​Kembara Xtra - Medicine - Ischemic Colitis

​Kembara Xtra - Medicine - Ischemic Colitis 
Introduction 

Ischemic colitis (IC) is caused when there is a reduction in the amount of blood that flows to the colon, which in turn causes inflammation and tissue damage.
More common in adults over the age of 65; nevertheless, patients of any age might be affected.
In 80% of individuals, IC will go away on its own and can even be reversed:
– Twenty percent of patients will develop to full-thickness necrosis, which will require surgical intervention. – Ischemia is most typically associated with a nonocclusive reduction in blood flow. – Full-thickness necrosis will require surgical intervention. Patients who have acute IC often show with localized abdomen discomfort and tenderness. However, the presentation of the condition might vary.
Within 12 to 24 hours of the commencement, frequent diarrhea that is bloody and loose might be observed. Laboratory and radiographic findings are nonspecific and must be connected with the patient's clinical presentation.
● The most reliable method for diagnosing IC is colonoscopy. Supportive therapy, which typically consists of intravenous fluids, bowel rest, and clinical monitoring, helps the majority of patients recover.

Epidemiology (Incidence and Prevalence) 

 Evidence of IC is observed in one out of every one hundred endoscopies. The risk of developing IC increases with age, particularly after the age of 69.
Considerations Regarding the Aged
Rare in individuals who are younger than 60 years old. Average age upon diagnosis is 70.
In the general population, the incidence ranges from 4.5 to 44 instances per 100,000 people (although this number may be overestimated because of the vague clinical signs).
19 new cases for every 100,000 people in the general population represents the prevalence.

Causes and effects: etiology and pathophysiology 
The ability to satisfy metabolic requirements is hindered when the colon suffers from localized hypoperfusion. There is also the possibility of reperfusion damage playing a role.
Both the superior and inferior mesenteric arteries (also known as the IMAs and SMAs, respectively) as well as branches of the internal iliac arteries supply blood to the colon. Because of the vast collateral circulation, occlusion of branches of the internal mammary artery (IMA) or the superior mesenteric artery (SMA) seldom results in ischemic effects.
Ischemic injury is most likely to occur in the watershed sections of the colon, which include the splenic flexure and the rectosigmoid junction. These areas are supplied by slender terminal branches of the SMA and IMA, respectively.
The left colon is the one that is typically impacted, as opposed to the right; isolated disease on the right side of the colon has the worst prognosis. Because of the increased blood supply provided by the internal iliac arteries, the rectum is frequently spared during surgery.
Type I: unclear etiology; most likely caused by illness of the tiny vessels; supportive care is recommended.
Type II: The etiology has been determined; treatment will focus on the underlying cause.

 Low blood pressure as a result of shock or trauma
Embolic occlusion of the mesenteric vessels Sickle cell disease Hypercoagulable states vasculitis Embolic occlusion of the mesenteric vasculature Sickle cell disease

Surgical problems; arterial thrombosis; venous thrombosis; mechanical obstruction of the colon (such as a tumor, adhesions, hernia, volvulus, prolapse, or diverticulitis); and thrombosis of the veins and arteries.
Abuse of cocaine and drugs (including compounds that are vasoconstrictive to the intestines and medications that cause hypotension and, as a result, hypoperfusion) are the two main causes of hypoperfusion.
 Dissection of the aorta
Repeated episodes of ischemia and inflammation can lead to chronic colonic ischemia, potential stricture formation, recurrent bacteremia, and sepsis. This can be caused by strenuous physical activity (such as long-distance running), as well as repeated episodes of ischemia. These patients might have patches of colitis that aren't getting better, thus they might need segmental colonic resection.

Genetics Various deficits of coagulation factors, such as protein C, protein S, antithrombin III, and factor V Leiden mutation, have been linked to IC.
Coagulation testing on a routine basis is not justified, with the exception of younger patients and individuals who have recurrent IC.


Risk Factors Patients who are over the age of 60 years old (90% of patients) Patients who smoke cigarettes (the leading cause of recurrent IC) Patients who have hypertension or diabetes mellitus Patients who have rheumatologic illnesses or vasculitis Patients who have cerebrovascular disease or ischemic heart disease
Recent abdominal surgery, such as an ileostomy; constipation; drugs that induce constipation; and medications that treat constipation.
vascular surgery in the patient's past Chronic obstructive pulmonary disease (COPD) hypoalbuminemia; hemodialysis hypercoagulability, oral contraceptives

 Immunosuppression (due to the side effects of medicine or CMV-induced IC) Irritable bowel syndrome 

The history, risk factors, and results from a physical examination are used to form the basis of a diagnosis, while laboratory values and radiographic findings are typically nonspecific.

● Colonoscopy is diagnostic.

Providing Some Background Information The most frequent symptom is abdominal pain.
 There is a possibility that the pain is disproportionate to the findings of the physical examination.
Sudden onset of mild to moderate abdominal pain with tenderness over the affected segment of the bowel Sudden urge to defecate followed by passage of either bright red or maroon feces typically within 12 to 24 hours of the start of abdominal pain Tenderness over the affected segment of the bowel after the urge to defecate Typically within 12 to 24 hours of the onset of abdominal pain 
Bleeding from the lower GI tract is rarely severe.


The Patient's Clinical Examination 

Individual signs and symptoms are not very good at predicting the presence of IC. Vital signs: hypotension and tachycardia
Soreness over the portion of the bowel that is implicated. Abdominal distention accompanied by vomiting (owing to the possibility of an accompanying ileus).

Patients who have transmural ischemia may, in extremely rare cases, exhibit peritoneal symptoms such as rebounding and guarding in their abdominal cavity.


Differential Diagnosis Colon cancer, diverticulitis Pseudomembranous colitis Infectious colitis Inflammatory bowel disease (ulcerative colitis, Crohn disease) Infectious colitis Inflammatory bowel disease (ulcerative colitis, Crohn disease) Colon cancer

The Results of the Laboratory Investigations and Tests 
This is dependent on the patient's clinical presentation, the degree to which the colon is involved, transmural involvement, and acuity.
Patients who are experiencing nonspecific abdominal pain typically undergo a CT scan as the first diagnostic test.

● Colonoscopy for definite diagnosis
Radiographic examinations and laboratory results are, on the other hand, not very specific.
 
   Initial Tests (lab, imaging)
The following signs of ischemia seen in lab tests are not unique to IC but might be helpful in evaluating the severity of the disease:
 CBC (leukocytosis), BMP (signs of metabolic acidosis), ABG (signs of metabolic acidosis), Lactate, LDH, CPK, amylase, Alkaline phosphatase, and Albumin are some of the tests that may be performed.

 Abdominal plain film: 20% of patients show thumbprinting and mural thickening; may predict worse prognosis Abdominal CT scan with contrast: thickening of the colonic wall and pericolonic fat stranding Abdominal plain film: 20% of patients show thumbprinting and mural thickening.Other signs include hyperdense mucosa, submucosal edema, and inflammation of the mesentery. Pneumatosis, pneumoperitoneum, and free peritoneal fluid are all indications that severe ischemia is present.
Multiphasic CTA is recommended in cases when right-sided ischemic cardiomyopathy is suspected or when acute mesenteric ischemia cannot be ruled out.

. Follow-Up Tests, as well as Other Particular Concerns
Stool cultures, fecal leukocytes, stool ova, and stool parasites to rule out infection Patients undergoing aortic surgery may benefit from postoperative colonoscopy within two to three days to screen for symptoms of inflammatory bowel disease (IBD).

 If needed, cardiac workup including EKG, Holter monitoring, or transthoracic echocardiography to exclude cardiogenic embolism. Screening for drugs and toxicology. If colon cancer screening is indicated, perform it several weeks after the patient has recovered from the ischemic insult.


Diagnostic Methods and Other Procedures
Colonoscopy is considered the gold standard, and sigmoidoscopy is utilized in the evaluation of postoperative left-sided ischemia.
Ischemia may be seen when there is cyanotic hemorrhagic tissue and edematous mucosa.
– Rectal sparing, segmental distribution (watershed), and hemorrhagic nodules were observed in this patient. 
The "colon single-stripe sign" is characterized by a single line of erythema and has a histopathologic yield of 75%.
It is no longer recommended to perform routine biopsies because the results are often nonspecific.
 For patients who have an isolated right IC, noninvasive vascular imaging investigations are the best option for determining whether or not they have acute SMA blockage.
The Interpretation of Tests

The specimens that were biopsied exhibit mucosal infarction as well as ghost cells, which have normal cellular outlines but do not contain any intracellular contents.


Management ● Treatment varies on disease severity.

 Ongoing clinical observation, including the recording of vital signs and repeated abdominal examinations
Supportive therapy is effective for the majority of patients as long as there is no evidence of colonic necrosis or perforation.
– Bed rest for the bowels. – Intravenous fluids to keep the patient's hemodynamics stable.Steer clear of vasoconstrictive drugs that have an intestinally active component.
 Steroids taken systemically should be avoided since they can make ischemia worse and raise the risk of perforation. If ileus is present, a nasogastric tube should be inserted.

If there is evidence of radiographic abnormalities, repeated x-rays of the abdomen might assist monitor any signs of recovery.

Consider surgical intervention in the event that the patient is showing signs of clinical deterioration despite receiving supportive care, such as increased abdominal discomfort, peritoneal signs, persistent diarrhea, bleeding, or sepsis.


Medication Certain medications, such as those that cause constipation (like opioids), have been linked to irritable bowel syndrome (IC). These medications include:
Immunomodulators (including anti-TNF inhibitors and type 1 interferon-/)
● Illicit drugs (cocaine, amphetamines)
First Line
Antibiotics with a broad spectrum of activity against both aerobic and anaerobic bacteria should be considered in order to prevent bacterial translocation caused by damage to the colonic mucosal lining.

 Ciprofloxacin, 400 mg intravenously twice daily or 500 mg orally twice daily. Metronidazole, 500 mg oral or intravenous three times daily.


Considerations Necessary for Future Consultations 
Initiate the necessary treatment as soon as possible if the cardiac workup reveals CHF or cardiac arrhythmias.

Consider surgical intervention in the event that the patient is showing signs of clinical deterioration despite receiving supportive care, such as increased abdominal discomfort, peritoneal signs, persistent diarrhea, bleeding, or sepsis.


Procedures Involving Surgery Twenty percent of patients will need surgical intervention. Surgery may be indicated for the following conditions: – Peritoneal signs; increased abdominal tenderness; new-onset shock; lactic acidosis; or acute renal failure; pneumatosis intestinalis; portal vein air; or free peritoneal air; diarrhea; lower gastrointestinal bleeding; or exudative colitis that has persisted for more than 14 days.
The colectomy with end ileostomy is the surgical procedure that is performed the most frequently (6) [A].
Cholecystectomy has the potential to avoid acute acalculous cholecystitis that is caused by resuscitation.


Medication that Is Supplemental 
Ginko biloba extract has been investigated as a potential supplementary treatment for a variety of conditions.
Ephedra, ma huang, bitter orange, and white willow bark are some of the weight reduction supplements and herbal supplements that have been linked to occurrences of irritable bowel syndrome (IC).


Admission 

ICU patients are a challenging population to diagnose with IC due to the presence of concomitant comorbidities and clinical treatment (sedation/ventilation) that can hide the typical signs and symptoms.
● Consider bedside colonoscopy in critically unwell patients.

Ongoing Care Bowel rest till symptoms improve Parenteral nourishment for patients requiring prolonged bowel rest who cannot undergo surgery due to medical reasons.
There is an increased risk of IC when taking weight loss medicines or natural supplements.

The majority of patients who have IC will get relief from their symptoms within 24 to 48 hours.
Resolution of radiographic or endoscopic findings within two weeks.
IC on the right side is the most important factor in determining the final result. Right-sided IC is associated with a death rate that is two times higher and a morbidity rate that is four times higher. Secondary cardiovascular prophylaxis helps to reduce the risk of recurrence.
Poor prognostic variables include male gender, low hemoglobin levels, low serum albumin levels, elevated BUN levels, and the presence of metabolic acidosis.
(1) Mortality rates in IC are higher for those who have chronic kidney illness, COPD, and who live in long-term care institutions.

Complications 

Twenty to thirty percent of individuals may develop chronic IC, which will either result in persistent diarrhea or the creation of a stricture that will require surgery.

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