Approach to postoperative abdominal pain: Clinical sciences

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Introduction0:00–0:29

Postoperative, abdominal pain is commonly reported by patients after surgery. There are many causes, some even life threatening, but they can all be summed up into three categories, disruption of normal healing, infection or other benign physiologic processes.
Abdominal pain can be superficial or limited to the abdominal wall or it can be deep involving organ space. The first step in evaluating a patient with signs and symptoms, suggestive of post operative.

Acute management0:29–1:27

Abdominal pain is to perform the ABCDE assessment to determine if the patient is stable or unstable. If the patient is unstable, start acute management before doing any diagnostic workup.
This means that you might need to stabilize their airway, provide supplemental oxygen, establish IV access and consider starting IV fluids while continuously monitoring their vitals.
Some important examples that can cause a patient to be unstable in the postoperative period include acute abdomen caused by free air or diffuse fluid spillage as well as vascular rupture such as a ruptured abdominal aortic aneurysm and necrotizing fasciitis, which is a deep bacterial infection along the fascial plane causing the patient to be critically ill with severe pain and crepitus under the skin.
And it's a surgical emergency. All right now, that unstable patients are stabilized.

Focused History and Physical1:27–2:38

Let's talk about the stable ones. Your first step here is to obtain a focused history and physical examination.
You should find out what type of operation the patient had and when and quickly assess for any signs of acute abdomen. Now, if you find a severely distended and rigid abdomen with diffuse tenderness, rebound, pain guarding and sometimes tachycardia and tachypnea.
The patient has an acute abdomen which is a surgical emergency. So call the surgical team immediately for consultation and a possible exploratory laparotomy surgery should not be delayed to get additional diagnostic tests.
As exploratory laparotomy is both therapeutic and diagnostic. It might reveal some important diagnosis like intraabdominal bleeding, gross gi tract spillage or abdominal sepsis.
If theres time, though you may still get some imaging such as a bedside ultrasound to look for free fluid or an upright chest X ray to check for free air.
All right. Once you have ruled out acute abdomen, the next step is to assess for other causes of abdominal pain.

Superficial abdominal pain2:38–3:05

Let's first talk about superficial abdominal pain which is limited to the skin and the abdominal wall. Most patients will describe this type of pain as localized soreness and they can often point with one finger to the exact location of the pain.

Fascial dehiscence3:05–4:14

The most urgent cause of superficial abdominal pain is fascial dehiscence. Now, fascial dehiscence most commonly occurs in patients who underwent open abdominal or pelvic procedures.
Risk factors for poor healing include obesity, diabetes, or immunocompromised status. Due to steroid use.
History usually reveals the sudden onset of pain and distension. After feeling a popping sensation around the incision site, the popping sensation is caused by tearing of the approximated abdominal wall edges which might occur when lifting heavy objects.
Usually within four weeks of surgery. Since the edges haven't properly healed yet, the physical exam might reveal a soft abdomen with a large incision and a possibly tender bulge that protrudes on valsalva, which is actually a hernia.
The next step is to get an ultrasound or ct. The imaging might show separation of the fascial layers which confirms the diagnosis of fascial dehiscence.
In some cases, dehiscence can lead to an urgent condition called evisceration, which is when abdominal organs protrude through the open wound.
Another cause of superficial postoperative abdominal pain is formation of a seroma or hematoma which are fluid collections composed of either serous fluid or blood.

Seroma/Hematoma4:14–5:13

They usually occur near the incision site because the vessels or tissues that were cut during surgery can leak between tissue planes created with surgical dissection.
If there is bleeding into the rectus muscle, a rectus sheath hematoma can form, patients typically report mild pain, a normal diet and unchanged bowel habits.
However, if they report a rapidly enlarging mass around the surgical site, it should make you suspicious of seromas or hematomas.
The physical exam might reveal a soft, nondistended abdomen with a palpable, possibly tender, well circumscribed mass around the surgical site.
If this is the case order an ultrasound. If it shows a fluid filled collection, the diagnosis of seroma or hematoma is confirmed.

Surgical site infection and normal healing incision5:13–6:04

Next, let's talk about superficial surgical site infection or SSI for short patients with SSIs usually report mild to moderate pain around the incision site.
Sometimes with a fever on physical exam, you will see a soft, nondistended abdomen with erythema, mild induration which is thickening or hardening of the skin and tenderness around the incision.
If you suspect SSI mark the edges of the erythema to track its progression. If the erythema is spreading and especially if you see purulent drainage, the diagnosis is SSI.
On the other hand, if there's minimal erythema located just on the wound edge or around sutures and staples with little to no drainage, the pain is likely from the normal wound healing process.

Deep abdominal pain6:04–6:34

All right. Now that we're done with the superficial abdominal pain, let's switch gears and talk about deep abdominal pain.
Deep abdominal pain is related to intraabdominal organ space. It can present in different ways, determining if it's diffuse or localized crampy or dull or what helps make it better or worse can give clues about the underlying cause.
Now, because this pain can indicate an organ pathology, it can be life threatening. First, let's talk about the serious one called an anastomotic leak in an anastomotic leak.

Anastomotic leak6:34–8:08

The history usually reveals that the patient had surgery with resection and reanastomosis of parts of the gastrointestinal tract.
Although this can present as an intraabdominal abscess, patients typically report severe diffuse pain with nausea, vomiting and decreased oral tolerance.
Along with constipation or obstipation. On physical exam.
You might find distension, tenderness and rebound pain as well as rigidity and guarding your. Next step is to obtain labs including CBC CMP and lactate.
Labs usually show leukocytosis with a left shift electrolyte imbalances like low magnesium and phosphorus and metabolic acidosis with elevated lactate.
Additionally, order an abdominal X ray series or a point of care, ultrasound or pocus as well as a CT scan of the abdomen and pelvis with oral IV or even rectal contrast with approval by the surgical team on X ray or pocus.
Look for pneumoperitoneum, which is indicative of possible viscous perforation. Similarly, CT might show free air and fluid within the peritoneal cavity.
And if oral contrast is given in addition to IV contrast, then you may see extravasation which will confirm your diagnosis of an anastomotic leak.

Intestinal obstruction and postop ileus8:08–10:22

The next worrisome diagnoses to look out for involve gastrointestinal issues. There are two types, you should be aware of mechanical obstruction, which is a true blockage of the intestinal lumen from edema, bowel, kinking or scar tissue and functional obstruction or a paralytic ileus, which is due to absence of peristalsis rather than an actual blockage.
Both types can present with diffuse, colicky pain, nausea, vomiting, decreased oral tolerance, constipation, and even obstipation, which is a more severe form of constipation where the patient can't pass gas or stool.
However, if the patient also has a history of taking narcotic pain medications including postoperative pain meds or decreased ambulation.
You should consider postoperative ileus on physical exam. You might find a distended abdomen with mild to moderate tenderness to deep palpation that is hypertympanic to percussion as well as absent or decreased bowel sounds.
If you suspect intestinal issues, Order, labs including CBC CMP and lactate as well as an abdominal X ray series and sometimes a CT.
If the X ray is unclear. Now, labs might show leukocytosis and electrolyte abnormalities with elevated lactate on X ray.
There are distended, loops of small bowel with visible air fluid levels but without any air in the colon. Finally, CT might also show dilated loops of small bowel with or without a transition point or point of obstruction and collapsed bowel distal to the obstruction.
In this case, the diagnosis is intestinal obstruction. All right.
Let's go back to our labs if the labs are normal and the abdominal X ray shows diffusely dilated loops of bowel with air in the colon or CT shows diffusely distended, bowel loops without a transition point.
Your diagnosis is a postoperative ileus. Another possible cause of postoperative abdominal pain is an intraabdominal abscess or infection.

Intra-abdominal abscess/infection10:22–11:35

This usually occurs after bowel surgery or an infectious condition like appendicitis or cholecystitis. Patients typically present with deep pain within the quadrant of the surgery, nausea, vomiting, decreased oral tolerance and changes in bowel habits.
Along with fever and chills on physical exam. You might find a mildly distended, hypertympanic abdomen with tenderness to deep palpation in the affected quadrant and guarding or rebound pain.
In this case, your next step is to draw labs like CBC and lactate and order a CT of the abdomen and pelvis labs usually reveal leukocytosis with a left shift and elevated lactate.
While CT typically shows an intraabdominal fluid collection or a Phlegmon near the operative site. If you see this, you can diagnose an intra abdominal abscess or infection.
Lastly, let's talk about insufflation, gas or CO2 peritonitis. This usually occurs hours to days after a laparoscopic surgery in which CO2 gas was used to insufflate the abdomen while the gas itself is harmless and gets absorbed quickly, it can irritate the peritoneum and be contained under the diaphragm.

Insufflation gas (CO2) peritonitis11:35–13:00

This causes abdominal pain that is referred to the shoulder and scapula via the phrenic nerve. Other than pain, patients do not have any issues tolerating a diet and have normal bowel function on a physical exam.
You might find a soft, nondistended abdomen and mild diffuse tenderness with clean dry and intact incisions on chest X ray.
This appears as air under the diaphragm. So if you see this, it's important to know if the patient just had laparoscopic surgery because it could be normal postoperatively, the patient will look well.
Instead of sick and serial chest x rays will show the air decreasing. On the other hand, if the serial chest x rays reveal increasing air under the diaphragm or exam reveals a peritoneal or acute abdomen, they need to go to surgery.
Keep in mind that CO2 peritonitis is a diagnosis of exclusion. So make sure you rule out all other causes first.
All right, as a quick recap, postoperative abdominal pain is a common surgical complication that might be life threatening.

Review13:00–13:56

First, you want to assess ABCD S to see whether the patient is stable, then quickly look for signs of an acute abdomen, which is a surgical emergency.
Once you have ruled out an acute abdomen, you should assess for other common causes by determining if the pain is superficial or deep causes of superficial pain, localized to the abdominal wall, include fascial dehiscence, which is a surgical emergency seromas or hematomas, surgical site infections and lastly a normal healing incision.
On the other hand, if the patient complains of deep pain, you should be on the lookout for an anastomotic leak, which is another surgical emergency, intestinal obstruction, postoperative ileus, intraabdominal abscess or infection and CO2