Differential Diagnosis for Acute Abdominal Pain in a 4-year-old Boy
Single Most Likely Diagnosis
- Constipation: This is a common cause of abdominal pain in children, often due to a low-fiber diet, dehydration, or bowel habits.
- History findings: Infrequent bowel movements, hard stools, or straining during defecation argue for this diagnosis. A recent change in diet or fluid intake may also be relevant.
- Physical exam findings: Abdominal distension, palpable stool in the rectum, or a hard stool on rectal exam support this diagnosis.
- Lab/other tests findings: The absence of other significant lab findings (e.g., normal complete blood count (CBC), normal urinalysis) and a positive response to a bowel regimen or stool softeners argue for constipation.
Other Likely Diagnoses
- Gastroenteritis: Viral or bacterial infections can cause abdominal pain, vomiting, and diarrhea in children.
- History findings: Recent travel, sick contacts, vomiting, diarrhea, or fever argue for this diagnosis.
- Physical exam findings: Signs of dehydration (e.g., dry mouth, decreased urine output), abdominal tenderness, or guarding support this diagnosis.
- Lab/other tests findings: Positive stool cultures or the presence of viral antigens in stool, elevated white blood cell count, or evidence of dehydration on lab tests argue for gastroenteritis.
- Urinary Tract Infection (UTI): UTIs can cause abdominal pain, especially if the infection involves the kidneys.
- History findings: Dysuria, frequency, urgency, or a history of UTIs argue for this diagnosis.
- Physical exam findings: Costovertebral angle tenderness, suprapubic tenderness, or a positive urine dipstick test support this diagnosis.
- Lab/other tests findings: Positive urine culture, positive urinalysis (e.g., leukocyte esterase, nitrites), or elevated CBC argue for a UTI.
- Appendicitis: Although less common in young children, appendicitis is a significant concern due to the risk of perforation.
- History findings: Initial pain around the navel that migrates to the lower right abdomen, fever, vomiting, or anorexia argue for this diagnosis.
- Physical exam findings: Tenderness in the right lower quadrant, rebound tenderness, or a positive psoas sign support this diagnosis.
- Lab/other tests findings: Elevated white blood cell count, imaging studies (e.g., ultrasound, CT scan) showing appendiceal inflammation, or free fluid in the abdomen argue for appendicitis.
Do Not Miss Diagnoses
- Intussusception: A condition where a part of the intestine telescopes into another, causing bowel obstruction and potentially ischemia.
- History findings: Sudden onset of severe abdominal pain, currant jelly stool, or a history of intestinal polyps argue for this diagnosis.
- Physical exam findings: A palpable abdominal mass, signs of obstruction (e.g., vomiting, abdominal distension), or currant jelly stool on rectal exam support this diagnosis.
- Lab/other tests findings: Imaging studies (e.g., ultrasound, air enema) showing intussusception, or evidence of bowel obstruction argue for this condition.
- Testicular Torsion: Although not directly an abdominal issue, testicular torsion can refer pain to the abdomen and is a surgical emergency.
- History findings: Sudden onset of severe testicular pain, swelling, or a history of similar episodes argue for this diagnosis.
- Physical exam findings: Testicular swelling, elevation, or transverse lie of the testis, and a lack of cremasteric reflex support this diagnosis.
- Lab/other tests findings: Doppler ultrasound showing reduced blood flow to the testis argues for testicular torsion.
Rare Diagnoses
- Meckel's Diverticulum: A congenital anomaly of the small intestine that can cause bleeding, obstruction, or inflammation.
- History findings: Painless rectal bleeding, abdominal pain, or a history of similar episodes argue for this diagnosis.
- Physical exam findings: Signs of bleeding (e.g., pallor, tachycardia), abdominal tenderness, or a palpable mass support this diagnosis.
- Lab/other tests findings: Imaging studies (e.g., technetium-99m pertechnetate scan) showing a Meckel's diverticulum, or evidence of gastrointestinal bleeding argue for this condition.
- Henoch-Schönlein Purpura (HSP): A systemic vasculitis that can cause abdominal pain, purpura, and joint pain.
- History findings: Recent upper respiratory infection, joint pain, or a rash argue for this diagnosis.
- Physical exam findings: Purpura, joint swelling, or abdominal tenderness support this diagnosis.
- Lab/other tests findings: Elevated IgA levels, purpura on biopsy, or evidence of renal involvement argue for HSP.