What is the appropriate workup for catatonia?

Workup for Catatonia

The appropriate workup for catatonia begins with clinical diagnosis using a validated rating scale (Bush-Francis Catatonia Rating Scale), followed by a systematic investigation to identify the underlying etiology through targeted history, physical examination, laboratory studies, neuroimaging, and EEG. 1, 2

Clinical Assessment and Diagnosis

Rating Scale Assessment

Use the Bush-Francis Catatonia Rating Scale (BFCRS) to establish the diagnosis and measure severity 3, 4, 5. This validated tool should be applied at initial presentation and serially to monitor treatment response.

Key Historical Elements

Obtain specific information about:

• Medication exposure: Recent antipsychotic use or dopaminergic drug withdrawal (to differentiate from neuroleptic malignant syndrome) 6
• Psychiatric history: Depression, mania, schizophrenia, schizoaffective disorder, autism spectrum disorder 6, 2
• Recent infections or fever: Particularly relevant for autoimmune encephalitis 1, 5
• Substance use: Including withdrawal states 1
• Timeline of symptom onset: Acute versus subacute presentation 7

Physical Examination Findings

Document specific catatonic signs:

• Motor abnormalities: Stupor, catalepsy, waxy flexibility, posturing, mutism 4, 8
• Echophenomena: Echolalia, echopraxia 4
• Autonomic instability: Fever, tachycardia, blood pressure fluctuations, diaphoresis (suggests malignant catatonia) 9, 4
• Rigidity pattern: "Lead pipe" rigidity suggests neuroleptic malignant syndrome rather than catatonia 9

Laboratory Investigations

Essential Laboratory Studies

Order the following baseline tests 1, 2, 5:

• Complete blood count with differential
• Comprehensive metabolic panel (electrolytes, renal function, liver function)
• Creatine kinase (markedly elevated in neuroleptic malignant syndrome; may be mildly elevated in catatonia)
• Thyroid function tests (TSH, free T4)
• Urinalysis
• Toxicology screen

Expanded Workup Based on Clinical Context

Consider additional testing when indicated 1, 2, 5:

• Autoimmune encephalitis panel: Serum and CSF neuronal autoantibodies (particularly NMDAR antibodies) if acute onset, fever, or seizures present
• Lumbar puncture: If infection or autoimmune encephalitis suspected
• Inflammatory markers: ESR, CRP if systemic lupus erythematosus or other inflammatory conditions considered
• Ceruloplasmin and copper studies: In younger patients to exclude Wilson's disease
• HIV testing: In appropriate clinical contexts

Neuroimaging

CT head without contrast is the initial neuroimaging study of choice for rapid exclusion of structural lesions 10. However, MRI brain with and without contrast is more sensitive and should be obtained when feasible, particularly to evaluate for:

• Autoimmune encephalitis
• Posterior reversible encephalopathy syndrome
• Structural lesions
• Inflammatory conditions 1, 2

The yield of neuroimaging in catatonia varies, but it is essential to exclude treatable medical causes 10, 11.

Electroencephalography (EEG)

EEG should be performed to evaluate for:

• Non-convulsive status epilepticus
• Encephalopathy patterns
• Focal abnormalities suggesting structural lesions 1, 2

EEG is particularly important when there is diagnostic uncertainty or concern for seizure activity 5.

Critical Differential Diagnoses to Exclude

The workup must systematically rule out conditions that mimic catatonia 12, 9, 3:

Neuroleptic Malignant Syndrome (NMS)

• History of antipsychotic exposure within 3 days
• "Lead pipe" rigidity (versus waxy flexibility in catatonia)
• Markedly elevated creatine kinase (typically >1000 U/L)
• Leukocytosis (15,000-30,000 cells/mm³)
• Onset over days rather than hours 9

Serotonin Syndrome

• History of proserotonergic medication exposure
• Hyperreflexia and clonus (especially in lower extremities)
• Mydriasis and hyperactive bowel sounds
• Onset within hours of medication change 9

Autoimmune Encephalitis

• Acute onset with fever
• Seizures or abnormal movements
• Positive neuronal autoantibodies in serum or CSF
• MRI may show characteristic patterns 1, 5

Algorithmic Approach

Step 1: Apply BFCRS—if ≥3 signs present, catatonia is diagnosed

Step 2: Obtain immediate laboratory studies (CBC, CMP, CK, TSH, toxicology)

Step 3: Order CT head without contrast emergently; pursue MRI brain when available

Step 4: Obtain EEG within 24 hours

Step 5: If fever, altered mental status, or acute onset: expand workup to include autoimmune panel, lumbar puncture, and inflammatory markers

Step 6: Review medication history carefully—if recent antipsychotic exposure with markedly elevated CK and rigidity, consider NMS over catatonia

Common Pitfalls

• Delaying diagnosis while awaiting imaging: Clinical diagnosis using BFCRS should prompt immediate treatment consideration 5
• Attributing all rigidity to catatonia: NMS presents with "lead pipe" rigidity and much higher CK elevations 9
• Missing autoimmune encephalitis: Particularly in acute presentations with fever—requires CSF studies 1, 5
• Inadequate assessment of medication history: Both antipsychotic exposure and withdrawal of dopaminergic agents can cause catatonia-like syndromes 6

Special Populations

Pediatric Patients

The workup is similar but should have lower threshold for autoimmune evaluation and consideration of autism spectrum disorder as underlying condition 5, 8. Developmental history is essential.

Medically Complex Patients

Expand workup based on comorbidities—thyroid disease, systemic lupus erythematosus, and epilepsy are important medical causes 1, 11.

The workup should be initiated immediately upon clinical suspicion and should not delay treatment with lorazepam, as early intervention improves outcomes 5, 13.