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A 44-year-old Italian man presented to the emergency department on three occasions over 4 days with severe left flank pain. Initial investigations including a renal tract ultrasound were normal and he was discharged with analgaesia. On his third presentation, a CT angiogram was performed due to persisting pain, which demonstrated infarction of his left kidney as well as thickening of the anterior branch of left renal artery and complete occlusion with focal intimal dissection of the coeliac artery. His antineutrophil cytoplasmic antibody was negative. A medium vessel vasculitis was suspected and confirmed on positron emission tomography-CT, which revealed increased metabolic activity involving the right internal mammary artery and coeliac artery. Treatment with pulse methylprednisolone was started followed by a tapering prednisolone regimen, with a rapid reduction in his inflammatory indices. Twenty-four months later his renal function remains normal off all immunosuppression.
The vasculitides are rare (20 cases per million) inflammatory diseases of the blood vessel walls. Diagnosing this condition is important as, if left untreated, it can be associated with significant morbidity and mortality. The inflammatory process in vasculitides may be primary (idiopathic) or secondary to underlying diseases, often infections and are traditionally classified by the size of the blood vessels affected.1 2 Small vessel vasculitides such as microscopic polyangiitis, granulomatosis with polyangiitis, Henoch-Schonlein purpura and cryoglobulinaemic vasculitis, frequently involve the kidneys and cause glomerular inflammation, which can lead to renal failure.3 Medium vessel vasculitides, including polyarteritis nodosa, are associated with renal and intestinal infarction.4
Signs and symptoms depend on the organs involved and the clinical presentation can vary from non-specific constitutional symptoms to life-threatening bleeding.5 A high index of suspicion is often required to make the diagnosis and investigations should include assessment for autoantibodies and infectious agents, including hepatitis B virus. Key aims are to identify secondary causes and to uncover the extent of the disease. Definitive diagnosis requires demonstration of vascular involvement by either biopsy or imaging.5
Renal infarction due to vasculitis is an uncommon presentation that should be considered in the differential diagnosis of loin pain and haematuria. Our case highlights the role modern imaging techniques play in establishing the diagnosis.
A 44-year-old man presented to the emergency department with a 2-day history of sudden onset non-radiating sharp left flank pain that was associated with nausea and vomiting. His medical history included a non-obstructive renal calculus treated with lithotripsy and alopaecia universalis. There was no family history of renal disease. He was an ex-smoker and did not consume alcohol. He had never used illicit drugs. His examination findings were normal. A urine dipstick demonstrated trace amounts of protein and blood and a renal calculus was suspected. He proceeded to have a CT of the kidney, ureter and bladder, which revealed an oedematous left kidney. The radiological differential diagnoses included a renal calculus that had passed or pyelonephritis; however, the urine dipstick did not suggest infection. The patient was therefore presumed to have a kidney stone and discharged home with oral analgaesia.
He re-presented the next day with worsening left flank pain and nausea. This settled with analgaesia and he was again discharged after a few hours. He then re-presented to the emergency department for the third time with similar symptoms, but on this occasion was noted to have raised inflammatory markers and a slightly elevated serum creatinine level. A Nephrology opinion was sought. A renal Doppler was performed, which was normal followed by a CT angiogram because of ongoing haematuria. This revealed a partially infarcted left kidney with a thickened anterior branch of the left renal artery and complete occlusion with focal intimal dissection of the coeliac artery (figures 1 and and22).
A screen for autoimmune and infectious diseases was negative and due to the risks associated with attempting to biopsy the affected vessels, an 18F-fluorodeoxy-glucose positron emission tomography (FDG PET) scan was organised. The scan revealed intense activity in the right internal mammary artery; and coeliac axis consistent with vasculitis (figures 3 and and4)4) and no FDG activity were noted in the left kidney due to tissue necrosis. In the absence of an identifiable cause, a decision was made to treat this as an autoimmune condition, and the patient was pulsed with 500 mg intravenous methylprednisolone daily for 3 days, followed by oral prednisolone at 1 mg/kg/day. His inflammatory markers rapidly improved after initiating steroid therapy, which was weaned over 2 months to 5 mg/day. He was not able to tolerate the steroid sparing agent azathioprine, so continued on prednisolone for a further 3 months. He remains in clinical remission with normal inflammatory markers 24 months following his initial presentation.
Initial blood tests revealed elevated inflammatory markers with a white cell count of 14.3 cells×109/L, C reactive protein of 370 mg/L and ESR of 45 mm/h, and his creatinine at presentation was 87 µmol/L. Antinuclear antibody, antineutrophil cytoplasmic antibody, antistreptolysin O, anti-DNAseB, complement levels and hypercoagulability screen were normal. Hepatitis, HIV, Q fever, Epstein-Bar virus and cytomegalovirus serology were negative. 18F-FDG PET revealed moderate FDG uptake along the right internal mammary artery and moderate activity at the coeliac axis.
Follow-up blood tests and ultrasonography 3 months postdiagnosis revealed normal biochemistry, renal function and inflammatory markers with normal renal anatomy.
The differential diagnosis of loin pain and haematuria in a 44-year man includes renal or ureteric calculi, pyelonephritis, trauma, polycystic kidney disease, renal tumours (benign or malignant), infarction or papillary necrosis and glomerulonephritis. It is indeed difficult to distinguish these causes based on history alone, and in recurrent presentations special investigations are required to understand the aetiology and to guide appropriate management.
Our patient was pulsed with 500 mg intravenous methylprednisolone over 3 days, followed by oral prednisolone at 1 mg/kg daily, which was weaned over 2 months. He did not tolerate azathioprine, so was maintained on 5 mg oral prednisolone for a further 3 months. On recent review 24 months after his initial presentation, he remains in remission off all immunosuppression (figure 5).
In this patient with medium vessel vasculitis we report an excellent clinical outcome with corticosteroid immunosuppression, with preserved renal function and no clinical manifestations of disease on follow-up. Although a repeat PET-CT was requested to confirm the remission, he declined to attend.
In patients without significant atherosclerotic disease or other risk factors for arterial occlusion (such as atrial fibrillation), vasculitis should be considered in the differential diagnosis of renal infarction. The patient in our case report was discharged three times from the emergency department with oral analgaesics for a presumed renal calculus even with no evidence of a stone on imaging. Despite the elevated inflammatory markers noted at the time of admission, our patient did not have constitutional symptoms such as fatigue, fever or arthralgias, and did not have systemic signs such as skin lesions, hypertension or neurological dysfunction, which are common in other medium vessel vasculitides such as polyarteritis nodosa. In addition, his CT angiogram did not reveal any small or large vessel aneurysms, and FDG uptake was absent in the left kidney due to underlying infarction secondary to thrombosed anterior branch of the left renal artery.
Renal infarction is uncommon and often associated with underlying conditions such as atrial fibrillation, cholesterol emboli or infective endocarditis. Although medium vessel vasculitis can cause renal infarction, other clinical features are usually present such as purpura, myalgia, weight loss, neuropathy and skin rash.3 4 Non-invasive imaging methods including 18F-FDG PET CT may provide additional information to assist in the diagnosis and management of vasculitis.4 6–8
This case highlights an unusual presentation of vasculitis and the utility of non-invasive imaging studies in making a diagnosis. Once the diagnosis is established, if no secondary causes are evident, corticosteroid-based immunosuppression can be highly efficacious in inducing remission.
Twitter: Follow Vinothkumar Kavarthapol Jayaraman at @kj_vino
Competing interests: None declared.
Patient consent: Obtained.
Provenance and peer review: Not commissioned; externally peer reviewed.