Human health and medicine

Para ovarian cyst

Para ovarian cyst (paraovarian, paratubal cyst; ICD-11 GA18.4): benign fluid-filled sac in the broad ligament beside the ovary, 5–20% of adnexal masses, usually asymptomatic, treated expectantly or by laparoscopic cystectomy.

Para-central scotoma

Para-central scotoma (ICD-11 9D42.5), also called paracentral scotoma, is a blind spot within about 10 degrees of visual fixation, sparing fixation itself; caused mainly by glaucoma, diabetic retinopathy, retinal tears, and PAMM.

para-Toluenesulfonamide injection (PTS)

Para-toluenesulfonamide injection (甲苯磺酰胺注射液, PTS, brand 普罗仙安/PTS-302) is a chemical class 1 intratumoral chemical ablation drug approved in China on 15 November 2022 for severe airway obstruction in central NSCLC, given by bronchoscopic tumor injection.

Paracentesis

Paracentesis is needle or cannula drainage of ascitic fluid from the peritoneal cavity, done diagnostically (SBP, SAAG) or therapeutically; ultrasound guidance cuts bleeding complications, and >5 L removal requires albumin infusion.

Paracervical block

A paracervical block is a regional anesthesia technique in which local anesthetic injected beside the cervix numbs the cervix and lower uterus, used for IUD insertion, hysteroscopy, and brachytherapy.

Paracetamol

Paracetamol (acetaminophen, APAP, Tylenol) is a first-line analgesic and antipyretic synthesized in 1878, marketed from 1955, metabolized mainly via glucuronidation, and a leading cause of acute liver failure in overdose.

Paracetamol poisoning

Paracetamol (acetaminophen) poisoning: liver injury from overdose via NAPQI-mediated glutathione depletion. Managed with the Rumack-Matthew nomogram, activated charcoal, and N-acetylcysteine, the antidote most effective within 8 hours.

Parachute tricuspid valve

Parachute tricuspid valve (PTV), a rare congenital heart defect where all tricuspid chordae attach to a single papillary muscle, causing stenosis or regurgitation, usually with other defects; about 14 cases reported 1979-2019.

Paracoccidioidomycosis

Paracoccidioidomycosis (PCM), South America's systemic endemic mycosis from Paracoccidioides fungi, acquired by inhaling soil spores in rural Latin America; chronic lung and mucosal disease, itraconazole treatment, underreported despite 15,000+ cases.

Paradadi Lepa

Paradadi Lepa (Pāradādi Lepa) is a classical Ayurvedic mercury-and-sulfur topical paste from Yogaratnakara's Upadamsha Chikitsa, used externally for syphilitic lesions (upadamsha) and skin diseases such as dadru and mandala kushta.

Oct 20, 2026

PARADIGM study

PARADIGM (Progression of AtheRosclerotic PlAque DetermIned by Computed TomoGraphic Angiography Imaging) is a multinational serial CCTA registry of 2,252 patients quantifying coronary plaque progression, diabetes and statin effects, and MACE prediction.

PARADIGM-HF trial

PARADIGM-HF was a randomized trial of 8,442 patients comparing sacubitril/valsartan with enalapril in chronic heart failure with reduced ejection fraction, stopped early in 2014 for a 20% reduction in cardiovascular death.

Paradoxical embolism

Paradoxical embolism, also called paradoxical embolization, is venous thrombus crossing a right-to-left shunt, usually a patent foramen ovale, into the arteries, causing stroke or limb ischemia; first described by Cohnheim in 1877.

Paradoxical intention

Paradoxical intention (PI), a logotherapy technique developed by Viktor Frankl, treats anticipatory anxiety by having patients intend what they fear; adapted by Ascher and Efran for insomnia, patients try to stay awake, reducing sleep performance anxiety.

Paradoxical reaction

Paradoxical reaction: an adverse drug effect opposite to the drug's expected pharmacological action, classically agitation or aggression from sedative benzodiazepines like midazolam, occurring in under 1% of patients and reversible with flumazenil.

Paraduodenal pancreatitis

Paraduodenal pancreatitis, also called groove pancreatitis, is a rare focal chronic pancreatitis of the pancreaticoduodenal groove, affecting middle-aged men with alcohol and smoking histories and mimicking pancreatic cancer on imaging.

Paraesophageal hernia repair

Paraesophageal hernia repair is a surgical operation that returns the stomach and other herniated organs from the chest into the abdomen and closes the diaphragmatic hiatus, usually done laparoscopically.

Paraffin embedding

Paraffin embedding is a histology technique in which fixed tissue is infiltrated with molten paraffin wax, forming FFPE blocks cut into thin sections for microscopy.

Paraganglioma

Paraganglioma: rare neuroendocrine tumor of paraganglia outside the adrenal glands (extra-adrenal pheochromocytoma); sympathetic or parasympathetic forms, ~40% hereditary via SDHx, 35-50% may metastasize, Zellballen histology.

PARAGON-HF trial

PARAGON-HF (NCT01920711): phase 3 Novartis trial of sacubitril-valsartan vs valsartan in 4,822 HFpEF patients (LVEF ≥45%); primary endpoint missed (RR 0.87, P=0.06), benefit suggested at lower LVEF and in women.

Paragonimiasis

Paragonimiasis, or lung fluke disease, is a foodborne Paragonimus trematode infection of the lungs from raw or undercooked crabs and crayfish; it mimics tuberculosis, infects an estimated 20.7 million people, and is treated with praziquantel or triclabendazole.

Parallel group trial

A parallel group trial, also called a parallel design, is a clinical trial design in which participants are randomized to separate arms, each receiving only one treatment.

Parallel imaging (MRI)

Parallel imaging is an MRI acceleration technique that uses receiver coils with different spatial sensitivities to reduce scan time, with SENSE and GRAPPA the main reconstruction methods.

Paralysis

Paralysis: loss of voluntary muscle movement from disrupted nerve signals, also called palsy when tremors occur. Causes include stroke, spinal cord injury, Bell's palsy, and multiple sclerosis; types range from monoplegia to quadriplegia.

Paralytic gait

Paralytic gait (麻痺性歩行), ICD-11 MB44.1 and ICD-10-CM R26.1, is a symptom code for walking disturbed by weakness, paralysis, or spasticity, typically from upper motor neuron lesions such as stroke, cerebral palsy, or myelopathy.

Paralytic illness of Franklin D. Roosevelt

Paralytic illness of Franklin D. Roosevelt: 1921 paralysis at Campobello diagnosed as polio, leading to Warm Springs, the National Foundation for Infantile Paralysis, the March of Dimes, and a lasting polio-versus-GBS diagnostic debate.

Oct 20, 2026

Paralytic lagophthalmos

Paralytic lagophthalmos is incomplete eyelid closure from facial nerve (CN VII) paralysis, mainly Bell's palsy, also leprosy, trauma, or tumors; it risks exposure keratopathy and is treated with lubricants, tarsorrhaphy, or eyelid weight implants.

Paramedian nasal cleft

Paramedian nasal cleft (Tessier number 1 cleft, alar cleft, isolated coloboma of the nose) is a rare congenital nasal coloboma beside the midline, ranging from a small notch with septal deviation to alar clefts, isolated or with cleft lip and hypertelorism.

Paramedic

Paramedic: highest US EMS licensure level (with EMR, EMT, AEMT), providing advanced out-of-hospital care; about 102,200 US jobs, $60,600 median wage, roots in 1960s Pittsburgh Freedom House.