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== Irritable Bowel Syndrome ==
 
{{WikiDoc CMG}}{{AE|AE=}}{{MWH}}
 
  
'''''Synonyms and Keywords:''''' Spastic colon, functional bowel disorder, IBS
+
== <big>Gastrointestinal Bleeding</big> ==
<br />
+
<references />{{WikiDoc CMG}}{{AE}}{{MWH}}
 
 
== Historical Perspective ==
 
Irritable Bowel syndrome (IBS) was first mentioned in the Rocky Mountain Medical Journal in 1950. IBS was described as a psychosomatic disorder, not explained by any biochemical or structural abnormalities. Apley and Nash conducted a famous study on 1000 children in Bristol, United Kingdom and were the first to describe recurrent abdominal pain (RAP) as the predominant feature of IBS. In 1978, the first diagnostic criteria i.e. the Manning criteria was described. It did not specify any required duration for the symptoms of IBS. The subsequent criteria saw a reduction in the required duration of symptoms to facilitate early diagnosis and treatment. In Rome in 1995, an international group of gastroenterologist defined the diagnostic criteria for IBS and this was published in 1999 under the title of the Rome II criteria. This criteria underwent modification and was described as the Rome III criteria. Since June 2016, the criteria being followed is the Rome IV criteria.
 
 
 
=== Discovery ===
 
 
 
* In 1950, the concept of irritable bowel syndrome (IBS) was mentioned for the first time without the recognition of any particular etiology, in the ''Rocky Mountain Medical Journal.''
 
* IBS was described as a psychosomatic disorder, not explained by any biochemical or structural abnormalities.
 
* In 1958, Apley and Nash conducted a study on 1000 children in Bristol, United Kingdom and were the first to describe Recurrent abdominal pain (RAP), as the predominant feature of IBS.
 
* Recurrent abdominal pain was defined as pain in the abdomen occurring over a duration of at least 3 months, with the severity enough to cause significant impairment of function.<br />
 
<references />
 
 
 
== Classificatiion ==
 
Irritable bowel syndrome (IBS) may be classified according to Rome IV criteria into 4 sub-types based on predominant type of bowel habits:
 
 
 
* IBS with predominant constipation
 
* IBS with predominant diarrhea
 
* IBS with mixed bowel habits:
 
** Alternating patterns of stool passage which is not in conjuncture with the normal bowel movements.
 
* IBS unclassified:
 
** Patients who meet the diagnostic criteria for IBS but whose bowel habits do not fit into any of the above subtypes.
 
 
 
* Post infectious IBS (PI-IBS):
 
** Post-infectious IBS is an additional sub-type that is acute in onset and occurs subsequent to an infectious illness of the gastrointestinal tract. Post-infectious IBS is characterized by two or more of the following:
 
*** Vomiting
 
*** Fever
 
*** Positive stool culture
 
*** Diarrhea
 
 
 
{| class="wikitable"
 
|+
 
!Subtype
 
!Hard or Lumpy Stools
 
!Soft (Mushy) or Watery Stools
 
|-
 
|IBS with Constipation
 
|≥ 25 percent
 
|≤ 25 percent
 
|-
 
|IBS with Diarrhea
 
|≤ 25 percent
 
|≥ 25 percent
 
|-
 
|Mixed IBS
 
|≥ 25 percent
 
|≥ 25 percent
 
|-
 
|Unsubtyped IBS
 
|colspan="3" align="center"| Insufficient abnormality of stool consistency to meet criteria for IBS with constipation, diarrhea or mixed sub types
 
|}<ref name="pmid15862928">{{cite journal| author=Longstreth GF| title=Definition and classification of irritable bowel syndrome: current consensus and controversies. | journal=Gastroenterol Clin North Am | year= 2005 | volume= 34 | issue= 2 | pages= 173-87 | pmid=15862928 | doi=10.1016/j.gtc.2005.02.011 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15862928  }} </ref><ref name="pmid25731138">{{cite journal| author=Sayuk GS, Gyawali CP| title=Irritable bowel syndrome: modern concepts and management options. | journal=Am J Med | year= 2015 | volume= 128 | issue= 8 | pages= 817-27 | pmid=25731138 | doi=10.1016/j.amjmed.2015.01.036 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25731138  }} </ref><ref name="pmid26929659">{{cite journal| author=Lacy BE| title=Diagnosis and treatment of diarrhea-predominant irritable bowel syndrome. | journal=Int J Gen Med | year= 2016 | volume= 9 | issue=  | pages= 7-17 | pmid=26929659 | doi=10.2147/IJGM.S93698 | pmc=4755466 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26929659  }} </ref><ref name="pmid20502449.">{{cite journal| author=Wong RK, Palsson OS, Turner MJ, Levy RL, Feld AD, von Korff M | display-authors=etal| title=Inability of the Rome III criteria to distinguish functional constipation from constipation-subtype irritable bowel syndrome. | journal=Am J Gastroenterol | year= 2010 | volume= 105 | issue= 10 | pages= 2228-34 | pmid=20502449. | doi=10.1038/ajg.2010.200 | pmc=3786710 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20502449  }} </ref><ref name="pmid10457044">{{cite journal| author=Thompson WG, Longstreth GF, Drossman DA, Heaton KW, Irvine EJ, Müller-Lissner SA| title=Functional bowel disorders and functional abdominal pain. | journal=Gut | year= 1999 | volume= 45 Suppl 2 | issue=  | pages= II43-7 | pmid=10457044 | doi=10.1136/gut.45.2008.ii43 | pmc=1766683 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10457044  }} </ref><ref name="pmid12241674">{{cite journal| author=Talley NJ, Spiller R| title=Irritable bowel syndrome: a little understood organic bowel disease? | journal=Lancet | year= 2002 | volume= 360 | issue= 9332 | pages= 555-64 | pmid=12241674 | doi=10.1016/S0140-6736(02)09712-X | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=12241674  }} </ref><ref name="pmid12776965">{{cite journal| author=Holten KB, Wetherington A, Bankston L| title=Diagnosing the patient with abdominal pain and altered bowel habits: is it irritable bowel syndrome? | journal=Am Fam Physician | year= 2003 | volume= 67 | issue= 10 | pages= 2157-62 | pmid=12776965 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=12776965  }} </ref>
 
 
 
== Pathophysiology ==
 
 
 
=== Pathogenesis ===
 
IBS occurs as a result of an interplay between four main factors:
 
 
 
{{Family tree/start}}
 
{{Family tree||||||||||A01||||||||||A01= '''CNS dysregulation and psychosocial factors'''}}
 
{{Family tree||||||||||!||||||||||}}
 
{{Family tree||||||||||!||||||||||}}
 
{{Family tree||||||||||!||||||||||}}
 
{{Family tree|B01|-|-|-|-|-|-|B02|-|-|-|-|-|B03|B01= '''Intrinsic gastrointestinal factors''':<br>• Motor abnormalities<br>• Visceral hypersensitivity<br>• Immune activation and mucosal inflammation<br>• Altered gut microbiota<br>• Abnormal serotonin pathways|B02= '''Irritable Bowel Syndrome'''|B03= '''Genetic factors''':<br>• Twin concordance<br>• Familial aggregation<br>• Single nucleotide polymorphisms(SNPs)<br>• TNF polymorphism}}
 
{{Family tree||||||||||!||||||||||}}
 
{{Family tree||||||||||!||||||||||}}
 
{{Family tree||||||||||!||||||||||}}
 
{{Family tree||||||||||C01||||||||||C01= '''Environmental factors''':<br> •Diet<br> •Infections}}
 
{{Family tree||||||||||||||||||||}}
 
{{Family tree||||||||||||||||||||}}
 
{{Family tree||||||||||||||||||||}}
 
{{Family tree/end}}<br />
 
=== Environmental factors ===
 
 
 
=== Diet ===
 
 
 
* Fermentable oligosaccharides, monosaccharides, disaccharides, and polyols (FODMAPs) are present in stone fruits, artificial sweeteners, lactose-containing foods, and legumes. Changes in diet such as increased amounts (FODMAPs) can alter gut microflora.
 
* Fermentation and osmotic effects of FODMAPs produce abdominal discomfort and diarrhea in IBS.
 
* FODMAPs yield carbon dioxide, methane, and hydrogen that are responsible for bloating.
 
* Osmotically active carbohydrate by products lead to diarrhea by enhancing intestinal contractions and precipitating fluid secretion.
 
 
 
'''<big>Infection</big>'''
 
 
 
* Infectious gastroenetritis triggers micro inflammation and up to one third of irritable bowel syndorme cases follow acute gastroenteritis[[Gastroenteritis|.]]
 
* Micro inflammation of the gut causes activation of the lymphocytes, mast cells and pro inflammatory cytokines that stimulate the enteric nervous system and lead to abnormal visceral and motor responses within the gastrointestinal tract.
 
 
 
=== Intrinsic gastrointestinal factors[edit | edit source] ===
 
 
 
* '''Motor abnormalities:'''
 
** IBS is referred to as ‘spastic colon’ due to changes in colonic motor function.
 
** Manometry recordings from the transverse, descending and sigmoid colon have shown that IBS leads to altered colonic and small intestinal tumor function, such as increased frequency and irregularity of luminal contractions.
 
** Motor changes lead to symptoms of diarrhea and constipation.
 
*** Diarrhea-prone IBS patients have increased responses to ingestion, CRH ([[Corticotropin-releasing hormone|corticotropin releasing hormone]]), CCK ([[cholecystokinin]]), which increase the peak amplitude of high-amplitude propagating contractions (HAPCs) and lead to abdominal discomfort with accelerated transit through the colon.
 
*** Constipation-prone IBS patients show fewer high-amplitude propagating contraction (HAPCs) as compared to diarrhea prone IBS patients, delayed transit through the colon and decreased motility.
 
 
 
'''<big>Visceral hypersensitivity:</big>'''
 
 
 
* IBS is associated with a decreased threshold for perception of visceral stimuli (i.e. visceral hypersensitivity)
 
* Rectal distension produces painful and non-painful sensations at lower volumes in [[Irritable bowel syndrome|IBS]] patients as compared to healthy controls, suggesting the presence of afferent pathway disturbances in visceral innervation.
 
* Visceral hypersensitivity contributes to IBS by involving the following:
 
** '''Spinal hyperexcitability'''
 
*** Secondary to activation of neurotransmitters such as:
 
*** NDMA receptor
 
*** Nitric oxide
 
** '''Activation of specific gastrointestinal mediators''' that lead to afferent nerve fiber sensitization:
 
*** Kinins
 
*** Serotonin
 
** '''Central (brainstem and sortical) modulation''' with increased activation of anterior cingulate cortex, thalamus and insula.
 
*** These structures are involved in processing of pain.
 
*** Cortical and brainstem modulation translate into long term hypersensitivity due to neuroplasticity.
 
*** Semi permanent changes(seen on functional MRI and PET scan) in the neural response to visceral stimulation contribute to visceral hypersensitivity.
 
** '''Recruitment of peripheral silent nocireceptors''' cause increased end organ sensitivity due to
 
*** Hormonal activation ( increased serotonin affects gastrointestinal and visceral pain perception)
 
*** Immune activation(recruitment of inflammatory mediators)
 
 
 
 
 
{{Family tree/start}}
 
{{Family tree ||||||||||||||||||||}}
 
{{Family tree ||||||||||||||||,|-|A01|-|A02|||||||A01= Spinal hyperexcitability|A02= Activation of<br>• N-methyl D aspartate (NMDA) receptor<br>• nitric oxide}}
 
{{Family tree ||||||||||||||||!||||}}
 
{{Family tree ||||||||||||||||)|-|B01|-|B02|||||||B01= Central (brainstem and cortical) modulation|B02= Increased activation of:<br>• Anterior cingulate cortex<br>• Thalamus<br>• insula}}
 
{{Family tree ||||||||||||||||!||||}}
 
{{Family tree ||||||||||||C01|-|(||||C01= Visceral Hypersensitivty}}
 
{{Family tree ||||||||||||||||!||||}}
 
{{Family tree ||||||||||||||||)|-|D01|-|D02||||||||||D01= Activation of specific gastrointestinal mediators|D02= Kinins and serotonin activation lead to afferent nerve fiber sensitization}}
 
{{Family tree ||||||||||||||||!||||}}
 
{{Family tree ||||||||||||||||`|-|E01|-|E02||||||||||E01= Recruitment of peripheral silent nociceptors|E02= Increased end organ sensitivity due to hormonal or immune activation}}
 
{{Family tree ||||||||||||||||||||}}
 
{{Family tree/end}}
 
 
 
 
 
 
 
'''<big>Immune activation and mucosal inflammation</big>'''
 
 
 
<br />
 
 
 
{{Family tree/start}}
 
{{Family tree|A01|-|-|-|A02|-|-|-|A03|||||||||A01= '''Mast cells'''|A02= '''IMMUNE ACTIVATION AND MUCOSAL INFLAMMATION'''|A03= '''Lymphocytes'''|}}
 
{{Family tree||||||||!||||||||||}}
 
{{Family tree||||||||!||||||||||}}
 
{{Family tree|||||||B01||||||||||B01= '''Proinflammatory cytokines'''}}
 
{{Family tree||||||||||||||||||||}}
 
{{Family tree/end}}
 
 
 
 
 
 
 
* IBS in patients with history of inflammatory bowel disease, celiac disease or microscopic colitis points towards the fact that immune activation and local gastrointestinal mucosal inflammation play an important role in its pathogenesis.
 
* IBS patients have high mucosal counts of lymphocytes (T cells, B cells), mast ''cells'' and immune ''mediators'' such as prostanoids, proteases, cytokines and histamines.
 
 
 
'''<big>Lymphocytes:</big>'''
 
 
 
* Activation of humoral immunity in IBS is specific for the gastrointestinal tract. Increased number of lymphocytes have been found in the small intestine and colon of IBS patients.
 
* IBS patients with diarrhea have enhanced mucosal humoral activity, associated with activation and proliferation of B cells and immunoglobin production, identified by microarray profiling.
 
* IBS patients with severe disease have an increase in lymphocyte infiltration in the myentric plexus.
 
 
 
'''<big>Mast cells:</big>'''
 
 
 
* IBS leads to an increased number of mast cells in IBS patients in the jejunum, terminal ileum and colon.
 
* Higher numbers of activated mast cells are found in proximity to colonic nerve fibres in the mucosa of the gastrointestinal tract of IBS patients
 
 
 
'''<big>Proinflammatory cytokines:</big>'''
 
 
 
* Cytokines are protein mediators of the immune response. Increased levels of cytokines have been found in IBS patients.
 
* Higher amounts of TNF are produced by the peripheral blood mononuclear cells of IBS patients.
 
* Other cytokines such as interleukin 6, interleukin 10, and TNF alpha are raised in IBS patients.
 
* Increased concentration of cytokines is directly proportional to the severity and frequency of pain.
 
* The TNF antagonist infliximab counteracts pain in IBS patients, proving TNF involvement in mechanical hypersensitivity of the colonic afferent nerve endings.
 
 
 
<br />
 
 
 
== Associated conditions ==
 
Several medical comorbidities appear with greater frequency in IBS patients.
 
 
 
=== Headache, Fibromyalgia, and Depression ===
 
IBS patients may be identified with comorbidities such as headache, fibromyalgia and depression.
 
 
 
=== Inflammatory Bowel Disease ===
 
 
 
* IBS and IBD are interrelated diseases, as patients with IBD experience IBS-like symptoms when their IBD is in remission.
 
* IBS is believed to be a type of low-grade IBD as serum markers associated with inflammation have also been found in patients with IBS.
 
* IBS patients are 16.3 times more likely to develop IBD.
 
 
 
=== Abdominal Surgery ===
 
 
 
* IBS patients are 87% more likely to undergo abdominal and pelvic surgery, and three times more likely to undergo gallbladder surgery.
 
* IBS patients were twice as likely to undergo hysterectomy.
 
 
 
=== Endometriosis[edit | edit source] ===
 
There is a statistically significant link between migraine headaches, IBS, and endometriosis.
 
 
 
== Gross Pathology ==
 
 
 
* On gross pathology, the GI tract appears normal in IBS.
 
 
 
== Microscopic Pathology ==
 
Microscopic changes that may be found in IBS patients are as follows:
 
<br />
 
{| class="wikitable"
 
|+
 
!Location
 
!Layer of Intestine involved
 
!Mast Cells
 
!T Lymphocytes
 
!Enterochromaffin Cells
 
|-
 
|Rectum
 
|Mucosa
 
| +++/-
 
| +/-
 
| +/-
 
|-
 
|Terminal Ileum
 
|Mucosa
 
| -
 
| ++
 
| -
 
|-
 
|Cecum
 
|Mucosa
 
| ++
 
| -
 
| -
 
|-
 
|Colon
 
|Muscularis Externa
 
| +/-
 
| -
 
| -
 
|-
 
|Jejunum
 
|Myenteric Plexus
 
| ++
 
| -
 
| -
 
|}
 
 
 
== Risk Factors ==
 
Common risk factors in the development of IBS may be categorized as psychological, epidemiological, genetic, and infections.
 
 
 
=== Common risk factors ===
 
Common risk factors in the development of IBS include:
 
 
 
'''Psychological risk factors''':
 
 
 
* Stress
 
* Anxiety
 
 
 
'''Psychiatric risk factors:'''
 
 
 
* Depression
 
 
 
* Panic disorders
 
 
 
* History of physical or sexual abuse or adverse early life events
 
 
 
'''Past medical history'''
 
 
 
* History of gastrointestinal disorders such as IBD
 
* History of acute GI infections such as traveler's diarrhea i.e post infectious state
 
** Salmonella infection
 
** Giardiasis
 
* History of antibiotic use
 
* Immune causes:
 
** History of IBD
 
** Celiac disease
 
** Microscopic colitis
 
 
 
=== Less common risk factors ===
 
 
 
* Less common risk factors in the development of IBS include:
 
** Age: Second decade of life
 
** Gender: Women (possibly due to changes in menstrual cycle)
 
** Past history of abuse
 
** Family history of IBS (genetics)
 
** Hormonal changes
 
*** Alteration of sex hormones
 
*** Alteration of serotonin levels
 
** History of migraine headaches
 
** History of pain disorders such as fibromyalgia
 
** Food sensitivities: Fatty food, wheat, carbonated drinks, sorbitol and alcohol
 
* Abdominal obesity
 
 
 
== Epidemiology and Demographics ==
 
 
 
=== Incidence ===
 
 
 
* The incidence of IBS is approximately 200 per 100,000 individuals worldwide.
 
 
 
=== Prevalence ===
 
 
 
* The prevalence of IBS is approximately 11,200 per 100,000 individuals worldwide.
 
* The prevalence of IBS varies with geographical and demographic distribution.
 
* The prevalence of IBS in USA and Europe is ranges from a low of 10,000 per 100,000 individuals to a high of 20,000 per 100,000 individuals.
 
 
 
=== Age ===
 
 
 
* IBS commonly affects individuals younger than 35 years of age.
 
* The incidence of IBS decreases with age.
 
* The prevalence of IBS is 25% lower in individuals over 50 years of age.
 
 
 
=== Race ===
 
 
 
* There is no racial predilection to IBS.
 
 
 
=== Gender ===
 
 
 
* Females are more commonly affected by IBS than males. The female to male ratio is approximately 1:2. This is due to social and biological factors.
 
 
 
'''<big>Social factors:</big>'''
 
 
 
* Females are predominantly affected by IBS as the likelihood of diagnosis of IBS is 2-3 times more in women as compared to men. This is because health care seeking behavior for symptoms is 4-5 times higher in women as compared to men.
 
 
 
'''<big>Biological factors:</big>'''
 
  
* The fluctuation of sex hormones in women during the menstrual cycle causes exacerbation of IBS symptoms.
+
'''''Synonyms and Keywords:''''' Blood loss from GI tract; bloody stool; blood in feces; PR bleeding; gastrointestinal hemorrhage; gastrointestinal hemorrhage; GI bleeding; bright red blood per rectum; BRBPR.
* Women have a lower threshold for pain and are at greater risk for development of functional and chronic pain disorders such as IBS and fibromyalgia.
 
* '''Pediatric population:'''
 
* Worldwide, the prevalence of IBS is higher in girls.
 
* The prevalence of IBS in Asia is higher in girls as compared to boys.
 
  
'''<big>Children</big>'''
+
== Overview ==
 +
Gastrointestinal (GI) bleeding is defined as bleeding from any part of GI tract starting from mouth to anus. It can also be called as gastrointestinal hemorrhage. Based on the origin of bleeding it can be classified into upper gastrointestinal bleeding and lower gastrointestinal bleeding. Upper gastrointestinal bleeding (UGIB) is defined as bleeding from the gastrointestinal tract that originates proximal to the ligament of Treitz. Lower gastrointestinal bleeding is defined as blood loss originating distal to the ligament of Treitz. The most common causes of UGIB are peptic ulcer disease and esophageal varices while diverticulosis is the most commonly responsible for lower gastrointestinal bleeding. Clinical presentation includes overt bleeding from the gastrointestinal tract, rapid or slow, either manifested by hematemesis of fresh (blood-streaked to frankly bloody), old ('coffee ground') vomitus, melena and or as frank blood per rectum.
  
* In the Western pediatric population, IBS is the commonest cause of functional recurrent abdominal pain (RAP) as it accounts for more than 50% of all cases.
+
Common risk factors in the development of GI bleeding include advancing age, previous history of gastrointestinal bleeding, chronic constipation, hematologic disorders, anticoagulants medications, NSAIDs. It is essential to distinguish between lower gastrointestinal bleeding and brisk upper gastrointestinal bleeding as they can present with similar symptoms. Patients with severe bleeding or hemodynamic disturbance require hospitalization and urgent investigation. Treatment depends on the cause and the severity of the bleeding.
  
=== Developed and developing countries ===
+
== Types of bleeding ==
 +
Bleeding from the gastrointestinal tract can be of the following types:
  
* In USA and Australia, 1 in every 10 people fulfill the Rome IV criteria  for IBS.
+
* '''Hematemesis''': Vomiting fresh red blood.
* In Asia, Africa and South America, IBS is becoming increasingly prevalent as a disease of urbanization and industrialization. This is due to increased access to health care, higher stress levels and differing dietary choices.
+
* '''Coffee ground emesis''': Vomiting of altered black blood.
 +
* '''Melena''': Passage of black tarry stools.
 +
* '''Hematochezia''': Passage of red blood per rectum (usually due to bleeding from the lower gastrointestinal tract but occasionally can be due to massive upper gastrointestinal bleeding).
 +
* '''Rebleeding''': Defined as fresh hematochezia and/or melena associated with the development of shock (pulse greater than 100 beats/min, systolic pressure less than 100 mm Hg), a fall in CVP greater than 5 mm Hg, or a reduction in hemoglobin concentration greater than 20 g/l over 24 hours. Rebleeding should always be confirmed by endoscopy.
  
== Differentiating Irritable Bowel Syndrome from other Diseases ==
+
== Causes ==
 
 
=== Diseases with similar symptoms ===
 
 
 
* Celiac disease
 
* Crohn's disease
 
* Zollinger-Ellison Syndrome
 
* VIPoma
 
* Diverticulitis
 
* Endometriosis
 
* Gallstones
 
* Gastroesophageal reflux disease (GERD)
 
* Inflammatory bowel disease
 
* Lactose Intolerance
 
* Thyroid disease--Hyperthyroidism / Hypothyroidism
 
* Chronic Pancreatitis
 
* Small Intestinal Bacterial Overgrowth
 
* Intermittent Small Bowel Obstruction
 
 
 
<br />'''<big>Differential Diagnosis of Irritable bowel syndrome on the basis of abdominal pain and diarrhea</big>'''
 
 
 
Diarrhea with abdominal pain/cramping may be caused by infectious causes, celiac disease, parasites, food allergies and lactose intolerance. See the list of causes of diarrhea for other conditions which can cause diarrhea. Celiac disease in particular is most often misdiagnosed as IBS. The differential diagnosis of irritable bowel syndrome based on abdominal pain and diarrhea is as follows:
 
 
{| class="wikitable"
 
{| class="wikitable"
 
|+
 
|+
| colspan="3" rowwspan="2" align="center" style="background: blue; color:white"|'''Cause'''
+
!Gastrointestinal Bleeding
| colspan="2" align="center" style="background: blue; color:white"|'''Osmotic Gap'''
+
!Lethal Causes
|align="center" style="background: blue; color:white"|'''History'''
+
!Common causes
|align="center" style="background: blue; color:white"|'''Physical Examination'''
+
!Less Common causes
|align="center" style="background: blue; color:white"|'''Gold Standard'''
 
|align="center" style="background: blue; color:white"|'''Treatment'''
 
 
|-
 
|-
| rowspan="8" |Watery
+
|Upper gastrointestinal bleeding
| rowspan="4" |Secretory
 
|Crohns
 
 
 
*
 
|<nowiki>+</nowiki>
 
 
 
*
 
|<nowiki>-</nowiki>
 
 
 
*
 
|
 
* Abdominal pain followed by diarrhea
 
 
|
 
|
*Abdominal tenderness when palpated in severe disease
+
* Anthrax
* Blood seen on rectal exam
+
* Ebola virus
* Fever
 
* Tachycardia
 
* Hypotension
 
 
|
 
|
* '''Colonoscopy with Biopsy'''
+
* Duodenal ulcer
 +
* Esophagitis
 +
* Esophageal varices
 +
* Gastric tumors
 +
* Gastric ulcer
 +
* Gastritis
 +
* Mallory-Weiss Syndrome
 +
* Peptic ulcer
 
|
 
|
*'''Topical mucosamine''' and '''corticosteroids''' are preferred
+
* Gastric cancer
*'''Mesalamine''' and '''sulfasalazine''' are used for remission
+
* Esophageal Tumors
 +
* Esophagitis
 +
* Gastric erosions/gastropathy
 +
* Dieulafoy lesions
 +
* Gastric antral vascular ectasia
 
|-
 
|-
|Zollinger-Ellison Syndrome
+
|Lower gastrointestinal bleeding
|<nowiki>+</nowiki>
 
|<nowiki>-</nowiki>
 
 
|
 
|
* Abdominal Pain and diarrhea
 
* Dyspepsia
 
* Upper or lower gastrointestinal bleeding
 
 
|
 
|
*Abdominal tenderness when palpated in severe disease
+
* Diverticulosis
* Blood seen on rectal exam
+
* Vascular ectasias
* Hematemesis
+
* Ischemic colitis
* Tachycardia
+
* Colorectal malignancy
* Hypotension
+
* Hemorrhoids
|
+
* Anal fissures
* Gastrin levels
+
* Crohn's disease
|
+
* Ulcerative colitis
* Proton pump inhibitors
+
* Infectious colitis
* Octreotide
+
* Colonic polyps
|-
+
* Radiation proctitis
|Hyperthyroidism
+
* Rectal varices
| +
+
* Stercoral ulceration
| -
+
* Meckel diverticulum
|
+
* Intussusception
* Abdominal Pain and diarrhea
+
* Henoch-Scholein Purpura (HSP)
* Dyspepsia
 
* Upper or lower gastrointestinal bleeding
 
|
 
* Lump in the neck
 
 
 
*Proptosis
 
* Tremors
 
* Increased DTR
 
|
 
* TSH levels with T3 and T4
 
|
 
* Carbimazole and methimazole
 
* Prpylthiouracil
 
*Beta Blockers
 
*Iodine-131
 
|-
 
|VIPoma
 
|<nowiki>+</nowiki>
 
|<nowiki>-</nowiki>
 
|
 
* Watery diarrhea
 
* Dehydration (thirst, dry skin, dry mouth, tiredness, headaches, and dizziness)
 
* Lethargy, muscle weakness
 
* Nausea, vomiting
 
* Crampy abdominal pain
 
* Weight loss
 
* Flushing
 
|
 
* Lump in the neck
 
* Proptosis
 
* Tremors
 
* Increased DTR
 
|
 
* Elevayed VIP levels
 
* Followed by imaging
 
|
 
* Somatostatin or chemotherapy for malignant tumors
 
* Surgical removal of the tumor
 
|-
 
| rowspan="2" |Osmotic
 
|Lactose Intolerance
 
|<nowiki>-</nowiki>
 
|<nowiki>+</nowiki>
 
|
 
* Abdominal pain
 
* Bloating
 
* Diarrhea
 
* Flatulance
 
|
 
* Abdominal tenderness
 
|
 
* Intestinal Biopsy
 
|
 
* Avoidance of dietary lactose
 
* Substitution to maintain nutrient intake
 
* Regulation of calcium intake
 
* Use of enzyme lactase
 
|-
 
|Celiac disease
 
|<nowiki>-</nowiki>
 
|<nowiki>+</nowiki>
 
|
 
* May be asymptomatic
 
* Vague abdominal pain
 
* Diarrhea
 
* Weight loss
 
* Malabsorption
 
* Bloating
 
|
 
* Abdominal pain and cramping
 
* Abdominal distension
 
* Tetany
 
* Mouth ulcers
 
* Dermatitis Herpetiformis
 
* Signs of the fat-soluble Vitamin A, D, E, and K deficiency
 
|
 
* IgA tissue Transglutaminase antibody
 
|
 
* Gluten free diet
 
|-
 
|Functional
 
|Irritable bowel syndrome
 
| -
 
| -
 
|Abdominal pain or discomfort recurring at least 3 days per month in the past 3 months and associated with 2 or more of the following:
 
 
 
* Improvement with defecation
 
 
 
* Onset associated with a change in frequency of stool
 
 
 
* Onset associated with a change in consistency or form of stool
 
* Straining during defecation, dyspepsia, bloating and flatulence may be present
 
|
 
* Abdominal tenderness
 
* Hard stool in the rectal vault
 
|Clinical diagnosis
 
 
 
* ROME IV criteria
 
* Exclusion of organic causes based on laboratory investigations and imaging
 
|
 
* Low FODMAP diet (fructose -when in excess of glucose, fructans, galacto-oligosaccharides, lactose, and polyols (eg. sorbitol and mannitol), high dietary fiber, physical exercise
 
* Osmotic laxatives such as polyethylene glycol, sorbitol, and lactulose for constipation-predominant IBS
 
* Opioids such as loperamide and chloride channel activators such as linaclotide and lubipristone for diarrhea-predominant IBS
 
* Antispasmodic drugs (e.g. anticholinergics such as hyoscyamine or dicyclomine), antidepressants and anxiolytics for pain predominant IBS
 
 
|}
 
|}
  
=== Differential diagnosis based on diarrhea ===
+
== Classification ==
The following table outlines the major differential diagnoses based on diarrhea as the major presenting symptoms:
+
The following flow chart elobarates the classification of gastrointestinal bleeding:
  
 +
{{Family tree/start}}
 +
{{Family tree||||||||||||||||||||A01||||||||||A01= '''Gastointestinal'''<br> '''bleeding'''}}
 +
{{Family tree|||||||||||||||||||||!|||||||||||}}
 +
{{Family tree|||||||||||||,|-|-|-|-|-|-|-|^|-|-|-|-|-|-|-|-|-|-|.||||||}}
 +
{{Family tree|||||||||||||!|||||||||||||||||||!||||||}}
 +
{{Family tree|||||||||||||!|||||||||||||||||||!||||||}}
 +
{{Family tree||||||||||||B01|||||||||||||||||B02|||||||B01= '''Upper GI bleeding'''|B02= '''Lower GI bleeding'''}}
 +
{{Family tree|||||||||||||!|||||||||||||||||||!||||||}}
 +
{{Family tree||||||||||||C01|||||||||||||||||C02|||||C01= Based on blood loss|C02= Based on severity of blood loss}}
 +
{{Family tree|||||||,|-|-|-|-|-|+|-|-|-|-|-|.|||||||,|-|-|-|-|-|+|-|-|-|-|-|.||}}
 +
{{Family tree|||||D01|||||D02||||D03|||||D04||||D05|||||D06|||||||D01= Overt|D02= Occult|D03= Obscure|D04= Severe|D05= Moderate|D06= Occult}}
 +
{{Family tree|||||||!||||||!||||||!|||||||!||||||!||||||!|}}
 +
{{Family tree|||||E01|||||E02||||E03|||||E04||||E05|||||E06|||||||||||E01= Hematemesis Coffee-ground emesis Melena|E02= Microscopic Hemorrhage Heme-Occult positive stools|E03= Source is not identified|E04= Hematochezia|E05= Hematochezia|E06= Microscopic Hemorrhage Heme-Occult positive stools}}
 +
{{Family tree||||||||||||||||||||||||||||||}}
 +
{{Family tree||||||||||||||||||||||||||||||}}
 +
{{Family tree||||||||||||||||||||||||||||||}}
 +
{{Family tree||||||||||||||||||||||||||||||}}
 +
{{Family tree||||||||||||||||||||||||||||||}}
 +
{{Family tree/end}}<br />
  
 +
== Syndrome of Inappropriate antidiuretic hormone classification ==
 +
SIADH may be classified into several sub-types based on the pattern of arginine vasopressin (AVP) secretion in response to a range of plasma osmolalities into type A, type B, type C, and type D.
 +
<br />
  
{| style="border: 0px; font-size: 90%; margin: 3px; width: 1000px" align="center"
+
{| class="wikitable"
| valign="top" |
+
! style="background: #4479BA; width: 100px;" | {{fontcolor|White|'''Classification'''}}
|+
+
! style="background: #4479BA; width: 500px;" | {{fontcolor|White|'''Features'''}}
! style="background: Blue; width: 200px;" | {{fontcolor|#FFF|Differential Diagnosis for Diarrhea predominant symptoms}}
 
! style="background: Blue; width: 300px;" | {{fontcolor|#FFF|Clinical features}}
 
! style="background: Blue; width: 300px;" | {{fontcolor|#FFF|Diagnosis}}
 
 
|-
 
|-
| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold; text-align:center;" |Crohn's disease
+
| style="background: #DCDCDC; text-align:center;" |'''Type A'''
| style="padding: 5px 5px; background: #F5F5F5;" |
+
| style="background: #F5F5F5;" |
* Diarrhea, abdominal pain
+
* Accounts for about 60-70% of SIADH
| style="padding: 5px 5px; background: #F5F5F5;" |
+
*Excessive secretion of arginine vasopressin (AVP) is noted
* Colonoscopy, [[small bowel barium radiograph]], [[CT enterography]], [[magnetic resonance enterography]]
+
*Associated with lung cancer and nasopharyngeal tumors
 +
* Patients are more susceptible to development of severe hypo<nowiki/>natremia
 
|-
 
|-
| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold; text-align:center;" |Ulcerative colitis
+
| style="padding: 5px 5px; background: #DCDCDC; text-align:center;" |'''Type B'''
| style="padding: 5px 5px; background: #F5F5F5;" |
 
* Present with abdominal pain, tenesmus, have diarrhea and rectal bleeding
 
 
| style="padding: 5px 5px; background: #F5F5F5;" |
 
| style="padding: 5px 5px; background: #F5F5F5;" |
* Colonoscopy
+
* Accounts for (20–40%) of the cases
 +
* Secretion of AVP occurs at lower than normal plasma osmolalities
 
|-
 
|-
| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold; text-align:center;" |Microscopic colitis
+
| style="background: #DCDCDC; text-align:center;" |'''Type C'''
| style="padding: 5px 5px; background: #F5F5F5;" |
+
| style="background: #F5F5F5;" |  
* Watery diarrhea with nocturnal symptoms
+
* Failure to suppress AVP secretion at plasma osmolalities below the osmotic threshold
| style="padding: 5px 5px; background: #F5F5F5;" |
+
* Occurs due to dysfunction of inhibitory neurons in the hypothalamus, leading to persistent low-grade basal AVP secretion
* Colonoscopy, flexible sigmoidoscopy and biopsy
 
|}
 
 
 
<br>
 
 
 
=== Differential diagnosis of irritable bowel syndrome on the basis of constipation ===
 
The differential diagnosis of irritable bowel syndrome based on constipation as the predominant symptom is as follows:
 
{|
 
 
|-
 
|-
 
+
| style="background: #DCDCDC; text-align:center;" |'''Type D'''
|}
+
| style="background: #F5F5F5;" |
{| style="border: 0px; font-size: 100%; margin: 3px; width: 1000px" align="center"
+
* Low or undetectable AVP levels and circulating AVP response is not defective 
| valign="top" |
+
*Nephrogenic SIADH (NSIAD) may be attributed to this condition
|+
+
*Associated with gain-of-function mutations in the vasopressin-2 (V2 receptor) receptor leading to a clinical picture of SIADH, with undetectable AVP levels
! style="background: Blue; width: 200px;" | {{fontcolor|white|Differential Diagnosis for Constipation predominant symptoms}}
+
*The condition is inherited in an X-linked manner, although heterozygous females may have inappropriate anti-diuresis of varying degrees.
! style="background: Blue; width: 300px;" | {{fontcolor|white|Clinical features}}
 
! style="background: Blue; width: 300px;" | {{fontcolor|white|Diagnosis}}
 
 
|}
 
|}
  
<br>
+
==Classification of Constipation==
 +
Constipation may be classified according to etiology into five subtypes:
 +
* '''Gastrointestinal'''
 +
* '''Neurologic'''
 +
* '''Metabolic'''
 +
* '''Endocrine'''
 +
* '''Psychiatric'''
  
== Natural History, Complications, and Prognosis ==
+
<br />
  
=== Natural History ===
+
{{Family tree/start}}
 
+
{{Family tree|||||||||||||||||||||||||||||||||||||||||||||||||||A01|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||A01='''Contipation''' <br> Classification}}
* The symptoms of IBS usually develop in the second decade of life, and start with symptoms such as abdominal pain, diarrhea and constipation.
+
{{Family tree||||||||||||||||||||||||||||||||||||||||||||||||||||!|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||}}
* The symptoms of IBS typically develop after exposure to early life adverse events, sexual abuse, anxiety, depression and stressors. Psychological conditions may also develop as complications of the disease.
+
{{Family tree|||||||||||||||||||||||||||||||||||||||||||||||||||B01|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||B01='''Etiology'''}}
* If left untreated, patients with IBS may progress to develop malnutrition (resulting from food intolerance), impacted bowel, and poor quality of life.
+
{{Family tree|||||||||||||||||||||||||||||||||,|-|-|-|-|-|v|-|-|-|-|-|v|-|-|-|-|-|-|+|-|-|-|-|-|v|-|-|-|-|-|v|-|-|-|.||||||||||||||||||||||||||||||||||||||||||||||||||}}
 
+
{{Family tree|||||||||||||||||||||||||||||||C01|||||C02||||C03|||||C04||||C05||||C06|||C07||||||||||||||||||||||C01= '''Neurologic'''|C02= '''Metabolic'''|C03= '''Endocrine'''|C04= '''Gastrointestinal'''|C05= '''Psychiatric'''|C06= '''Drugs'''|C07= '''Idiopathic'''}}
=== Complications ===
+
{{Family tree|||||||||||||||||||||||||||||||||!||||||!||||||!|||,|-|-|-|+|-|-|-|.||!||||||!||||!||||||||||||||||||||||||||||||}}
Complications of IBS may include:
+
{{Family tree|||||||||||||||||||||||||||||||||!||||||!||||||!||D01||D02||D03|!||||||!||||!|||||||||||||||||||||||||||||||||D01= Obstruction|D02= Agangliosis|D03= Idiopathic megacolon}}
 +
{{Family tree|||||||||||||||||||||||||||||||||!||||||!||||||!||||,|-|-|^|-|-|.|||!||||||!||||!|||||||||||||||||||||||||||||||||}}
 +
{{Family tree|||||||||||||||||||||||||||||||||!||||||!||||||!|||E01||||E02||!||||||!||||!|||||||||||||||||||||||||||||||E01= Hirschprung disease|E02= Chagas disease}}
 +
{{Family tree|||||||||||||||||||||||||||||||||!||||||!||||||!|||||||||||||!||||||!||||!||||||||||||||||||||||||||||||||||||||||||}}
 +
{{Family tree|||||||||||||||||||||||||||||||||!||||||!||||||!|||||||||||||!||||||!||||!||||||||||||||||||||||||||||||||||||||||||}}
 +
{{Family tree|||||||||||||||||||||||||||||||||!||||||!||||||!|||||||||||||!||||||!||||!||||||||||||||||||||||||||||||||||||||||||}}
 +
{{Family tree|||||||||||||||||||||||||||||||||!||||||!||||||!|||||||||||||!||||||!||||!||||||||||||||||||||||||||||||||||||||||||}}
 +
{{Family tree|||||||||||||||||||||||||||||||F01|||||F02||||F03|||||||||||F04||||F05||F06||||||||||||||||||||||||||||||||||||||||||||||||||||F01= Multiple sclerosis Parkinson's disease Spinal cord Injury|F02= Hypercalcemia Hypermagnesemia Porphyria Hypokalemia|F03= Hypothroidism Diabetes mellitus Panhypopituitarism|F04= Depression Eating disorder|F05= Analgesics Anticholinergics Cation containing agents Neuron targeting agents|F06= Normal colonic transit Sloww colonic transit Dyssynergic defecation}}
 +
{{Family tree|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||}}
 +
{{Family tree|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||}}
 +
{{Family tree|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||}}
 +
{{Family tree/end}}<br />
  
* Dehydration in the case of diarrhea predominant IBS leading to loss of water and electrolytes.
+
= Colorectal cancer pathophysiology =
 +
The pathogenesis of colorectal carcinoma (CRC) involves the molecular pathways for both sporadic and colitis-associated CRC. Sporadic instability originates from the epithelial cells that line the colon or rectum. Colitis-associated CRC includes genetic instability, epigenetic alteration, chronic inflammation, oxidative stress, and intestinal microbiota. According to the World Health Organization (WHO) histological classification, most colorectal tumors are carcinomas of which almost 90% are adenocarcinomas.
  
* Impacted bowel
+
=== Sporadic colorectal cancers ===
 +
The picture below depicts the molecular pathogenesis of sporadic colon cancer:
 +
[[Image:Sporadic Colon Cancer3.jpg|center|1000x1000px|frame|Molecular pathogenesis of sporadic colon cancer]]
  
=== Prognosis ===
+
*'''APC gene'''
 +
:*Produces the APC protein, which prevents the accumulation of β-catenin protein (responsible for stem cell renewal)
  
* Prognosis is good, as IBS does not lead to life threatening complications or shorten lifespan of an individual.
+
:* Mutation of the APC protein leads to the accumulation of β-catenin protein and causes inappropriately high levels of stem cell renewal.
* IBS patients tend to have long symptom free intervals interspersed with periods of severe symptoms.
+
*'''TP53|TP53 gene'''
 +
:*Produces the P53 (protein)|p53 protein, which monitors cell division and promotes apoptosis if there are cell defects
 +
:*mutation|Mutation <nowiki/> mutation|s result in loss of control over cell division or apoptosis
 +
*'''TGF beta|TGF-β and DCC (Deleted in Colorectal Cancer)'''
 +
:*Usually responsible for apoptosis, but deactivated in colorectal cancer
 +
*'''Oncogenes'''
 +
:*Stimulate cellular division
 +
:*Mutations lead to over-activation of cell proliferation

Latest revision as of 12:23, 30 May 2020


Gastrointestinal Bleeding

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Muhammad Waleed Haider, M.D.[2]

Synonyms and Keywords: Blood loss from GI tract; bloody stool; blood in feces; PR bleeding; gastrointestinal hemorrhage; gastrointestinal hemorrhage; GI bleeding; bright red blood per rectum; BRBPR.

Overview

Gastrointestinal (GI) bleeding is defined as bleeding from any part of GI tract starting from mouth to anus. It can also be called as gastrointestinal hemorrhage. Based on the origin of bleeding it can be classified into upper gastrointestinal bleeding and lower gastrointestinal bleeding. Upper gastrointestinal bleeding (UGIB) is defined as bleeding from the gastrointestinal tract that originates proximal to the ligament of Treitz. Lower gastrointestinal bleeding is defined as blood loss originating distal to the ligament of Treitz. The most common causes of UGIB are peptic ulcer disease and esophageal varices while diverticulosis is the most commonly responsible for lower gastrointestinal bleeding. Clinical presentation includes overt bleeding from the gastrointestinal tract, rapid or slow, either manifested by hematemesis of fresh (blood-streaked to frankly bloody), old ('coffee ground') vomitus, melena and or as frank blood per rectum.

Common risk factors in the development of GI bleeding include advancing age, previous history of gastrointestinal bleeding, chronic constipation, hematologic disorders, anticoagulants medications, NSAIDs. It is essential to distinguish between lower gastrointestinal bleeding and brisk upper gastrointestinal bleeding as they can present with similar symptoms. Patients with severe bleeding or hemodynamic disturbance require hospitalization and urgent investigation. Treatment depends on the cause and the severity of the bleeding.

Types of bleeding

Bleeding from the gastrointestinal tract can be of the following types:

  • Hematemesis: Vomiting fresh red blood.
  • Coffee ground emesis: Vomiting of altered black blood.
  • Melena: Passage of black tarry stools.
  • Hematochezia: Passage of red blood per rectum (usually due to bleeding from the lower gastrointestinal tract but occasionally can be due to massive upper gastrointestinal bleeding).
  • Rebleeding: Defined as fresh hematochezia and/or melena associated with the development of shock (pulse greater than 100 beats/min, systolic pressure less than 100 mm Hg), a fall in CVP greater than 5 mm Hg, or a reduction in hemoglobin concentration greater than 20 g/l over 24 hours. Rebleeding should always be confirmed by endoscopy.

Causes

Gastrointestinal Bleeding Lethal Causes Common causes Less Common causes
Upper gastrointestinal bleeding
  • Anthrax
  • Ebola virus
  • Duodenal ulcer
  • Esophagitis
  • Esophageal varices
  • Gastric tumors
  • Gastric ulcer
  • Gastritis
  • Mallory-Weiss Syndrome
  • Peptic ulcer
  • Gastric cancer
  • Esophageal Tumors
  • Esophagitis
  • Gastric erosions/gastropathy
  • Dieulafoy lesions
  • Gastric antral vascular ectasia
Lower gastrointestinal bleeding
  • Diverticulosis
  • Vascular ectasias
  • Ischemic colitis
  • Colorectal malignancy
  • Hemorrhoids
  • Anal fissures
  • Crohn's disease
  • Ulcerative colitis
  • Infectious colitis
  • Colonic polyps
  • Radiation proctitis
  • Rectal varices
  • Stercoral ulceration
  • Meckel diverticulum
  • Intussusception
  • Henoch-Scholein Purpura (HSP)

Classification

The following flow chart elobarates the classification of gastrointestinal bleeding:

Gastointestinal
bleeding
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Upper GI bleedingLower GI bleeding
 
 
 
 
Based on blood lossBased on severity of blood loss
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
OvertOccultObscureSevereModerateOccult
 
 
 
 
 
 
 
 
 
 
 
 
Hematemesis Coffee-ground emesis MelenaMicroscopic Hemorrhage Heme-Occult positive stoolsSource is not identifiedHematocheziaHematocheziaMicroscopic Hemorrhage Heme-Occult positive stools


Syndrome of Inappropriate antidiuretic hormone classification

SIADH may be classified into several sub-types based on the pattern of arginine vasopressin (AVP) secretion in response to a range of plasma osmolalities into type A, type B, type C, and type D.

Classification Features
Type A
  • Accounts for about 60-70% of SIADH
  • Excessive secretion of arginine vasopressin (AVP) is noted
  • Associated with lung cancer and nasopharyngeal tumors
  • Patients are more susceptible to development of severe hyponatremia
Type B
  • Accounts for (20–40%) of the cases
  • Secretion of AVP occurs at lower than normal plasma osmolalities
Type C
  • Failure to suppress AVP secretion at plasma osmolalities below the osmotic threshold
  • Occurs due to dysfunction of inhibitory neurons in the hypothalamus, leading to persistent low-grade basal AVP secretion
Type D
  • Low or undetectable AVP levels and circulating AVP response is not defective
  • Nephrogenic SIADH (NSIAD) may be attributed to this condition
  • Associated with gain-of-function mutations in the vasopressin-2 (V2 receptor) receptor leading to a clinical picture of SIADH, with undetectable AVP levels
  • The condition is inherited in an X-linked manner, although heterozygous females may have inappropriate anti-diuresis of varying degrees.

Classification of Constipation

Constipation may be classified according to etiology into five subtypes:

  • Gastrointestinal
  • Neurologic
  • Metabolic
  • Endocrine
  • Psychiatric


Contipation
Classification
 
 
Etiology
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
NeurologicMetabolicEndocrineGastrointestinalPsychiatricDrugsIdiopathic
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ObstructionAgangliosisIdiopathic megacolon
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Hirschprung diseaseChagas disease
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Multiple sclerosis Parkinson's disease Spinal cord InjuryHypercalcemia Hypermagnesemia Porphyria HypokalemiaHypothroidism Diabetes mellitus PanhypopituitarismDepression Eating disorderAnalgesics Anticholinergics Cation containing agents Neuron targeting agentsNormal colonic transit Sloww colonic transit Dyssynergic defecation


Colorectal cancer pathophysiology

The pathogenesis of colorectal carcinoma (CRC) involves the molecular pathways for both sporadic and colitis-associated CRC. Sporadic instability originates from the epithelial cells that line the colon or rectum. Colitis-associated CRC includes genetic instability, epigenetic alteration, chronic inflammation, oxidative stress, and intestinal microbiota. According to the World Health Organization (WHO) histological classification, most colorectal tumors are carcinomas of which almost 90% are adenocarcinomas.

Sporadic colorectal cancers

The picture below depicts the molecular pathogenesis of sporadic colon cancer:

Molecular pathogenesis of sporadic colon cancer
  • APC gene
  • Produces the APC protein, which prevents the accumulation of β-catenin protein (responsible for stem cell renewal)
  • Mutation of the APC protein leads to the accumulation of β-catenin protein and causes inappropriately high levels of stem cell renewal.
  • TP53|TP53 gene
  • Produces the P53 (protein)|p53 protein, which monitors cell division and promotes apoptosis if there are cell defects
  • mutation|Mutation mutation|s result in loss of control over cell division or apoptosis
  • TGF beta|TGF-β and DCC (Deleted in Colorectal Cancer)
  • Usually responsible for apoptosis, but deactivated in colorectal cancer
  • Oncogenes
  • Stimulate cellular division
  • Mutations lead to over-activation of cell proliferation

Linked-in.jpg