1,527 articles
Thinking epilepsy
Thinking epilepsy is a rare form of reflex epilepsy in which seizures are induced by cognitive tasks such as arithmetic, Rubik's cube, chess, cards, decision-making, and abstract reasoning.
Thoracic outlet syndrome
Thoracic outlet syndrome (TOS): compression of the brachial plexus, subclavian artery, or vein between the clavicle and first rib; three types, neurogenic about 95% of cases; treated first with physical therapy.
Tic
Tic is a sudden, rapid, recurrent movement or sound that people may suppress. It defines childhood neurodevelopmental conditions including Tourette syndrome and provisional tic disorder.
Tic disorder
Tic disorder: DSM-5-TR neurodevelopmental conditions with motor and/or vocal tics, covering Tourette syndrome, persistent (chronic) motor or vocal tic disorder, and provisional tic disorder, diagnosed by tic type, duration, and onset before age 18.
Tietz syndrome
Tietz syndrome (TADS, Tietz albinism-deafness syndrome, OMIM 103500): rare autosomal dominant MITF basic-domain disorder with congenital profound bilateral sensorineural hearing loss and generalized albino-like hypopigmentation, allelic to Waardenburg syndrome type 2.
Tingling of skin
Tingling of skin (ICD-11 ME65.4) is a pricking type of paresthesia: pins-and-needles sensations without external stimulus. Brief post-pressure episodes are benign; persistent tingling signals nerve, metabolic, or vascular disease.
Titubation
Titubation is a rhythmic head or truncal tremor, classically a cerebellar sign seen during stance and gait; ICD-11 code MB46.4, distinguished from essential and dystonic head tremor.
Tolosa-Hunt syndrome
Tolosa-Hunt syndrome (THS), painful ophthalmoplegia syndrome, is a rare granulomatous inflammation of the cavernous sinus or orbital apex causing unilateral orbital pain and cranial nerve III, IV, or VI palsy, steroid-responsive, about one case per million yearly.
Torpedo Maculopathy
Torpedo maculopathy (TM), or solitary hypopigmented nevus of the RPE, is a rare congenital torpedo-shaped retinal pigment epithelium lesion temporal to the fovea, usually unilateral and asymptomatic, first described by Roseman and Gass in 1992.
Torsional nystagmus
Torsional (rotary) nystagmus: involuntary twisting eye movements about the line of sight, usually conjugate. Caused by vertical semicircular canal dysfunction; common causes are infarction and multiple sclerosis, with high specificity for central lesions.
Tourette syndrome
Tourette syndrome (Gilles de la Tourette syndrome, maladie des tics) is a neurodevelopmental disorder of multiple motor and vocal tics, onset ages 5-10, prevalence about 0.5%, treated with CBIT and medication, described by Gilles de la Tourette in 1885.
Transient refractive change
Transient refractive change is a temporary, reversible shift in the eye's refractive state, classified in ICD-11 as 9D00.6; it is best known in diabetes, where glucose swings shift refraction.
Transverse myelitis
Transverse myelitis (TM), also called acute or idiopathic transverse myelitis, is spinal cord inflammation damaging myelin, causing weakness, sensory loss, and bladder dysfunction below a band-like level; about 1,400 new US cases yearly, treated with IV steroids and plasma exchange.
Traumatic cataract
Traumatic cataract: lens opacity from blunt, penetrating, radiation, electrical, or chemical eye injury; occurs in 27-65% of ocular trauma; rosette morphology; managed by globe closure then cataract extraction with IOL.
Traumatic keratitis
Traumatic keratitis: corneal inflammation caused by mechanical, chemical, thermal, or UV injury rather than primary infection; classified under BETT, with secondary bacterial or fungal keratitis the main risk, especially after untreated abrasions in agricultural settings.
Traumatic macular hole
Traumatic macular hole (TMH), post-traumatic foveal retinal defect, full-thickness hole after blunt ocular trauma in young men; closes spontaneously in 10-67% within months, vitrectomy achieves 82-96% closure.
Traumatic optic neuropathy
Traumatic optic neuropathy (TON): optic nerve injury from direct or indirect craniofacial trauma causing vision loss. IONTS and Cochrane reviews show no proven benefit of steroids or decompression over observation.
Traumatic orbital haemorrhage
Traumatic orbital haemorrhage (ICD-11 NA06.3), also called traumatic retrobulbar hemorrhage, is bleeding into the orbit after facial trauma, especially orbital floor fractures, causing orbital compartment syndrome; treated emergently by lateral canthotomy and cantholysis.
Traumatic subarachnoid haemorrhage
Traumatic subarachnoid haemorrhage (TSAH, post-traumatic SAH): bleeding into the subarachnoid space from head trauma, not aneurysm rupture. Occurs in 33-60% of moderate/severe TBI; isolated TSAH in mild TBI rarely needs surgery.
Traumatic subdural haemorrhage
Traumatic subdural haemorrhage (subdural hematoma, SDH): blood between dura and arachnoid after head injury, from torn bridging veins. Acute form is a neurosurgical emergency; CT shows crescentic collection; BTF thresholds 10 mm thickness or 5 mm midline shift.
Tremor
Tremor, also called shaking, is an involuntary rhythmic oscillatory movement and the most common movement disorder. Classified as resting or action tremor; key types are essential tremor and parkinsonian tremor, treated with propranolol, levodopa, DBS, or focused ultrasound.
Trichomegaly-retina pigmentary degeneration-dwarfism syndrome
Trichomegaly-retina pigmentary degeneration-dwarfism syndrome, or Oliver-McFarlane syndrome (OMCS, OMIM 275400), is an extremely rare autosomal recessive PNPLA6 disorder with trichomegaly, chorioretinal atrophy, hypopituitarism, short stature, and intellectual disability.
Trigeminal neuralgia
Trigeminal neuralgia: sudden severe electric-shock-like unilateral facial pain from trigeminal nerve compression, usually by the superior cerebellar artery; treated first with carbamazepine, then microvascular decompression, radiosurgery, or rhizotomy.
Tritanopia
Tritanopia, or blue color blindness, is a rare autosomal dominant color vision deficiency caused by OPN1SW mutations that eliminate S-cone (blue) function, causing blue-green and yellow-violet confusions without reducing visual acuity.
Tropicamide
Tropicamide (Mydriacyl) is a short-acting anticholinergic mydriatic eye drop, FDA-approved in 1960, used for pupil dilation and cycloplegia; onset 15–30 minutes, duration 3–8 hours, also abused systemically.
Types of seizures
The types of seizures are classified by the ILAE as focal onset, generalized onset, or unknown onset, based on where the seizure begins in the brain.
Unilateral ocular duplication
Unilateral ocular duplication (triophthalmia, unilateral diplophthalmia) is a rare embryonic defect with a duplicated eye on one side, always with CNS and craniofacial anomalies, epilepsy, and intellectual disability.
Unilateral polymicrogyria
Unilateral polymicrogyria (unilateral PMG, ORPHA:268943) is a cerebral cortical malformation with excessive small folds and abnormal layering on one side of the brain; hemispheric or focal subtypes, perisylvian predominance, epilepsy, genetic or acquired causes.
Upbeat nystagmus
Upbeat nystagmus (UBN) is acquired vertical nystagmus with downward slow phases and upward quick phases in straight-ahead gaze, signaling central vestibular dysfunction from medullary, pontine, or cerebellar lesions, caused by stroke, MS, tumors, or Wernicke's encephalopathy, treated with 4-aminopyridine.
Upward gaze deviation
Upward gaze deviation (ICD-11 9C83.11) is a conjugate upward deviation of both eyes, seen as paroxysmal tonic upgaze of childhood, oculogyric crisis, or posthypoxic sustained upgaze in coma.