Nursing Field Notes / Gastrointestinal · Med-Surg Course
Peritonitis 🔥
Rigid abdomen · rebound tenderness · a surgical emergency
NG-397
Gastrointestinal
ADHD-friendly visual edition
The peritoneum is inflamed, almost always because something perforated and spilled into it. The abdomen becomes board-like and silent, and she will not let you press on it. This is a surgical problem, not a medical one.
The classic findingRigid, board-like abdomen with rebound tenderness
The positionKnees drawn up, absolutely still — moving hurts
Bowel soundsAbsent. The gut has stopped.
NeverNo heat, no enema, no laxative, nothing by mouth
🧨 What starts it
What spills, and what happens next
- A hollow organ perforates — a ruptured appendix, a perforated ulcer, diverticulitis, bowel obstruction, trauma.
- Gastric contents, stool or bile enter the sterile peritoneal cavity. Bacteria multiply fast.
- The peritoneum inflames and weeps fluid — liters of it — out of the circulation and into the abdomen. That is a third-space loss.
- The gut stops moving: paralytic ileus. Distension, vomiting, absent bowel sounds.
- Circulating volume falls while bacteria enter the blood → hypovolemic and septic shock.
Where it comes from
- Ruptured appendix — the classic in a young patient
- Perforated peptic ulcer
- Diverticulitis that perforates
- Bowel obstruction with strangulation
- Penetrating or blunt abdominal trauma
- Peritoneal dialysis — cloudy outflow is peritonitis until proven otherwise
- Post-operative anastomotic leak
The relief that is a disaster
In appendicitis, sudden relief of the pain followed by a rigid abdomen means the appendix has ruptured. The pressure is off, so it briefly feels better. That is not improvement.
🔎 What you will see
How she presents
- Severe, constant abdominal pain, worse with any movement — even the bed being bumped.
- Rigid, board-like abdomen. Involuntary guarding — she cannot relax it.
- Rebound tenderness — it hurts more when you release than when you press.
- Absent bowel sounds, distension, nausea and vomiting.
- She lies still with her knees drawn up. Anyone rolling around is probably colicky, not peritonitic.
- Fever, tachycardia, shallow rapid breathing — deep breaths hurt.
- Later: hypotension, oliguria, altered mental status.
What confirms it
- WBC high with a left shift. In the elderly it may not rise at all.
- Upright abdominal x-ray: free air under the diaphragm = perforation.
- CT abdomen finds the source.
- Rising lactate, falling bicarbonate — she is heading for shock.
- Peritoneal dialysis patient: cloudy effluent, send it for cell count and culture.
The older adult
An elderly patient may have no fever, no rigidity and a normal white count. Confusion and a low-grade tachycardia may be the only signs. Take the abdomen seriously anyway.
🩺 What you do
What you do
- Nothing by mouth. Immediately.
- NG tube to suction — decompresses the gut and stops more spilling.
- Large-bore IV, aggressive fluids. She has lost liters into her abdomen.
- Broad-spectrum IV antibiotics after cultures.
- Semi-Fowler’s — it localizes the contamination to the lower abdomen and eases breathing.
- Analgesia, oxygen, urinary catheter to track output.
- Prepare for surgery. The source has to be closed.
What you monitor
- Urine output — the first thing to fall when she is volume depleted. Under 30 mL/hr is reportable.
- Vital signs and abdominal girth, marked and measured at the same spot.
- Bowel sounds returning and the first flatus — that is the ileus resolving.
- Electrolytes, lactate, white count.
Never do these
- No heat to the abdomen — it speeds rupture and spread.
- No enemas or laxatives — increased motility perforates further.
- Nothing by mouth, including sips and ice chips, until surgery clears it.
- Do not delay reporting a rigid abdomen while you finish an assessment. It is a call now.
⚡ Quick recall
The classic findingRigid, board-like abdomen with rebound tenderness
The positionKnees drawn up, absolutely still — moving hurts
Bowel soundsAbsent. The gut has stopped.
NeverNo heat, no enema, no laxative, nothing by mouth
What does a board-like abdomen with rebound tenderness mean?
Peritonitis. Surgical emergency — NPO, NG to suction, fluids, antibiotics, call.
Appendicitis pain suddenly stops. Is that good?
No. It usually means it has ruptured. Expect a rigid abdomen next.
Why semi-Fowler position?
It keeps the contamination in the lower abdomen and lets her breathe more easily.
Three things you never do?
No heat, no enema or laxative, nothing by mouth.
A peritoneal dialysis patient has cloudy outflow. What is it?
Peritonitis until proven otherwise. Send the effluent for cell count and culture.