What is the approach to diagnosing and managing neurological conditions?

Approach to Diagnosing and Managing Neurological Conditions

Initial Assessment and Examination

Serial bedside neurological examination remains the cornerstone of neurological assessment, with standardized tools providing the most reliable framework for diagnosis and monitoring. 1

Core Examination Components

The neurological examination must systematically evaluate:

• Mental status assessment using standardized scoring tools such as the Glasgow Coma Scale and Confusion Assessment Method 1
• Brainstem reflexes including pupillary light response, oculocephalic, corneal, and cough/gag reflexes 1
• Motor examination of all extremities, though this requires lightening or discontinuing sedation when applicable 1
• Sensory examination when feasible, though often limited in critically ill patients 1

Examination Frequency

• Daily assessment by a neurologist or neurointensivist improves neurological care when available 1
• More frequent bedside nursing assessments every 1-4 hours based on acute brain injury risk 1
• Baseline assessment before any intervention, followed by serial evaluations throughout treatment and after intervention completion 1

Differential Diagnosis Framework

Critical "Must-Not-Miss" Pathologies

When evaluating neurological symptoms, immediately consider:

Structural emergencies:

• Stroke, intracerebral hemorrhage, subdural hematoma, subarachnoid hemorrhage, epidural hematoma 1
• CNS malignancy or tumors 1
• Hydrocephalus 1
• Spinal cord compression 2

Infectious causes:

• Meningitis, encephalitis, brain abscess, epidural abscess, spinal abscess 1
• HIV, syphilis 1

Metabolic and endocrine emergencies:

• Hyponatremia, hypocalcemia, hypoglycemia, hyperglycemia, ketoacidosis 1
• Uremia, hyperammonemia 1
• Thyroid storm, Addison disease, Cushing disease 1

Seizures and status epilepticus:

• Clinical or subclinical seizures requiring urgent EEG 2
• Elevated intracranial pressure and herniation syndromes 2

Distinguishing Epilepsy from Syncope

Complete flaccidity during unconsciousness argues against epilepsy (except rare atonic seizures in children with pre-existing neurological problems). 1

Key differentiating features:

Epilepsy characteristics:

• Movements last approximately 1 minute, are coarse, rhythmic, and usually synchronous 1
• Rarely triggered by external factors 1
• Typical aura includes rising epigastric sensation and/or unusual unpleasant smell 1
• Tongue bite occurs on the side of the tongue 1
• Prolonged post-ictal confusion 1

Syncope characteristics:

• Movements last only seconds, are small, asynchronous, and non-rhythmic 1
• Usually triggered by specific factors 1
• Sweating and pallor are common 1
• Tongue bite occurs on the tip 1
• Immediate clearheadedness after recovery 1

Hepatic Encephalopathy Differential

In cirrhotic patients with neurological symptoms, the initial evaluation must include:

• Recent medical history: infections, trauma, withdrawal, psychotropic drugs 1
• Complete medical history: diabetes, neurovascular diseases, epilepsy, known complications of cirrhosis 1
• Complete neurological examination including cognitive, motor, sensory, neurovisual, and cranial nerve testing 1
• Asterixis is strongly suggestive of metabolic encephalopathy when present at grade 2 West-Haven score 1
• Common blood tests: electrolytes, glucose, calcium, cell blood count, hemostasis, inflammatory proteins, urea, creatinine 1
• Brain imaging, preferably MRI 1

Neuroimaging Protocols

Brain MRI Protocol

Contrast-enhanced cross-sectional imaging using CT or MRI is needed when intracranial lesions are suspected, particularly in cirrhotic patients or heavy drinkers who have higher risk of intracerebral hemorrhage. 1

Essential sequences include:

• T2-weighted imaging at 4-5 mm thickness or isotropic volume 1
• Fluid-attenuated inversion recovery (FLAIR) at 4-5 mm thickness 1
• T2*-weighted gradient echo (GRE) or susceptibility-weighted imaging (SWI) at 2-5 mm thickness 1
• Precontrast and postcontrast 3D isotropic volumetric T1-weighted acquisitions 1

Wilson's Disease Imaging

The most frequent MRI finding is hyperintensity on T2-weighted imaging in the basal ganglia region, with MRI being more sensitive than CT. 3

Pathognomonic findings include:

• Hyperintensities in the tectal plate (75% of cases) and central pons (62.5% of cases) are virtually pathognomonic 3
• Simultaneous involvement of basal ganglia, thalamus, and brainstem (55.3% of cases) is highly specific 3
• The "face of the giant panda" sign is characteristic but found in only 14-15% of all cases 3

MRI should be considered prior to treatment in all patients with neurologic Wilson's disease. 3

Spine MRI Protocol

For suspected spinal pathology:

• Fat-suppressed T2-weighted sequence (STIR or equivalent) 1
• T2-weighted sagittal imaging at 3-4 mm thickness in three parts 1
• T2-weighted axial imaging at 3-4 mm thickness of select spinal segments 1
• High-resolution steady-state or heavily T2-weighted 3D sequence 1

Laboratory Investigations

When Laboratory Testing is NOT Routinely Indicated

Routine urine drug testing has little to no utility in psychiatric presentations. In one study, only 5% of routine toxicology screens were positive with no changes in patient management. 1

Routine testing should be avoided unless:

• Specific clinical features suggest toxidrome 1
• Abnormal vital signs are present 1
• History and physical examination suggest specific intoxication 1

Essential Blood Work

For any initial neurological evaluation:

• Blood electrolytes (particularly sodium and calcium) 1
• Blood glucose 1
• Cell blood count 1
• Hemostasis parameters 1
• Inflammatory markers 1
• Blood urea and creatinine 1

Blood Ammonia Sampling (When Indicated)

Venous blood sampling must be performed in a fasting patient, avoiding venous stasis, with immediate placement on ice and transport to laboratory within 60-90 minutes. 1

Specialized Monitoring

Multimodal Neurological Monitoring

Standardized neurological monitoring, clinical assessment, and sedation cessation protocols may increase acute brain injury detection and improve outcomes. 1

Available monitoring tools include:

• Near-infrared spectroscopy (NIRS) for cerebral oxygenation 1
• Transcranial Doppler ultrasound for cerebral blood flow velocities 1
• Continuous EEG monitoring for seizure detection 2

Sedation Management

Intermittent (as-needed) analgo-sedation is preferred over continuous infusion, with short-acting, non-benzodiazepine sedatives considered optimal. 1

Critical practices:

• Standardized sedation protocols using Richmond Agitation Sedation Scale 1
• Daily reassessment of sedation goals 1
• Stepwise sedation weaning 1
• Sedation interruptions to improve neurological examination accuracy 1

Referral Pathways

Timing of Neurological Referral

Patients with suspected neurological conditions should be referred to a neurologist within 2-4 weeks if able to self-care, within 48 hours if unable to self-care but have help, and require emergency admission if unable to self-care without help. 1

Specialist Center Criteria

Referral to a specialist neuroscience center is indicated when:

• Diagnosis is in doubt 1
• First-line treatments fail 1
• Rapid clinical deterioration occurs 1
• Serious complications develop (e.g., subdural hematoma with mass effect) 1

Assessment in a specialist center should occur within 1 month for non-urgent cases. 1

Common Pitfalls to Avoid

Examination Pitfalls

• Do not assume fixed, dilated pupils indicate irreversible brain injury during resuscitation, as epinephrine administration frequently causes this finding and patients can achieve favorable outcomes despite these findings 1
• Do not rely solely on motor examination in sedated or paralyzed patients 1
• Do not perform comprehensive examinations when focused assessment is more appropriate for the clinical context 4

Diagnostic Pitfalls

• Do not diagnose transient ischemic attack (TIA) as causing loss of consciousness without focal neurological signs - vertebrobasilar TIA always includes limb weakness, ataxia, oculomotor palsies, or oropharyngeal dysfunction 1
• Do not attribute all neurological symptoms in cirrhotic patients to hepatic encephalopathy without excluding differential diagnoses 1
• Do not order routine toxicology screens in psychiatric presentations without specific clinical indication 1

Management Pitfalls

• Never abruptly discontinue antiepileptic drugs in patients with seizure disorders due to risk of precipitating status epilepticus 5
• Do not delay neuroimaging when structural abnormalities are suspected 2
• Do not overlook the need for early EEG and lumbar puncture based on clinical suspicion 2