Porokeratosis, disseminated superficial actinic 2: A type of inherited skin spot that develops on exposure to sun. The spots start as reddish-brown skin bumps which gradually enlarge and become lighter in the middle with a dark rim. The scaly lesions tend to affect mainly the lower arms and legs.
Porphyria cutanea tarda (PCT) is the most common subtype of porphyria. The disorder results from low levels of the enzyme responsible for the fifth step in heme production. Heme is a vital molecule for all of the body's organs. It is a component of hemoglobin, the molecule that carries oxygen in the blood. Hepatoerythropoietic porphyria has been described as a homozygous form of porphyria cutanea tarda, although it can also be caused if two different mutations occur at the same locus.
Porphyria, Ala-D: A very rare inherited disorder where involving a lack of the enzyme delta-aminolevulinic acid dehydratase.
In medicine, portal hypertension is hypertension (high blood pressure) in the portal vein and its tributaries. It is often defined as a portal pressure gradient (the difference in pressure between the portal vein and the hepatic veins) of 5 mm Hg or greater.
Portal hypertension may be due to a suprahepatic or infrahepatic block. Suprahepatic blocks result in Budd-Chiari syndrome. Their principal cause is myeloproliferative syndromes and invasion of the hepatic veins by a tumour. Their main manifestations are ascites and liver enlargement. Treatment consists of re-establishing the hepatofugal drainage. Infrahepatic blocks are due to obstruction of the portal vein, either by thrombosis facilitated by thrombogenic diseases, or by a tumour. Their main consequences are gastrointestinal hemorrhages. Treatment consists of preventing the rupture of oesophageal varices.
Portal thrombosis: Clotting or obstruction of blood flow along the veins from the intestines and spleen and into the liver. This causes blood to back up and results various problems such as enlarged spleen and abdominal pain . The obstruction can occur acutely (over a short space of time) or chronically (over a longer period of time).
Portal vein thrombosis is a form of venous thrombosis affecting the hepatic portal vein, which can lead to portal hypertension and reduction in the blood supply to the liver.
Portuguese type amyloidosis: An inherited form of systemic amyloidosis which involves deposits of a substance called amyloid throughout various parts of the body.
Positive rheumatoid factor polyarthritis: A form of rheumatoid arthritis which involves the presence of rheumatoid factor in the blood. More than one joint is involved.
Post-polio syndrome (PPS, or post-poliomyelitis syndrome) is a condition that affects approximately 50% of people who have previously contracted poliomyelitis—a viral infection of the nervous system—after recovery from the initial paralytic attack. Typically the symptoms appear 15-30 years after the original infection, at an age of 35 to 60. Symptoms include acute or increased muscular weakness, pain in the muscles, and fatigue. The precise mechanism that causes PPS is unknown. It shares many features with the post-viral chronic fatigue syndrome, but unlike that disorder it tends to be progressive, and as such can cause a tangible loss of muscle strength. Treatment is primarily limited to adequate rest, conservation of available energy, and supportive measures, such as leg braces and energy-saving devices such as powered wheelchairs, analgesia (pain relief) and sleep aids.
Post-infectious myocarditis: Heart muscle inflammation that occurs after an infection such as measles, influenza virus, enteroviruses and adenoviruses.
Post-infectious reactive arthropathy: Joint disease that occurs up to a month following an infection in some other part of the body.
Post-orgasmic illness syndrome (POIS) is a condition characterized by debilitating symptoms following orgasm that last for a few hours up to several days. It appears to be principally a male orgasmic disorder and is believed to affect between 0.25-1% of the population.
Post-Streptococcal Neurologic Disorders: A rare autoimmune disorder where the body develops an abnormal autoimmune response to streptococcal infection and causes neurological symptoms.
Post-transplant lymphoproliferative disorder (PTLD) is the name given to a group of B cell lymphomas occurring in immunosuppressed patients following organ transplant. It is an uncommon condition occurring in 0.2% of patients within one year of transplant, with an annual incidence of 0.04% thereafter. The risk of developing the disease is higher in children and recipients of heart transplants.
Post-traumatic epilepsy (PTE) is a form of epilepsy that results from brain damage caused by physical trauma to the brain (traumatic brain injury, abbreviated TBI). A person with PTE suffers repeated post-traumatic seizures (PTS, seizures that result from TBI) more than a week after the initial injury. PTE is estimated to constitute 5% of all cases of epilepsy and over 20% of cases of symptomatic epilepsy (in which seizures are caused by an identifiable organic brain condition). It is not known how to predict who will develop epilepsy after TBI and who will not. However, the likelihood that a person will develop PTE is influenced by the severity and type of injury; for example penetrating injuries and those that involve bleeding within the brain confer a higher risk. The onset of PTE can occur within a short time of the physical trauma that causes it, or months or years after. People with head trauma may remain at a higher risk for seizures than the general population even decades after the injury. PTE may be caused by several biochemical processes that occur in the brain after trauma, including overexcitation of brain cells and damage to brain tissues by free radicals. Diagnostic measures include electroencephalography and brain imaging techniques such as magnetic resonance imaging, but these are not totally reliable. Antiepileptic drugs do not prevent the development of PTE after head injury, but may be used to treat the condition if it does occur. When medication does not work to control the seizures, surgery may be needed. Modern surgical techniques for PTE have their roots in the 19th century, but trepanation (cutting a hole in the skull) may have been used for the condition in ancient cultures.
Hypothyroidism postaxial polydactyly mental retardation: A very rare syndrome characterized by abnormally low thyroid levels, extra digits, mental retardation and unusually facial appearance.
Posterior column ataxia with retinitis pigmentosa: A very rare syndrome characterized mainly by progressive ataxia and eye degeneration resulting in blindness by the third decade as well as muscle problems.
Posterior fossa subdural hematoma (PFSDH), also known as subdural hematomas of the posterior fossa is very rare and most cases are related to head injury. When it happenes in a serious and rare condition in newborns, generally occurring after difficult deliveries. The influence of anticoagulation in the cases of spontaneous development is well known. Although diagnosis is easily achieved by CT scan, atypical form may lead to the wrong diagnosis of cerebellar hematoma.
Posterior urethral valves(PUV), a congential condition that occurs only in boys, are excess flaps of tissue in the urethra, which is the tube that drains urine from the bladder to the outside of the body for elimination. See Urinary Tract Anatomy. This excess tissue can block or reverse the flow of urine and can affect all of the urinary tract organs including the urethra, bladder, ureters, and kidneys. The organs of the urinary tract become engorged with urine and swell, causing tissue and cell damage. The degree of urinary outflow obstruction will determine the severity of the urinary tract problems.
Postural orthostatic tachycardia syndrome (often referred to as just postural tachycardia syndrome or POTS) is a condition of dysautonomia, and more specifically, orthostatic intolerance, in which a change from the supine position to an upright position causes an abnormally large increase in heart rate, called tachycardia. This is often, but not always, accompanied by a fall in blood pressure. Several studies show a decrease in cerebral blood flow with systolic and diastolic CBF velocity decreased 44 and 60%, respectively Patients with POTS have problems maintaining homeostasis when changing position, i.e. moving from one chair to another or reaching above their heads. Many patients also experience symptoms when stationary or even while lying down. Symptoms present in various degrees of severity depending on the patient. POTS is a serious, though non-life threatening, medical condition that can be severely disabling and debilitating. Many patients are unable to attend school or work, and especially severe cases can completely incapacitate the patient.
Potassium aggravated myotonia: A rare genetic disorder characterized by the inability to relax muscles after movement. There is no associated weakness and the duration, frequency and severity of the episodes is variable.
Synonyms: rum nose, rhinophyma, rum-blossom, hammer nose, copper nose, toper's nose, potato nose, hypertrophic rosacea, brandy nose enlargement of the nose with dilation of follicles and redness and prominent vascularity of the skin; often associated with excessive consumption of alcohol
Potocki-Lupski Syndrome (PTLS) is a recently discovered condition linked to a microduplication of chromosome 17p11.2..All reported cases have occurred sporadically without bias in the parental origin of rearrangements. Most duplications are 3.7 Mb in size and only identifiable by array comparative genomic hybridization (CGH) analysis. Approximately 60% of PTLS patients harbor a microduplication of chromosome 17p11.2
Potocki-Shaffer syndrome: A very rare syndrome caused by the absence of a portion of chromosome 11p and characterized mainly by bone growths, enlarged fontanel and parietal foramina.
Type I is due to autosomal recessive polycystic kidney disease (ARPKD), which occurs at a frequency of approximately one in 16,000 infants. The kidneys of the fetus/neonate will be enlarged, have many small cysts filled with fluid and will fail to produce an adequate volume of fetal urine. The liver and pancreas of the fetus may also show fibrosis and/or a cystic change.
Type III is due to Autosomal dominant polycystic kidney disease (ADPKD) linked to mutations in the genes PKD1 and PKD2. While ADPKD is considered to be an adult-onset polycytic kidney disease, it can also present in the fetus and neonate in rare cases. Like ARPKD, ADPKD can also present with hepatic cysts and an enlarged spleen. An increased prevalence of vascular disease is also observed in these cases of ADPKD.