1,527 articles
Disturbances of smell or taste
Disturbances of smell or taste (ICD-11 MB41): anosmia, hyposmia, parosmia, phantosmia, dysgeusia, hypogeusia, ageusia. Mostly sinonasal, postinfectious, or posttraumatic; diagnosed by ENT psychophysical testing; olfactory training is the main treatment.
Divergence excess
Divergence excess, also called divergence excess exotropia, ICD-11 9C83.62, is an intermittent exotropia pattern with a distance deviation at least 10 prism diopters greater than near; true versus simulated forms are separated by the monocular occlusion patch test.
Divergence insufficiency
Divergence insufficiency, also called age-related distance esotropia, is an acquired comitant esotropia greater at distance than near causing distance diplopia, mainly in adults over 50, treated with prism or strabismus surgery.
Divergence nystagmus
Divergence nystagmus (分离性眼球震颤), ICD-11 9C84.51, is a rare disconjugate nystagmus with the eyes beating in opposite directions, caused by vergence imbalance and associated with midline cerebellar and dorsal pontine lesions.
Divergence paralysis
Divergence paralysis (divergence palsy, ICD-11 9C83.61) is a rare acquired ocular motility disorder: complete loss of divergence with distance esotropia, normal convergence, and horizontal diplopia at distance, linked to raised intracranial pressure and brainstem lesions.
Dizziness
Dizziness: impaired spatial orientation covering vertigo, light-headedness, and unsteadiness; 11% one-year U.S. prevalence, classified into acute, episodic, and chronic vestibular syndromes, evaluated with the HINTS bedside examination.
Dizziness or giddiness
Dizziness, or giddiness, is an imprecise symptom covering vertigo, disequilibrium, presyncope, and lightheadedness; modern diagnosis relies on timing, triggers, HINTS examination, and targeted testing rather than symptom description.
Donald Triplett
Donald Gray Triplett (1933-2023), Forest, Mississippi banker known as 'Case 1, Donald T.', the first person formally diagnosed with autism in Leo Kanner's 1943 paper; worked 65 years at a bank, traveled widely, died at 89.
DOORS syndrome
DOORS syndrome (DOOR syndrome, deafness-onychodystrophy-osteodystrophy-intellectual disability-seizures syndrome, OMIM 220500) is a rare autosomal recessive congenital disorder, often caused by TBC1D24 mutations, with sensorineural deafness, absent nails, short digits, intellectual disability, and infantile seizures.
Dopa-responsive dystonia due to sepiapterin reductase deficiency
Dopa-responsive dystonia due to sepiapterin reductase deficiency (SRD, DYT-SPR, SPR deficiency) is a very rare autosomal recessive neurometabolic disorder caused by SPR gene mutations, with dystonia, oculogyric crises, developmental delay, normal phenylalanine, and dramatic levodopa response; about 43 cases reported.
Downbeat nystagmus
Downbeat nystagmus (DBN), ICD-11 9C84.20, is the most common acquired central nystagmus: upward slow drift, downward quick phase, worsened by downgaze; caused by cerebellar or brainstem lesions, treated with aminopyridines.
Downward gaze deviation
Downward gaze deviation (ICD-11 9C83.12), also called downgaze palsy, is a conjugate downward eye deviation or supranuclear limitation of downward gaze; chronic isolated downgaze palsy with preserved vestibulo-ocular reflex points to progressive supranuclear palsy.
Dravet syndrome
Dravet syndrome, formerly severe myoclonic epilepsy of infancy (SMEI), is a rare genetic epileptic encephalopathy starting in infancy, usually from de novo SCN1A mutations causing Nav1.1 loss in inhibitory interneurons, with drug-resistant seizures, intellectual disability, and elevated SUDEP risk.
Drop attack
Drop attack: sudden fall from loss of postural tone without warning, usually without loss of consciousness, with rapid recovery; ICD-11 MB46.3. Causes include cardiovascular, vertebrobasilar, epileptic (atonic seizures), and Tumarkin otolithic crises in Ménière's disease.
Drug-induced chorea
Drug-induced chorea (ICD-10 G25.4; ICD-11 8A01.16) is involuntary, rapid, irregular choreiform movement caused by prescribed or illicit drugs, including levodopa, neuroleptics, antiepileptics, stimulants, and oral contraceptives; it usually resolves on stopping the drug, except tardive dyskinesia.
Drug-induced dystonia
Drug-induced dystonia is a movement disorder of involuntary muscle contractions causing twisting movements and abnormal postures, caused by drugs such as antipsychotics and antiemetics in acute or tardive forms.
Drug-induced myasthenia gravis
Drug-induced myasthenia gravis (ICD-11 8C60.0): MG caused de novo or worsened by drugs, via immune mechanisms (checkpoint inhibitors, penicillamine) or impaired neuromuscular transmission (macrolides, fluoroquinolones, aminoglycosides, magnesium).
Drug-induced parkinsonism
Drug-induced parkinsonism (DIP), or iatrogenic parkinsonism, is reversible parkinsonism caused by dopamine-blocking or dopamine-depleting drugs such as antipsychotics and metoclopramide; normal DaTSCAN imaging and recovery within 6-12 months of withdrawal distinguish it from Parkinson's disease.
Drug-induced polyneuropathy
Drug-induced polyneuropathy (DIPN) is a disorder of many peripheral nerves caused by medications, typically producing numbness, tingling, and burning pain, and often triggered by chemotherapy drugs.
Dry eye syndrome
Dry eye syndrome (keratoconjunctivitis sicca, dry eye disease): multifactorial loss of tear film homeostasis causing burning, blurry vision, and surface damage; affects about 8% of US adults, treated with artificial tears, anti-inflammatory drops, and devices.
Duane retraction syndrome
Duane retraction syndrome (Stilling-Turk-Duane syndrome) is a congenital, nonprogressive strabismus disorder with limited abduction or adduction, globe retraction, and fissure narrowing on adduction, caused by abducens nerve agenesis with aberrant oculomotor innervation of the lateral rectus.
Dysarthria
Dysarthria is a motor speech disorder from weak or poorly coordinated speech muscles, causing slurred speech. Types include flaccid, spastic, ataxic, hypokinetic, hyperkinetic, and mixed; common after stroke and Parkinson's disease.
Dysembryoplastic neuroepithelial tumor
Dysembryoplastic neuroepithelial tumor (DNET/DNT), a benign WHO grade I glioneuronal brain tumor first described in 1988, typically causing drug-resistant focal epilepsy in children and young adults, mostly in the temporal lobe.
Dysesthesia
Dysesthesia, an unpleasant abnormal sensation defined by the IASP, distinct from paresthesia; includes allodynia and hyperalgesia, occurs in neuropathic pain, skin and neurological disorders, with causes, diagnosis, and treatments.
Dysgeusia
Dysgeusia is a taste disorder in which taste is distorted, so a foul, salty, rancid, or metallic taste persists in the mouth; it is distinct from ageusia, the complete loss of taste.
Dysgraphia
Dysgraphia, also called disorder of written expression, is a neurological learning disorder causing writing difficulty despite adequate instruction. Estimated 5-20% prevalence; treated with remedial education, occupational therapy, and accommodations.
Dyskinetic cerebral palsy
Dyskinetic cerebral palsy (athetoid, dystonic CP; ICD-11 8D21): CP subtype with involuntary movements and dystonia from basal ganglia/thalamus injury; 6-15% of CP cases, second most common after spastic CP.
Dyslexia or alexia
Dyslexia or alexia (ICD-11 MB4B.0) is the acquired loss, usually in adulthood after stroke or brain injury, of previously fluent reading and comprehension, distinct from developmental dyslexia; syndromes include pure, surface, phonological, and deep dyslexia.
Dyssomnia
Dyssomnia: umbrella term for sleep disorders affecting the amount, quality, or timing of sleep, including insomnia, hypersomnia, narcolepsy, and sleep apnea; a DSM-IV-TR and ICSD category retired in DSM-5 and ICSD-2/3 in favor of sleep-wake disorders.
Dysthyroid orbitopathy
Dysthyroid orbitopathy, also called thyroid eye disease or Graves' orbitopathy, is an autoimmune orbital disorder driven by TSHR and IGF-1R antibodies, causing proptosis, diplopia, and sometimes dysthyroid optic neuropathy, treated by glucocorticoids, biologics, and surgery.