Acute lower gastrointestinal bleeding (LGIB) is a common reason for patients to be admitted to the hospital, and it stands out as a particularly expensive and dangerous condition. This article elaborates on an organised way of controlling LGIB provided by the recently updated ACG Guideline.

---

Acute lower gastrointestinal bleeding (LGIB)

It is assumed that the incidence of LGIB ranges between 33 and 87 per 100,000 people; however, high-quality epidemiologic data on LGIB are missing. The increased frequency of LGIB may be attributable to an older population and rising anticoagulant usage. Patients presenting with LGIB are often older than those with UGIB.

Causes

1. Antiplatelet usage, including aspirin, nonsteroidal anti-inflammatory medications (NSAIDs), and P2Y12 inhibitors such as clopidogrel, are risk factors for the development of LGIB.
2. Additional frequent causes of LGIB include ischemic colitis, haemorrhoids, angioectasias, colorectal neoplasia, post polypectomy bleeding, colitis (inflammatory, bacterial, or due to radiation), rectal/stercoral/NSAID-induced ulcers, and radiation protopathic.
3. Less prevalent etiologies may include the Dieulafoy lesion and colorectal varices.
4. Depending on the timing and usage of inpatient colonoscopy, individuals treated with LGIB are often found to have no source of bleeding. In reality, 23 per cent of LGIB patients in the UK audit had no identified cause of bleeding.

The recently revised ACG Guideline provides a methodical approach to managing LGIB.

---

Evaluating and prioritising potential issues from the outset

At the time of patient presentation, a focused history, physical examination, and laboratory assessment should be performed to identify the degree of bleeding and its likely location and origin. Simultaneous initial patient evaluation and hemodynamic resuscitation are required.

Risk assessment

Recommendations propose the use of risk stratification methods (e.g., Oakland score< 8) to identify LGIB patients at low risk for early discharge and outpatient diagnostic examination. The use of risk ratings should augment but not replace physician judgment (Conditional recommendation, low-quality evidence).

Oakland et al. developed and validated a clinical score to predict safe discharge, which they defined as the lack of rebleeding, blood transfusion, or 28-day hospital readmission.

Initiating a hemodynamic resuscitation

Prior to endoscopic evaluation/intervention, patients with hemodynamic instability and/or suspected continuous bleeding should undergo intravenous fluid resuscitation with the objective of optimising blood pressure and heart rate.

In hemodynamically stable patients with LGIB, researchers recommend a limited red blood cell transfusion approach (transfusion threshold of 7 g/dL) (Conditional recommendation, low-quality evidence).

Exclusion of the source of proximal bleeding

Hematochezia accompanied by hemodynamic instability may be suggestive of a UGIB source, and if the suspicion is strong, an upper endoscopy should be conducted to rule out a proximal cause of bleeding.

---

Coagulopathy reversal and antithrombotic management

Treatment of VKA-treated patients

Endoscopic hemostasis may be deemed safe and successful in individuals who have an international normalised ratio (INR) of 2.5 or below.

While the majority of VKA-treated patients with LGIB are unlikely to need reversal, we recommend reversal for patients who come with a life-threatening LGIB and an INR significantly over the therapeutic range. For patients on VKAs to avoid stroke in nonvalvular atrial fibrillation who need reversal, 4-factor prothrombin complex concentrate (PCC) is recommended over fresh frozen plasma (FFP) because of the quickness of INR lowering (Conditional recommendation, very low-quality evidence).

DOAC reversal

For patients on DOACs who arrive with a life-threatening LGIB that does not respond to first resuscitation and discontinuation of the anticoagulant alone, experts recommend reversal. For individuals needing reversal, targeted reversal medicines (idarucizumab for dabigatran and andexanet alfa for apixaban and rivaroxaban) should be given if the DOAC was taken within 24 hours. (Conditional recommendation, very low-quality evidence).

Management of antiplatelets in an acute setting

Platelets should be provided in severe LGIB to maintain a platelet count of >30 109/L; a higher threshold of >50 109/L should be considered if endoscopic operations are necessary. There is no advantage to regular platelet transfusions for antiplatelet-treated individuals.

Whenever feasible, individuals with LGIB receiving cardiac aspirin for secondary prevention should continue to take aspirin throughout hospitalisation. Antiplatelet agents that are not aspirin-based should be withheld in the beginning for patients with severe hematochezia. Therefore, a multidisciplinary approach should be employed to establish the safety of temporarily suspending antiplatelet therapy in patients having recent coronary stents implanted within the last year.

Role of antifibrinolytic agents

---

Diagnostic testing

Role of colonoscopy

After insertion and withdrawal, the colonic mucosa should be thoroughly scrutinised, and the remaining stool and blood should be aggressively washed to locate bleeding sites. Where possible, the terminal ileum should be intubated to eliminate proximal causes of bleeding if no colonic source is identified. It is suggested to wear a transparent hat to aid in the diagnosis and management of bleeding.

1. Researchers suggest colonoscopy for the majority of patients hospitalised with LGIB due to its usefulness in finding the source of bleeding (Strong recommendation, low-quality evidence).
2. Nevertheless, a colonoscopy may not be necessary for individuals whose bleeding has ceased and who have had a high-quality colonoscopy within the last 12 months with proper intestinal preparation revealing diverticulosis without colorectal cancer (Conditional recommendation, very low-quality evidence).

Role of CTA

Researchers recommend a CTA as the first diagnostic test for individuals with persistent hematochezia that is hemodynamically significant. Nevertheless, CTA has a poor rate of success in individuals with modest LGIB or when clinically detectable bleeding has ceased. (Conditional recommendation, low-quality evidence)

---

Management of positive CTA 

Guidelines urge that patients whose CTA reveals extravasation be referred immediately to interventional radiology for transcatheter arteriography and possibly embolisation. After a positive CTA, specialist facilities with expertise doing endoscopic hemostasis may additionally consider a colonoscopy. (Strong recommendation, moderate quality evidence)

---

Timing of colonoscopy

For patients hospitalised with LGIB who need a colonoscopy, guidelines advocate a nonurgent inpatient colonoscopy since urgent colonoscopies performed within 24 hours have not been demonstrated to enhance clinical outcomes such as rebleeding and death. (Strong recommendation, moderate-quality evidence)

---

Bowel preparation

Historically, 4–6 L of polyethylene glycol (PEG)-based stool preparation has been suggested for patients having inpatient colonoscopy; however, split-dose preparation and/or the use of low-volume preparations may also be explored. Unprepared assessment or regular flexible sigmoidoscopy is not advised unless it is known that the source is in the anorectal region or distal colon.

---

Endoscopic treatment

Role of treatment of SRH

Regardless of the cause, endoscopic treatment is advised when current bleeding or stigmata of recent haemorrhage (SRH) are seen.

Treatment of diverticular haemorrhage

Diverticular SRH should be treated with through-the-scope clips, EBL, or coagulation when found. (Strong recommendation, moderate-quality evidence)

The role of a repeat colonoscopy, angiography, and surgery

Repeat colonoscopy may be recommended for individuals who have to rebleed after initial hemostasis or cessation of bleeding, based on the patient's stability and probability of successful repeat endoscopic treatment. Observation may be an option for individuals with suspected recurrent diverticular bleeding and a recent colonoscopy who are hemodynamically stable.

Resumption of antiplatelet medications and risk of recurrence

1. Guidelines suggest quitting nonaspirin nonsteroidal anti-inflammatory drugs (NSAIDs) following hospitalisation for diverticular bleeding.
2. Given the likelihood of recurrent diverticular bleeding, Guidelines advise quitting aspirin for primary cardiovascular protection following hospitalisation for diverticular haemorrhage.
3. Patients with a history of cardiovascular disease should continue taking aspirin following hospitalisation for diverticular bleeding due to the advantages of preventing future ischemic episodes.
4. Guidelines propose that doctors reevaluate the risks against the advantages of maintaining nonaspirin antiplatelets, such as P2Y12 receptor antagonists, in a multidisciplinary environment following hospitalisation for diverticular haemorrhage, given the risks of recurrent diverticular haemorrhage.

Resumption of anticoagulants and risk of recurrence

Recommendations advise restarting anticoagulation upon discontinuation of LGIB because resuming anticoagulation has been found to reduce the risk of post-bleeding thromboembolism and death. (Strong recommendation, moderate-quality evidence)

Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.
About the author of this article: Dr Monish Raut is a practising super specialist from New Delhi.