Background

Acute appendicitis is one of the most common acute pediatric surgical condition and is commonly seen in 10–19-years-old teenage patients [1]. Septic thrombophlebitis, which is more commonly seen in adults, is an uncommon but severe complication of intra-abdominal infection such as appendicitis, diverticulitis, and pancreatitis. In view of the potential complication of mesenteric or liver infarction and its high mortality, early identification of portomesenteric venous thrombosis is crucial. The exact pathophysiology of septic thrombophlebitis and thrombosis remained unknown, but it is proposed to be related to sepsis-induced endothelial injury, which was one of the risk factors of thrombosis according to Virchow’s triad [2].

In the case report, we will present a case of acute appendicitis complicated with portomesenteric venous thrombosis and discuss on its diagnosis and management.

Case presentation

A 12-year-old boy with insignificant past health presented with a 5-day history of fever, periumbilical and right lower quadrant (RLQ) abdominal pain, blood-stained loose stool, and vomiting. There was no family history of hematological diseases.

At the time of presentation, he had fever 39.2 °C with otherwise stable vital signs. Examination showed diffuse abdominal tenderness, which was most severe over right upper quadrant (RUQ) with guarding but negative Murphy’s sign. Laboratory tests showed elevated white cell count (WCC) of 15.7 × 109/L with absolute neutrophil counts (ANC) of 12.7 × 109/L and C-reactive protein (CRP) of 272.0 mg/L. There was also deranged liver function at presentation, with normal total bilirubin 20 μmol/L, alkaline phosphatase (ALP) up to 552 U/L and alanine aminotransferase (ALT) 141 U/L, and deranged clotting profile with prolonged prothrombin time (PT) 13.9 s and activated partial thromboplastin time (APTT) 39.5 s. Platelet count was normal 201 × 109/L. X-rays were unremarkable.

Top differential diagnosis upon clinical assessment included ruptured appendicitis, ruptured hollow viscus, gastroenteritis, and hepatitis. Therefore, contrast computed tomography (CT) scan was arranged in view of the atypical presentation, showing a ruptured dilated 1.2 cm acute necrotic appendicitis and filling defect in superior mesenteric vein before joining the portal vein (Fig. 1a). Patchy hypoenhancement was also detected over right hepatic lobe (Fig. 1b), suspicious of suboptimal blood supply to the liver.

Fig. 1
figure 1

Computed tomography scan on day of admission. a Computed tomography scan on day of admission showing filling defect in superior mesenteric vein (arrow). b Computed tomography scan on day of admission showing patent left and right portal vein and filling defect in superior mesenteric vein. c Computed tomography scan on day of admission showing patent main portal vein. d Computed tomography scan showing patchy hypoenhancement over right hepatic lobe (arrow)

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Emergency laparoscopic appendicectomy was performed on day 1 of hospitalization with operative findings of ruptured appendicitis with no evidence of bowel or liver ischemic changes seen laparoscopically. Preoperative intravenous antibiotics with Meropenem 40mg/kg was given. No anticoagulation was started before operation. Aerobic and anaerobic cultures were performed, with the blood culture yielding Escherichia coli and peritoneal fluid culture yielding multiple organisms from the genera of Bacteroides, Slackia, Gemella, and Parvimonas.

The early post-operative course was eventful with systemic inflammatory response syndrome with tachycardia, fever, bilateral pleural effusion requiring respiratory support and elevated WCC, requiring admission to pediatric intensive care unit. He was kept nil by mouth to promote bowel rest and prevent bowel ischemia. He was also started on intravenous antibiotics (initially Amikacin 15 mg/kg/dose Q24H, Meropenem 40mg/kg/dose Q8H, Vancomycin 10 mg/kg/dose Q8H and Flagyl 7.5/kg/dose Q8H, later to Cefotaxime 40 mg/kg/dose Q8H and Flagyl 10 mg/kg/dose Q8H according to culture results, respiratory support by high flow oxygen and started on fish-oil based total parenteral nutrition with aggressive fluid replacement regimen. However, there was progressive derangement of liver function with ALP 791 U/L, ALT85U/L, aspartate transaminase (AST) 356 U/L, gamma-glutamyl transferase (GGT) 356 U/L, bilirubin 22 μmol/L and elevation of platelet up to 1112 × 109/L. A follow-up contrast CT scan was arranged on day 7 showing interval progression of portomesenteric thrombosis involving superior mesenteric vein (SMV), main portal vein, proximal right portal vein and left portal vein and its branches. In view of the progression of thrombosis, low molecular weight heparin (LMWH) at a dosage of 0.8 mg/kg Q12H was started (Fig. 2).

Fig. 2
figure 2

Computed tomography scan on post-operative day 7. a Axial view CT scan showing interval progression of portomesenteric thrombosis involving main portal vein (arrow). b Coronal view CT scan showing interval progression of portomesenteric thrombosis involving superior mesenteric vein (arrow)

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Patient showed gradual improvement clinically with resolution of tachycardia, fever, and weaned off respiratory support. Inflammatory markers and liver function were normalized at post-operative 4 weeks. LMWH dose was further titrated against regular blood anti-Xa monitoring for LMWH was done with a target range of 0.5–1.0units/ml. He was discharged at post-operative 5 weeks with oral levofloxacin, flagyl, and intramuscular enoxaparin. All hematological workup so far showed that patient has no underlying clotting disorder.

Gradual improvement of thrombus was observed on the 4 weeks post-operative CT scan and partial recanalization of hepatic and portal veins. Multidisciplinary approach was adopted with expert opinions from Radiologist and Paediactric Hematologist obtained. Since the infective source was removed, LMWH was stopped at post-operative 6 months as thrombosis likely secondary to the infective episode. Also, long term follow-up for portal hypertension with ultrasound was planned.

Discussion

Septic thrombophlebitis is a rare but potentially fatal complication of intra-abdominal infection. Therefore, early detection and proper management is paramount. A literature review of all reported case in English language using PubMed, MEDLINE, and ScienceDirect since 1990 was reviewed. The clinical presentation, laboratory results, diagnostic modalities, extent of thrombosis, culture results and final treatment were summarized and presented. Our patient and the 17 pediatric case reports regarding the condition since 1990 were included (Table 1).

Table 1 Summary of 17 pediatric cases of acute appendicitis with portomesenteric thrombosis since 1990
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Presentation of acute appendicitis with septic thrombosis can vary from days to weeks of abdominal pain, diarrhea, vomiting or fever [3, 4, 6,7,8,9,10,11,12, 14,15,16,17] to persistent pain or vomiting and diarrhea post-appendectomy [5, 13, 16]. The most common presenting symptom were fever (n = 16/18, 89%), deranged liver function (n = 13, 72%), RUQ pain (n = 10, 56%) and diarrhea (n = 8, 44%). Patient presenting with RLQ pain were only seen in (n = 4, 22%). Only one patient out of the whole case series was found to have an underlying Protein S/C, anti-thrombin III deficiency. The most common causative organisms were Escherichiae coli and Bacteroides fragilis.

In regard of the diagnostic imaging modality, even though ultrasound remains the first-line imaging modality for suspected acute appendicitis in pediatrics to minimize childhood radiation [18], computed tomography (CT) scan was helpful in case of acute appendicitis with septic thrombosis. Diagnosis was made by computer tomography (n = 15, 83%), ultrasound (USG) (n = 1, 5%), magnetic resonance imaging (MRI) (n = 1, 5%) and laparotomy (n = 1, 5%). CT scan also allowed detection of other complications including liver abscess and bowel ischemia. Five cases developed liver abscess following the portal branches of septic thrombophlebitis [3, 9,10,11, 14] However, there was no reported case developing bowel ischemia following portomesenteric thrombosis-complicating appendicitis in pediatrics. Regarding the follow-up imaging for thrombosis, there was no consensus over the modality of imaging used. Doppler ultrasound, CT scan, or even magnetic resonance imaging were used in the case reports. Comparing to doppler ultrasound, CT scan might bear the advantage of detailed and non-operator-dependent scanning, but also bear risks of radiation if repeated follow-up scans are needed. In our case, patient was initially followed up by CT scan for progress of progression and later by ultrasound for any portal hypertension as a long-term follow-up.

For the management of acute appendicitis complicated with portomesenteric thrombophlebitis, adequate sepsis control including broad-spectrum antibiotics and appendectomy were well adopted in the reported cases [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17]. Surgical intervention includes early operative intervention (n = 13, 50%) including laparoscopic or open appendicectomy (n = 12, 66.7%), ileocolic resection (n = 1, 5.6%), and right hemicolectomy (n = 1, 5.6%). Concomitant thrombectomy was seen in 1 patient. Four patients (n = 4, 22.2%) had interval appendicectomy with a median time of 3.5 months after presentation (range 0.5 to 4 months).

Anticoagulant was used in 14 patients with a mean treatment duration of 7 months (ranged from 3 months to 1.5 years) [2, 5, 6, 8,9,10,11,12,13, 15,16,17]. However, anticoagulant use and its duration remained controversial with 4 cases reporting resolution of thrombus without anticoagulant use. The American Society of Hematology 2018 Guidelines for management of venous thromboembolism suggested that for provoked venous thromboembolism events, duration of anticoagulation should be less than or equal to 3 months in pediatrics if provoking factor resolves [19]. Antithrombotic Therapy in Neonates and Children Guideline suggested thromboembolism to be managed with pediatric hematologists with a monitoring of anti-Xa blood level if low molecular weight heparin (LMWH) is prescribed [20]. In our case, we had consulted pediatric hematologists for their expert opinions before starting on LMWH with regular anti-Xa monitoring. Sepsis was well controlled with appendectomy and board-spectrum antibiotics with follow-up CT scans showed interval reduction of portomesenteric thrombus at post-operative 1 month and partial recanalization at post-operative 6 months. Therefore, anticoagulant was offed at post-operative 6 months.

Conclusion

Portomesenteric thrombosis as a rare but severe complication of acute appendicitis. A high index of suspicion is needed to diagnose patient with acute appendicitis complicated by portomesenteric thrombosis. It should be considered in patient with atypical presentation especially with fever and RUQ pain. Management might include appendectomy, antibiotics and anticoagulants. In view of the controversial use of anticoagulants, multidisciplinary management with pediatric hematologist consultation for individualized management might provide additional benefit.