Nervous and sensory conditions

Palilalia

Palilalia is the involuntary repetition of one's own words or phrases, first described by Souques in 1908, with accelerating, fading repetitions; a complex phonic tic in Tourette syndrome and a sign of stroke, parkinsonism, and dementia.

Palsy of conjugate gaze

Palsy of conjugate gaze (ICD-11 9C83.0, ICD-10 H51.0): both eyes cannot move together in one direction, usually horizontal from pontine stroke, vertical from midbrain lesions, Parinaud syndrome, or PSP.

Papillary conjunctivitis

Papillary conjunctivitis: conjunctival inflammation with vascular papillae on the tarsal conjunctiva, mainly allergic, drug-induced, or mechanical; giant papillary conjunctivitis (GPC) is the contact lens form, first described by Spring in 1974.

Papillary glioneuronal tumor

Papillary glioneuronal tumor (PGNT), a rare WHO grade I mixed glial-neuronal brain tumor of young adults with SLC44A1::PRKCA fusion, pseudopapillary histology, and favorable prognosis after gross total resection.

Papillary tumor of the pineal region

Papillary tumor of the pineal region (PTPR), a rare WHO grade 2-3 neuroepithelial tumor near the pineal gland, first described 2003, arising from subcommissural organ ependymal cells, with high local recurrence and 73% 5-year survival.

Papilloedema

Papilloedema (papilledema) is optic disc swelling from raised intracranial pressure, most often idiopathic intracranial hypertension; almost always bilateral, an emergency requiring neuroimaging, and detectable on fundus photos by AI with ~95% sensitivity.

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.

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.

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.

Paraneoplastic sensory ganglionopathy

Paraneoplastic sensory ganglionopathy (paraneoplastic sensory neuronopathy, Denny-Brown syndrome): immune-mediated dorsal root ganglion neuron loss from cancer, usually anti-Hu antibodies with small-cell lung cancer, causing subacute asymmetric sensory loss, ataxia, and pain without weakness.

Paraneoplastic uveitis

Paraneoplastic uveitis is intraocular inflammation caused by an immune response to systemic malignancy rather than tumor invasion, often anti-CRMP-5-associated, mimicking VKH-like or sarcoid-like uveitis and frequently preceding cancer diagnosis.

Paraparetic variant of Guillain-Barré syndrome

The paraparetic variant of Guillain-Barré syndrome is a rare GBS form in which leg weakness and areflexia spare the arms, cranial nerves, and respiratory muscles.

Parasomnia

Parasomnia: abnormal behaviors or experiences during sleep, sleep onset, or waking, including sleepwalking, night terrors, sleep paralysis, and REM sleep behavior disorder; classified as NREM, REM, or other parasomnias.

Paraspinal arteriovenous malformation

Paraspinal arteriovenous malformation (paraspinal arteriovenous shunt, PAVS): a rare artery-vein shunt outside the spinal canal, classified by the Stuttgart scheme as isolated or genetically associated, usually treated by endovascular embolization.

Paraspinal neuroblastoma

Paraspinal neuroblastoma: neuroblastoma arising in sympathetic ganglia alongside the spine from neck to pelvis, prone to dumbbell intraspinal extension, cord compression, and emergent chemotherapy.

Paresis of accommodation

Paresis of accommodation (ICD-11 9D01.1) is partial loss of lens-focusing power from ciliary muscle or parasympathetic pathway disruption, caused by CN III palsy, drugs, diphtheria, diabetes, or midbrain lesions.

Paresthesia

Paresthesia is an abnormal spontaneous sensation such as tingling, pins and needles, or burning, occurring transiently or persistently anywhere along the somatosensory pathway; distinct from dysesthesia (unpleasant) and numbness (lost sensation), with causes ranging from harmless limb compression to neuropathy.

Parkinsonian-pyramidal syndrome

Parkinsonian-pyramidal syndrome (pallidopyramidal syndrome, PARK15) is a rare autosomal recessive genetic disorder combining parkinsonian and pyramidal signs, mainly from FBXO7 mutations.

Parkinsonism with polyneuropathy

Parkinsonism with polyneuropathy (PKNPY, OMIM 619279, ORPHA:611237) is a rare autosomal dominant neurodegenerative disorder with levodopa-responsive tremor-dominant parkinsonism from ages 40–70 and polyneuropathy from the early twenties, linked to UQCRC1 variants.

Parosmia

Parosmia (ICD-11 MB41.1) is a distorted perception of smell in the presence of an odor, common after COVID-19; distinguished from phantosmia; treated mainly with olfactory training.

Paroxysmal exertion-induced dyskinesia

Paroxysmal exertion-induced dyskinesia (PED, DYT18, GLUT1 deficiency syndrome 2) is a rare autosomal dominant dyskinesia triggered by prolonged exercise, often caused by SLC2A1 mutations and treated by trigger avoidance and ketogenic diet.

Paroxysmal extreme pain disorder

Paroxysmal extreme pain disorder, formerly familial rectal pain syndrome, is a rare inherited condition causing attacks of severe pain with skin flushing due to SCN9A mutations.

Paroxysmal hemicrania

Paroxysmal hemicrania, also called chronic paroxysmal hemicrania (CPH), is a rare trigeminal autonomic cephalalgia: unilateral 2–30 minute headache attacks over 5 times daily with ipsilateral autonomic signs, absolutely responsive to indomethacin.

Paroxysmal kinesigenic dyskinesia

Paroxysmal kinesigenic dyskinesia (PKD) is a rare movement disorder with brief attacks of chorea or dystonia triggered by sudden voluntary movement. Mainly caused by PRRT2 gene mutations; responds to carbamazepine.

Paroxysmal non-kinesigenic dyskinesia

Paroxysmal non-kinesigenic dyskinesia (PNKD), historically Mount-Reback syndrome, is a rare inherited neurological disorder causing dystonic attacks triggered by alcohol, caffeine, stress, or fatigue, lasting minutes to hours.

Partington syndrome

Partington syndrome (PRTS, Partington-Mulley syndrome), an X-linked recessive ARX-gene (Xp22.13) disorder with intellectual disability, dysarthria, and progressive focal hand dystonia (Partington sign), first described in 1988.

Paul Alexander (polio survivor)

Paul Richard Alexander (1946–2024), 'the man in the iron lung', was a Texas lawyer paralyzed by polio in 1952 at age 6 who used an iron lung for 73 years, a Guinness World Record, practiced law, and wrote a memoir.