauroselcholic acid, IEL: Intraepithelial lymphocytes, MRCP: Magnetic resonance cholangiopancreatography, ANA: Antinuclear antibodies, AMA: Anti-mitochondrial antibody, LDH: Lactate dehydrogenase, CPK: Creatine phosphokinase, PCR: Polymerase chain reaction, ELISA: Enzymelinked immunosorbent assay, LT: Heatlabile enterotoxin, ST: Heatstable enterotoxin, RT-PCR: Reversetranscriptase polymerase chain reaction, CD4: Cluster of differentiation 4, HIV: Human immunodeficiency virus, RUQ: Right-upper quadrant, VIP: Vasoactive intestinal peptide, GI: Gastrointestinal, FAP: Familial adenomatous polyposis, HNPCC: Hereditary nonpolyposis colorectal cancer, MTP: Microsomal triglyceride transfer protein, Scl70: Antitopoisomerase I, TSH: Thyroid-stimulating hormone, T4: Thyroxine, T3: Triiodothyronine, DTR: Deep tendon reflex, RNA: Ribonucleic acid

# Related Chapters
- Constipation
- Gastroenteritis