Polyarteritis nodosa presenting as profuse gastrointestinal bleeding

Abstract

A 70-year-old man presented with acute onset of profuse bleeding per rectum. An urgent colonoscopy showed blood throughout the colon and distal ileum but failed to localise the source. Subsequent visceral arteriography revealed pseudoaneurysms of the branches of the superior mesenteric artery and left gastric artery. The bleeding stopped spontaneously and the aetiology of the bleeding was later found out to be secondary to polyarteritis nodosa (PAN). The presence of profuse gastrointestinal bleeding as the sole manifestation at presentation in PAN is under-reported. Early diagnosis of PAN in patients with haemodynamically significant bleeding is necessary as prompt initiation of immunosuppressive therapy helps prevent relapses. With this case report, we highlight one of the unusual presentations of PAN and the favourable response to immunosuppression with pulsed dose steroids.

Background

Polyarteritis nodosa (PAN) as the cause of acute onset gastrointestinal (GI) bleed has seldom been reported in the past. The diagnosis is often missed especially if it is the sole manifestation at presentation of PAN. In an acute setting with seemingly obscure findings, the proper use of imaging modalities and due consideration to rare causes of bleeding can avoid unnecessary laparotomies. The prompt detection and treatment of PAN with immunosuppressive therapy can avoid fatal consequences through relapses.

Case presentation

A 70-year-old Caucasian man presented with acute episodes of bright red blood per rectum, associated with dizziness and fatigue. The patient had no history of abdominal pain, fever, diarrhoea, prior history of GI bleeding or underlying coagulation disorder. His previous colonoscopy in 2009 was unremarkable. His medical history was pertinent for hypertension and prostatic cancer status post resection. He was not on any non-steroidal anti-inflammatory drugs or anticoagulants. Family and social history was unremarkable with respect to his presenting symptoms.

On physical examination, the patient was awake and alert, but hypotensive (blood pressure 86/52 mm Hg), tachycardic (heart rate 112 bpm) and orthostatic. Cardiovascular and respiratory system examination was otherwise unremarkable. Abdominal examination revealed tenderness in the left lower quadrant of the abdomen without guarding, rigidity or rebound tenderness. Peripheral pulses were weak and extremities were cold. Digital rectal examination revealed bright red blood on the examining finger.

Investigations

His initial laboratory results showed a blood urea nitrogen of 21 mg/dL and creatinine 1.5 mg/dL compared with a baseline of 8 and 0.9 mg/dL, respectively, haemoglobin 7.5 g/dL compared with a baseline of 14 g/dL. Haematocrit was 24.9 g/dL, with platelet count of 55×10³/µL and International Normalised Ratio of 1.37.

Following resuscitation with intravenous fluids and 6 units of packed RBCs, upper GI endoscopy was performed which showed grade 2 oesophageal varices with no stigmata of recent bleeding and one small, non-bleeding gastric polyp. Colonoscopy showed copious amount of blood in the colon and distal ileum, with no active source of bleeding. As the patient continued to have large bloody bowel movements and haemodynamic instability, he was transferred to our tertiary hospital for further treatment.

On presentation at our facility, a repeat colonoscopy showed dark blood adherent to the entire examined colon and terminal ileum but the source of bleeding could not be identified. Tagged RBC scan showed evidence of active bleeding from the small bowel. During the hospitalisation, his bleeding seemed to gradually recede. Visceral arteriography showed diffuse irregularity of the branches of the SMA with multiple narrowing and small pseudoaneurysms (figure 1). The pseudoaneurysms were also seen in the left gastric artery and the splenic artery but with no evidence of active extravasation (figure 2).

Figure 1.

Visceral arteriogram of superior mesenteric artery showing multiple narrowings and small pseudoaneurysms (yellow arrow).

Figure 2.

Visceral arteriogram of the coeliac artery showing pseudoaneurysms in the left gastric artery (blue arrow) and splenic artery (red arrow).

Differential diagnosis

The initial differentials included the more common causes such as diverticulosis, inflammatory bowel disease, angiodysplasia and neoplasm. The early workup failed to reveal any obvious cause; however, the arteriography findings raised a suspicion of an underlying vasculitis syndrome such as PAN and systemic lupus erythematosus.

Treatment

The patient was started on pulsed intravenous methylprednisolone (1 g/day) and he did not have any further episodes of bleeding during his hospital stay. He was discharged home in 3 days on prednisone 60 mg daily with outpatient rheumatology follow-up.

Outcome and follow-up

Outpatient rheumatology workup showed low C3 and C4 levels with normal erythrocyte sedimentation rate and C reactive protein and negative antinuclear antibody, anti-ds-DNA and proteinase-3 antibodies. Hepatitis B and C antibodies were negative. HIV test was negative. Biopsies from the ileum and colon were unremarkable. A diagnosis of PAN was made based on the arteriographic findings and the negative lupus workup.

The patient was continued on high-dose prednisone for 4 weeks and scheduled on a taper thereafter. He has yet not reported any recurrence of GI bleeding.

A follow-up CT angiography of the abdomen carried out 6 months later showed microaneurysms along the splenic and left gastric artery with no evidence of bleeding (figures 3 and 4).

Figure 3.

CT angiography abdomen showing partially rim-calcified microaneurysm in the distal splenic artery (green arrow).

Figure 4.

CT angiography abdomen showing three partially rim-calcified microaneurysms along the splenic artery (green arrows).

Discussion

zPAN is a multisystemic vasculitis syndrome characterised by fibrinoid necrosis and leucocyte infiltration of the walls of medium-sized and small-sized arteries. At presentation, the disease may have variable organ involvement, including kidneys, skin, GI tract, heart, peripheral nerves, genitals or muscles, and thus the presenting symptoms vary. PAN typically presents as abdominal, testicular or muscular pain¹ and systemic symptoms such as fever, malaise or unintentional weight loss. The symptoms appear gradually and the disease has an insidious course for a prolonged period of time. Nevertheless, it is unlikely for PAN to have a catastrophic presentation, as happened in our case.

The incidence of GI involvement in PAN is up to 65%.^{2 3} Abdominal pain is the most common GI finding and considered a constant feature in most patients.⁴ Occurrence of pain necessitates further workup, often subjecting the patient to numerous tests before an incidental finding of pseudoaneurysm or mesenteric vascular occlusion is made.

The presence of profuse GI bleeding as the sole manifestation at presentation in PAN is under-reported and not widely known in clinical practice.^{5 6} Perez et al⁷ reported the first case of GI bleeding at presentation in a PAN case in 2000. In a retrospective study conducted by Pagnoux et al⁸ in 348 patients, GI bleeding was present in less than 4% of the patients at the time of diagnosis.

High clinical suspicion is necessary when diagnosing PAN as the disease is rare and the diagnosis is often confounded by its variable presentation often mimicking other more common diseases. The diagnosis is often offset by the lack of sensitive tests and the commonly inaccessible biopsy sites.⁹ In such situations, imaging techniques such as CT and MR angiography can be important tools to make the distinction, and these new techniques do not carry the adverse effects of traditional angiography.¹⁰ Limitations to their widespread use include high cost, time consumption (which may be detrimental in a haemodynamically unstable patient) and the lack of widespread equipment availability. In fact, the incidence of PAN-associated GI bleeding may actually be much higher than what was previously thought. Fortunately, in most cases, the bleeding resolves spontaneously. In persistent bleeders, the treatment involves occlusion of the bleeding vessel most commonly through embolisation via coils or chemical agents such as N-butyl cyanoacrylate or onyx.¹¹ Initial pharmacotherapy involves induction of remission with glucocorticoids alone, which is effective in about half the patients.¹² Addition of other immunosuppressive agents like pulsed dose cyclophosphamide may improve the remission rate¹² but with questionable mortality benefits.¹³

As more cases of PAN-associated profuse GI bleeding come to light,⁹ with the improvement in diagnostic techniques, it becomes imperative to conduct research into understanding the mechanism of the disease. The answer to this question holds the key to the development of better diagnostic tests. Early detection of the presence of PAN in patients with haemodynamically significant bleeding is necessary as prompt initiation of immunosuppressive therapy helps prevent relapses. Untreated PAN carries a high mortality rate² and profuse GI bleeding is one the leading causes of death in PAN.^{13 14}

Learning points.

• Polyarteritis nodosa (PAN) can present late with catastrophic symptoms such as profuse gastrointestinal (GI) bleed.

• High index of suspicion is necessary when dealing with seemingly obscure GI bleeding cases. Imaging techniques such as arteriography, CT and MR angiography help with the diagnosis in such cases.

• Early detection of PAN is imperative to initiate immunosuppressive therapy in order to avoid early relapse, as untreated PAN is associated with high mortality.

• Further research is needed to understand the causation of the disease, which will enable the development of better and less invasive diagnostic techniques.