Page 145 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 4-60 Rashes

Polyarteritis nodosa with characteristic multisystem involvement
POLYARTERITIS NODOSA Myalgia and/or
arthralgia often
associated with
Polyarteritis nodosa is a rare chronic form of vasculitis abdominal
of the medium to small vessels with significant cutane- problems,
ous and systemic manifestations. It is a rare condition, anorexia, fever,
with an estimated incidence of 5 per 1,000,000 persons. and weight loss.
The symptoms depend on the organ system involved Skin may show
and the extent of vasculitis. Uniquely and for unknown vasculitis
reasons, the respiratory system is spared. Polyarteritis or livedoid
nodosa has been found in some cases to be a chronic, appearance.
non–life-threatening disease that affects only the skin. Coarsely nodular, Hypertension Angiogram showing
More often, it is a multisystem disease, with the skin irregularly scarred common microaneurysm of
being affected along with other organ systems. Many kidney. Cut section small mesenteric
other organ system may be involved, and the skin fea- reveals organizing artery
tures may be the presenting sign of the disease. Exci- infarcts and throm-
sional skin biopsies of cutaneous lesions of polyarteritis bosed aneuysms
nodosa show the characteristic necrotizing vasculitis of in corticomedullary
medium vessels within the deep reticular dermis. The region.
cutaneous diagnosis of polyarteritis nodosa should alert
the clinician to the possibility of systemic disease, and
appropriate testing should be undertaken to evaluate
for widespread disease. Most cases of polyarteritis
nodosa are idiopathic, but this condition can be seen in
association with viral infections, malignancy, or autoim- CNS involvement may
mune disease. Coinfection with the hepatitis B virus is cause headache, ocular
the most classic and most frequent association with disorders, convulsions,
polyarteritis nodosa. aphasia, hemiplegia,
Clinical Findings: The primary cutaneous manifesta- and cerebellar signs.
tion of polyarteritis nodosa is palpable purpura. The Inflammatory cell infiltration and fibrinoid
cutaneous findings tend to be spread over wide areas of necrosis of walls of small arteries lead to
the body and are not found entirely in dependent infarction in various organs or tissues.
regions, as is the case with leukocytoclastic vasculitis.
Deeper, tender dermal nodules may form. These
nodules usually follow the course of an underlying Mononeuritis multiplex with polyarteritis nodosa
artery. The patient may develop livedo reticularis of the
extremities, and secondary ulcerations may form as the Pattern of diverse, asymmetric
vasculitis progresses and causes necrosis of the overlying nerve involvement (non-
skin. The diagnosis of the type of vasculitis is difficult simultaneous in onset)
to make from clinical examination alone. Tissue sam-
pling is needed to determine the type of vessel affected Unilateral ulnar nerve
by the inflammatory vasculitis. Polyarteritis nodosa has
also been shown to have nonspecific findings, such as
red macules and papules, that mimic drug eruptions or Unilateral radial nerve
viral infections. If the only organ system involved is the
integumentary system, the prognosis is good, and the
disease typically follows a chronic, treatable course.
Once the diagnosis of cutaneous polyarteritis nodosa
has been made, a systemic evaluation must be under- Unilateral femoral nerve
taken to pursue potential life-threatening involvement.
If other organ systems are involved, the patient will Unilateral tibial nerve
need to undergo systemic therapy, and a multidisci-
plinary approach is required. The sensory nerves are Bilateral peroneal nerves
almost always affected by mononeuritis multiplex. This
leads to a peripheral neuropathy, and it is cited as the
most common extracutaneous finding in polyarteritis (Lower limb more
nodosa. The kidneys, heart, and gastrointestinal tract Sudden occurrence of Sudden buckling of knee commonly affected)
are also routinely affected, and any of these can lead to foot drop while walking while going downstairs
life-threatening complications. Renal artery aneurysms (peroneal nerve) (femoral nerve)
can form along the branches of the renal artery and
can become thrombosed. This leads to wedge-shaped
infarcts in the kidney with varying amounts of kidney
function loss. Gastrointestinal arterial infarcts can Histology: Necrotizing vasculitis of medium and Treatment: The first-line therapy is with oral corti-
also cause bowel ischemia and symptoms of an acute small arteries in the deep reticular dermis is the hallmark costeroids. The use of steroid-sparing agents early in
abdomen. The central nervous system and the muscu- of polyarteritis nodosa. The inflammatory infiltrate is the course of the disease may help decrease steroid-
loskeletal system are also frequently affected. predominantly made up of neutrophils with an admix- induced side effects. Cyclophosphamide is the major
Pathogenesis: The pathomechanisms that incite ture of other leukocytes. Fibrinoid necrosis is promi- steroid-sparing agent used. Therapy for polyarteritis
polyarteritis nodosa are poorly understood. Hepatitis- nent, and intraluminal clotting is often seen. Depending nodosa induced by hepatitis B virus infection is targeted
induced polyarteritis is believed to be partially caused on the type of skin lesion biopsied, varying amounts of at the replicating viral particles.
by viral disruption of arterial endothelial cells as a result skin necrosis are seen. This is most commonly observed
of circulating antigen-antibody complexes. in areas of infarcted skin and ulceration.

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 131