Splenic Hematoma After Colonoscopy: CT Diagnosis, Active Bleeding Assessment, and Modern Management

When Sudden Left Upper Quadrant Pain After a Routine Colonoscopy Is More Than Post-Procedural Discomfort

A colonoscopy is generally a safe and routinely performed procedure. Mild abdominal distension or transient discomfort after the examination is common. But when a patient develops sudden, persistent left upper quadrant pain within hours or a day after colonoscopy, the clinical question should change.

Could this be an iatrogenic splenic injury?

This question becomes particularly important when the patient has no history of recent abdominal trauma. The spleen lies close to the splenic flexure of the colon, and mechanical forces generated during colonoscope advancement can, in rare circumstances, produce capsular injury, subcapsular hematoma, laceration, or more extensive hemorrhage.

The case discussed here involves a woman in her late 50s who presented with acute left-sided abdominal pain after colonoscopy and polypectomy. CT demonstrated a large subcapsular splenic hematoma involving more than 50% of the splenic surface, with a small amount of hemoperitoneum. The injury was described in the case material as an AAST grade III splenic injury.

Yet the most important finding was not simply the size of the hematoma.

CT angiography demonstrated no active contrast extravasation and no imaging evidence of pseudoaneurysm.

That distinction is central to radiologic interpretation.

A large hematoma does not automatically mean that active bleeding is continuing at the moment of imaging. Conversely, the absence of active extravasation does not mean that the patient is free of risk.

The radiologist therefore has to answer two different questions:

How extensive is the splenic injury?

and

Is there evidence that bleeding is currently active or associated with a vascular complication?

The answers can substantially influence subsequent management.

Executive Clinical Summary

Post-colonoscopy splenic injury is rare, but it can become life-threatening when diagnosis is delayed.

The characteristic presentation is acute or persistent left upper quadrant abdominal pain after colonoscopy, sometimes accompanied by left shoulder pain, dizziness, tachycardia, hypotension, syncope, abdominal distension, or a fall in hemoglobin.

In the present case, CT demonstrated a large subcapsular splenic hematoma and a small amount of hemoperitoneum. The hematoma followed the contour of the spleen and compressed the splenic parenchyma inward.

CT angiography did not demonstrate active contrast extravasation or pseudoaneurysm.

The clinically useful radiologic diagnosis is therefore:

Large subcapsular splenic hematoma without CT evidence of active bleeding.

This wording is more informative than simply reporting “splenic hematoma,” because it communicates both the structural injury and the absence of an important vascular complication.

Key Clinical Questions

Why can colonoscopy cause splenic injury?
What does a subcapsular splenic hematoma look like on CT?
Why are coronal reconstructions important?
How should hemoperitoneum be assessed?
What distinguishes active bleeding from a contained hematoma?
When should pseudoaneurysm be considered?
Does an AAST grade III injury automatically require surgery?
What role can splenic artery embolization play?
How should radiologists communicate these findings?
Where could artificial intelligence realistically assist—and where could it fail?

Introduction

The spleen is a highly vascular organ located in the left upper quadrant, immediately adjacent to the splenic flexure of the colon. This anatomical relationship explains why an apparently uncomplicated endoscopic procedure can, in rare circumstances, result in splenic injury.

The mechanism is usually not direct penetration of the spleen by the colonoscope. Instead, mechanical forces can be transmitted through the splenic flexure and its supporting structures.

Difficult colonoscope advancement, looping, traction on the splenocolic ligament, manipulation around the splenic flexure, or excessive external pressure over the left upper abdomen have all been described as possible mechanisms.

Once the splenic capsule is injured, blood may accumulate between the capsule and the splenic parenchyma, producing a subcapsular hematoma.

At first, the intact capsule may partially contain the hemorrhage.

But containment is not equivalent to safety.

An enlarging hematoma can increase capsular tension, and capsular rupture may lead to intraperitoneal hemorrhage. Therefore, the radiologist should evaluate not only the hematoma itself but also the integrity of the spleen, the presence of hemoperitoneum, and evidence of vascular injury.

Clinical Hook: The Question That Can Change the Diagnosis

In the emergency department, the first history question may be deceptively simple:

“Have you recently undergone colonoscopy?”

If the answer is yes and the patient has unexplained left upper quadrant pain, splenic injury should enter the differential diagnosis.

This is especially important when the patient denies trauma.

An absence of trauma does not exclude splenic injury.

Iatrogenic splenic injury can occur without an external traumatic event, and the temporal relationship between the procedure and symptoms can provide a crucial diagnostic clue.

Left shoulder pain is another important clinical signal. Blood or irritation around the spleen can stimulate the diaphragm and produce referred shoulder pain, traditionally described as Kehr's sign.

The combination of recent colonoscopy, left upper quadrant pain, and left shoulder pain should therefore prompt consideration of splenic injury rather than being automatically attributed to post-procedural bowel gas.

Learning Objectives

By the end of this article, readers should be able to:

Recognize the CT appearance of a subcapsular splenic hematoma.
Understand the anatomical relationship between the splenic flexure and spleen.
Distinguish a large hematoma from active hemorrhage on CT angiography.
Identify important vascular complications such as pseudoaneurysm.
Understand why hemodynamic status must be integrated with CT findings.
Appreciate how imaging, interventional radiology, surgery, and clinical monitoring interact in modern splenic injury management.

Anatomy Review: Why the Splenic Flexure Matters

The spleen occupies the left upper quadrant and lies in close proximity to the splenic flexure of the colon.

This relationship is clinically important because colonoscope manipulation at the splenic flexure can transmit mechanical forces toward the spleen.

Several structures contribute to this relationship, including the splenocolic ligament and surrounding peritoneal attachments.

During difficult colonoscopy, the instrument may form loops. Attempts to advance or withdraw the colonoscope can create traction forces. Excessive pressure applied to the left upper abdomen can also transmit force toward the spleen.

The resulting injury may be subtle.

A small capsular injury can initially produce a contained subcapsular hematoma. The patient may therefore appear relatively stable before developing more significant bleeding.

This is one reason why the timing of symptoms matters.

Table 1. Clinical Presentation and Warning Signs

Clinical feature	Potential significance
Sudden left upper quadrant pain	Important warning sign
Persistent abdominal pain	Should prompt further evaluation
Left shoulder pain	Possible diaphragmatic irritation
Tachycardia	May indicate physiological response to blood loss
Hypotension	Possible hemodynamic instability
Dizziness or syncope	Possible significant blood loss
Abdominal distension	May accompany hemoperitoneum
Falling hemoglobin	Supports ongoing or recent blood loss
Recent colonoscopy	Important etiologic clue
No trauma history	Does not exclude iatrogenic splenic injury

The combination of symptoms should be interpreted in context rather than individually.

Case Presentation

The case concerns a woman in her late 50s who presented with acute left-sided abdominal pain.

The available clinical information identifies a recent colonoscopy and polypectomy.

Abdominal CT and CT angiography demonstrated a large subcapsular splenic hematoma involving more than 50% of the splenic surface. A small amount of blood was also present in the perihepatic region, paracolic gutters, and pelvis, consistent with hemoperitoneum.

The case material describes the splenic injury as AAST grade III.

The critical additional finding was the absence of active contrast extravasation.

No CT evidence of pseudoaneurysm was identified.

Thus, the imaging diagnosis is best expressed as:

Large subcapsular splenic hematoma with associated hemoperitoneum, without CT evidence of active bleeding or pseudoaneurysm.

Imaging Features

Axial CT

Figure 1. Axial CT demonstrating a large subcapsular splenic hematoma.

Radiologist Interpretation

The axial CT image demonstrates a low-attenuation collection along the peripheral aspect of the spleen. The collection follows the contour of the splenic capsule and produces inward compression of the splenic parenchyma.

This crescentic configuration is characteristic of a subcapsular collection.

The relationship between the collection and the splenic capsule is diagnostically important.

A free intraperitoneal fluid collection may surround abdominal organs without following the splenic contour in this manner. A subcapsular hematoma, by contrast, conforms closely to the external surface of the spleen.

Clinical Significance

The finding establishes that blood has accumulated within the potential space beneath the splenic capsule.

The next question is not simply whether a hematoma exists.

The radiologist must determine:

How extensive is the hematoma?
Is the splenic parenchyma lacerated?
Is there hemoperitoneum?
Is there active bleeding?
Is there a pseudoaneurysm?
Is there another vascular injury?

Coronal CT

Figure 2. Coronal CT demonstrating the longitudinal extent of the subcapsular splenic hematoma.

Radiologist Interpretation

Coronal reconstruction demonstrates the superior-to-inferior extent of the hematoma more intuitively than a single axial image.

This is particularly useful when the hematoma extends along a substantial portion of the splenic surface.

Coronal images also allow simultaneous assessment of the surrounding abdominal cavity.

Clinical Significance

Emergency abdominal CT should not be interpreted exclusively in the axial plane.

Multiplanar reconstruction can clarify:

The longitudinal extent of the splenic hematoma.
The relationship between the spleen and adjacent structures.
The distribution of hemoperitoneum.
The presence of additional abdominal abnormalities.

In an injury whose mechanism may not initially be obvious, multiplanar evaluation improves the anatomical understanding of the lesion.

Coronal CT and Hemoperitoneum

Figure 3. Coronal CT demonstrating splenic injury and associated intraperitoneal blood.

Radiologist Interpretation

Blood is not confined to the perisplenic region.

The available case material describes fluid or blood in the perihepatic space, paracolic gutters, and pelvis.

This distribution supports the presence of hemoperitoneum.

Clinical Significance

Hemoperitoneum indicates that bleeding has extended beyond the subcapsular compartment.

However, hemoperitoneum alone does not determine whether surgery is required.

Management depends on the complete clinical picture, particularly hemodynamic stability and evidence of ongoing bleeding or vascular injury.

What Does a Subcapsular Splenic Hematoma Look Like?

The classic CT appearance is a peripheral collection that conforms to the splenic surface.

The hematoma may appear crescentic and can compress the underlying splenic tissue.

Its attenuation varies with the age and composition of the blood. The case material primarily emphasizes the anatomical appearance and extent rather than providing a quantitative attenuation measurement.

A radiologist should therefore avoid overinterpreting an exact CT density when that value is not available.

The more important observation is the anatomical relationship:

blood beneath the splenic capsule, following the spleen's contour and compressing the underlying parenchyma.

CT Assessment: Five Findings That Should Not Be Missed

When splenic injury is suspected, CT interpretation should be systematic.

1. Subcapsular Hematoma

Look for blood tracking along the splenic surface.

Assess its extent and whether it compresses the underlying parenchyma.

2. Splenic Laceration

Search for linear or irregular low-attenuation defects within the splenic parenchyma.

A laceration may coexist with a subcapsular hematoma.

3. Active Contrast Extravasation

Active hemorrhage appears as contrast material outside the expected vascular lumen, particularly on arterial-phase imaging.

Comparison with later phases can help determine whether the focus changes in size or configuration.

4. Pseudoaneurysm

A pseudoaneurysm may appear as a focal enhancing vascular structure during the arterial phase.

This is fundamentally different from a simple hematoma.

5. Hemoperitoneum

Inspect the entire abdomen and pelvis.

Do not stop after identifying blood around the spleen.

CT Angiography

Figure 4. Multiphase CT demonstrating the splenic hematoma on non-contrast, arterial, and portal venous imaging.

Radiologist Interpretation

The figure compares:

Non-contrast imaging.
Arterial-phase imaging.
Portal venous-phase imaging.

The non-contrast phase helps characterize the hematoma.

The arterial phase is particularly important for evaluating vascular injury and active hemorrhage.

The portal venous phase allows broader assessment of the splenic parenchyma, hematoma, hemoperitoneum, and surrounding abdominal structures.

In this case, the arterial and delayed imaging did not demonstrate contrast extravasation.

There was also no imaging evidence supporting a pseudoaneurysm.

The Critical Radiologic Distinction

Large hematoma ≠ active bleeding.

This is perhaps the most important lesson of the case.

A hematoma records blood that has already accumulated.

Active extravasation indicates that contrast is escaping from the vascular system during the examination.

The two findings are related but not interchangeable.

Is There Active Bleeding?

Figure 5. Axial CT assessment for active contrast extravasation.

Radiologist Interpretation

The key question is whether contrast material is seen outside the expected vascular structures.

In this case, no active extravasation was demonstrated in the arterial or delayed phases.

The imaging diagnosis can therefore be summarized as:

Large subcapsular splenic hematoma without CT evidence of active bleeding.

This statement provides clinically useful information beyond the simple presence of a hematoma.

Imaging Physics: Why the Arterial Phase Matters

CT angiography is not merely another set of images.

It is a temporal experiment.

Contrast enters the arterial circulation and subsequently distributes through the vascular system and parenchymal compartments.

If an arterial injury is actively leaking, contrast may appear outside the expected vascular lumen during the arterial phase.

A contained vascular lesion such as a pseudoaneurysm may instead appear as a focal enhancing structure corresponding to a vascular abnormality.

This is why multiphase imaging can answer a question that routine portal venous CT may not answer adequately:

Is there an identifiable vascular source of bleeding?

Arterial-phase imaging has demonstrated additional value for detecting contained splenic vascular injuries in the appropriate clinical setting.

The practical lesson is straightforward:

When vascular injury is clinically suspected, the CT protocol and interpretation must be designed around the question of vascular integrity.

Pathophysiology: How Can Colonoscopy Injure the Spleen?

The mechanism is usually mechanical rather than direct.

Several potential mechanisms have been proposed.

1. Excessive Instrument Manipulation

Difficulty advancing the colonoscope through the splenic flexure may generate traction.

2. Loop Formation

Formation of a loop can increase the mechanical forces transmitted to the colon and its attachments.

3. Splenocolic Ligament Traction

Traction transmitted through the splenocolic relationship can place tension on the splenic capsule.

4. External Pressure

Pressure over the left upper abdomen can transmit force toward the spleen.

5. Procedure-Associated Manipulation

Polypectomy or biopsy may occur during the same procedure, but the presence of polypectomy should not automatically be interpreted as the direct cause of splenic injury.

The broader mechanism is the mechanical interaction between colonoscope manipulation, the splenic flexure, and the spleen.

Table 2. Mechanisms and Imaging Consequences

Potential mechanism	Possible consequence
Difficult intubation	Increased mechanical traction
Loop formation	Transmission of force toward splenic flexure
Splenocolic ligament traction	Capsular stress
External left upper quadrant pressure	Splenic compression
Capsular microinjury	Subcapsular hematoma
Capsular disruption	Hemoperitoneum
Vascular injury	Active bleeding or pseudoaneurysm

Epidemiology: Rare Does Not Mean Harmless

Splenic injury after colonoscopy is uncommon.

A recent large systematic review and meta-analysis of colonoscopy-related adverse events estimated splenic injury at approximately 0.61 per 10,000 colonoscopies, although rates vary according to population and study design.

Older systematic reviews and case-based literature have reported substantial mortality among recognized splenic injury cases, emphasizing the consequences of delayed recognition.

The important clinical point is not to memorize a single incidence number.

It is to understand the asymmetry between probability and consequence.

The complication is rare.

The consequence of missing it can be severe.

Therefore, a low prior probability should not override a strong clinical signal.

Clinical Presentation

Symptoms may develop within hours or within the first day after colonoscopy.

Important warning signs include:

Sudden left upper quadrant pain.
Persistent abdominal pain.
Left shoulder pain.
Dizziness.
Syncope.
Tachycardia.
Hypotension.
Abdominal distension.
Falling hemoglobin.

The temporal relationship to colonoscopy is particularly important.

A patient may not volunteer the procedure history unless specifically asked.

For this reason, procedural history should be incorporated into the diagnostic reasoning process.

Differential Diagnosis

The principal diagnostic alternatives include vascular lesions and other splenic abnormalities.

Table 3. Differential Diagnosis of a Post-Colonoscopy Splenic Abnormality

Diagnosis	Key imaging finding	Clinical clue	Differentiating point
Subcapsular splenic hematoma	Peripheral blood collection following splenic contour	Recent procedure, LUQ pain	Subcapsular location
Active splenic hemorrhage	Contrast extravasation	Hemodynamic deterioration possible	Contrast outside vessels
Splenic artery pseudoaneurysm	Focal arterial enhancement	Vascular injury	Enhancing contained vascular lesion
Splenic artery aneurysm	Arterial dilatation	May be incidental	True arterial dilatation
Splenic AV fistula	Abnormal arterial-venous communication	Vascular abnormality	Arterial and venous communication
Splenic infarction	Wedge-shaped low attenuation	Ischemic context	Perfusion abnormality rather than hematoma

The distinction between pseudoaneurysm and active extravasation is particularly important.

A pseudoaneurysm represents a contained vascular injury.

Active extravasation suggests ongoing leakage.

They are not interchangeable terms.

AAST Grade III: What Does It Mean?

The case describes a subcapsular hematoma involving more than 50% of the splenic surface and classifies the injury as AAST grade III.

The AAST Organ Injury Scale provides an anatomical framework for describing splenic injury severity.

However, anatomical grade should not be interpreted in isolation.

A high-grade injury does not automatically mean that splenectomy is mandatory.

Modern management integrates:

Hemodynamic stability.
Blood pressure.
Heart rate.
Hemoglobin trajectory.
Transfusion requirements.
Active contrast extravasation.
Pseudoaneurysm.
Associated injuries.
Overall clinical condition.

This distinction between anatomical severity and physiological instability is central to modern splenic trauma management.

Table 4. Imaging Severity Versus Clinical Risk

Finding	What it tells us
Large subcapsular hematoma	Significant anatomical injury
Hemoperitoneum	Blood has entered the peritoneal cavity
Active extravasation	Imaging evidence of ongoing bleeding
Pseudoaneurysm	Contained vascular injury
Stable vital signs	Supports consideration of non-operative management
Falling hemoglobin	May indicate ongoing blood loss
Persistent hypotension	Major clinical warning sign
Need for repeated transfusion	Suggests clinically significant bleeding

Multimodal Imaging Comparison

Table 5. Imaging Modalities in Suspected Splenic Injury

Modality	Strength	Limitation	Best clinical question
Ultrasound	Rapid detection of free fluid	Limited characterization of injury	Is there intraperitoneal fluid?
Contrast-enhanced CT	Comprehensive anatomical assessment	Radiation and contrast considerations	What is the extent of injury?
CT angiography	Vascular assessment	Requires appropriate protocol	Is there active bleeding or vascular injury?
MRI	Detailed soft-tissue characterization	Less practical in acute instability	Selected problem-solving situations

CT is particularly valuable because it can simultaneously evaluate the spleen, vascular structures, hemoperitoneum, and surrounding organs.

Treatment: Why Timing Matters

Management should be individualized by the treating clinical team according to the patient's physiology, imaging findings, and available resources.

For a hemodynamically stable patient without active bleeding, non-operative management may be considered.

This can involve:

Close clinical monitoring.
Serial vital-sign assessment.
Serial hemoglobin measurement.
Repeated abdominal examination.
Appropriate transfusion support.
Follow-up imaging when clinically indicated.

The term non-operative management should not be confused with “doing nothing.”

It is an active strategy requiring monitoring and the ability to escalate treatment rapidly.

When Active Bleeding Is Present

If CT demonstrates active extravasation or a vascular complication such as pseudoaneurysm, angiographic intervention may become an important option.

Splenic artery embolization has increasingly been incorporated into treatment pathways for suitable patients because it can control hemorrhage while potentially preserving splenic tissue.

Recent systematic evidence specifically addressing colonoscopy-associated splenic injury suggests that splenic artery embolization can be an effective treatment option in appropriately selected patients with high-grade injury.

When Surgery May Be Required

Hemodynamic instability changes the management equation.

Persistent hypotension, ongoing blood loss, repeated hemoglobin decline, substantial transfusion requirements, persistent intraperitoneal bleeding, or failed embolization may lead to operative management.

The modern objective, when feasible, is increasingly centered on controlling hemorrhage while preserving splenic function.

Table 6. Conceptual Management Framework

Clinical/imaging situation	General management direction
Hemodynamically stable, no active bleeding	Non-operative management may be considered
Stable patient with vascular lesion	Consider interventional radiology assessment
Active extravasation	Embolization may be appropriate
Pseudoaneurysm	Interventional treatment may be considered
Persistent hemodynamic instability	Urgent escalation, potentially surgery
Failed embolization with ongoing bleeding	Surgical management may be required

This is a conceptual framework rather than individualized medical advice.

Why CT Is So Important

Ultrasound can be useful for rapidly detecting free intraperitoneal fluid.

But when the clinical question is:

“What exactly happened to the spleen?”

contrast-enhanced CT becomes substantially more informative.

CT can simultaneously demonstrate:

Subcapsular hematoma.
Splenic laceration.
Intraparenchymal hematoma.
Hemoperitoneum.
Active hemorrhage.
Pseudoaneurysm.
Adjacent organ injury.

This is why unexplained severe left upper quadrant pain after colonoscopy should not be dismissed simply because the procedure itself was considered routine.

The Seven-Step Radiologist Checklist

A practical reporting sequence can be built from the case.

1. Is there a subcapsular hematoma?

2. How much of the splenic surface is involved?

3. Is there a parenchymal laceration?

4. Is there hemoperitoneum?

5. Is there active arterial extravasation?

6. Is there a pseudoaneurysm or AV fistula?

7. What is the patient's hemodynamic status?

The final question technically lies outside the image itself, but it is essential for clinical interpretation.

Radiology does not operate in isolation.

The image and the patient's physiology must be integrated.

Imaging Diagnostic Algorithm

Artificial Intelligence Perspective

AI has a potentially useful role in this clinical scenario, but it should support—not replace—radiologist interpretation.

A clinically meaningful AI system could be trained to identify several imaging features:

Splenic contour abnormalities.
Subcapsular collections.
Hemoperitoneum.
Focal contrast extravasation.
Vascular abnormalities.
Splenic lacerations.

Computer vision models could potentially perform object detection or segmentation of the spleen and adjacent collections.

A segmentation model could estimate the relationship between the hematoma and splenic surface.

A detection model could flag suspicious regions for radiologist review.

A multimodal system could theoretically combine imaging with clinical metadata such as:

Recent colonoscopy.
Time since procedure.
Left upper quadrant pain.
Hemoglobin change.
Heart rate.
Blood pressure.

But these possibilities should remain clearly separated from established clinical practice.

An AI model should not be assumed to diagnose colonoscopy-related splenic injury safely simply because it can detect an abnormality.

AI Development Pipeline

It may be deployment.

A model trained on conventional trauma CT may encounter very different cases in patients with iatrogenic splenic injury.

This creates the possibility of domain shift.

AI Failure Modes

An AI system could fail in several realistic ways.

False Negative

A subtle subcapsular hematoma may be missed.

False Positive

Normal perisplenic fluid or adjacent anatomical structures may be incorrectly labeled as hemorrhage.

Anatomical Mislocalization

The model may identify blood but incorrectly attribute its source.

Poor Image Quality

Motion, reconstruction artifacts, or suboptimal contrast timing can degrade performance.

Domain Shift

A model trained predominantly on traumatic splenic injuries may not generalize perfectly to iatrogenic injury after colonoscopy.

Workflow Failure

Even a technically accurate alert may be clinically ineffective if it is delivered too late or buried among competing notifications.

Alert Fatigue

Repeated non-actionable alerts can reduce clinician attention.

Hallucinated Explanation

A generative AI system may produce a plausible-sounding explanation that is not actually supported by the image.

Therefore, the radiologist must verify the image itself.

Enterprise Healthcare Workflow

A patient with suspected splenic injury could theoretically trigger a model specialized for hemorrhage detection, while other models evaluate abdominal findings.

An orchestration layer could determine which models should process the study and how results are returned to the radiologist.

PACS/RIS/EMR Integration

An enterprise implementation should preserve the normal clinical workflow.

AI should not require the radiologist to leave the PACS environment unnecessarily.

A useful integration could provide:

DICOM-based image processing.
PACS visualization.
Structured AI findings.
Priority notification when appropriate.
RIS integration.
EMR availability.
Audit logging.
Model-version tracking.

The AI result should remain clearly distinguishable from the radiologist's final interpretation.

Explainable AI: What Should the Radiologist See?

For a suspected splenic hematoma, explainability should ideally be anatomical.

A useful system might show:

A bounding box around the suspected hematoma.
Segmentation of the splenic contour.
A highlighted region of suspected extravasation.
A confidence score.
A comparison between arterial and delayed phases.

But visual highlighting is not proof of correctness.

A heat map can tell the radiologist where a model is responding.

It cannot guarantee that the model understood the underlying pathology.

The radiologist must determine whether the highlighted region actually corresponds to hemorrhage, vascular enhancement, artifact, or normal anatomy.

Enterprise AI Failure Analysis

Table 7. AI Risk in Splenic Injury Detection

AI risk	Example	Human verification
False negative	Missed subcapsular hematoma	Review entire spleen
False positive	Mistaking normal enhancement for bleeding	Compare phases
Mislocalization	Blood attributed to wrong organ	Multiplanar review
Domain shift	Iatrogenic injury differs from training data	Clinical validation
Poor image quality	Missed subtle vascular finding	Manual image review
Alert fatigue	Too many emergency alerts	Workflow governance
Hallucinated explanation	Unsupported AI rationale	Verify against images
Model drift	Performance changes over time	Continuous monitoring

Healthcare Economics and ROI

The financial value of an AI system in this scenario should not be reduced to the cost of a software license.

A realistic enterprise evaluation should consider:

AI licensing.
PACS/RIS integration.
Infrastructure.
Cloud or edge computing.
Maintenance.
Cybersecurity.
Staff training.
Workflow redesign.
Radiologist adoption.
Monitoring.
Clinical impact.

The basic ROI framework is:

ROI = (Financial Benefit − Total Cost of Ownership) / Total Cost of Ownership

However, no guaranteed financial return should be assumed.

The most meaningful value may arise from faster recognition of clinically significant abnormalities, better prioritization, improved communication, or reduced diagnostic delay.

Those benefits must be demonstrated in the actual clinical environment.

Regulatory Perspective

Any AI system intended for clinical use must be evaluated within the applicable regulatory framework.

Relevant considerations include:

Software as a Medical Device.
Clinical validation.
Intended use.
Performance monitoring.
Change management.
Cybersecurity.
Human oversight.
Post-market surveillance.

Regulatory authorization should never be inferred merely because a model performs well in a research dataset.

Expert Insights

Expert Insight 1 — Radiologist Perspective

The most important imaging question is not simply whether a splenic hematoma exists. The report should communicate its extent, associated hemoperitoneum, and whether active bleeding or vascular injury is present.

Expert Insight 2 — Emergency Department Perspective

The procedural history may be the clue that transforms an apparently nonspecific abdominal pain presentation into a focused splenic injury evaluation.

Expert Insight 3 — Gastroenterology Perspective

Colonoscopy is generally safe, but rare complications require awareness precisely because clinicians may not initially expect them.

Expert Insight 4 — Anatomy Perspective

The proximity of the splenic flexure to the spleen explains why mechanical forces generated during colonoscopy can produce splenic injury.

Expert Insight 5 — CT Perspective

Axial images establish the diagnosis, but coronal reconstruction often clarifies the full longitudinal extent of the hematoma and distribution of hemoperitoneum.

Expert Insight 6 — Vascular Imaging Perspective

The distinction between hematoma, active extravasation, and pseudoaneurysm is clinically consequential.

Expert Insight 7 — Interventional Radiology Perspective

When vascular injury is demonstrated and the patient is an appropriate candidate, embolization can offer a spleen-preserving strategy.

Expert Insight 8 — Hospital Workflow Perspective

The diagnostic pathway must connect emergency assessment, CT acquisition, radiologist interpretation, interventional radiology, surgery, and monitoring.

Expert Insight 9 — AI Deployment Perspective

An AI model developed for traumatic splenic injury should not automatically be assumed to generalize to iatrogenic post-colonoscopy injury.

Expert Insight 10 — Patient Journey Perspective

The patient may initially interpret post-colonoscopy pain as normal. Clear communication about warning symptoms can therefore contribute to earlier recognition.

Expert Insight 11 — Clinical Governance Perspective

AI alerts must be actionable. An alert that arrives too late or produces excessive false positives may create workflow burden rather than clinical benefit.

Expert Insight 12 — Future Technology Perspective

The most valuable future systems may combine imaging, procedural history, vital signs, laboratory trends, and longitudinal clinical information rather than analyzing a CT examination in isolation.

Clinical Pearls

Recent colonoscopy is an important clue in unexplained left upper quadrant pain.
Splenic injury can occur without external trauma.
Left shoulder pain may reflect diaphragmatic irritation.
A subcapsular hematoma follows the contour of the spleen.
Coronal reconstruction can clarify the longitudinal extent of injury.
Hemoperitoneum should be assessed throughout the abdomen and pelvis.
A large hematoma does not automatically indicate active bleeding.
Arterial-phase imaging is important when vascular injury is suspected.
Pseudoaneurysm and active extravasation are different entities.
AAST grade should not be used as the sole determinant of treatment.
Hemodynamic stability is central to management decisions.
Non-operative management requires active monitoring.
Splenic artery embolization can be an important spleen-preserving option in selected patients.
AI should support radiologist judgment rather than replace it.
Every AI result should be verified against the actual imaging findings.

Common Diagnostic Pitfalls

Pitfall 1: Assuming Post-Colonoscopy Pain Is Always Benign

Mild discomfort may be expected, but severe or persistent left upper quadrant pain requires clinical reassessment.

Pitfall 2: Forgetting the Procedure History

If a recent colonoscopy is not known, the connection to splenic injury may be missed.

Pitfall 3: Looking Only at the Spleen

Hemoperitoneum can extend far from the original injury.

Pitfall 4: Reviewing Only Axial Images

Coronal and other multiplanar reconstructions may reveal the full extent of injury.

Pitfall 5: Equating a Large Hematoma With Active Bleeding

The presence of a large collection does not establish ongoing extravasation.

Pitfall 6: Missing a Small Pseudoaneurysm

Vascular complications can be subtle and may be most conspicuous on arterial-phase imaging.

Pitfall 7: Treating AAST Grade as a Treatment Order

Anatomical grade must be integrated with clinical physiology.

Pitfall 8: Assuming Absence of Extravasation Means No Risk

A patient can have significant splenic injury without visible active bleeding during the examination.

Pitfall 9: Overtrusting AI

A model can miss pathology, mislocalize it, or produce an unsupported explanation.

Pitfall 10: Failing to Communicate Urgency

When significant splenic injury is identified, radiologic communication should be timely and clinically clear.

FAQ

What is a splenic hematoma after colonoscopy?

It is a rare iatrogenic splenic injury in which blood accumulates within or around the spleen after colonoscopy. A subcapsular hematoma forms beneath the splenic capsule and can be associated with hemoperitoneum or vascular injury.

What is the key CT finding?

The key finding in this case is a large subcapsular hematoma following the splenic contour and compressing the underlying splenic parenchyma.

Can colonoscopy really injure the spleen?

Yes. Although rare, mechanical forces around the splenic flexure can transmit traction to the spleen and its supporting structures.

What symptoms should raise concern?

Sudden or persistent left upper quadrant pain after colonoscopy is particularly important. Left shoulder pain, dizziness, syncope, tachycardia, hypotension, abdominal distension, and falling hemoglobin increase concern.

Does a large splenic hematoma always mean active bleeding?

No. A hematoma represents accumulated blood. Active bleeding requires evidence of ongoing vascular leakage, such as contrast extravasation.

Why is CT angiography useful?

It can evaluate the extent of splenic injury and identify active bleeding or vascular abnormalities such as a pseudoaneurysm.

Does AAST grade III automatically require surgery?

No. Management depends on the complete clinical picture, including hemodynamic stability, blood loss, active bleeding, vascular injury, associated injuries, and overall patient condition.

What is the role of splenic artery embolization?

In appropriately selected patients with vascular bleeding or high-grade injury, embolization can control hemorrhage while potentially preserving splenic tissue.

Can ultrasound replace CT?

Ultrasound can be useful for rapid assessment of free fluid, but CT provides a much more comprehensive evaluation of splenic injury and vascular complications.

Can AI diagnose splenic injury independently?

AI may assist with detection and prioritization, but clinical deployment requires validation, monitoring, and human oversight. The radiologist remains responsible for verifying the imaging findings.

Featured Snippet Answers

What is splenic hematoma after colonoscopy?

Splenic hematoma after colonoscopy is a rare iatrogenic splenic injury caused by mechanical forces around the splenic flexure. CT typically demonstrates a subcapsular or intraparenchymal hematoma, with possible hemoperitoneum. The presence or absence of active contrast extravasation is important for determining the significance of vascular injury.

What is the key imaging finding?

The key finding in this case is a large subcapsular splenic hematoma involving more than 50% of the splenic surface, accompanied by a small amount of hemoperitoneum but without CT evidence of active extravasation or pseudoaneurysm.

When is CT indicated?

CT should be considered when a patient develops significant or persistent abdominal pain after colonoscopy, particularly left upper quadrant pain or associated signs suggesting internal bleeding. CT is especially valuable when splenic injury or hemoperitoneum is suspected.

Quiz

Question 1

A patient develops severe left upper quadrant pain the day after colonoscopy. CT demonstrates a crescentic collection following the external contour of the spleen. What is the most likely diagnosis?

① Splenic infarction
② Splenic artery aneurysm
③ Splenic artery pseudoaneurysm
④ Subcapsular splenic hematoma
⑤ Splenic AV fistula

Correct Answer: ④ Subcapsular splenic hematoma

Explanation: A collection following the splenic contour and compressing the underlying parenchyma is characteristic of a subcapsular hematoma.

Question 2

A large splenic hematoma is present, but no contrast extravasation is seen on arterial or delayed CT images. What is the most appropriate interpretation?

① Active bleeding is definitely present
② Pseudoaneurysm is definitely present
③ There is no imaging evidence of active bleeding
④ Splenic infarction is confirmed
⑤ Splenectomy is mandatory

Correct Answer: ③ There is no imaging evidence of active bleeding

Explanation: The absence of extravasation means that active bleeding is not demonstrated on the CT examination. Clinical risk must still be assessed.

Question 3

Which clinical finding is particularly concerning after colonoscopy?

① Mild transient bloating
② Brief mild abdominal discomfort
③ Persistent left upper quadrant pain with left shoulder pain
④ Mild thirst
⑤ Temporary fatigue

Correct Answer: ③ Persistent left upper quadrant pain with left shoulder pain

Explanation: The combination raises concern for splenic injury and diaphragmatic irritation.

Question 4

Which finding most strongly supports an active vascular bleeding complication?

① Stable subcapsular hematoma
② Wedge-shaped splenic hypoperfusion
③ Contrast extravasation outside a vessel
④ Mild bowel distension
⑤ Normal splenic enhancement

Correct Answer: ③ Contrast extravasation outside a vessel

Explanation: Active extravasation represents contrast escaping from the vascular system and is a key CT sign of active bleeding.

Question 5

Which principle best reflects modern management of splenic injury?

① Every grade III injury requires splenectomy
② Imaging findings alone determine treatment
③ Hemodynamic status and anatomical injury should be considered together
④ Hemoperitoneum always requires laparotomy
⑤ AI should make the final treatment decision

Correct Answer: ③ Hemodynamic status and anatomical injury should be considered together

Explanation: Modern splenic injury management integrates physiology, anatomy, vascular findings, associated injuries, and the patient's overall condition.

Ultimate Guide to Splenic Hematoma After Colonoscopy: Suggested Content Cluster

Splenic Injury After Colonoscopy: A Complete Case Review
Subcapsular Splenic Hematoma on CT: Imaging Diagnosis
CT Angiography of Splenic Injury: Active Extravasation vs Pseudoaneurysm
AAST Splenic Injury Grading: What Radiologists Need to Know
Hemoperitoneum on CT: Distribution and Clinical Significance
Splenic Artery Embolization: Imaging and Clinical Workflow
Colonoscopy Complications: Beyond Perforation and Bleeding
Kehr Sign and Referred Shoulder Pain in Splenic Injury
AI Detection of Abdominal Hemorrhage on CT
Enterprise AI Workflow for Emergency Abdominal Imaging
PACS-Based AI Triage for Acute Hemorrhage
Human Oversight in Medical Imaging AI

Conclusion

Splenic hematoma after colonoscopy is rare, but the rarity of the complication should never become a reason to overlook it.

The diagnostic challenge begins with recognizing the clinical pattern.

A patient develops sudden or persistent left upper quadrant pain after colonoscopy.

The patient may have no history of external trauma.

The next step is not simply to ask whether the patient has abdominal gas.

It is to consider whether an iatrogenic splenic injury has occurred.

CT can reveal the answer.

In this case, the dominant imaging abnormality was a large subcapsular splenic hematoma involving more than 50% of the splenic surface, accompanied by a small amount of hemoperitoneum.

But the decisive imaging observation was different:

There was no CT evidence of active contrast extravasation or pseudoaneurysm.

That distinction illustrates a fundamental principle of radiology.

The size of an injury and the presence of active bleeding are different questions.

A large hematoma indicates substantial prior bleeding or blood accumulation.

Active extravasation indicates ongoing vascular leakage at the time of imaging.

The radiologist must communicate both.

The most useful assessment therefore follows a structured sequence:

Injury pattern → extent → hemoperitoneum → vascular injury → active bleeding → clinical stability.

This sequence is more informative than simply labeling the examination as “splenic hematoma.”

Modern management also demonstrates why imaging should never be separated from clinical physiology.

A patient who is hemodynamically stable and has no imaging evidence of active bleeding may be considered for non-operative management with close monitoring.

A patient with active bleeding or vascular injury may require interventional radiology.

A patient with persistent hemodynamic instability or uncontrolled hemorrhage may require surgery.

The objective is not to treat the CT image.

The objective is to treat the patient using the CT image as a critical component of clinical decision-making.

The same principle applies to artificial intelligence.

AI may eventually improve detection of subcapsular hematoma, hemoperitoneum, active extravasation, and vascular complications. It may prioritize suspicious examinations and integrate imaging with clinical data.

But AI cannot be allowed to obscure the fundamental clinical reasoning process.

The radiologist must still ask:

What does the image show?

Why does it look this way?

Is there active bleeding?

What could mimic this finding?

Does the imaging agree with the patient's physiology?

And perhaps the most important question in this case is the simplest:

When a patient develops significant left upper quadrant pain after colonoscopy, did we remember to consider the spleen?

That question can change the diagnosis.

And sometimes, recognizing the diagnosis early can change the patient's outcome.

Key Takeaways

Splenic injury is a rare but potentially serious complication of colonoscopy.
Sudden or persistent left upper quadrant pain after colonoscopy is an important warning sign.
Left shoulder pain may indicate diaphragmatic irritation.
A subcapsular hematoma follows the contour of the spleen.
Coronal CT reconstruction helps define the extent of injury.
Hemoperitoneum should be assessed throughout the abdomen and pelvis.
Active extravasation must be distinguished from an established hematoma.
Pseudoaneurysm represents a different vascular complication.
AAST grade alone does not determine treatment.
Hemodynamic stability is central to management.
Non-operative management requires active clinical monitoring.
Splenic artery embolization can be an important spleen-preserving treatment option in selected patients.
AI may assist detection and workflow prioritization but requires validation and human oversight.
The most important radiologic question is not only “How large is the hematoma?” but also “Is there evidence that the patient is actively bleeding?”

References

[1] R. Hassan, A. Abd Aziz, A. R. Md Ralib, and A. Saat, “Computed tomography of blunt spleen injury: A pictorial review,” Malays. J. Med. Sci., vol. 18, no. 1, pp. 60–67, 2011.

[2] S. Shankar and S. Rowe, “Splenic injury after colonoscopy: Case report and review of literature,” Ochsner J., vol. 11, no. 3, pp. 276–281, 2011.

[3] G. Piccolo et al., “Presentation and management of splenic injury after colonoscopy: A systematic review,” Surg. Laparosc. Endosc. Percutan. Tech., vol. 24, no. 2, pp. 95–102, 2014, doi: 10.1097/SLE.0b013e3182a83493.

[4] J. W. Uyeda, C. A. LeBedis, D. R. Penn, J. A. Soto, and S. W. Anderson, “Active hemorrhage and vascular injuries in splenic trauma: Utility of the arterial phase in multidetector CT,” Radiology, vol. 270, no. 1, pp. 99–106, 2014, doi: 10.1148/radiol.13121242.

[5] A. Boscak and K. Shanmuganathan, “Splenic trauma: What is new?” Radiol. Clin. North Am., vol. 50, no. 1, pp. 105–122, 2012, doi: 10.1016/j.rcl.2011.08.008.

[6] F. Coccolini et al., “Splenic trauma: WSES classification and guidelines for adult and pediatric patients,” World J. Emerg. Surg., vol. 12, p. 40, 2017, doi: 10.1186/s13017-017-0151-4.

[7] R. A. Kozar et al., “Organ injury scaling 2018 update: Spleen, liver, and kidney,” J. Trauma Acute Care Surg., vol. 85, no. 6, pp. 1119–1122, 2018, doi: 10.1097/TA.0000000000002058.

[8] J. Ha Fong and D. Minchin, “Splenic injury in colonoscopy: A review,” Int. J. Surg., vol. 7, no. 5, pp. 424–427, 2009, doi: 10.1016/j.ijsu.2009.07.010.

[9] C. R. Petersen et al., “Splenic injury after colonoscopy,” Endoscopy, vol. 40, no. 1, pp. 76–79, 2008, doi: 10.1055/s-2007-966940.

[10] M. Lukies and W. Clements, “Splenic artery embolisation for splenic injury during colonoscopy: A systematic review,” United European Gastroenterol. J., vol. 12, no. 1, pp. 44–55, 2024, doi: 10.1002/ueg2.12498.

[11] A. Jehangir, D. R. Poudel, A. Masand-Rai, and A. Donato, “A systematic review of splenic injuries during colonoscopies: Evolving trends in presentation and management,” Int. J. Surg., vol. 33, pp. 55–59, 2016, doi: 10.1016/j.ijsu.2016.07.067.

[12] T. J. Clark, S. Cardoza, and N. Kanth, “Splenic trauma: Pictorial review of contrast-enhanced CT findings,” Emerg. Radiol., vol. 18, no. 3, pp. 227–234, 2011, doi: 10.1007/s10140-010-0933-4.

[13] M. Podda et al., “Follow-up strategies for patients with splenic trauma managed non-operatively: The 2022 World Society of Emergency Surgery consensus document,” World J. Emerg. Surg., vol. 17, p. 52, 2022, doi: 10.1186/s13017-022-00457-5.

[14] X. H. Lv, Q. Lu, Z. J. Wang, Z. Wang, and J. L. Yang, “Colonoscopy-related adverse events in the 21st century: An updated systematic review and meta-analysis,” Am. J. Gastroenterol., 2025, doi: 10.14309/ajg.0000000000003429.

[15] S. Singla, D. Keller, P. Thirunavukarasu et al., “Splenic injury during colonoscopy—a complication that warrants urgent attention,” J. Gastrointest. Surg., vol. 16, pp. 1225–1234, 2012, doi: 10.1007/s11605-012-1871-0.

Medical Disclaimer

This article is provided for medical education and professional discussion. It does not replace clinical assessment, diagnosis, or treatment by a qualified healthcare professional. Individual management decisions should be based on the patient's clinical condition, imaging findings, laboratory data, institutional protocols, and multidisciplinary assessment.