Vasculitis: Pathology review

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Questions

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A 52-year-old man comes to the clinic due to fatigue, joint pain, and recent appearance of skin lesions on his legs. His medical history is noncontributory except for a car accident as a child which required hospitalization and multiple blood transfusions. He has not seen a physician in more than 10 years. The patient does not use tobacco, alcohol or illicit drugs. He is monogamous with one sexual partner. Temperature is 37.0°C (98.6°F), pulse is 75/min, and blood pressure is 130/85 mmHg. Physical exam shows purpuric papules covering the lower extremities that do not blanch with pressure. The rest of the physical examination is unremarkable. Laboratory tests are obtained and shown below:  

 
 Laboratory value  Result 
 Hemoglobin   15 g/dL 
 Leukocyte count   7,000/mm3 
 Platelets    250,000/mm3 
 ALT  110 U/L 
 AST  75 U/L 
 Rheumatoid factor   Positive   
 Antinuclear antibodies  Negative  
 
 Urinalysis is unremarkable. Serum protein electrophoresis and immunofixation reveals polyclonal IgG and monoclonal IgM bands. Testing for cryoglobulins shows no precipitation after 24 hours. Which of the following tests is most likely to reveal this patient's underlying condition?  

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At the clinic, two very different people with very different symptoms showed up. Novakova is a 60 year old woman from Czech Republic who’s been having a headache by the right temple, progressive jaw pain during chewing, and shoulder and hip stiffness, particularly in the morning. Her ESR levels are elevated, and she is beginning to develop vision loss in the right eye. The other person is Hikaru, a cute 3-year-old Japanese boy brought by his mother. He has a red, swollen tongue, unilateral neck swelling, a desquamating rash, and a fever for the past 6 days. An ECG reveals elevation of the ST segment, and an echocardiogram shows evidence of a coronary artery aneurysm.

At first glance, you’d think Novakova and Hikaru symptoms have nothing in common. But the fact is, they both have different forms of vasculitis. The majority of vasculitides are caused by some form of immune-mediated damage. Some are type III hypersensitivities caused by immune complexes that deposit in vessels and cause damage. They could also be triggered by autoantibodies, like anti-neutrophil cytoplasmic antibodies, or ANCA. Lastly, they might be caused by cell-mediated immunity due to monocytes, macrophages or lymphocytes.

Whatever the cause, immune cells cause inflammation, which damages the endothelial wall, exposing the underlying collagen. This results in thrombosis and could lead to ischemia of the organs supplied by the affected vessels. Also, inflammation weakens the structural integrity of the blood vessel wall, leading to aneurysms. In addition, inflammation can spread to the supplied organ itself, causing tissue damage.

Since vasculitides are systemic inflammatory disorders, non-specific symptoms like fever, arthritis, myalgia, weight loss, and night sweats might be present. The symptoms specific to each disease depends on which blood vessels are affected, and we can classify vasculitides into large, medium, and small-vessel vasculitis.

For large vessel vasculitis, let’s start big, with temporal, or giant cell arteritis. Age is the greatest risk factor, and it typically affects people older than 50 years. It's also more common in females of Northern European descent. Giant cell arteritis affects the branches of the carotid artery like the temporal artery. For your exams, remember the person with this disorder often complains of having an unilateral headache located in the temporal area. They might also have fatigue or pain during chewing, or jaw claudication, which is caused by ischemia of the masseter muscle.

Summary

Vasculitis is a condition in which there is inflammation of the blood vessels, typically caused by immune-mediated damage to the endothelial cells. The inflammation can affect blood vessels of different sizes, ranging from small capillaries to larger arteries and veins. There are many different types of vasculitis, which can affect various parts of the body, including the skin, joints, and internal organs.

Common types of vasculitis include giant cell arteritis, takayasu arteritis, polyarteritis nodosa, kawasaki disease, wegener's granulomatosis, churg-Strauss syndrome, henoch-Schonlein purpura, etc. Symptoms vary depending on the type and location of the vasculitis, but may include fever, fatigue, weight loss, joint pain, skin rashes, and organ dysfunction. Treatment for vasculitis may involve medications to suppress the immune system and reduce inflammation, such as corticosteroids.

Sources

  1. "Pathophysiology of Heart Disease" Wolters Kluwer Health (2015)
  2. "Rapid Review Pathology" Elsevier (2018)
  3. "Fundamentals of Pathology" H.A. Sattar (2017)
  4. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  5. "Arthritis Rheum (2013) 2012 revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides.pdf" Jennette JC (2013)