In a 3‑month‑old infant with mild hepatomegaly, reversal of portal‑vein flow, an enlarged hepatic artery on CT (computed tomography), early portal‑venous changes, and no radiological evidence of shunts, what is the likely diagnosis and recommended management?

Diagnosis: Congenital Arterioportal Malformation

This 3-month-old infant most likely has a congenital arterioportal malformation (APM), and should undergo urgent Doppler ultrasound confirmation followed by embolization of the feeding artery with or without surgical resection as soon as the diagnosis is confirmed 1.

Clinical Reasoning

The imaging constellation you describe is pathognomonic for arterioportal shunting in an infant:

• Reversed portal vein flow indicates arterial blood being forced retrograde into the portal system
• Enlarged hepatic artery reflects the high-flow arterial component feeding the shunt
• Mild hepatomegaly results from the vascular congestion
• Absence of visible shunts on CT is common—these are often microscopic or small vessel communications that require angiography for definitive visualization

The age of presentation (3 months) is typical, as congenital APMs manifest portal hypertension within the first year of life with splenomegaly, hypersplenism, and/or variceal hemorrhage 1. Approximately 75% of cases become symptomatic by age 2 years 2.

Immediate Diagnostic Algorithm

1. Doppler ultrasound is the single most useful diagnostic method for confirming arterioportal malformations 1

   • Look for: arterial waveforms in portal veins, enlarged hepatic artery, direction of portal flow, splenomegaly
   • This should be performed urgently given the risk of life-threatening complications

2. If Doppler US confirms the diagnosis, proceed directly to digital subtraction angiography for both diagnosis and potential intervention 2

   • Angiography will definitively map the feeding vessels and allow immediate therapeutic embolization

3. Do not delay for additional cross-sectional imaging—the clinical and initial imaging findings are sufficient to proceed with definitive evaluation

Management Strategy

Lesions should be treated as soon as they are diagnosed 1. The treatment options in order of preference are:

Primary Treatment

• Endovascular embolization of the feeding artery is first-line therapy 1, 2
  • Highly effective with documented resolution of portal hypertension
  • Can be performed at the time of diagnostic angiography
  • Recent case reports demonstrate complete symptom resolution and normalization of portal pressures within weeks 2

Surgical Backup

• Surgical resection with or without embolization if endovascular approach is unsuccessful 1

Salvage Option

• Liver transplantation is mentioned as a therapeutic option only if embolization is unsuccessful 1

Critical Monitoring Requirements

After successful embolization, serial monitoring is essential:

• Color Doppler ultrasound at 1 week to assess for:

  • Portal vein thrombosis (occurs in ~15% of cases post-intervention) 2
  • Reduction in spleen size (indicates decreased portal pressure)
  • Normalization of portal flow direction

• Follow-up imaging at 3 weeks and 10 months to confirm:

  • Resolution of any thrombosis
  • Sustained normalization of portal hemodynamics
  • No recurrence of shunt 2

Life-Threatening Complications to Anticipate

Without treatment, this infant is at immediate risk for:

1. Variceal hemorrhage (can be triggered by intercurrent infections that exacerbate portal hypertension) 2
2. High-output cardiac failure from the arteriovenous shunting
3. Progressive portal hypertension with splenomegaly and hypersplenism
4. Hepatic encephalopathy from portosystemic shunting (though less common in pure APMs)

Common Diagnostic Pitfall

Do not misdiagnose this as chronic portal vein thrombosis—a critical error that delays appropriate treatment 3. Both conditions can show:

• Non-visualization of normal portal vein
• Compensatory hepatic artery enlargement

However, portal vein thrombosis would show:

• Cavernous transformation (absent here)
• Signs of chronic portal hypertension with collaterals
• Underlying predisposing factors

Your case lacks these features and the reversed flow is diagnostic of APM, not thrombosis 3.

Prognosis

With prompt embolization, the prognosis is excellent. Case series demonstrate complete resolution of portal hypertension, normal liver function, and asymptomatic status at long-term follow-up 2. Delay in diagnosis and treatment significantly increases morbidity and mortality risk.