25,729 articles
Pornography addiction
Pornography addiction, also called porn or sex addiction, is a popular label for compulsive pornography use but is not a DSM-5 or ICD-11 diagnosis; research uses problematic pornography use (PPU), with moral incongruence and low-quality treatment evidence.
Porokeratosis of Mibelli
Porokeratosis of Mibelli (Mibelli disease), a chronic annular plaque skin disorder first described by Vittorio Mibelli in 1889, second most common porokeratosis variant, cornoid lamella hallmark, about 7-10% malignant transformation risk.
Porokeratosis plantaris palmaris et disseminata
Porokeratosis plantaris palmaris et disseminata (PPPD, OMIM 175850) is a rare hereditary porokeratosis beginning on palms and soles in adolescence and spreading to the trunk, with cornoid lamella histology and MVD gene involvement.
Porokeratotic eccrine ostial and dermal duct nevus
Porokeratotic eccrine ostial and dermal duct nevus (PEODDN, comedo nevus of the palm) is a rare benign eccrine hamartoma with linear keratotic papules on palms and soles, cornoid lamella histology, and somatic GJB2 mutations.
Porous silicon nanoparticles
Porous silicon nanoparticles (pSiNPs) are biodegradable silicon particles with tunable nanoscale pores, studied for targeted drug delivery, biosensing, and implant coatings; no clinical trials yet.
Porphyria due to ALA dehydratase deficiency
Porphyria due to ALA dehydratase deficiency (ALAD porphyria, Doss porphyria, plumboporphyria): ultra-rare autosomal recessive acute hepatic porphyria, fewer than a dozen cases, elevated urinary ALA with normal PBG, ALAD gene 9q32.
Porphysomes
Porphysomes are liposome-like nanovesicles, about 100 nm in diameter, self-assembled from porphyrin-conjugated phospholipids, first reported in 2011 and used as multimodal imaging and therapy agents.
Port-wine stain
Port-wine stain (nevus flammeus, capillary malformation) is a congenital pink-to-purple vascular birthmark present in 0.3–0.5% of infants, caused by somatic GNAQ R183Q mutations, often facial, sometimes linked to Sturge-Weber syndrome, treated with pulsed dye laser.
Portable X-Ray
Portable X-ray machines are movable radiography units that image patients at the bedside, in nursing homes, prisons, homes, and the field. Developed for World War I armies, they now use battery-powered digital detectors for ICU monitoring and tuberculosis screening.
Portal hypertension
Portal hypertension is elevated blood pressure in the portal venous system, the veins carrying blood from the digestive organs to the liver, most often a complication of cirrhosis.
Portal hypertensive gastropathy
Portal hypertensive gastropathy (PHG), congestive gastropathy, ICD-11 DA43.3: gastric mucosal changes of portal hypertension with a mosaic snakeskin endoscopic pattern in fundus and body; treated with beta-blockers, TIPS, or transplant.
Portal imaging
Portal imaging, also called electronic portal imaging, acquires images using the radiotherapy treatment beam itself, captured by an electronic portal imaging device to verify patient positioning and delivered dose.
Portal vein
Portal vein (hepatic portal vein): large vein formed by the splenic and superior mesenteric veins, carrying about 75% of liver blood flow; divides into right and left branches, with variants in 20–35% of people, and prone to portal vein thrombosis.
Portal vein embolization
Portal vein embolization is a percutaneous radiology procedure that blocks portal vein branches to the liver segments to be resected, causing the future liver remnant to grow before major hepatectomy.
Portal vein resection
Portal vein resection is the en-bloc removal of a portal vein or superior mesenteric vein segment during pancreatic surgery, followed by reconstruction to restore blood return.
Portal vein thrombosis
Portal vein thrombosis (PVT) is clot formation in the portal vein, affecting about 1% of the population and up to 25% of decompensated cirrhosis patients; classified as recent or chronic, treated with anticoagulation, DOACs, or TIPS.
Portography
Portography: radiographic imaging of the portal venous system after contrast injection; direct (splenic, transhepatic, transjugular) or indirect arterial techniques, historically central to portal hypertension, now mainly interventional.
Portopulmonary hypertension
Portopulmonary hypertension (PoPH, POPH) is Group 1 pulmonary arterial hypertension arising in portal hypertension, diagnosed by RHC (mPAP >20 mm Hg, PVR >2 WU, PAWP ≤15 mm Hg). Poorer survival than idiopathic PAH; treated to enable liver transplantation.
Portosinusoidal vascular disease
Portosinusoidal vascular disease (PSVD), used interchangeably with non-cirrhotic portal fibrosis, is a group of liver vascular conditions that damage intrahepatic portal venules and sinusoids, causing portal hypertension without cirrhosis; it was named in 2019.
Portosystemic shunt
A portosystemic shunt is a surgical or interventional connection between the portal and systemic venous circulations that lowers portal pressure, used mainly for variceal bleeding and ascites in portal hypertension.
Porustobart
Porustobart (HBM4003) is a fully human heavy chain-only anti-CTLA-4 antibody from Harbour BioMed, Fc-enhanced G1v7, in Phase II trials with PD-1 inhibitors; licensed ex-Greater China to Solstice Oncology in 2026.
Positive airway pressure
Positive airway pressure (PAP), including CPAP, APAP, and BiPAP, delivers pressurized air through a mask to keep the upper airway open during sleep; first reported by Sullivan in 1981, it is the mainstay treatment for obstructive sleep apnea.
Positive and Negative Syndrome Scale
The Positive and Negative Syndrome Scale (PANSS) is a 30-item clinician-rated interview measuring schizophrenia symptom severity, widely used as a gold standard and a primary endpoint in drug trials.
Positive end-expiratory pressure
Positive end-expiratory pressure (PEEP) is pressure above atmospheric held in a ventilated patient's airways after exhalation, keeping alveoli inflated and improving oxygenation in lung injury.
Positive occult blood in stool
Positive occult blood in stool: a fecal occult blood test (FOBT, gFOBT, or FIT) has found hidden blood, signaling digestive tract bleeding from hemorrhoids, polyps, ulcers, or colorectal cancer; colonoscopy follow-up is standard.
Positive psychotherapy
Positive psychotherapy is a strength-based therapy for depression that builds positive emotions, character strengths, and meaning, introduced by Martin Seligman, Tayyab Rashid, and Acacia Parks in 2006.
Positive sputum culture
Positive sputum culture: growth of pathogenic bacteria or fungi from coughed-up lung mucus (phlegm), used to diagnose pneumonia, tuberculosis, and bronchiectasis; interpretation limited by oropharyngeal contamination and prior antibiotics.
Positive throat culture
A positive throat culture is a laboratory result showing group A Streptococcus growing from a throat swab, confirming strep throat and usually leading to antibiotics.
Positron emission tomography
Positron emission tomography (PET) is a nuclear medicine imaging method using positron-emitting tracers such as F-18 FDG and annihilation coincidence detection, chiefly for cancer staging via PET/CT, with PET/MRI emerging.
Possession trance disorder
Possession trance disorder, ICD-11 code 6B63, is a dissociative disorder in which a possessing spirit or deity involuntarily replaces a person's identity, causing distress; diagnosis excludes cultural or religious practices.