Abdominal X-Ray Interpretation Using PPPE + ABCDO

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Step 1: PPPE – Technical Adequacy

• Projection/Position: Frontal AP supine abdominal radiograph (the patient is lying flat, labeled “liegend”). Given the patient’s condition, only a supine film was possible (no erect film due to instability).

• Patient Details: The film is labeled for the correct patient and dated. There is an “L” marker indicating the left side.

• Positioning: The image captures the entire abdomen. There may be slight rotation (the spinous processes are just a touch off-center), but overall, it’s acceptable.

• Exposure: Adequate. Despite patient factors (possible colonic dilatation causing high diaphragms), the exposure penetrates enough to see gas outlines and some soft tissue detail. The lung bases are included at the top (critical for assessing free air under diaphragm – none noted here).
   

Step 2: A – Air (Gas Pattern)

• Abnormal gas distribution: There is massive gas distension of the colon, especially the transverse colon which is ballooned out in the upper abdomen. The colon looks diffusely dilated from the cecum through the rectum on this film. The transverse colon measures well over 6 cm in diameter (significantly enlarged). Haustral markings are very sparse; the colon has a stretched, smooth outline in places. This suggests severe ulcerative colitis with loss of normal haustra (a “lead pipe” appearance) combined with acute dilatation.

• Air-fluid levels: On this supine film, air-fluid levels are not easily assessed (an erect film would show any levels; in toxic megacolon, patients often can’t stand for imaging). However, there may be multiple gas and fluid levels if a decubitus or CT were done, reflecting ileus.

• No free intraperitoneal air: Crucially, no free air is seen under the diaphragm on this film, so we do not see evidence of perforation at the time of X-ray. (Free air would indicate that the colon has perforated which is a surgical emergency on top of an emergency.)
   

Step 3: B – Bowel 

• Colon findings: The colon is massively dilated throughout. The ascending colon and cecum are dilated (though perhaps less than the transverse). The transverse colon is extremely distended, almost spanning the width of the abdomen. The descending colon is also dilated. The colonic haustra are blunted or absent in much of the colon on this film, consistent with chronic ulcerative colitis changes. In some areas one might see thumbprinting which could be pseudopolyps or mucosal edema causing indentations though on plain AXR this can be subtle.

• Small bowel: There may be some secondary ileus of small bowel, but no clear small-bowel obstruction pattern. Some gas is visible in loops of small intestine, but they are not as distended as the colon. This matches an acute colitis with toxic megacolon: the primary problem is the colon.

• Measurement: Toxic megacolon is typically defined by a transverse colon diameter >6 cm on X-ray with signs of systemic toxicity, which this film demonstrates (in fact, the transverse colon here looks to be ~8 cm).
   

Step 4: C – Calcifications and Bones

• Calcifications: No abnormal calcifications are noted. Importantly, no sign of colonic perforation such as intraperitoneal calcified fecoliths (would be an odd finding anyway) or gallstone (to consider gallstone ileus) – irrelevant here as history points to colitis.

• Bones: The bony structures (spine, pelvis) show no acute abnormalities. The sacroiliac joints might be fused (not clearly seen) – interestingly, ulcerative colitis can be associated with ankylosing spondylitis, but that’s beyond this image’s primary findings.

Step 5: D – Devices and Foreign Bodies

• Devices: The patient has no surgical clips or foreign devices visible in the abdomen. If a central venous line or NG tube is present, it might be seen in the chest portion, but none is obvious on this cropped view. No stents or ostomy appliances (he hasn’t had surgery for UC yet).

• Foreign bodies: None seen.
   

Step 6: O – Other Findings (Organs & “Oh no!”)

• Organ outlines/soft tissue: The liver shadow is displaced a bit by the distended colon, but no hepatomegaly. The spleen is not clearly enlarged. There is no abnormal intra-abdominal mass aside from the dilated bowel. There might be some edema in the abdominal wall (difficult to tell on plain film). No unusual gas collections in the soft tissue.

• “Oh no!” findings: The entire picture is a red flag for toxic megacolon is itself an emergency. The X-ray confirms the dangerous dilatation. We specifically look for free air (“Oh no!” perforation), fortunately none is seen (the diaphragmatic contour is intact with no beneath-air). If free air were present, it would indicate the colon has perforated, requiring immediate surgery. Even without free air, this degree of dilatation with systemic toxicity signals a high risk.
   

Summary of Findings and Diagnosis

The abdominal X-ray reveals a dramatically distended colon (especially transverse colon >6 cm) with loss of normal haustration, in a patient with acute colitis. These findings, combined with the clinical scenario (severe ulcerative colitis flare with toxicity), are diagnostic of Toxic Megacolon. The colon’s extreme dilation and the patient’s systemic toxicity fulfill the criteria for toxic megacolon, a life-threatening complication of ulcerative colitis.

 

Diagnosis: Toxic megacolon
 

Key Teaching Points:
 

• Toxic Megacolon Criteria: Toxic megacolon is defined by non-obstructive colonic dilatation >6 cm (often in transverse colon) plus signs of systemic toxicity (fever, tachycardia, hypotension, etc.). It most commonly occurs as a complication of severe ulcerative colitis, but can also result from other colitides (e.g., Crohn’s, infectious colitis like C. difficile, ischemic colitis). Recognizing the dilated colon on X-ray in the appropriate clinical context is crucial for diagnosis.
   

• Radiographic Features: On AXR, look for marked colonic dilation without mechanical obstruction. The haustra may be lost (giving a “smooth” colon outline). There may be multiple air-fluid levels and mucosal thumbprinting, though these can be subtle on plain film. No perforation is a key thing to check.
   

• Do NOT Mistake for Ileus Alone: While an ileus can cause diffuse bowel dilation, toxic megacolon will have the clinical picture of severe colitis. In an ileus, patients are usually not shocky; in toxic megacolon, they are toxic (hence the name). The X-ray in toxic megacolon might resemble a large ileus, but context and severity of dilation (and often colon > small bowel) give it away.
   

• Pitfalls: Always differentiate toxic megacolon from acute colonic pseudo-obstruction (Ogilvie’s syndrome); the latter occurs without such severe systemic toxicity and has different management (neostigmine, etc.)

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