Differential Diagnosis

The patient presents with a complex clinical picture following recent gastric bypass and hiatus hernia repair. The differential diagnosis can be organized into the following categories:

• Single most likely diagnosis:

  • Postoperative ileus or bowel obstruction: The patient's symptoms of vomiting, profuse diarrhea, severe generalized abdominal pain, and lack of urination despite fluid intake, following a recent abdominal surgery, suggest a possible postoperative ileus or bowel obstruction. The elevated CRP and WCC also indicate an inflammatory response, which could be consistent with these conditions.

• Other Likely diagnoses:

  • Dehydration and electrolyte imbalance: The patient's symptoms of vomiting, diarrhea, and not being able to stay hydrated despite drinking fluids, suggest significant fluid loss and potential electrolyte disturbances.
  • Surgical site infection or abscess: Although the patient does not have a fever, the elevated CRP and WCC, along with abdominal pain, could indicate an infection or abscess at the surgical site.
  • Gastrointestinal leak: A leak from the gastric bypass or hernia repair site could cause severe abdominal pain, vomiting, and diarrhea, although this would typically be associated with more significant signs of peritonitis or sepsis.

• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):

  • Mesenteric ischemia: This is a rare but potentially life-threatening condition that could occur after abdominal surgery, especially if there was any compromise to the blood supply of the intestines during the procedure.
  • Sepsis: Although the patient does not have a fever, the combination of recent surgery, abdominal pain, and elevated inflammatory markers means sepsis cannot be ruled out without further investigation.
  • Internal hernia: This is a complication that can occur after gastric bypass surgery, where part of the intestine herniates through a defect in the mesentery, which could cause bowel obstruction or ischemia.

• Rare diagnoses:

  • Adhesive bowel obstruction: Although less likely given the early postoperative period, adhesive bowel obstruction could still occur and cause the patient's symptoms.
  • Gastric stump leak: If the patient had a previous gastric surgery, there's a small chance of a leak from the gastric stump, which would require urgent attention.

Next Best Steps

1. Imaging: An urgent CT scan of the abdomen with contrast would be crucial to evaluate for bowel obstruction, ileus, leaks, or other complications.
2. Fluid resuscitation and electrolyte management: Given the symptoms of dehydration and potential electrolyte imbalance, aggressive fluid resuscitation and monitoring of electrolytes are essential.
3. Broad-spectrum antibiotics: If there's suspicion of infection or sepsis, starting broad-spectrum antibiotics pending culture results would be appropriate.
4. Surgical consultation: Given the recent surgery and severity of symptoms, early involvement of the surgical team is crucial for potential re-exploration or intervention.
5. Monitoring: Close monitoring of the patient's vital signs, fluid status, and abdominal symptoms is necessary to quickly identify any deterioration.