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I read with interest the article by Kamisawa et al regarding the aetiology of autoimmune pancreatitis (
). The cause of a significant proportion of cases of acute pancreatitis remains uncertain. I would like to describe a case of acute pancreatitis associated with antiphospholipid syndrome to highlight another potentially important cause of autoimmune pancreatitis which I believe has not been previously described.
A 30 year old woman was admitted twice in the space of three months with acute pancreatitis. She had a past medical history of anxiety and occasional migraines, for which she took alprazolam and propranolol, respectively. She had suffered two miscarriages and had one healthy child. She drank 3 units of alcohol per day. She was otherwise well and had no history of musculoskeletal problems.
On both occasions her amylase level was significantly elevated (787 and 364, respectively (normal range 30–154)). Ultrasound and computed tomography of her abdomen were carried out each time and demonstrated a diffusely swollen pancreas consistent with acute pancreatitis, but with no evidence of gall stones or biliary duct dilatation.
Liver function tests were all normal with the exception of a slightly elevated gamma glutamyl transferase level. Glucose, lipids, thyroid stimulating hormone, calcium, and clotting (international normalised ratio and activated partial thromboplastin time) were all normal. Full blood count was normal except for a neutrophilia during her acute illness. Her erythrocyte sedimentation rate was raised at 78. Urine microscopy and urinary protein excretion were both normal.
On her second admission to hospital she had four generalised seizures and magnetic resonance imaging showed cortical vein thrombosis with associated venous infarction. Subsequent investigation revealed a strongly positive antinuclear antibody (1 in 640) but her extractable nuclear antigens and dsDNA were negative, as was her antineutrophil cytoplasmic autoantibodies and her antimitochondrial and antismooth muscle antibodies. Her thrombophilia screen was negative but her IgG anticardiolipin antibodies were positive at 22.3 (0–5.5).
A diagnosis of antiphospholipid syndrome was made. She was treated with heparin and warfarin and subsequently made a good recovery.
Primary antiphospholipid syndrome is defined as the presence of antiphospholipid antibodies (lupus anticoagulant or anticardiolipin antibodies) in association with thrombosis or recurrent miscarriage, but in the absence of an associated connective tissue disorder such as systemic lupus erythematosis (SLE).1
SLE has previously been described as an unusual cause of acute autoimmune pancreatitis. In the literature there are a small number of cases of pancreatitis in association with SLE and antiphospholipid syndrome.2,3 A single case of pancreatitis associated with lupus anticoagulant but without anticardiolipin antibodies has also been described.4 However, to my knowledge this is the first reported case of primary antiphospholipid syndrome associated with anticardiolipin antibodies causing acute pancreatitis.
In the antiphospholipid syndrome, vascular occlusion is due to thromboembolism whereas in SLE the primary abnormality is vasculitis. In a single post mortem case of pancreatitis due to antiphospholipid syndrome associated with SLE, the pathological abnormality was vascular occlusion due to thromboembolism.1 Oral anticoagulation rather than steroids is therefore the treatment of choice for antiphospholipid syndrome.5
The patient described fulfils the criteria for a diagnosis of primary antiphospholipid syndrome. While there is no histological proof that her pancreatitis was due to vaso-occlusive thromboembolism, several facts make this the likely explanation. The recurrent episodes in the absence of another cause, the proven cerebral thromboembolism at the time of her second attack of pancreatitis, and her positive anticardiolipin antibodies are highly suggestive that thromboembolism of her pancreatic blood vessels was indeed the cause of her pancreatitis.
I suggest that the investigation of patients with idiopathic pancreatitis should include checking their antiphospholipid antibodies.
Autoimmune pancreatitis is a recently described clinical entity in which autoimmune mechanisms are involved in the pathogenesis. As Etemad and colleagues1 described that autoimmunity was one of six risk factors of chronic pancreatitis, autoimmune pancreatitis is not acute but chronic pancreatitis. Patients with autoimmune pancreatitis rarely showed acute attacks of pancreatitis or marked elevation of serum amylase.2 Although the pancreas of autoimmune pancreatitis is swollen similar to acute pancreatitis on ultrasound and computed tomography, it is induced by dense lymphoplasmacytic infiltration with fibrosis.
Obliterated phlebitis throughout the pancreas is one of the characteristic pathological findings of autoimmune pancreatitis. The lumen of the vein was filled with prominent cellular infiltrates and fibrosis. Venous occlusion was not due to thromboembolism but to phlebitis. Although the role of obliterated phlebitis is unknown in the pathogenesis of autoimmune pancreatitis, many IgG4 positive plasma cells, which might be closely related to pathogenesis, were observed in the obliterated veins. Signs of thrombosis were not observed in any organs of our patients with autoimmune pancreatitis. We think that autoimmune pancreatitis is quite different from the pancreatitis reported by Spencer.