PAN has mulitsystem involvement and progresses within few weeks to months [13]. It may affect a single organ or lead to visceral failure. Symptoms depend on the affected organs

• Musculoskeletal involvement – patients with musculoskeletal involvement present with common symptoms like fever, malaise, myalgia, arthralgia, anorexia, and weight loss
• Central nervous system involvement – when CNS is involved, temporary monocular blindness, cerebral ischemia, and subarachnoid hemorrhage may result. Lesions in CNS usually happen 2-3 years after the onset of PAN. Stroke, seizure, and focal deficits also present with CNS involvement. 
• Peripheral nervous system involvement – about 60% of the patients present peripheral neuropathy. Mononeuritis multiplex, distal polyneuropathy, and cutaneous neuropathy are also reported. 
• Skin involvement – this is one of the most common symptoms of PAN and is more common in legs. Rash, gangrene, cutaneous infarcts, nodules and livedo reticularis may be seen as manifestations of skin involvement. 
• Gastrointestinal involvement – most of the symptoms of GI involvement are nonspecific like abdominal pain, nausea and vomiting. In serious cases of PAN, pancreatic infarction, cholecystitis, and intestinal perforation may be noted. 
• Renal involvement – vasculitis of arteries in the kidney may result in renal failure and/or hypertension. Many patients complain of flank pain. 
• Other organ involvement – when other organs and organ systems like genitourinary system are affected, additional symptoms may be presented. Pain in testicular or ovarian area, chest pain, congestive heart failure, myocardial infarction, blurred vision, headache, psychosis and depression also may be seen depending on the organ affected. 

• Pain

  Polyarteritis nodosa mnemonic It usually presents with vague symptoms like myalgias, arthralgias, abdominal pain, fatigue. Renal involvement manifests as hypertension, renal insufficiency. [medicowesome.com]

  In this form joint pains and strokes are common. [vasculitis.org.uk]

  Here, we present a 42-year-old man who was hospitalised because of severe right upper quadrant abdominal pain that started 2 months before. Physical examination was remarkable for right upper quadrant abdominal tenderness. [ncbi.nlm.nih.gov]

  and 3, abundant nodules, medium-sized to large ulcers without tendency to heal, livedo reticularis, and severe pain). [doi.org]

  […] extremity pain skin ulcers livedo reticularis purpura renal glomerulonephritis hematuria new onset hypertension pulmonary typically spares lungs, though may involve bronchial arteries gastrointestinal abdominal pain rectal bleeding Imaging Angiography [step2.medbullets.com]

• Fever

  Interestingly, both had Mediterranean fever gene (MEFV) mutation, i.e. heterozygous E148Q. They also shared HLA-A24, -DR15 alleles. Simultaneous occurrence of MEFV mutation and HLA alleles with CPAN has never been reported in Japan. [ncbi.nlm.nih.gov]

  The first case of CPAN reported in the English-language literature may be that of a 7-year-old boy who, in 1870, died of "scarlet fever" at St. Bartholomew Hospital in London. [emedicine.com]

  Diagnosis A doctor may suspect polyarteritis nodosa when a patient has unexplained fever, stomach pain, kidney failure or high blood pressure. [cedars-sinai.org]

  Fever, rash, and musculoskeletal symptoms are common in children and cPAN needs to be differentiated from other diagnostic entities. [bjmp.org]

• Weight Loss

  Patients typically present with systemic symptoms such as fever, weight loss, and malaise. The kidneys, skin, joints, muscles, nerves, and gastrointestinal tract are commonly involved, usually in some combination. [ncbi.nlm.nih.gov]

  His symptoms are associated with malaise, fever, and weight loss. He does not have a family history of malignancy and his last colonoscopy was unremarkable. His blood pressure is 155/98 mmHg (his blood pressure is usually 125/74 mmHg). [step2.medbullets.com]

  […] of appetite, weight loss, muscle and joint aches, rashes, numbness, and abdominal pain. [autoimmune.org]

  PAN typically presents with non-specific symptoms, such as fever, weight loss and myalgias, and symptoms related to the system involved. [reumatologiaclinica.org]

• Weakness

  A 71-year-old man was hospitalized because of muscle weakness of the lower limbs that persisted for 1 month. On a physical examination, rapidly progressive lower proximal muscle weakness and bilateral drop foot were observed. [ncbi.nlm.nih.gov]

  Symptoms include: abdominal pain, decreased appetite, fatigue, fever, joint aches, muscle aches, unintentional weight loss, and weakness. If nerves are affected, you may have numbness, pain, burning, and weakness. [autoimmune.org]

  Damage to the blood vessel walls can also cause weak spots (aneurysms) that bulge from the pressure of the blood through the vessel and are at risk of bursting open. [cedars-sinai.org]

  Symptoms include: Abdominal pain Decreased appetite Fatigue Fever Joint aches Muscle aches Unintentional weight loss Weakness If nerves are affected, you may have numbness, pain, burning, and weakness. [nlm.nih.gov]

  Night sweats and generalized weakness are common symptoms. Other symptoms occur when the arteries that carry blood to an organ are damaged, and the organ does not receive enough blood to function normally. [merckmanuals.com]

• Fatigue

  Polyarteritis nodosa mnemonic It usually presents with vague symptoms like myalgias, arthralgias, abdominal pain, fatigue. Renal involvement manifests as hypertension, renal insufficiency. [medicowesome.com]

  Symptoms include: abdominal pain, decreased appetite, fatigue, fever, joint aches, muscle aches, unintentional weight loss, and weakness. If nerves are affected, you may have numbness, pain, burning, and weakness. [autoimmune.org]

  Common Symptoms Fever, weight loss, loss of appetite, abdominal, joint, muscle, and/ or chest pain, shortness of breath, fatigue, and malaise. [autoimmuneinstitute.org]

  Abdominal pain, fever, fatigue, and myalgia were the most frequent complaints. Doppler ultrasonography (US) was used in the diagnosis of seven patients and computed tomography (CT) angiography was done in four patients. [ncbi.nlm.nih.gov]

  They can include skin rashes and ulcers, muscle and joint aches, fever, fatigue, weakness, abdominal pain, and loss of appetite. Nerve pain and numbness also can be associated with PAN. [kidshealth.org]

• Abdominal Pain

  Polyarteritis nodosa mnemonic It usually presents with vague symptoms like myalgias, arthralgias, abdominal pain, fatigue. Renal involvement manifests as hypertension, renal insufficiency. [medicowesome.com]

  Here, we present a 42-year-old man who was hospitalised because of severe right upper quadrant abdominal pain that started 2 months before. Physical examination was remarkable for right upper quadrant abdominal tenderness. [ncbi.nlm.nih.gov]

  A 72-year-old man presented with acute abdominal pain and rectal bleeding. [pubs.rsna.org]

  Images Snapshot A 52-year-old man presents to the emergency department with abdominal pain and rectal bleeding. His symptoms are associated with malaise, fever, and weight loss. [step2.medbullets.com]

• Nausea

  There maybe nausea, vomiting and abdominal pain due to GI involvement (Untreated patients may die of bowel infarcts, perforations) Peripheral neuropathy, rash, purpura, CHF, CVA, etc are other manifestations of the disease. [medicowesome.com]

  He reported nausea and one episode of nonbloody, nonbilious emesis. Funding and Disclosures Disclosure forms provided by the authors are available with the full text of this article at NEJM.org. [doi.org]

  […] and muscle pain Skin: Rashes or small bumps under the skin Open sores Bruises Death of skin tissue Nervous system: Tingling, burning, pain, or numbness in the feet, hands, legs, arms, and face Weakness Problems thinking Gastrointestinal: Belly pain Nausea [winchesterhospital.org]

  […] levels of protein in the urine Numbness, tingling or weakness of the hands and feet Pain in the joints, especially the large ones Skin rash with raised reddish-purple patches and knobs that can be felt along affected arteries Stomach pain sometimes with nausea [cedars-sinai.edu]

  Skin: Rashes Open sores Small bumps under the skin Bruises Death of skin tissue Nervous system: Tingling, burning, pain, or numbness in your feet, hands, legs, arms, and face Decreased alertness Inability to think clearly Gastrointestinal: Belly pain Nausea [cancercarewny.com]

• Loss of Appetite

  Common Symptoms Fever, weight loss, loss of appetite, abdominal, joint, muscle, and/ or chest pain, shortness of breath, fatigue, and malaise. [autoimmuneinstitute.org]

  They can include skin rashes and ulcers, muscle and joint aches, fever, fatigue, weakness, abdominal pain, and loss of appetite. Nerve pain and numbness also can be associated with PAN. [kidshealth.org]

  […] of appetite, weight loss, muscle and joint aches, rashes, numbness, and abdominal pain. [autoimmune.org]

  Patients who have PAN may feel generally ill and fatigued, have fevers, or have loss of appetite and weight. [my.clevelandclinic.org]

• Acute Abdomen

  Here we report a case of a young Chinese patient who presented with an acute abdomen requiring surgery and made good recovery post operatively. He remains free of symptoms while on steroid therapy. [ncbi.nlm.nih.gov]

  A localized type of PN in the gallbladder has been rarely reported with or without signs of autoimmune diseases or acute abdomen [ 8 - 12 ]. [alliedacademies.org]

  Perforation of the gallbladder with acute abdomen may occur. Vasculitis of medium-sized mesenteric arteries causes abdominal pain, nausea, vomiting (with or without bloody diarrhea), malabsorption, intestinal perforation, and acute abdomen. [merckmanuals.com]

  Rupture of renal or mesenteric micoaneurysms can simulate an acute abdomen. [hopkinsvasculitis.org]

• Intestinal Perforation

  Perforation of the gallbladder with acute abdomen may occur. Vasculitis of medium-sized mesenteric arteries causes abdominal pain, nausea, vomiting (with or without bloody diarrhea), malabsorption, intestinal perforation, and acute abdomen. [merckmanuals.com]

  Mona Mlika, Heifa Azouz, Inès Chelly, Sofiène Ayadi, Wael Rbai, Nidhameddine Kchir, Slim Haouet and Mohamed Moncef Zitouna, About a rare cause of intestinal perforation, Open Journal of Internal Medicine, 01, 02, (14), (2011). [doi.org]

  In serious cases of PAN, pancreatic infarction, cholecystitis, and intestinal perforation may be noted. Renal involvement – vasculitis of arteries in the kidney may result in renal failure and/or hypertension. Many patients complain of flank pain. [symptoma.com]

  GI involvements of PAN patients commonly occur in the intestine from the small bowel to the colon [ 4, 7 ]. Rectal involvements are quite rare, and there is one case report of rectal hemorrhage [ 8 ], but no rectal perforation. [surgicalcasereports.springeropen.com]

• Hypertension

  Classifying hypertension as ‘primary’ or ‘secondary’ depends on the underlying mechanism. [ncbi.nlm.nih.gov]

  Complications Without treatment, hypertension-induced acute kidney injury is a cause of great morbidity and mortality. [patient.info]

  In a few patients, ischemic stroke and cerebral hemorrhage occur, sometimes resulting from hypertension. [merckmanuals.com]

  Renal involvement manifests as hypertension, renal insufficiency. [medicowesome.com]

• Vascular Disease

  disease w polyarteritis Polyneuropathy in collagen vascular disease with polyarteritis Polyneuropathy in polyarteritis nodosa Clinical Information Form of necrotizing vasculitis involving small- and medium-sized arteries; signs and symptoms result from [icd9data.com]

  Obstructive intestinal symptoms are described but usually resolve with treatment of the underlying vascular disease. [ncbi.nlm.nih.gov]

  A case of polyarteritis nodosa presenting initially as peripheral vascular disease. J Gen Intern Med, 23 (2008), pp. 1528-1531 [8] Swedish Council on Health Technology Assessment. [reumatologiaclinica.org]

  Abstract Periarteritis nodosa is an obliterative, inflammatory, vascular disease involving the small arteries and arterioles. [annals.org]

• Tachycardia

  She was in septic shock with tachycardia, tachypnea, and hypotension. [surgicalcasereports.springeropen.com]

  Protein in urine Gastrointestinal System: GI bleeding Abdominal pain Nausea/vomiting Constipation Melena Hematochezia Possible hemmorrhage or perforation (rare) Musculoskeletal System: Arthralgia Myalgia Arthritis (less common) Cardiac System: Chest pain Tachycardia [physio-pedia.com]

• Hypotension

  She was in septic shock with tachycardia, tachypnea, and hypotension. [surgicalcasereports.springeropen.com]

• Myalgia

  Myalgia is reported in 72% of childhood patients[10]. The typical presentation in children is one- or two-organ involvement, with constitutional symptoms, and the diagnosis is often based on pathology[11]. [patient.info]

  It is limited to the skin and has a recurrent and chronic course, possibly associated with fever, arthralgia, myalgia and neuropathy, but without visceral involvement. [ncbi.nlm.nih.gov]

  Polyarteritis nodosa mnemonic It usually presents with vague symptoms like myalgias, arthralgias, abdominal pain, fatigue. Renal involvement manifests as hypertension, renal insufficiency. [medicowesome.com]

  Myalgias, weakness or leg tenderness : diffuse myalgia (excluding shoulders and hip girdle) or weakness of muscles or tenderness of leg muscles. [rheumtutor.com]

• Arthralgia

  It is limited to the skin and has a recurrent and chronic course, possibly associated with fever, arthralgia, myalgia and neuropathy, but without visceral involvement. [ncbi.nlm.nih.gov]

  Polyarteritis nodosa mnemonic It usually presents with vague symptoms like myalgias, arthralgias, abdominal pain, fatigue. Renal involvement manifests as hypertension, renal insufficiency. [medicowesome.com]

  A diagnosis of cPAN should be considered in a child with fever, tender subcutaneous nodules, livido reticularis, and arthralgias/arthritis. [bjmp.org]

• Purpura

  PANpable: Palpable purpura is seen in PAN. That's all! -IkaN [medicowesome.com]

  The skin can demonstrate a range of lesions, including purpura, livedoid, subcutaneous nodules and necrotic ulcers[3]. Neurologically, mononeuritis multiplex is the most common presentation. [patient.info]

  Small-vessel vasculitis includes Wegener granulomatosis, Churg-Strauss syndrome, microscopic polyangiitis (microscopic polyarteritis), Henoch-Schönlein purpura, essential cryoglobulinemic purpura, and cutaneous leukocytoclastic angiitis. [emedicine.com]

  Feels like there is an outbreak of vasculitis recently at the SFVA with a few morning reports on palpable purpura and it’s characteristic finding on pathology: leukocytoclastic vasculitis (LCV)! [ucsfmed.wordpress.com]

• Palpable Purpura

  PANpable: Palpable purpura is seen in PAN. That's all! -IkaN [medicowesome.com]

  Feels like there is an outbreak of vasculitis recently at the SFVA with a few morning reports on palpable purpura and it’s characteristic finding on pathology: leukocytoclastic vasculitis (LCV)! [ucsfmed.wordpress.com]

  Microscopic polyangiitis commonly manifests with palpable purpura, alveolar hemorrhage, symptomatic cardiac involvement but is less likely to have hypertension, neuropathy, or hepatitis B. [rheumaknowledgy.com]

  Skin manifestations: erythema, painful subcutaneous nodules, petechiae, palpable purpura, livedo vascularis, ulcus, skin necrosis (if only the skin is affected, we speak of polyarteritis nodosa cutanea). [wikilectures.eu]

  Livedo vascular pattern typical of cutaneous polyarteritis nodosa Expected results of diagnostic studies In the case of palpable purpura the cutaneous biopsy will show leukocytoclastic vasculitis. [dermatologyadvisor.com]

• Skin Ulcer

  Other features include livedo reticularis, skin ulcers and tender indurated plaques. We report a 51-year old woman with a primarily livedo reticularis presentation of cutaneous polyarteritis nodosa without a nodular component. [ncbi.nlm.nih.gov]

  Cutaneous: Livedo reticularis, skin ulcers, tender erythematous nodules, bullous or vesicular eruptions, infarction and gangrene of fingers or toes, or a combination may occur. [merckmanuals.com]

  […] rupture which can result in organ ischemia and hemorrhage Presentation Symptoms/physical exam systemic symptoms fever weight loss malaise neurologic mononeuritis multiplex polyneuropathy stroke confusion musculoskeletal articular pain extremity pain skin [step2.medbullets.com]

  […] prognosis hepatitis B-associated disease has a worse prognosis Presentation Symptoms/physical exam systemic symptoms fever weight loss malaise neurologic mononeuritis multiplex polyneuropathy stroke confusion musculoskeletal articular pain extremity pain skin [medbullets.com]

• Cutaneous Manifestation

  The most frequent cutaneous manifestations were ulcers, livedo racemosa, subcutaneous nodules, atrophie blanche lesions and purpuras; with lower limb involvement in all cases, however other areas were also involved. [ncbi.nlm.nih.gov]

  A study of the cutaneous manifestations of Behcet's disease in patients from the United States. J Am Acad Dermatol 1999;41:540 4. Mangelsdorf HC, et al. [escholarship.org]

  […] i, in which the cutaneous manifestations are associated with slightly elevated AFRs; class ii, in which constitutional symptoms are also present, with fever and marked elevation of the AFRs; and class iii, in which the cutaneous form progresses to systemic [actasdermo.org]

  Comparison of cutaneous manifestations in systemic polyarteritis nodosa and microscopic polyangiitis. Br J Dermatol. 2008; 159: 615-620 Lindberg K. Ein Beitrag zur Kenntnis der Periarteritis nodosa. Acta Med Scand. 1931; 76: 183-225 Mimouni D. [jaad.org]

• Skin Rash

  A 22 year old female presented with vasculitic skin rash. She was incidentally found to be hypertensive and had proteinuria. Skin biopsy showed leuco-cytoclastic vasculitis. [ncbi.nlm.nih.gov]

  Table: Common symptoms in children and adults with PAN according to frequency Symptoms Adults Children Most Frequent Nerve involvement Skin –rashes, nodules, ulcers Skin –rashes, nodules, ulcers, muscle aches, weight loss Fever, joint pains, muscle aches [vasculitis.org.uk]

  The condition may also be suspected if a patient with nephritis or a heart condition has unexplained joint pain, muscle tenderness or weakness, nodes beneath the skin, purplish skin rashes, pain in the stomach, hands or feet or high blood pressure that [cedars-sinai.org]

  They can include skin rashes and ulcers, muscle and joint aches, fever, fatigue, weakness, abdominal pain, and loss of appetite. Nerve pain and numbness also can be associated with PAN. [kidshealth.org]

• Kidney Failure

  Serious complications can include strokes, seizures, and kidney failure. Keep in Mind While polyarteritis nodosa can be serious, many people with the condition do very well. [kidshealth.org]

  Two thirds of patients die of kidney failure and many succumb to bowel problems and additional complicating infection. [netdoctor.co.uk]

  Nervous system:Decreased alertness Peripheral neuropathy Muscle pain, numbness or tingling Tingling, numbness and pain in feet, legs, hands and arms Seizures Slurred speech Kidneys: Fluid retention Hypertension Kidney failure Skin: Hives Nodules Rashes [foundationforpn.org]

  The condition often causes failure of the heart, kidneys or other vital organisms or a ruptured aneurysm. [cedars-sinai.org]

• Hematuria

  We describe the case of a 51-year-old woman who presented with a 4-day-history of intense pain in her left flank, hypertension, fever, microscopic hematuria, and acute renal failure. [ncbi.nlm.nih.gov]

  Unexplained systemic illness with multiple system involvement (renal, neurologic, dermatologic) Laboratory Testing Nonspecific testing – helpful in excluding other diagnoses or identifying organ dysfunction CBC – rule out infection Urinalysis (UA) – hematuria [arupconsult.com]

  Leukocytosis up to 20,000 to 40,000/microL (20 to 40 × 109/L), proteinuria, and microscopic hematuria are the most common abnormalities. [merckmanuals.com]

  Glomerular ischemia may result in mild proteinuria or hematuria, but red cell casts are absent because glomerular inflammation is not a feature. [online.epocrates.com]

• Oliguria

  Renal: If small- and medium-sized arteries in the kidneys are affected, patients may have hypertension, oliguria, uremia, and a nonspecific urinary sediment with hematuria, proteinuria, and no cellular casts. Hypertension may worsen rapidly. [merckmanuals.com]

• Stroke

  This report shows that ischemic strokes may occur as a result of minocycline-induced vasculitis. [ncbi.nlm.nih.gov]

  Death mainly occurs due to cardiovascular complications (breakage of aneurysms or dissections, internal bleeding, infarcts, shock), gastrointestinal perforation, stroke. [eurorad.org]

• Peripheral Neuropathy

  There maybe nausea, vomiting and abdominal pain due to GI involvement (Untreated patients may die of bowel infarcts, perforations) Peripheral neuropathy, rash, purpura, CHF, CVA, etc are other manifestations of the disease. [medicowesome.com]

  The patient should also be monitored for: Headache Dementia Psychosis Encephalopathy Cerebrovascular events Peripheral neuropathy Prognosis Almost half will die within three months of diagnosis if untreated, usually secondary to chronic kidney disease [patient.info]

  neuropathy Tender subcutaneous nodules Gangrene of fingers and toes Kidney (most frequently affected): 85% Multiple intrarenal aneurysms Multiple aneurysms of renal vessels in Polyarteritis Aneurysms may thrombose and disappear Appear in new locations [learningradiology.com]

  Symptoms of peripheral nerve damage: pain paresthesia, paresis (peripheral neuropathy with manifestations of mononeuritis multiplex). Symptoms of kidney damage: hypertension, renal insufficiency, proteinuria, hematuria. [wikilectures.eu]

  The presentation of PAN may also include skin abnormalities (rash, ulcers) and peripheral neuropathy (pain, the sensations of burning, tingling, or numbness, or weakness in a hand or foot). [hopkinsvasculitis.org]

• Seizure

  CASE PRESENTATION: A 26-year-old South-Asian female presented with left sided focal seizures with secondary generalization and visual disturbance for 2 days duration. [ncbi.nlm.nih.gov]

  Serious complications can include strokes, seizures, and kidney failure. Keep in Mind While polyarteritis nodosa can be serious, many people with the condition do very well. [kidshealth.org]

  You may have problems with attention, memory, and processing information, along with seizures, problems with alertness, and other issues. These problems can happen 2 to 3 years after first getting PAN. [webmd.com]

  Damage to the nervous system may cause strokes or seizures. Current treatments with steroids and other drugs that suppress the immune system can improve symptoms and the chance of long-term survival. [autoimmune.org]

• Tingling

  Nervous system:Decreased alertness Peripheral neuropathy Muscle pain, numbness or tingling Tingling, numbness and pain in feet, legs, hands and arms Seizures Slurred speech Kidneys: Fluid retention Hypertension Kidney failure Skin: Hives Nodules Rashes [foundationforpn.org]

  Common problems include: General: Fever Weight loss Joint and muscle pain Skin: Rashes or small bumps under the skin Open sores Bruises Death of skin tissue Nervous system: Tingling, burning, pain, or numbness in the feet, hands, legs, arms, and face [winchesterhospital.org]

  The most common symptoms are: Blood in the urine Fever High blood pressure High levels of protein in the urine Numbness, tingling or weakness of the hands and feet Pain in the joints, especially the large ones Skin rash with raised reddish-purple patches [cedars-sinai.edu]

  This includes tingling, numbness and/or pain in the hands, arms, feet, and legs. [hopkinsvasculitis.org]

  Common problems include: General: Fever Weight loss Joint and muscle pain Skin: Rashes Open sores Small bumps under the skin Bruises Death of skin tissue Nervous system: Tingling, burning, pain, or numbness in your feet, hands, legs, arms, and face Decreased [cancercarewny.com]

• Headache

  Seven years later the left unruptured aneurysm enlarged, causing a sudden severe headache and a cavernous sinus syndrome. [ncbi.nlm.nih.gov]

  Presentation Diagnosis is not easy, as PAN often presents in a vague manner with symptoms including fever, weight loss, headache and myalgia. There is a spectrum of organ involvement ranging from a single organ to multisystem disease. [patient.info]

  Neurologic manifestations resolved with treatment including corticosteroids and cyclophosphamide; however, persistent fevers, rash, and headaches interfered with attempts at a corticosteroid taper. [pediatrics.aappublications.org]

  Rheumatology [2] in 1990 established ten criteria, three of which have to be fulfilled for the diagnosis of PAN: - unexplained weight loss > 4 kg - livedo reticularis, rash, Raynaud phenomenum - testicular or ovaric pain - myalgias and weakness, fever, headache [eurorad.org]

PAN is an uncommon disease with many clinical manifestations that make diagnosis difficult. Many diseases that affect the vascular integrity or result in vascular occlusion may present PAN-like symptoms. Certain drugs are also known to cause manifestations similar to that of vasculitis. Thus, it is important to distinguish the different causes for better treatment and prognosis.
Among the different imaging techniques for diagnosis, angiography is suggested when the affected tissue is inaccessible. This is preferred for aneurysms and stenosis in medium-sized blood vessels. It is also useful in case of gastrointestinal involvement, particularly when liver and kidney functions are affected. Microaneurysms in small arteries can be revealed using arteriograms. CT scan and MRI are other imaging methods that are used to check varied manifestations of PAN. These imaging techniques may be used in case of nonspecific presentations like thickening in the wall of intestine, obstruction in bowel movement, and thickening of mucosal folds. MRI is also suggested in CNS involvement where intracranial hemorrhage is suspected. Electromyography facilitates the detection of peripheral neuropathy, one of the most common complication associated with PAN.
When the affected tissue is accessible, biopsy is recommended. This includes skin, skeletal muscle and testes. Biopsy of muscles and arteries enables identification of inflammation. Histology of the affected tissue will show the presence of cellular infiltration within the wall of the vessel. In nerve cells, axonal degeneration is seen with loss of fibrous tissue. Laboratory studies are helpful in finding the systemic nature of PAN. Some of the common finding include elevated ESR, hepatitis B surface antigen, leukocytosis, proteinuria, elevated levels of liver enzymes and hypergammaglobulinemia. HBV-related PAN have increased levels of cryoglobulins.
Thus for a definitive diagnosis of the condition there should be one of the following findings: 1) histological proof of vasculitis, 2) positive serology of anti-neutrophil cytoplasmic antibodies (ANCA), 3) angiography or biopsy findings suggestive of vasculitis, and 4) elevated ESR [14].

• Pericardial Effusion

  effusion Pleural effusion Discoid atelectasis Nodules which may cavitate Patchy consolidation Liver: affected 66% of cases Treatment Corticosteroids 50% 5 year survival Bockus, Henry L. [learningradiology.com]

• Thrombocytosis

  Other general laboratory findings may include anemia and thrombocytosis. Testing for anti-neutrophil cytoplasmic antibodies (ANCAs) may be useful for ruling out the ANCA-associated vasculitides, particularly microscopic polyangiitis. [cancertherapyadvisor.com]

  Diagnostic Testing: Nonspecific inflammatory markers include elevated ESR or CRP, leukocytosis, anemia of chronic disease, and thrombocytosis. [rheumaknowledgy.com]

  Patients may have thrombocytosis, markedly elevated erythrocyte sedimentation rate, anemia caused by blood loss or renal failure, hypoalbuminemia, and elevated serum immunoglobulins. [merckmanuals.com]

  Laboratory Investigations Leukocytosis and thrombocytosis are frequent, along with elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels. Mild anemia may occur as well. [musculoskeletalkey.com]

• Leukocytes Increased

  Despite ongoing methotrexate treatment, the number of leukocytes increased after 18 months and was accompanied by worsening of the clinical picture ( Figure 2 ). [doi.org]

• Neutrophilia

  In 75% of PAN patients there is leukocytosis, mainly neutrophilia with no eosinophilia; microcytic anaemia, increased VES, circulating immunocomplexes [3]. [eurorad.org]

• Eosinophils Increased

  Eosinophils increased focally in some parts of the arteries. Among the infiltrating lymphocytes, CD8 were more predominant than CD4, and they had infiltrated all the arterial walls ( Fig. 4D ). [alliedacademies.org]

The main component of treatment for PAN is corticosteroids. If any of the major organs are involved or if the patient is steroid refractory, cyclophosphamide is also added to the treatment. The normal course suggested is high-dose of oral prednisone at 1mg/kg/day. Once the symptoms improve and ESR normalize, prednisone dose can be lowered gradually over a period of time. Those who are receiving steroid treatment for a long-term should be given calcium and vitamin D supplementation to overcome the risk of osteoporosis.
For those with HBV-related PAN, corticosteroids are recommended with antivirals and plasmapheresis. Antiviral medication is started after steroid withdrawal. Along with antivirals, plasma exchange is recommended 3 times a week for 3 weeks. This is gradually reduced and can be stopped once seroconversion occurs. The same treatment modality is being followed for PAN related to HCV infection. For cutaneous involvement in PAN, agents like NSAIDs, colchicine, and dapone are used. In severe cases of skin involvement, steroids and additional cyclophosphamide are recommended. Those with PAN induced by streptococcal infection, penicillin is recommended. These patients may need long-tern prophylaxis and this is particularly true of children. Further consultations depend on the organ affected.
Patients with PAN should be monitored carefully to look out for relapse or symptoms of a new organ being affected. Dosage of cyclophosphamide should be adjusted based on immunosuppression.

Prognosis of PAN is related to the amount of damage to the organs. The chances of mortality increases with factors including renal insufficiency, proteinuria, gastrointestinal complications, cardiomyopathy, and involvement of central nervous system [11]. A prospective study on 342 patients showed that when none of the factors are present, the mortality rate is 11.9% in five years. If left untreated, the survival rate in 5 years is 13%. But treatment with corticosteroids may improve the survival rate which might go up to 50-60%. In general, relapse of PAN is rare. Worst prognosis is seen in the case of central nervous system involvement [12]. Those who have abdominal syndromes tend to have poor prognosis. If there is no systemic involvement, the outcome is better. It is uncommon for patients to have permanent morbidity. Death occurs with untreated and serious vasculitis, as a result of complications that arise from immunosuppression, myocardial infarction and stroke.

The actual cause of PAN is still elusive. There are some cases in which infections, particularly viral, are involved in the development of this condition. There is a strong relationship between hepatitis B infection and development of PAN. It was one of the most common causes of this condition. Vasculitis may occur at any stage but is usually seen within 6 months of HBV infection, irrespective of its course [4]. PAN linked to hepatitis infection is induced by immune complex. As the use of hepatitis vaccines increased, the incidence of HBV-related PAN decreased considerably.
Although it is not a very important etiological factor, hepatitis C infection is also found to be related to PAN in some cases. Other viral infections including HIV, herpes zoster, and herpesvirus 68 are possibly involved in the development of this vasculitis. PAN is also known to be associated with some cancers, rheumatic diseases and blood diseases. There is an increased association of PAN with rheumatoid arthritis. Group A streptococcal infections are known to cause a flare-up of this disease, particularly in children. Many other infectious organisms cause PAN-like diseases which include the species of Klebsiella, Pseudomonas, and Yersinia [5]. Exposure to Isotretinoin is reported to be related to the occurrence of vasculitis [6]. PAN is also found to occur at an increased frequency with ulcerative colitis which is probably due to exposure to immune complexes or altered permeability of the gut. A study reports increased incidence of this vasculitis with familial Mediterranean fever [7].

Reports of incidence of this disease varies in different countries. It is relatively uncommon, with about 1.6 cases in a million in Sweden. In England the estimated incidence rate is 4.6 cases in one million, while in U.S it is 3-4.5 cases in comparable populations. Among adults, about 30.7 cases in a million are reported in Paris [8]. It occurs in all age groups, from children to adults. The incidence of PAN is more among 10 year old children, while among adults the most commonly affected age group is 40 to 65 years [9]. All ethnic groups are affected by this condition but is more prevalent in regions where hepatitis B infection is endemic. Studies report that PAN is found to be more prevalent among men when compared to women.

Vascular lesions characteristic of PAN are more commonly found in the bifurcation point and branching regions of arteries. Inflammation affects the entire wall with the laminae often destroyed and replaced with a fibrin-like, amorphous eosinophilic material. Inflammation of the vessel wall is characterized by necrosis of media with cellular infiltration, particularly by neutrophils, lymphocytes and eosinophils. Aneurysms and thrombi may occur at the site of lesion as walls are weak. Aneurysms may lead to hemorrhage. With the progression of lesions on vessels, intimal may proliferate into the lesion leading to ischemia or infarction [10]. Necrotizing vasculitis may co-exist with a healed lesion in different tissues. This co-existence may also be noted in different parts of the same tissue. Lesions are found in medium-sized arteries and are rare in large and small blood vessels.

A definitive method to prevent PAN is not known yet. Prompt treatment and close monitoring are the best ways to avoid complications and help remission.

Polyarteritis nodosa or PAN, is a rare form of vasculitis that affects small and medium-sized arteries. Inflammation of the blood vessels may affect skin and many other organs including kidney, gut and nerves [1]. This condition, first described by Kussumaul and Maier, may develop in any age group. It is found to occur in association with infections like hepatitis B and streptococcal infections [2]. If the condition affects internal organs significantly, it may be life threatening and immunosuppression may be needed. Cases where inflammation is restricted to skin are mild and need only minimal therapy. Based on the size of the blood vessel affected, PAN is subdivided into two groups: 1) Classical PAN, when it affects medium-sized blood vessels and 2) Microscopic polyangiitis, when inflammation affects the small-sized vessels [3]. PAN is a progressive disease and may be sub-acute, acute or chronic.

Polyarteritis nodosa or PAN is a rare form of autoimmune disease characterized by inflammation of small and medium-sized arteries. Inflammation of the blood vessels may affect different organs including intestine, heart, kidney and nerves, and may be life threatening in certain cases. It is found to occur in all age groups but it is more common among men than in women. The actual cause of PAN is not yet known. It may occur as a part of many viral and bacterial infections, malignancies and other diseases. It is more commonly seen in people with hepatitis B infection.
Since many organs are affected by the condition, a variety of symptoms may be presented in PAN. Some of the common nonspecific symptoms include fever, muscle pain, tiredness, and loss of appetite. Symptom depend on the organ affected. Skin sores, ulcers, and nodules are seen when skin is affected. When the condition affects gastrointestinal tract, abdominal pain and blood in stools are common symptoms. Shortness of breath and chest pain is common when inflammation affects heart. Inflammation of arteries in kidneys may cause high blood pressure. When nerves are affected, it may result in stroke, seizure, and loss of strength.
A variety of sources are used for definitive diagnosis of PAN. A complete medical history helps in checking for presence of symptoms of PAN. Physical examination helps to identify the organ affected by the disease, and also to rule out the possibility of other diseases that mimic symptoms of PAN. Blood tests are also used to identify the affected organ or site of inflammation. Imaging techniques like CT scan and MRI are useful in identifying the site of vasculitis. A definitive diagnosis can be done with angiogram and biopsy of affected tissue sample.
The cornerstone for the treatment of PAN is corticosteroids and medications that suppress immune system. This helps to improve the symptoms caused by inflammation of the blood vessel. Once the symptoms improve, dosage of corticosteroids can be reduced gradually and then stopped completely. The treatment duration and dose varies with the severity of the condition. PAN related to hepatitis and other infections are treated similarly but with an addition of antiviral medications. Outcome of this condition depends on the severity and the organ involved. But studies show that over 80% of the people survive the effects of PAN with early treatment. Prompt treatment and close monitoring help in remission.

1. Pettigrew HD, Teuber SS, Gershwin ME. Polyarteritis nodosa. Compr Ther. 2007; 33(3): 144-9.
2. Duffy J, Lidsky MD, Sharp JT, et al. Polyarthritis, polyarteritis and hepatitis B. Medicine. 1976; 55: 19-37.
3. Jennette JC, Falk RJ, Andrassy K, et al. Nomenclature of systemic vasculitides. Proposal of an international consensus. Arthritis Rheum. 1994; 37(2): 187-92.
4. Trepo C, Guillevin L. Polyarteritis nodosa and extrahepatic manifestations of HBV infection: the case against autoimmune intervention in pathogenesis. J Autoimmun. 2001; 16(3): 269-74.
5. Somer T, Finegold SM. Vasculitides associated with infections, immunization, and antimicrobial drugs. Clin Infect Dis. 1995; 20(4): 1010-36.
6. Chochrad D, Langhendries JP, Stolear JC, Godin J. Isotretinoin-induced vasculitis imitating polyarteritis nodosa, with perinuclear antineutrophil cytoplasmic antibody in titres correlated with clinical symptoms. Revue Du Rhumatisme. 1997; 64: 129-31. 
7. Ozen S, Saatci U, Balkanci F, Besbas N, Bakkaloglu A, Tacal T. Familial Mediterranean fever and polyarterits nodosa. Scandinavian J Rheu. 1992; 21: 312-13. 
8. Mahr A, Guillevin L, Poissonnet M, Aymé S. Prevalences of polyarteritis nodosa, microscopic polyangiitis, Wegener's granulomatosis, and Churg-Strauss syndrome in a French urban multiethnic population in 2000: a capture-recapture estimate. Arthritis Rheum. 2004; 51(1): 92-9.
9. Ozen S. Juvenile polyarteritis: is it a different disease? J Rheumatol. 2004 ;31(4): 831-2.
10. Colmegna I, Maldonado-Cocco JA. Polyarteritis nodosa revisited. Curr Rheumatol Rep. 2005; 7(4): 288-96. 
11. Guillevin L, Lhote F, Gayraud M, Cohen P, Jarrousse B, Lortholary O. Prognostic factors in polyarteritis nodosa and Churg-Strauss syndrome. A prospective study in 342 patients. Medicine (Baltimore). 1996; 75(1): 17-28.
12. Hughes LB, Bridges SL Jr. Polyarteritis nodosa and microscopic polyangiitis: etiologic and diagnostic considerations. Curr Rheumatol Rep. 2002; 4(1): 75-82.
13. Stone JH. Polyarteritis nodosa. JAMA. Oct 2 2002;288(13):1632-9.
14. Kallenberg CG. The last classification of vasculitis. Clin Rev Allergy Immunol. 2008; 35(1-2): 5-10.