What is the appropriate workup for a 4-month postpartum female with intermittent nausea and vomiting after eating and intermittent abdominal pain?

Workup for 4-Month Postpartum Patient with Intermittent Nausea, Vomiting, and Abdominal Pain

This patient requires urgent evaluation to exclude serious postpartum complications, particularly uterine rupture or abscess if she had a cesarean delivery, followed by systematic investigation of gastrointestinal and metabolic causes if initial imaging is negative.

Initial Emergency Assessment

Immediately assess for life-threatening postpartum complications:

• If prior cesarean delivery: Uterine rupture or perforation must be excluded, especially with multiple prior C-sections as a risk factor—these patients present with abdominal pain and fever, and delayed diagnosis increases morbidity and mortality 1
• Check vital signs for fever (suggesting infection/abscess), tachycardia, or hypotension (suggesting perforation or sepsis) 1
• Examine for peritoneal signs: Rebound tenderness, guarding, or rigidity suggest surgical emergency 1
• Assess hydration status: Orthostatic hypotension, decreased skin turgor, dry mucous membranes indicate significant volume depletion 2

Essential Initial Laboratory Testing

Order the following blood work immediately:

• Complete blood count (looking for leukocytosis suggesting infection or anemia from bleeding) 3
• Serum electrolytes and glucose (vomiting causes hypokalemia and metabolic alkalosis) 3, 2
• Liver function tests (elevated in 40-50% of severe vomiting cases) 2
• Lipase (acute pancreatitis can present postpartum with nausea, vomiting, and abdominal pain) 4
• Thyroid function tests (hyperthyroidism causes nausea and vomiting) 2
• Urinalysis (to assess for ketones, infection, or renal involvement) 3

Imaging Strategy

CT abdomen and pelvis with IV contrast is the first-line imaging modality:

• CT has 89% sensitivity for urgent diagnoses in adults with abdominopelvic pain and provides comprehensive evaluation of both gynecologic and non-gynecologic causes 3
• CT will identify uterine perforation with adjacent abscess, which requires urgent surgical consultation 1
• Order CT immediately if: Prior cesarean delivery, fever present, peritoneal signs, or severe/localized pain 1
• CT effectively evaluates for ovarian cysts (common cause in this age group), ovarian torsion, fibroids with degeneration, pelvic abscess, appendicitis, and bowel obstruction 3

If CT is negative or unavailable, consider upper endoscopy:

• Esophagogastroduodenoscopy (EGD) excludes obstructive lesions and organic gastrointestinal disease causing episodic vomiting 3
• Avoid repeated endoscopies—one-time evaluation is sufficient unless new symptoms develop 3
• Recognize that recent vomiting may cause epiphenomena (mild gastritis, Mallory-Weiss tears, esophagitis) that are not causal 3

Do NOT order gastric emptying scans routinely:

• Few patients with cyclic vomiting have delayed emptying, and results are uninterpretable during acute episodes 3

Differential Diagnosis Framework

Gastrointestinal causes (most common at 4 months postpartum):

• Cyclic vomiting syndrome—episodic pattern with symptom-free intervals between episodes 3
• Gastroenteritis or viral syndrome—typically self-limiting 5, 6
• Peptic ulcer disease or gastritis—consider H2 blocker or proton pump inhibitor trial 3
• Small bowel obstruction—adhesions from prior surgery 3

Postpartum-specific complications:

• Uterine perforation/rupture with abscess (especially if prior C-section) 1
• Retained products of conception with endometritis 3
• Pelvic inflammatory disease from recent instrumentation 3

Gynecologic causes:

• Ovarian cyst (accounts for one-third of gynecologic pain in this age group) 3
• Ovarian torsion (enlarged, hypoenhancing ovary on CT with vascular pedicle swirling) 3
• Degenerating fibroid with acute infarction 3

Metabolic/endocrine causes:

• Hyperthyroidism (check TSH) 2
• Addison's disease (if hypotension, hyponatremia, hyperkalemia present) 3
• Acute pancreatitis (check lipase—can occur postpartum) 4

Central nervous system causes (if neurologic symptoms present):

• Brain imaging indicated only if localizing neurologic signs develop 3

Empiric Treatment While Awaiting Workup

Initiate supportive care immediately:

• IV hydration with normal saline plus potassium chloride guided by electrolyte monitoring 2
• Metoclopramide 10 mg IV slowly over 1-2 minutes every 6-8 hours as first-line antiemetic (safe, effective, fewer side effects than alternatives) 2
• Ondansetron 8 mg sublingual every 4-6 hours if metoclopramide ineffective or contraindicated (no pregnancy concerns at 4 months postpartum) 3, 2
• Promethazine 12.5-25 mg orally/rectally every 4-6 hours as alternative dopamine antagonist 3

Consider adding:

• Proton pump inhibitor if dyspepsia present 3
• Lorazepam 0.5-2 mg every 4-6 hours for anxiety component or refractory symptoms 3

Critical Pitfalls to Avoid

• Do not dismiss abdominal pain in postpartum patients with prior C-sections—uterine rupture is life-threatening and requires expeditious surgical management 1
• Do not attribute all symptoms to "normal postpartum changes"—4 months postpartum is beyond typical pregnancy-related nausea timeframe 2, 7
• Do not delay imaging if surgical emergency suspected—CT should be obtained urgently, not after prolonged observation 1
• Do not overlook cannabis use—ask specifically about frequency and duration, as cannabinoid hyperemesis syndrome requires 6 months cessation for diagnosis 3
• Do not forget thiamine supplementation if prolonged vomiting present—give 100 mg IV before any dextrose to prevent Wernicke encephalopathy 2

When to Hospitalize

Admit for inpatient management if:

• Signs of surgical emergency (peritonitis, suspected perforation, abscess) 1
• Severe dehydration or electrolyte abnormalities despite oral rehydration 2
• Inability to tolerate oral intake or medications 2
• Weight loss >5% or persistent vomiting despite outpatient antiemetics 2