Polyarteritis nodosa

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Ali Poyan Mehr, M.D. [2]; Associate Editor(s)-in-Chief: Sargun Singh Walia M.B.B.S.[3] Olufunmilola Olubukola M.D.[4] Cafer Zorkun, M.D., Ph.D. [5]; Haritha Machavarapu, M.B.B.S.

Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis that typically affects the medium (and occasionally, small-sized) muscular arteries. The Chapel Hill International Consensus Conference (CHCC) has differentiated PAN from microscopic polyangiitis which primarily affects small vessels ^[1]. The diagnosis of PAN is challenging due to of lack of a serological marker, and lack of specific histological characteristics. Polyarteritis nodosa unlike most other vasculidities is not Antineutrophil Cytoplasmic Antibodies (ANCA) positive ^[2]. PAN is a rare disease and often affects multiple organs but strikingly, PAN does not affect the lungs. The organs commonly affected by PAN include the kidneys, skin, joints, muscles, nerves, and gastrointestinal tract.

While it often has a multisystem presentation at diagnosis, variants like single-organ disease and cutaneous-only PAN do occur as well. PAN has been associated with hepatitis B and C virus infection.

Polyarteritis nodosa was first described macroscopically by the pathologist K. Rokitansky in 1842.He described the presence of aneurysms macroscopically and therefore missed the inflammatory nature of this disease.Polyarteritis nodosa was better described in 1866 by A. Kussmaul and R. Maier who provided a clinical description of a patient.Kussmaul and Maier introduced the term “periarteritis nodosa” to describe the nodules observed in intermediate-sized vascular arteries but this term was later changed to “Polyarteritis nodosa” when these nodules showed the involvement of all layers of the artery.

There is no established system for the classification of polyarteritis nodosa.

The exact pathogenesis of PAN is not fully understood.It is a disease of unknown cause that affects arteries, the blood vessels that carry oxygenated blood to organs and tissues.PAN affects the medium sized arterial vessels.PAN does not affect large arterial vessels, capillaries, small arterioles and venous system. It occurs when certain immune cells attack the affected arteries.Inflammation starts in the vessel intima and results in fibrinoid necrosis by destroying the internal and external elastic lamina.Aneurysms and thrombi may develop at the site of lesions.One hypothesis is that this condition is caused by antibodies against HBV, via atype IIII hypersensitivity reaction.Due to inflammation of the medium to small sized vessels in PAN and the presence of impaired endothelial function, there could be direct endothelial cell activation and damage resulting from proinflammatory cytokines or antibodies (anti-endothelial cells antibodies).Mutation in CECR1 can lead to vascular and inflammatory disorders which also include PAN.

The common causes of PAN are idiopathic, Hepatitis B infection, Hepatitis C infection, hairy cell leukemia and drug induced. Less common causes include varicella-zoster virus, parvovirus B-19, cytomegalovirus, human T-cell leukemia virus etc.

Polyarteritis nodosa must be differentiated from other diseases that cause may lead to medium vessel vasculitis. The diseases that can lead to medium vessel vasculitis are polyarteritis nodosa, kawasaki disease, infections, cardiovascular diseases and systemic diseases.

The incidence of polyarteritis nodosa is approximately 3 to 4 per 100,000 individuals worldwide.The prevalence among alaskan population suffering with hepatitis Binfection is approximately 7.7 per 100,000 individuals.Patients of all age groups may develop polyarteritis nodosa.There is no racial predilection to polyarteritis nodosa.Males are more commonly affected by polyarteritis nodosa than females.Population prevalence estimates for polyarteritis nodosa (PAN) range from 2 to 33 per million across the European Countries.

Common risk factors in the development of PAN include hepatitis B virus infection and age 40 to 60. Less common risk factors in the development of PAN include hairy cell leukemia, hepatitis C virus and male sex.

There is insufficient evidence to recommend routine screening for polyarteritis nodosa.

PAN if left untreated, the disease is fatal in most cases. The most serious associated conditions generally involve the kidneys and gastrointestinal tract. Common complications of PAN include Stroke,Kidney failure, heart attack,Intestinal necrosis and perforation. Prognosis is generally good if the treatment is started.Therapy results in remissions or cures in 90% of cases. Guillevin and coworkers have described five prognostic factors that predict high probability of mortality and are considered indications for another immunosuppressive drug in addition to prednisone.

Patients with polyarteritis nodosa may have an acute presentation.The prodrome of polyarteritis nodosa can range from anywhere between weeks to months. Polyarteritis nodosa is a multiorgan disorder but can also be seen in a single organ. Common symptoms include fatigue, weakness, fever,abdominal pain, decreased appetite etc

Physical examination plays an important role in diagnosing polyarteritis nodosa. Arteritis can be suspected with the presence of multiple mononeuropathies.Signs of ischemia such as extremity ischemia, hypertension and renovascular disease can help in diagnosing polyarteritis nodosa. Skin examination of patients with polyarteritis nodosa can show Livedo reticularis, ulceration, digital ischemia, and nodules. Polyarteritis nodosa may present with ophthalmologic symptoms like retinal vasculitis, retinal detachment and cotton-wool spots. Cardiovascular examination of patients with polyarteritis nodosa shows hypertension, tachycardia, pericardial friction rub, arrhythmias and congestive heart failure. Abdominal examination of patients with polyarteritis nodosa shows abdominal tenderness and gastro-intestinal bleeding. Neuromuscular examination of patients with polyarteritis nodosa shows sensory and/or motor neuropathies and mononeuritis multiplex.

There are no specific lab tests for diagnosing polyarteritis nodosa. Diagnosis is generally based upon the physical examination and a few laboratory studies that help to confirm the diagnosis. Laboratory findings helpful in the diagnosis of polyarteritis nodosa include CBC, ESR, C-reactive protein, p-ANCA, Hepatitis B surface antigen and hepatitic C serologies, elevated levels of liver enzymes, elevated creatinine level and hypergammaglobulinemia.

There are no ECG findings specific to polyarteritis nodosa but patients may present with arrhythmia.

There are no x-ray findings associated with polyarteritis nodosa.

CT scan may be helpful in the diagnosis of polyarteritis nodosa. Findings on CT scan of GI tract suggestive of polyarteritis nodosa include bowel wall thickening, mesenteric vascular engorgement, ascites, bowel obstruction and diffuse mucosal fold thickening.

MRI is useful to identify hemorrhage and ischemia in the central nervous system. New MRI techniques utilize perfusion weighted images and blood diffusion to distinguish intracranial hemorrhage and reversible ischemia. MRI can also be used to image the abdomen when there is GI involvement.

There are no echocardiography/ultrasound findings associated with PAN.

Arteriography is the best imaging study to diagnosis of PAN. Findings on an arteriography diagnostic of PAN include microaneurysm, saccular aneurysm and tortuous vessels showing irregular lumina, segmental luminal narrowing or dilatation, infarctions, vascular irregularity and segmental occlusions.

EMG and nerve conduction studies can be done in cases of nerve involvement and help in nerve biopsy. Tissue biopsy (reveals inflammation in small arteries, called arteritis).

Surgical intervention is not recommended for the management of polyarteritis nodosa.

Treatment involves medications to suppress the immune system such as prednisone and cyclophosphamide. Addition of immunosuppressants like cyclophosphamide, methotrexate, azathioprine to corticosteroid therapy has better prognosis. Patients with hepatitis B associated polyarteritis nodosa are treated with corticosteroid therapy, antiviral agents and plasma exchanges. Unlike hepatitis B associated PAN, Hepatitis C associated PAN is treated with Rituximab and corticosteoid therapy without antiviral agents, emphasizing the B cell targeted therapy. Mild cases of cutaneous polyarteritis nodosa are treated with nonsteroidal anti-inflammatory drugs. Severe cases are treated with corticosteroid and adjunctive therapy. Antibiotics are added to the treatment of patients with antecedent streptococcal infections or high ASO titer.Intravenous immunoglobulin is suggested for treatment of corticosteroid therapy resistant cases, but the effect is transient. It is also used in the treatment of Parvovirus B19 associated polyarteritis nodosa

There are no established measures for the primary prevention of polyarteritis nodosa.

There are no established measures for the secondary prevention of polyarteritis nodosa.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Ali Poyan Mehr, M.D. [2] Associate Editor(s)-in-Chief: Olufunmilola Olubukola M.D.[3] Cafer Zorkun, M.D., Ph.D. [4]; Haritha Machavarapu, M.B.B.S.

Polyarteritis nodosa was first described macroscopically by the pathologist K. Rokitansky in 1842.He described the presence of aneurysms macroscopically and therefore missed the inflammatory nature of this disease.Polyarteritis nodosa was better described in 1866 by A. Kussmaul and R. Maier who provided a clinical description of a patient.Kussmaul and Maier introduced the term “periarteritis nodosa” to describe the nodules observed in intermediate-sized vascular arteries but this term was later changed to “Polyarteritis nodosa” when these nodules showed the involvement of all layers of the artery.

• Polyarteritis nodosa was first described macroscopically by the pathologist K. Rokitansky in 1842.
  • He described the presence of aneurysms macroscopically and therefore missed the inflammatory nature of this disease ^[1].

• Polyarteritis nodosa was better described in 1866 by A. Kussmaul and R. Maier who provided a clinical description of a patient.
  • He included a post-mortem histological examination of blood vessels of the patient, arriving at a diagnosis of vasculitis.
• Kussmaul and Maier introduced the term “periarteritis nodosa” to describe the nodules observed in intermediate-sized vascular arteries but this term was later changed to “Polyarteritis nodosa” when these nodules showed the involvement of all layers of the artery ^[2].

• In 1931, Dr. Lindberg became the first person to recognize polyarteritis nodosa limited to skin ^[3].
• In 1970, Trepo and Thivolet reported the association of polyarteritis nodosa with hepatitis B virus (HBV) infection ^[4], later it became obvious that most polyarteritis nodosa cases were associated with HBV.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

There is no established system for the classification of polyarteritis nodosa.

• There is no established system for the classification of polyarteritis nodosa.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Ali Poyan Mehr, M.D. [2] Associate Editor(s)-in-Chief: Olufunmilola Olubukola M.D.[3]Cafer Zorkun, M.D., Ph.D. [4]Sargun Singh Walia M.B.B.S.[5]; Haritha Machavarapu, M.B.B.S.

The exact pathogenesis of PAN is not fully understood.It is a disease of unknown cause that affects arteries, the blood vessels that carry oxygenated blood to organs and tissues.PAN affects the medium sized arterial vessels.PAN does not affect large arterial vessels, capillaries, small arterioles and venous system. It occurs when certain immune cells attack the affected arteries.Inflammation starts in the vessel intima and results in fibrinoid necrosis by destroying the internal and external elastic lamina.Aneurysms and thrombi may develop at the site of lesions.One hypothesis is that this condition is caused by antibodies against HBV, via a type IIII hypersensitivity reaction.Due to inflammation of the medium to small sized vessels in PAN and the presence of impaired endothelial function, there could be direct endothelial cell activation and damage resulting from proinflammatory cytokines or antibodies (anti-endothelial cells antibodies).Mutation in CECR1 can lead to vascular and inflammatory disorders which also include PAN.

• Polyarteritis nodosa is a disease of unknown cause that affects arteries, the blood vessels that carry oxygenated blood to organs and tissues.
• PAN affects the medium sized arterial vessels.
  • Most commonly occurs at the branching vessels and bifurcation points.
• PAN does not affect:^[1]
  • Large vessels like aorta.
  • Capillaries
  • Small arterioles.
  • Venous system.
• It occurs when certain immune cells attack the affected arteries.
• Inflammation starts in the vessel intima and results in fibrinoid necrosis by destroying the internal and external elastic lamina.^[2]
• Aneurysms and thrombi may develop at the site of lesions.^[3]
  • The lesion can weaken the vessel and can further can lead to:
    • Obstruction
    • Ischemia and infarction
    • Rupture
    • Hemorrhage
• One hypothesis is that this condition is caused by antibodies against HBV, via a type IIII hypersensitivity reaction.
• Hepatitis C associated polyarteritis nodosa is the most common type among the hepatitis C associated vasculitis and has a severe clinical presentation.^[4]
• Clinical responses to immunosuppressive therapy suggest that immunological mechanisms play an active pathogenic role.
• Due to inflammation of the medium to small sized vessels in PAN and the presence of impaired endothelial function, there could be direct endothelial cell activation and damage resulting from proinflammatory cytokines or antibodies (anti-endothelial cells antibodies).
  • These anti-endothelial cells antibodies in turn stimulate greater production of cytokines and adhesion molecules potentiating the inflammation causing more damage to the vessels ^[5].

• The development of PAN is the result of multiple genetic mutations.
  • Mutation in CECR1 can lead to vascular and inflammatory disorders which also include PAN.^{[6] [7]}
    • CECR1 is also known as ADA2.
    • It is responsible for production of adenosine deaminase 2.

The following conditions are associated with the development of polyarteritis nodosa:

• Hepatitis B infection
• Hepatitis C infection

• Microscopic histopathological analysis of a biopsy sample from a patient of PAN reveals:
  • Focal necrotizing arteritis
    • Mixed cellular infiltrate are seen within the vessel wall.
  • Nerve biopsy
    • Axonal degeneration
    • Fiber loss
    • Wallerian degeneration
    • Perineural necrosis
    • Neoangiogenesis around epineurium or perineurium
  • Segmental demyelination^[8]

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Ali Poyan Mehr, M.D. [2] Associate Editor(s)-in-Chief: Sargun Singh Walia M.B.B.S.[3]

The common causes of PAN are idiopathic, Hepatitis B infection, Hepatitis C infection, hairy cell leukemia and drug induced. Less common causes include varicella-zoster virus, parvovirus B-19, cytomegalovirus, human T-cell leukemia virus etc.

PAN may be caused by:

• Idiopathic
• Hepatitis B infection^{[1] [2]}
• Hepatitis C infection.^[3]
• hairy cell leukemia.^[4]
• Drug induced
  • Sulfasalazine

PAN may be caused by:

• PAN may be caused secondary to infections such as:
  • Varicella-zoster virus
  • Parvovirus B-19
  • Cytomegalovirus
  • Human T-cell leukemia virus
  • Streptococcal species
  • Klebsiella species
  • Pseudomonas species
  • Yersinia species
  • Toxoplasma gondii
  • Rickettsiae
  • Trichinosis
  • Sarcosporidiosis
  • Tuberculosis^[5]
  • Human immunodeficiency virus^[6]
• PAN be be associated with certain syndromes like:
  • Rheumatoid arthritis^[7]
  • Sjögren syndrome
  • HLA-B39 spondyloarthritis^[8]
  • Common variable immunodeficiency^[9]
  • Psoriatic arthritis^[10]

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Eiman Ghaffarpasand, M.D. [2]

Polyarteritis nodosa must be differentiated from other diseases that cause may lead to medium vessel vasculitis. The diseases that can lead to medium vessel vasculitis are polyarteritis nodosa, kawasaki disease, infections, cardiovascular diseases and systemic diseases.

• The following table differentiates polyarteritis nodosa from other diseases that may lead to medium vessel vasculitis.

Abbreviations: ABG= Arterial blood gas, ANA= Antinuclear antibody, ANP= Atrial natriuretic peptide, ASO= Antistreptolysin O antibody, BNP= Brain natriuretic peptide, CBC= Complete blood count, COPD= Chronic obstructive pulmonary disease, CRP= C-reactive protein, CT= Computed tomography, CXR= Chest X-ray, DVT= Deep vein thrombosis, ESR= Erythrocyte sedimentation rate, HRCT= High Resolution CT, IgE= Immunoglobulin E, LDH= Lactate dehydrogenase, PCWP= Pulmonary capillary wedge pressure, PCR= Polymerase chain reaction, PFT= Pulmonary function test.

Diseases		Clinical manifestations								Para-clinical findings									Gold standard	Additional findings
		Symptoms					Physical examination
										Lab Findings				Imaging				Histopathology
		Headache	Fever	Weight loss	Arthralgia	Claudication	Bruit	HTN	Focal neurological disorder	Biomarker	CBC	ESR	Other	CT scan	Angiography	Ultrasound/ Echocardiography	Other
Polyarteritis nodosa[1]		+	+	+	+	+	+	+/-	+/-	LAMP-2 protein autoantibodies	Leukocytosis, Normochromic anemia, Thrombocytosis	↑	↑ Cr or BUN, ↑ ALT or AST, Proteinuria	Focal regions of infarction or hemorrhage	Multiple microaneurysms, Hemorrhage due to focal rupture, Occlusion	Aneurysms and renal arteriovenous fistula in color Doppler sonography	–	Necrotizing inflammatory lesions	Angiography	Sudden weight loss, Abdominal pain
Hepatitis B virus-associated polyarteritis nodosa[2]		+/-	+/-	+	+	+/-	+/-	+	–	HBsAg	Leukocytosis, Normochromic anemia, Thrombocytosis	↑	↑ ALT or AST	Focal regions of infarction or hemorrhage	Microaneurysms in mesenteric artery	Aneurysms and renal arteriovenous fistula in color Doppler sonography	–	Necrotizing inflammatory lesions	Angiography	Peripheral neuropathy, Livedo reticularis
Kawasaki disease[3]		–	+	+/-	+	+	–	+/-	–	NT-proBNP, Meprin A, Filamin C	Normochromic anemia, ↑WBC with a left shift, Thrombocytosis	↑	Acute-phase reactants, ↓Cholesterol, ↓HDL, ↓ApolipoA	Coronary artery calcifications	Coronary artery aneurysms, stenosis or occlusion	Coronary artery anomaly in echocardiography	Electron beam CT (EBCT)	Acute destruction of the media by neutrophils, with loss of elastic fibers	History and physical examination	Diarrhea, Vomiting
Infectious disease	Parvovirus B19 infection[4]	+	+	+	+	–	–	–	+/-	B19 DNA, ↓Reticulocyte count	Anemia	↑	anti–parvovirus B19 IgM	–	–	Hydrops in fetal ultrasonography	–	–	B19 DNA	Purpuric rash, Erythema multiforme
	Scarlet fever[5]	+	+	+/-	+	–	–	–	–	Antistreptolysin-O (ASO) titers	Leukocytosis	↑	↑CRP	Thickened pulmonary markings if pneumonia	–	–	–	Sparse neutrophilic perivascular infiltrate	History and physical examination	Sand-paper rashes, Sore throat
	Toxic shock syndrome[6]	+	+	+	+	–	–	–	+/-	Procalcitonin	Leukocytosis with left shift	↑	Myoglobinuria, Sterile pyuria	Acute respiratory distress syndrome	–	–	–	Necrolysis of keratinocytes in epidermis, Perivascular lymphocytic infiltrate	Clinical criteria	Peeling or rashes, Organ dysfunction
	Mononucleosis[7]	+	+	+	+	–	–	–	–	EBV DNA	Atypical lymphocyte	↑	Heterophile antibodies	CNS involvement	–	Splenomegaly	Encephalitis in MRI	Lymphoproliferative response in oropharynx, Lymphocytic infiltration in spleen	Heterophile antibody test	Splenomegaly, Palatal petechiae
	Leptospirosis[8]	+	+	+	+	+/-	–	–	–	IL-6, IL-8 and IL-10	Anemia	–	↑Cr or BUN, ↑ALT or AST, Proteinuria	Diffuse alveolar hemorrhage	–	–	–	Toxin-mediated break down of endothelial cell membranes of capillaries	Culture and the microscopic agglutination test	Red eyes, Skin rash
	Lyme Disease[9]	+/-	+	+/-	+	+/-	–	–	–	CXCL9 (MIG), CXCL10 (IP-10) and CCL19 (MIP3B)	Leukopenia, Thrombocytopenia	–	Microscopic hematuria, Proteinuria, ↑ALT or AST	Punctate lesions in periventricular white matter in brain SPECT	–	–	–	Acrodermatitis chronica atrophicans	Serologic tests	Erythema migrans
	Measles[10]	+/-	+	+/-	+	–	–	–	–	Measles IgM	Leukopenia, Lymphocytosis, Thrombocytopenia	–	↑ALT or AST	Pneumonia	–	–	CXR	Spongiosis and vesiculation in the epidermis with scattered dyskeratotic keratinocytes	PCR	Generalized rash, Cough, Coryza, or Conjunctivitis
	Rocky Mountain Spotted Fever[11]	+	+	+	+	–	–	–	–	R rickettsii serology	Thrombocytopenia, Anemia	–	↑ALT or AST, Hyponatremia	Infarction, edema, and meningeal enhancement	–	Myocardial or conduction abnormalities in echocardiography	–	Immunofluorescent or immunoperoxidase staining of R rickettsii	Clinical criteria and tick exposure	Rash on the palms and soles
	Staphylococcal Scalded Skin Syndrome[12]	+	+	+	+	–	–	+/-	+/-	Anti exfoliatin and anti alpha-toxin antibodies	Leukocytosis with left shift	↑	Blood culture	Pneumonia	–	–	–	Intraepidermal blister, dense superficial perivascular lymphohistiocytic infiltrate	Blood culture and clinical findings	Widespread skin erythema, fluid-filled blisters
	Toxic Epidermal Necrolysis[13]	–	+	+	–	–	–	–	+/-	MicroRNA-124	Normochromic normocytic anemia, Eosinophilia	↑	Fluid loss and electrolyte abnormalities	Tracheobronchial inflammation	–	–	–	Necrotic keratinocytes with full-thickness epithelial necrosis	Histopathology and clinical findings	Erythematous macular rash with purpuric centers
Cardiovascular disease	Atrial Myxoma[14]	–	–	+/-	–	–	–	–	+/-	Calretinin	Mild anemia, Leukocytosis	↑	↑IL-6	Atrial filling defect larger than a thrombus	–	Tumor location, size, attachment, and mobility in echocardiography	Size, shape, and surface characteristics in MRI	Lipidic cells embedded in a vascular myxoid stroma	Echocardiography	Dyspnea on exertion, Syncope
	Cholesterol Embolism[15]	+/-	+/-	–	–	+	–	–	+	IL-5	Eosinophilia, Leukocytosis	↑	Eosinophiluria	Thoracic and abdominal aortic sources of embolism	Atheroembolism in abdominal aorta and the lower extremity arteries	Excluding an intracardiac source of embolism with echocardiography	–	Birefringent crystals or biconvex needle-shaped ghostly clefts within the arterial lumen	Angiography	Livedo reticularis, Ischemic patches
	Segmental arterial mediolysis[16]	+	–	–	–	+	+	+	+/-	–	Leukocytosis	–	–	Visceral artery aneurysm in CT angiography	Alternating aneurysms and stenoses (beading)	Retroperitoneal hematoma	–	Disruption of the smooth muscle in the media	Angiography	Hematuria, Ischemic colitis
Systemic disease	Antiphospholipid Syndrome[17]	+	+	–	–	–	–	–	+/-	Antiphospholipid antibodies	Thrombocytopenia, Hemolytic anemia	–	Lupus anticoagulant (LA)	Stroke, Pulmonary embolism, Budd-Chiari syndrome	Thrombus in major vessels	Valve thickening, vegetations, or insufficiency in echocardiography	–	Noninflammatory bland thrombosis without perivascular inflammation	Hx of thrombosis and antiphospholipid antibodies	Miscarriage, Pulmonary hypertension
	Juvenile Idiopathic Arthritis[18]	–	–	–	+	+/-	–	–	–	Rheumatoid factor (RF), S100A12	Lymphocytosis, Thrombocytopenia	↑	Myeloid-related proteins 8/14 (MRP8/14)	Synovial hypertrophy, Joint effusions	Cerebral vasculitis	Inflamed synovium	Bone scanning	Vascular congestion, RBC extravasation, Venular lumen occlusion	Conventional radiography	Evanescent rash, Dactylitis

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Ali Poyan Mehr, M.D. [2] Associate Editor(s)-in-Chief: Sargun Singh Walia M.B.B.S.[3]

The incidence of polyarteritis nodosa is approximately 3 to 4 per 100,000 individuals worldwide.The prevalence among alaskan population suffering with hepatitis B infection is approximately 7.7 per 100,000 individuals.Patients of all age groups may develop polyarteritis nodosa.There is no racial predilection to polyarteritis nodosa.Males are more commonly affected by polyarteritis nodosa than females.Population prevalence estimates for polyarteritis nodosa (PAN) range from 2 to 33 per million across the European Countries.

• The incidence of polyarteritis nodosa is approximately 3 to 4 per 100,000 individuals worldwide.^[1]

• The prevalence among alaskan population suffering with hepatitis B infection is approximately 7.7 per 100,000 individuals.

• Patients of all age groups may develop polyarteritis nodosa.
• Polyarteritis nodosa is mostly diagnosed in patients aged 45-65 years. ^[2]

• There is no racial predilection to polyarteritis nodosa.

• Males are more commonly affected by polyarteritis nodosa than females. The male to female ratio is approximately 1.5 to 1.

• Population prevalence estimates for polyarteritis nodosa (PAN) range from 2 to 33 per million across the European Countries. ^[3]

• The annual incidence in three regions of Europe was estimated to be 4.4 to 9.7 per million ^[4].

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Sargun Singh Walia M.B.B.S.[2]

Common risk factors in the development of PAN include hepatitis B virus infection and age 40 to 60. Less common risk factors in the development of PAN include hairy cell leukemia, hepatitis C virus and male sex.

• Common risk factors in the development of PAN include:
  • Hepatitis B virus (HBV) infection^[1][2]
  • Age 40 to 60 years.

• Less common risk factors in the development of PAN include:
  • Hairy cell leukemia^[3]
  • Blood transfusion at a time before routine screening for hepatitis B virus (HBV).
  • Hepatitis C virus (HCV) infection^[4]
  • Male sex

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

There is insufficient evidence to recommend routine screening for polyarteritis nodosa.

There is insufficient evidence to recommend routine screening for polyarteritis nodosa.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Haritha Machavarapu, M.B.B.S.Sargun Singh Walia M.B.B.S.[3]

PAN if left untreated, the disease is fatal in most cases. The most serious associated conditions generally involve the kidneys and gastrointestinal tract. Common complications of PAN include Stroke,Kidney failure, heart attack,Intestinal necrosis and perforation. Prognosis is generally good if the treatment is started.Therapy results in remissions or cures in 90% of cases. Guillevin and coworkers have described five prognostic factors that predict high probability of mortality and are considered indications for another immunosuppressive drug in addition to prednisone.

• PAN if left untreated, the disease is fatal in most cases.
• The most serious associated conditions generally involve the kidneys and gastrointestinal tract.
• Without treatment, the outlook is poor.

• Common complications of PAN include:
  • Stroke
  • Kidney failure
  • Heart attack
  • Intestinal necrosis
  • perforation

• Prognosis is generally good if the treatment is started.
• Therapy results in remissions or cures in 90% of cases.
• Current treatments using steroids and other drugs that suppress the immune system (such as cyclophosphamide) can improve symptoms and the chance of long-term survival.^[1]
• Guillevin and coworkers have described five prognostic factors that predict high probability of mortality and are considered indications for another immunosuppressive drug in addition to prednisone.^[2]

1. Proteinuria >1g/day
2. Azotemia
3. Cardiomyopathy
4. Gastrointestinal involvement
5. Central nervous system disease With none of these factors, 5-year mortality is 12%. With 2 or more 5-year mortality is 46%^[3]

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