Ulcerative Colitis

Epidemiology and Pathophysiology

Epidemiology

• Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: bimodal distribution Bimodal distribution Measures of Central Tendency and Dispersion
  • 15–35 years (slightly older average than in Crohn’s disease [CD])
  • Smaller peak occurs between 50 and 70 years of age
• Men > women
• Disease risk is lower in smokers.
• Most common among whites and eastern European (Ashkenazi) Jews
• Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: 9–20 cases per 100,000 persons per year

Risk factors

An increased risk of developing ulcerative colitis Colitis Inflammation of the colon section of the large intestine, usually with symptoms such as diarrhea (often with blood and mucus), abdominal pain, and fever. Pseudomembranous Colitis (UC) may be associated with the following:

• Genetics Genetics Genetics is the study of genes and their functions and behaviors. Basic Terms of Genetics: HLA-B27 (encodes genes Genes A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. DNA Types and Structure for the major histocompatibility complex Major histocompatibility complex The genetic region which contains the loci of genes which determine the structure of the serologically defined (sd) and lymphocyte-defined (ld) transplantation antigens, genes which control the structure of the immune response-associated antigens, human; the immune response genes which control the ability of an animal to respond immunologically to antigenic stimuli, and genes which determine the structure and/or level of the first four components of complement. Innate Immunity: Phagocytes and Antigen Presentation [MHC])
• Family history Family History Adult Health Maintenance of irritable bowel disease (IBD)
  • Twin concordance rate is 10%–15%
  • First-degree relatives have a 4 times higher risk of developing UC.
• Increased dietary fat intake
• Nonsteroidal anti-inflammatory drug ( NSAID NSAID Nonsteroidal antiinflammatory drugs (NSAIDs) are a class of medications consisting of aspirin, reversible NSAIDs, and selective NSAIDs. NSAIDs are used as antiplatelet, analgesic, antipyretic, and antiinflammatory agents. Nonsteroidal Antiinflammatory Drugs (NSAIDs)) use
• Psychological stress Psychological stress Stress wherein emotional factors predominate. Acute Stress Disorder and intestinal infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease may trigger Trigger The type of signal that initiates the inspiratory phase by the ventilator Invasive Mechanical Ventilation disease onset.

Pathophysiology

The exact pathophysiology is unknown, but is likely associated with a combination of dysregulation of the intestinal epithelium Epithelium The epithelium is a complex of specialized cellular organizations arranged into sheets and lining cavities and covering the surfaces of the body. The cells exhibit polarity, having an apical and a basal pole. Structures important for the epithelial integrity and function involve the basement membrane, the semipermeable sheet on which the cells rest, and interdigitations, as well as cellular junctions. Surface Epithelium: Histology and the immune system Immune system The body’s defense mechanism against foreign organisms or substances and deviant native cells. It includes the humoral immune response and the cell-mediated response and consists of a complex of interrelated cellular, molecular, and genetic components. Primary Lymphatic Organs.

1. Defects in the lamina propria Lamina propria Whipple’s Disease and epithelial barrier of the gastrointestinal (GI) tract allow for more pathogens to penetrate → recruitment Recruitment Skeletal Muscle Contraction and activation of cytotoxic Cytotoxic Parvovirus B19 cells
2. As well, pANCA (perinuclear antineutrophil cytoplasmic antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins: Types and Functions) are thought to recognize nonpathogenic bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology and epithelial cells as pathogens.
3. Excessive release of pro-inflammatory cytokines Cytokines Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner. Adaptive Immune Response, especially from Th2 Th2 A subset of helper-inducer T-lymphocytes which synthesize and secrete the interleukins il-4; il-5; il-6; and il-10. These cytokines influence b-cell development and antibody production as well as augmenting humoral responses. T cells: Types and Functions cells, which seem to target epithelial cells → intestinal inflammation Intestinal inflammation Irritable Bowel Syndrome
4. Causes intestinal epithelium Epithelium The epithelium is a complex of specialized cellular organizations arranged into sheets and lining cavities and covering the surfaces of the body. The cells exhibit polarity, having an apical and a basal pole. Structures important for the epithelial integrity and function involve the basement membrane, the semipermeable sheet on which the cells rest, and interdigitations, as well as cellular junctions. Surface Epithelium: Histology damage including ulcerations, erosions Erosions Corneal Abrasions, Erosion, and Ulcers, and necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage

The inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation invariably involves the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy and may extend proximally through the colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy in a continuous fashion.

• Skip lesions Skip lesions Crohn’s Disease are not seen.
• The small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy is unaffected, except in severe cases of pancolitis.
• Pancolitis: affects the entire colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy
• Ulcerative proctitis Proctitis Inflammation of the mucous membrane of the rectum, the distal end of the large intestine. Chronic Granulomatous Disease or ulcerative proctosigmoiditis: effects limited to the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy or rectosigmoid

Clinical Presentation

The typical presentation for UC is a relapsing disorder that includes the following:

• GI manifestations:
  • Bloody diarrhea Bloody diarrhea Diarrhea that lasts from weeks to months (with or without mucus)
  • Fecal urgency and/or incontinence
  • Tenesmus
  • Colicky lower abdominal pain Abdominal Pain Acute Abdomen that is temporarily relieved by defecation Defecation The normal process of elimination of fecal material from the rectum. Gastrointestinal Motility
• General manifestations:
  • Signs of anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types: fatigue Fatigue The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli. Fibromyalgia, pallor, dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea, palpitations Palpitations Ebstein’s Anomaly
  • Weight loss Weight loss Decrease in existing body weight. Bariatric Surgery
  • Low-grade fever Low-Grade Fever Erythema Infectiosum
• Extraintestinal manifestations (in general, less common than in CD):
  • Primary sclerosing cholangitis Primary Sclerosing Cholangitis Primary sclerosing cholangitis (PSC) is an inflammatory disease that causes fibrosis and strictures of the bile ducts. The exact etiology is unknown, but there is a strong association with IBD. Patients typically present with an insidious onset of fatigue, pruritus, and jaundice, which can progress to cirrhosis and complications related to biliary obstruction. Primary Sclerosing Cholangitis (much more common in UC than CD)
  • Pyoderma gangrenosum Pyoderma gangrenosum An idiopathic, rapidly evolving, and severely debilitating disease occurring most commonly in association with chronic ulcerative colitis. It is characterized by the presence of boggy, purplish ulcers with undermined borders, appearing mostly on the legs. The majority of cases are in people between 40 and 60 years old. Its etiology is unknown. Crohn’s Disease: rapidly progressive painful, red papules → pustules → deep ulcers with central necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage
  • Erythema Erythema Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes. Chalazion nodosum: painful, red nodules that usually appear on the shins Shins Erythema Nodosum
  • Eye inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation (episcleritis, uveitis Uveitis Uveitis is the inflammation of the uvea, the pigmented middle layer of the eye, which comprises the iris, ciliary body, and choroid. The condition is categorized based on the site of disease; anterior uveitis is the most common. Diseases of the Uvea)
  • Oral ulcerations (aphthous stomatitis Stomatitis Stomatitis is a general term referring to inflammation of the mucous membranes of the mouth, which may include sores. Stomatitis can be caused by infections, autoimmune disorders, allergic reactions, or exposure to irritants. The typical presentation may be either solitary or a group of painful oral lesions. Stomatitis)
  • Peripheral arthritis Peripheral Arthritis Reactive Arthritis, ankylosing spondylitis Ankylosing spondylitis Ankylosing spondylitis (also known as Bechterew’s disease or Marie-Strümpell disease) is a seronegative spondyloarthropathy characterized by chronic and indolent inflammation of the axial skeleton. Severe disease can lead to fusion and rigidity of the spine. Ankylosing Spondylitis, or osteoporosis Osteoporosis Osteoporosis refers to a decrease in bone mass and density leading to an increased number of fractures. There are 2 forms of osteoporosis: primary, which is commonly postmenopausal or senile; and secondary, which is a manifestation of immobilization, underlying medical disorders, or long-term use of certain medications. Osteoporosis
  • Aphthous ulcers
  • Deep venous thrombosis Venous thrombosis The formation or presence of a blood clot (thrombus) within a vein. Budd-Chiari Syndrome and/or pulmonary embolism Pulmonary Embolism Pulmonary embolism (PE) is a potentially fatal condition that occurs as a result of intraluminal obstruction of the main pulmonary artery or its branches. The causative factors include thrombi, air, amniotic fluid, and fat. In PE, gas exchange is impaired due to the decreased return of deoxygenated blood to the lungs. Pulmonary Embolism

Diagnosis

Laboratory studies:

• Complete blood count will show anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types, leukocytosis Leukocytosis A transient increase in the number of leukocytes in a body fluid. West Nile Virus, and thrombocytosis (occasionally).
• Complete metabolic panel to check if chronic diarrhea Diarrhea Diarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea has caused electrolyte imbalance 
• ↑ ESR ESR Soft Tissue Abscess

Stool studies: may be used to exclude other causes of inflammatory diarrhea Diarrhea Diarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea (e.g., infection)

Abdominal imaging:

• X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests, computed tomography (CT) and/or magnetic resonance imaging (MRI):
  • Nonspecific findings: thickened bowel wall, colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy dilation
  • Barium enema Barium enema X-ray examination of lower gastrointestinal tract. Imaging is done while a barium compound (e.g., barium sulfate) fills the large intestine via the rectum as a contrast material. Diarrhea: micro-ulcerations, loss of haustra Haustra Colon, Cecum, and Appendix: Anatomy with “lead pipe” appearance, and granular mucosa
• Colonoscopy Colonoscopy Endoscopic examination, therapy or surgery of the luminal surface of the colon. Colorectal Cancer Screening with biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma:
  • Helps to determine the extent of disease
  • Contraindicated during an acute exacerbation due to risk of intestinal perforation Intestinal perforation Perforated viscus or GI perforation represents a condition in which the integrity of the GI wall is lost with subsequent leakage of enteric contents into the peritoneal cavity, resulting in peritonitis. The causes of perforated viscus include trauma, bowel ischemia, infections, or ulcerative conditions, all of which ultimately lead to a full-thickness disruption of the intestinal wall. Perforated Viscus
  • Macroscopic findings:
    • Diffuse and continuous mucosal inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation always involving the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy
    • Neutrophil infiltration limited to the mucosa and submucosa
    • Friable mucosa
    • Loss of haustra Haustra Colon, Cecum, and Appendix: Anatomy, giving the GI tract a “lead pipe” appearance
    • Pseudopolyps: raised areas caused by recurrent ulceration Ulceration Corneal Abrasions, Erosion, and Ulcers, healing, and scarring Scarring Inflammation of the mucosa
  • Microscopic findings:
    • Crypt abscesses
    • Broad-based ulcers that don’t penetrate the muscularis propria 
    • No granuloma formation
    • GI bleeding
    • Epithelial metaplasia Metaplasia A condition in which there is a change of one adult cell type to another similar adult cell type. Cellular Adaptation
    • Submucosal fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans and mucosal atrophy Atrophy Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. Cellular Adaptation

Management

Medical therapies for UC depend on the severity of the disease. The 2 main therapeutic goals are:

1. Terminating an acute, symptomatic attack
2. Preventing recurrent attacks

General therapeutic measures

• Preventative care: colonoscopy Colonoscopy Endoscopic examination, therapy or surgery of the luminal surface of the colon. Colorectal Cancer Screening to screen for colorectal cancer Colorectal cancer Colorectal cancer (CRC) is the 2nd leading cause of cancer-related deaths in the United States. Colorectal cancer is a heterogeneous disease that arises from genetic and epigenetic abnormalities, with influence from environmental factors. Colorectal Cancer (higher risk in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with UC)
  • 8–10 years after initial diagnosis 
  • Every 1–2 years thereafter
• Targeted medical therapy:
  • Corticosteroids Corticosteroids Chorioretinitis
    • For acute disease flare-ups
    • Duration is limited due to complications of long-term use
  • 5-ASA agents (topical or oral mesalamine, sulfasalazine Sulfasalazine A drug that is used in the management of inflammatory bowel diseases. Its activity is generally considered to lie in its metabolic breakdown product, 5-aminosalicylic acid released in the colon. Sulfonamides and Trimethoprim)
  • Immunomodulators ( 6-mercaptopurine 6-Mercaptopurine An antimetabolite antineoplastic agent with immunosuppressant properties. It interferes with nucleic acid synthesis by inhibiting purine metabolism and is used, usually in combination with other drugs, in the treatment of or in remission maintenance programs for leukemia. Antimetabolite Chemotherapy)
  • Anti-TNF therapies ( infliximab Infliximab A chimeric monoclonal antibody to tnf-alpha that is used in the treatment of rheumatoid arthritis; ankylosing spondylitis; psoriatic arthritis and Crohn’s disease. Disease-Modifying Antirheumatic Drugs (DMARDs), adalimumab Adalimumab A humanized monoclonal antibody that binds specifically to tnf-alpha and blocks its interaction with endogenous tnf receptors to modulate inflammation. It is used in the treatment of rheumatoid arthritis; psoriatic arthritis; Crohn’s disease and ulcerative colitis. Disease-Modifying Antirheumatic Drugs (DMARDs))
  • Antidiarrheal Antidiarrheal Antidiarrheal agents include several drug classes, including opioid agonists, somatostatin analogues, adsorbents, and bile acid sequestrants. These medications mainly work through antimotility and/or antisecretory effects. Antidiarrheal Drugs agents
• Surgical intervention:
  • Colectomy
    • Considered curative
    • Reserved for severe diseases, ineffective medical therapy, refractory toxic megacolon Toxic megacolon An acute form of megacolon, severe pathological dilatation of the colon. It is associated with clinical conditions such as ulcerative colitis; Crohn disease; amebic dysentery; or Clostridium enterocolitis. Megacolon, or biopsy-proven malignancy Malignancy Hemothorax
  • Required in case of complications

Management by severity

• Mild-to-moderate disease:
  • Topical mesalamine (via suppository or enema) for acute flares
  • If no response in 4 weeks, consider adding a topical/oral corticosteroid or an oral 5-ASA agent
• Moderate-to-severe disease:
  • Oral corticosteroid and 5-ASA agent for acute flares
  • If no response, consider adding anti-TNF therapies
  • Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship who achieve remission Remission A spontaneous diminution or abatement of a disease over time, without formal treatment. Cluster Headaches are maintained on oral mesalamine +/- an anti-TNF agent.
• Severe-fulminant or refractory disease:
  • Keep nothing by mouth (NPO) for 24–48 hours, administer IV fluids IV fluids Intravenous fluids are one of the most common interventions administered in medicine to approximate physiologic bodily fluids. Intravenous fluids are divided into 2 categories: crystalloid and colloid solutions. Intravenous fluids have a wide variety of indications, including intravascular volume expansion, electrolyte manipulation, and maintenance fluids. Intravenous Fluids, monitor electrolytes Electrolytes Electrolytes are mineral salts that dissolve in water and dissociate into charged particles called ions, which can be either be positively (cations) or negatively (anions) charged. Electrolytes are distributed in the extracellular and intracellular compartments in different concentrations. Electrolytes are essential for various basic life-sustaining functions. Electrolytes, and transfuse for anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types, as needed.
  • IV corticosteroids Corticosteroids Chorioretinitis
  • For patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship who do not respond to corticosteroids Corticosteroids Chorioretinitis within 4–7 days, further management includes infliximab Infliximab A chimeric monoclonal antibody to tnf-alpha that is used in the treatment of rheumatoid arthritis; ankylosing spondylitis; psoriatic arthritis and Crohn’s disease. Disease-Modifying Antirheumatic Drugs (DMARDs)/ cyclosporine Cyclosporine A cyclic undecapeptide from an extract of soil fungi. It is a powerful immunosupressant with a specific action on T-lymphocytes. It is used for the prophylaxis of graft rejection in organ and tissue transplantation. Immunosuppressants.
  • In the case of toxic megacolon Toxic megacolon An acute form of megacolon, severe pathological dilatation of the colon. It is associated with clinical conditions such as ulcerative colitis; Crohn disease; amebic dysentery; or Clostridium enterocolitis. Megacolon, broad-spectrum Broad-Spectrum Fluoroquinolones antibiotics may be added to reduce septic complications.

Complications

• Fulminant colitis Fulminant colitis Pseudomembranous Colitis
  • Caused by colonic mucosal inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation
  • Presents with > 10 bloody stools per day, abdominal pain Abdominal Pain Acute Abdomen and distension, and systemic symptoms of shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock
  • Increases risk of developing toxic megacolon Toxic megacolon An acute form of megacolon, severe pathological dilatation of the colon. It is associated with clinical conditions such as ulcerative colitis; Crohn disease; amebic dysentery; or Clostridium enterocolitis. Megacolon
• Toxic megacolon Toxic megacolon An acute form of megacolon, severe pathological dilatation of the colon. It is associated with clinical conditions such as ulcerative colitis; Crohn disease; amebic dysentery; or Clostridium enterocolitis. Megacolon
  • Involves inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation extending beyond the mucosal layers to the muscular layers of the colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy
  • Characterized by:
    • Colonic dilation of > 6 cm on plain film 
    • Signs of severe toxicity Toxicity Dosage Calculation
  • Treatment involves nasogastric suction Nasogastric suction Metabolic Alkalosis, NPO status, antibiotics, and corticosteroids Corticosteroids Chorioretinitis.
• Gastrointestinal bleeding Gastrointestinal bleeding Gastrointestinal bleeding (GIB) is a symptom of multiple diseases within the gastrointestinal (GI) tract. Gastrointestinal bleeding is designated as upper or lower based on the etiology’s location to the ligament of Treitz. Depending on the location of the bleeding, the patient may present with hematemesis (vomiting blood), melena (black, tarry stool), or hematochezia (fresh blood in stools). Gastrointestinal Bleeding: 
  • Can occur acutely during a flare or chronically
  • May lead to anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types
• Intestinal perforation Intestinal perforation Perforated viscus or GI perforation represents a condition in which the integrity of the GI wall is lost with subsequent leakage of enteric contents into the peritoneal cavity, resulting in peritonitis. The causes of perforated viscus include trauma, bowel ischemia, infections, or ulcerative conditions, all of which ultimately lead to a full-thickness disruption of the intestinal wall. Perforated Viscus: usually caused by performing a colonoscopy Colonoscopy Endoscopic examination, therapy or surgery of the luminal surface of the colon. Colorectal Cancer Screening during an acute flare
• Large bowel obstruction Bowel obstruction Any impairment, arrest, or reversal of the normal flow of intestinal contents toward the anal canal. Ascaris/Ascariasis: due to colonic stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) produced by recurrent episodes of ulceration Ulceration Corneal Abrasions, Erosion, and Ulcers, healing, and scarring Scarring Inflammation of the mucosa
• Increased risk of colorectal cancer Colorectal cancer Colorectal cancer (CRC) is the 2nd leading cause of cancer-related deaths in the United States. Colorectal cancer is a heterogeneous disease that arises from genetic and epigenetic abnormalities, with influence from environmental factors. Colorectal Cancer

Differential Diagnosis

The following conditions are differential diagnoses for ulcerative colitis Colitis Inflammation of the colon section of the large intestine, usually with symptoms such as diarrhea (often with blood and mucus), abdominal pain, and fever. Pseudomembranous Colitis:

• Irritable bowel syndrome Irritable bowel syndrome Irritable bowel syndrome (IBS) is a functional bowel disease characterized by chronic abdominal pain and altered bowel habits without an identifiable organic cause. The etiology and pathophysiology of this disease are not well understood, and there are many factors that may contribute. Irritable Bowel Syndrome: presents with recurrent abdominal pain Abdominal Pain Acute Abdomen; however, IBS IBS Irritable bowel syndrome (IBS) is a functional bowel disease characterized by chronic abdominal pain and altered bowel habits without an identifiable organic cause. The etiology and pathophysiology of this disease are not well understood, and there are many factors that may contribute. Irritable Bowel Syndrome requires 2 or more of the following: abdominal pain Abdominal Pain Acute Abdomen that improves with defecation Defecation The normal process of elimination of fecal material from the rectum. Gastrointestinal Motility, change in stool frequency, or change in stool consistency Consistency Dermatologic Examination (diarrhea-predominant, constipation-predominant, or mixed). Diagnosis is clinical, and the condition is not associated with structural abnormalities. 
• Infectious colitis Colitis Inflammation of the colon section of the large intestine, usually with symptoms such as diarrhea (often with blood and mucus), abdominal pain, and fever. Pseudomembranous Colitis: presents with acute-onset fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever and diarrhea Diarrhea Diarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea. Common causative enteric pathogens include Shigella Shigella Shigella is a genus of gram-negative, non-lactose-fermenting facultative intracellular bacilli. Infection spreads most commonly via person-to-person contact or through contaminated food and water. Humans are the only known reservoir. Shigella, Salmonella Salmonella Salmonellae are gram-negative bacilli of the family Enterobacteriaceae. Salmonellae are flagellated, non-lactose-fermenting, and hydrogen sulfide-producing microbes. Salmonella enterica, the most common disease-causing species in humans, is further classified based on serotype as typhoidal (S. typhi and paratyphi) and nontyphoidal (S. enteritidis and typhimurium). Salmonella, Campylobacter Campylobacter Campylobacter (“curved bacteria”) is a genus of thermophilic, S-shaped, gram-negative bacilli. There are many species of Campylobacter, with C. jejuni and C. coli most commonly implicated in human disease. Campylobacter, E. coli O157:H7, Yersinia Yersinia Yersinia is a genus of bacteria characterized as gram-negative bacilli that are facultative anaerobic with bipolar staining. There are 2 enteropathogenic species that cause yersiniosis, Y. enterocolitica and Y. pseudotuberculosis. Infections are manifested as pseudoappendicitis or mesenteric lymphadenitis, and enterocolitis. Yersinia spp./Yersiniosis, and Clostridioides difficile. These infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease may be self-limiting Self-Limiting Meningitis in Children or require antibiotic treatment and can be confirmed with stool cultures and polymerase chain reaction Polymerase chain reaction Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR) ( PCR PCR Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR)).
• Radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma colitis Colitis Inflammation of the colon section of the large intestine, usually with symptoms such as diarrhea (often with blood and mucus), abdominal pain, and fever. Pseudomembranous Colitis: also presents with bloody diarrhea Bloody diarrhea Diarrhea, but is usually preceded by pelvic irradiation (months/years ago). Histologic findings suggestive of radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma colitis Colitis Inflammation of the colon section of the large intestine, usually with symptoms such as diarrhea (often with blood and mucus), abdominal pain, and fever. Pseudomembranous Colitis include eosinophilic infiltrates, which can help to differentiate it from UC.
• Diverticular disease Diverticular disease Diverticula are protrusions of the bowel wall occurring most commonly in the colon. The condition of having diverticula (called diverticulosis) is mostly asymptomatic. These diverticula can become symptomatic, however, when associated with diseases. Diverticulitis is the inflammation of diverticula, often presenting with lower abdominal pain and changes in bowel habits. Diverticular Disease: also presents with bleeding per rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy, but can be differentiated from IBD by the presence of characteristic diverticula on colonoscopy Colonoscopy Endoscopic examination, therapy or surgery of the luminal surface of the colon. Colorectal Cancer Screening.
• Crohn’s disease: presents with intermittent, crampy abdominal pain Abdominal Pain Acute Abdomen, and non-bloody diarrhea Diarrhea Diarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea. This condition causes patchy, transmural inflammation Transmural inflammation Crohn’s Disease that can affect any area of the GI tract; however, the terminal ileum Ileum The distal and narrowest portion of the small intestine, between the jejunum and the ileocecal valve of the large intestine. Small Intestine: Anatomy and proximal colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy are most commonly involved. Intestinal biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma shows noncaseating granulomas Noncaseating granulomas Crohn’s Disease.
  One of the most effective ways to learn about ulcerative colitis Colitis Inflammation of the colon section of the large intestine, usually with symptoms such as diarrhea (often with blood and mucus), abdominal pain, and fever. Pseudomembranous Colitis is to compare and contrast it with Crohn’s disease, the other form of IBD. The table below provides a comparison: