Glossary

Perforation: A hole in an organ, such as the gastrointestinal tract.
Perinuclear: Of or pertaining to a nucleus; situated around a nucleus. In some forms of vasculitis (e.g., microscopic polyangiitis), anti-neutrophil cytoplasmic antibodies (ANCA) cause perinuclear staining on immunofluorescence tests.
Petechiae: Small red spots under the skin.
Plasma: Fluid portion of blood.
Plasmapheresis: Filtration of blood plasma through a machine to remove proteins.
Pleura: Sac lining of the lung.
Pneumocystis pneumonia (PCP): A serious infection that causes inflammation and fluid buildup in the lungs.
Pneumonia: An acute or chronic disease marked by inflammation of the lungs and caused by viruses, bacteria, or other microorganisms. Forms of vasculitis that involve the lung are often misdiagnosed as pneumonia. Pneumonia is also a type of opportunistic infection that may occur in vasculitis patients under treatment.
Polymyalgia rheumatic: Autoimmune disease of the joints and muscles seen in older patients with high sedimentation rates who have severe aching in their shoulders, upper arms, hips, and upper legs.
Prevalence: The total number of cases of a disease present within a given population at a particular time.
Progressive multifocal leukoencephalopathy (PML): A rare and usually fatal viral disease characterized by progressive damage (-pathy) or inflammation of the white matter (leuko-) of the brain (-encephalo-) at multiple locations (multifocal).
Protein: Collection of amino acids. Antibodies are proteins.
Proteinuria: Excess protein levels in the urine.
Pulmonary hemorrhage: An acute bleeding from the lung, especially in the upper respiratory tract and the trachea.
Purpura: Hemorrhage into the skin.