polyarteritis nodosa

An unusual
complication of polyarteritis nodosa with massive retroperitoneal hemorrhage: a case report. Mesenteric angiogram showing multiple visceral artery aneurysms (arrow heads) and Inferior pancreaticoduodenal artery along with the retro peritoneal hemorrhage.
intarchmed.biomedcentral.com • Open Access
Imaging of
intestinal vasculitis focusing on MR and CT enterography: a two-way street between radiologic findings and clinical data. Intestinal vasculitis in a 32-year-old female with PAN (polyarteritis nodosa) presenting with episodic abdominal pain, fever, anemia, and elevated liver enzymes and inflammatory markers. MRE was obtained. Coronal and axial T2-W images (A, B) show a single thickened segment of mid ileum (thick white arrows) with mild T2 hyperintensity more likely secondary to submucosal edema. This is associated with mild degree of upstream bowel distention. Coronal and axial post-contrast T1-W images (C, D) display mural hyperenhancement (thin white arrows) with a relatively striated pattern. DWI at a b-value of 800 s/mm2 (E) shows restricted diffusion (white arrowhead), suggesting increased inflammatory cell density. The patient underwent double-balloon enteroscopy following this MRE, but it was complicated by bowel perforation at this segment. Then, surgical resection and ileostomy were performed. Histopathological assessment of resected segment revealed vasculitis consistent with polyarteritis nodosa (PAN). Heterogeneous enhancement of liver at arterial phase is also depicted (C), which raises suspicion for microvascular involvement (white dotted oval)
insightsimaging.springeropen.com • CC-by-4.0
Imaging of
intestinal vasculitis focusing on MR and CT enterography: a two-way street between radiologic findings and clinical data. Vasculitis of splanchnic arteries in a 43-year-old male with a history of pathologically proven polyarteritis nodosa and segmental jejunal resection due to ischemia. He complains of postprandial abdominal pain, nausea, vomiting, hypertension, and elevated inflammatory markers. CTE was done. Axial and sagittal images (A–C) in the arterial phase demonstrate severe stenosis at the origin of the celiac trunk (thin white arrows) and complete occlusion and irregularity of proximal SMA (thin black arrows). Coronal CT images (D–F) reveal vessel irregularity and mild degree of aneurysmal dilations in a collateral branch between celiac trunk and SMA (white arrowheads), thickening and irregularity in jejunal branches of SMA (black dotted oval) adjacent to the previous site of jejunal resection and anastomosis (white curved arrows). The ileocolic branch of SMA also shows focal aneurysmal dilatation and mild thickening (white dotted oval)
insightsimaging.springeropen.com • CC-by-4.0
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Polyarteritis nodosa (PAN) is a systemic inflammatory necrotizing vasculitis that involves small to medium-sized arteries (larger than arterioles).

Epidemiology

PAN is more common in males and typically presents around the 5 to 7decades. 20-30% of patients are hepatitis B antigen positive.

Associations

Clinical presentation

Patients can present with systemic and focal symptoms.

Non-specific systemic signs and symptoms are almost always present and include fever, malaise and weight loss.

Localized symptoms relate to ischemia and infarction of affected tissues and organs. The most commonly involved vessels are the renal arteries , with visceral involvement also considered relatively common. The pulmonary circulation is typically spared, although bronchial arteries may occasionally be involved.

Frequent sites of involvement are :

  • renal: 80-90%, tends to be the prominent site and major cause of death
  • cardiac: ~70%
  • gastrointestinal tract: 50-70%
  • hepatic: 50-60%
  • spleen: 45%
  • pancreas: 25-35%  
  • CNS complications: 20-45% 

Pathology

Initially, there is transmural and necrotizing inflammation of medium-sized arteries, mostly involving part of the circumference which causes weakening of the wall leading to microaneurysm formation and subsequent focal rupture. There is a predilection for branch points. Fibrinoid necrosis of vessels promotes thrombosis of vessels followed by infarction of the tissue supplied. Fibrous thickening and mononuclear infiltration occur at a later stage. Different stages of inflammation can occur in the same vessel at different points.

Markers
  • pANCA: it has been claimed that pANCA levels may correlate with disease activity, although the utility of this marker has been debated

Radiographic features

CT

Routine contrast-enhanced CT may be entirely normal or may demonstrate focal regions of infarction or hemorrhage in affected organs.

Angiography (DSA / CT angiography)

Direct catheter angiography is far more sensitive to changes within small vessels, although a good quality CTA can also demonstrate changes. Findings include:

  • multiple microaneurysms
    • characteristic but not pathognomonic
    • typically 2-3 mm in size but can be up to 1 cm
    • in the kidneys, the microaneurysms typically involve the interlobar and arcuate arteries
  • hemorrhage may be present due to focal rupture
  • occlusion may be present

Treatment and prognosis

Polyarteritis nodosa is usually fatal if untreated, often as a result of progressive renal failure or gastrointestinal complications. Prompt treatment with corticosteroids and cyclophosphamide may result in remission, and a remission/cure can be achieved in 90% of patients .

History and etymology

It was initially described by Kussmaul and Maier in 1866.

Differential diagnosis

Siehe auch:
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Assoziationen und Differentialdiagnosen zu Polyarteriitis nodosa:
Vaskulitis
 
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Churg-Strauss-Syndrom
 
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