Polymyalgia rheumatica (PMR) is a chronic inflammatory disorder predominantly affecting adults over the age of 50. Characterized by pain and stiffness in the shoulders, neck, and hips, PMR is an immune-mediated condition that typically arises suddenly and symmetrically. It is closely associated with giant cell arteritis (GCA), a form of vasculitis, with up to 20%
Polymorphous light eruption (PMLE) is a common photosensitivity disorder characterized by an abnormal skin reaction to ultraviolet (UV) radiation, typically following sun exposure. It most commonly affects young adult women and individuals living in temperate climates. Unlike sunburn, PMLE is an immunologic reaction that does not require intense sun exposure to be triggered. The term
Polycythemia vera (PV) is a rare, chronic myeloproliferative neoplasm (MPN) marked by the overproduction of red blood cells in the bone marrow. In many cases, white blood cells and platelets are also elevated. The excessive cell production thickens the blood, increasing the risk of blood clots, stroke, and heart attack. PV is considered a slow-growing
Polycystic ovarian syndrome (PCOS) is a complex endocrine disorder affecting women of reproductive age. It is characterized by hormonal imbalances, irregular ovulation, and the presence of multiple small cysts in the ovaries. PCOS is a leading cause of infertility and is frequently associated with insulin resistance, obesity, and androgen excess. Key Diagnostic Criteria The Rotterdam
Polyarticular juvenile idiopathic arthritis (JIA) is a chronic autoimmune condition affecting five or more joints during the first six months of disease onset in children under 16 years. This subtype of JIA resembles adult rheumatoid arthritis and is characterized by persistent joint inflammation, stiffness, and pain, potentially leading to joint damage if untreated. There are
Polyarteritis nodosa (PAN) is a rare, systemic necrotizing vasculitis that primarily affects medium-sized muscular arteries. It results in inflammation and damage to vessel walls, leading to aneurysm formation, thrombosis, ischemia, and organ dysfunction. Unlike other vasculitides, PAN does not involve arterioles, capillaries, or venules, and typically spares the lungs. Etiology and Pathogenesis of PAN Underlying
Poliomyelitis, commonly known as polio, is a highly infectious viral disease that primarily affects young children and can lead to irreversible paralysis or death. Caused by the poliovirus, the disease has been significantly curtailed through widespread immunization. Poliomyelitis vaccination remains the cornerstone of global polio eradication strategies endorsed by the World Health Organization (WHO). Understanding
Poisoning due to scorpion venom, also known as scorpion envenomation, represents a significant medical emergency in tropical and subtropical regions. Among the 1,500+ species of scorpions worldwide, approximately 30 are considered dangerous to humans. Venomous scorpion stings can cause systemic toxicity, particularly in children and immunocompromised individuals, necessitating rapid identification and intervention. Composition and Pathophysiology
Poisoning Due to Nerve Agent: Nerve agent poisoning refers to the toxic effects caused by a group of highly lethal chemical compounds designed to disrupt the nervous system. These substances, including sarin, VX, soman, and tabun, are classified as organophosphorus compounds and are often deployed as chemical warfare agents. Exposure, even in minuscule quantities, can
Staphylococcus aureus, a gram-positive coccus, is a common cause of both community-acquired and hospital-acquired pneumonia. It is known for its aggressive nature, frequent complications, and a high incidence of antimicrobial resistance. Particularly concerning are infections caused by methicillin-resistant Staphylococcus aureus (MRSA), which necessitate urgent, targeted therapy. Pneumonia due to S. aureus often affects vulnerable individuals