Approach to vasculitis: Clinical sciences

Vasculitis refers to inflammation of blood vessels, which can result in vessel wall damage, bleeding, and ischemia of affected organs. Based on the size of the affected blood vessels, large-vessel vasculitis affects vessels like the aorta and its branches; medium-vessel vasculitis primarily affects major visceral arteries like renal and mesenteric arteries; small-vessel vasculitis mostly affects arterioles and capillaries; and variable-vessel vasculitis can affect vessels of any size.

Now, if your patient presents with a chief concern suggesting vasculitis, first perform an ABCDE assessment to determine if they are unstable or stable. If unstable, stabilize their airway, breathing, and circulation. Obtain IV access and put your patient on continuous vital sign monitoring including heart rate, blood pressure, and pulse oximetry; as well as cardiac telemetry. If needed, provide supplemental oxygen.

Now here’s a clinical pearl to keep in mind! Vasculitides that commonly present as unstable include ANCA-associated small-vessel vasculitis, which can cause diffuse alveolar hemorrhage; and anti-glomerular basement membrane or anti-GBM disease, which can cause damage to the glomerular basement membrane. Together, these conditions can result in pulmonary-renal syndrome, which can lead to respiratory and renal failure!

Now, let’s go back to the ABCDE assessment and discuss stable patients. In this case, obtain a focused history and physical examination; and order labs, including CBC, CMP, ESR, CRP, and urinalysis. Your patient will typically report constitutional symptoms, including fever, fatigue, anorexia, and weight loss; as well as epistaxis, limb claudication, and Raynaud phenomenon.

Ask about symptoms that could indicate involvement of specific organ systems. These patients may experience wheezing or hemoptysis; rash or skin discoloration; sensory disturbances like vision loss or limb weakness; or discolored urine or anuria. The physical exam may reveal an elevated temperature, as well as vascular findings like decreased, asymmetric pulses with vessel tenderness to palpation.

You may notice organ-specific findings like nasal crusting or abnormal lung sounds; palpable purpura or skin ulceration; sensory deficits, such as numbness; or motor deficits like foot drop.

As far as labs go, the CBC usually reveals leukocytosis with neutrophilic predominance, thrombocytosis, and low hemoglobin and hematocrit. The CMP might show elevated BUN and creatinine; the ESR and CRP are generally elevated, and the urinalysis may reveal hematuria or proteinuria.

With these findings, consider vasculitis, and order labs to confirm the diagnosis and determine the underlying cause. Start by ordering the antineutrophil cytoplasmic antibodies, or ANCA, subtypes MPO-ANCA and PR3-ANCA. Next, order antinuclear antibody or ANA and anti-glomerular basement membrane, or anti-GBM antibody, as well as serum cryoglobulins and rheumatoid factor, or RF. Also check the complement levels, serum immunoglobulins, and serologies for hepatitis B, hepatitis C, and HIV.

Now, let’s start with large-vessel vasculitis, which includes Takayasu arteritis and giant cell arteritis. Takayasu arteritis is more common in biological females under the age of 50. Patients usually report claudication, or pain in the limbs during movement. The physical exam will reveal unequal blood pressure between arms and diminished pulses in the extremities. Arterial bruits may also be present.

With these findings, consider Takayasu arteritis, and order MR angiography of the arterial tree. If CT or MR angiography reveals luminal narrowing or vascular wall thickening of large vessels such as the aorta or its primary branches, this confirms a diagnosis of Takayasu arteritis.

On the flip side, giant cell arteritis is more common in patients over 50 years of age, and is often associated with polymyalgia rheumatica. These individuals typically report unilateral headaches and jaw claudication while chewing. Some patients may also report vision loss. The physical exam often reveals an enlarged, tender, and nodular temporal artery.

At this point, consider giant cell arteritis. To confirm, obtain either a temporal artery biopsy or an ultrasound of the temporal artery with Doppler. If the biopsy reveals transmural inflammatory infiltration with giant cells, or the ultrasound shows a circumferential thickening of the vascular wall around the lumen, or the classic halo sign, diagnose giant cell arteritis.

Alright, switching gears to medium-vessel vasculitis, which includes polyarteritis nodosa and thromboangiitis obliterans. Individuals with polyarteritis nodosa typically report abdominal and extremity pain, and weakness. The physical exam reveals livedo reticularis, characterized by lacy, mottled skin discoloration often in combination with skin ulcers and nodules. Finally, you might notice concurrent sensorimotor deficits in various locations, such as sciatic and radial neuropathy, which is often referred to as mononeuritis multiplex.

Labs may reveal hematuria with no red blood cell casts, and in some cases, positive hepatitis B serology. With these findings, consider polyarteritis nodosa, and order a renal or mesenteric angiography. If it shows microaneurysms and focal vessel narrowing and occlusion, diagnose polyarteritis nodosa.

On the other hand, patients with thromboangiitis obliterans are almost exclusively younger than 50 years old, with heavy tobacco use. The physical exam typically reveals digital ulcers, and sometimes gangrene.

With these findings, consider thromboangiitis obliterans and obtain an ankle-brachial index or wrist-brachial index of the involved extremities. You may also need an angiogram of the extremities. If the ankle-brachial or wrist-brachial index is abnormal, or the angiography shows segmental arterial occlusions with collateral vessel formation which gives a classic ‘corkscrew’ appearance, diagnose thromboangiitis obliterans!