Makindo Medical Notes

Tardive Dyskinesia (TD) is a late-onset, drug-induced hyperkinetic movement disorder after chronic dopamine D₂ blockade. It classically presents with involuntary orofacial and limb/trunk movements that persist beyond 4–8 weeks and may be irreversible. Risk remains with atypicals (risperidone/olanzapine), especially at higher doses, older age, female sex, and longer exposure.

🔎 Definitions & Timing

• Latency: usually months–years after exposure; can appear after dose reduction or cessation (“withdrawal-emergent”).
• Persistence: symptoms last ≥1 month after stopping the drug (typical teaching ≥3 months).
• Core phenotype: choreo-athetoid movements (face, tongue, jaw) ± limbs/trunk; suppressible briefly; worsen with stress.

🧠 Pathophysiology (teaching pearl)

• D₂ supersensitivity: chronic blockade → up-regulation on striatal medium spiny neurons → hypersynchronous outputs.
• Maladaptive plasticity & oxidative stress: altered corticostriatal synaptic scaling; cumulative neurotoxic stress in basal ganglia.
• Genetic vulnerability (drug metabolism/receptor variants) likely explains inter-individual risk differences.

⚠️ Risk Factors

• Advanced age; female sex; mood disorders; diabetes; cumulative dose/duration; prior EPS; anticholinergic co-prescription; learning disability or brain injury.
• High-risk drugs: typical antipsychotics (haloperidol, fluphenazine) > risperidone/olanzapine > quetiapine/clozapine (lowest).
• Non-psychiatric culprit: metoclopramide (MHRA: restrict to short courses, usually ≤5 days).

🧩 Clinical Features

• Oro-bucco-lingual: grimacing, lip smacking, tongue protrusion/rolling, chewing; blepharospasm.
• Limbs/trunk: chorea/athetosis, piano-playing fingers, pelvic thrusting, rocking; respiratory dyskinesia (rare).
• Functional impact: speech/swallowing difficulty, social stigma, dental trauma, pain, falls.

🆚 Differentiate from Other Drug-Induced Movement Disorders

Syndrome	⏱ Timing	🤸 Phenotype	🔍 Key Clues	💊 Management
Tardive dyskinesia	📆 Months–years (± withdrawal-emergent)	Choreo-athetoid orofacial + limb movements	Persist >4–8 wks Exacerbated by stress	🔄 Optimise/↓ antipsychotic 🧪 VMAT2 inhibitor (valbenazine, deutetrabenazine) 🚫 Avoid anticholinergics
Akathisia	📅 Days–weeks	Inner restlessness Constant pacing, shifting	Subjective “can’t sit still” misery Movements non-choreiform	↘ Reduce dose 💊 Propranolol or mirtazapine 🧘 Clonazepam option
Acute dystonia	⏳ Hours–days	Sustained spasms (oculogyric crisis, torticollis, trismus)	Young ♂ more affected Linked to high-potency D₂ blockers	💉 IM/IV procyclidine or benztropine ⏱ Usually short-term cover