What diagnostics are best for a 25-year-old male with sudden loss of consciousness and a 5-day history of cough and fever after a fall with head injury?

Diagnostic Approach for 25-Year-Old Male with Sudden Loss of Consciousness, Cough, Fever, and Head Trauma

This patient requires immediate head CT imaging to rule out traumatic intracranial injury, followed by chest imaging and infectious workup given the 5-day prodrome of cough and fever, with cardiac evaluation and syncope workup only after excluding life-threatening structural and infectious causes.

Immediate Priority: Head Trauma Assessment

The fall with head injury mandates urgent non-contrast head CT as the first diagnostic step, regardless of the underlying cause of loss of consciousness 1. The unwitnessed nature of the fall means you cannot determine if trauma caused the loss of consciousness or vice versa 1.

Critical Red Flags Present in This Case:

• Hyperacute onset of unconsciousness (red flag for serious pathology) 2
• Head trauma with potential for intracranial injury 1
• Prodromal infectious symptoms (5 days of fever and cough) 1, 2

Second Priority: Infectious/Respiratory Evaluation

The 5-day history of cough and fever creates a critical differential that must be addressed immediately:

COVID-19 and Viral Encephalitis Considerations:

• SARS-CoV-2 testing (nasopharyngeal PCR) is essential given the presentation mimics reported COVID-19 cases with altered mental status, fever, and cough 1
• Chest CT or chest X-ray to evaluate for pneumonia, given cough syncope can occur with severe respiratory disease 3, 4
• COVID-19 has been documented to cause encephalitis with seizures and altered consciousness in young patients, with one 24-year-old presenting similarly with fever, cough, and subsequent loss of consciousness 1

Cough Syncope Mechanism:

• Cough syncope occurs when severe coughing elevates intrathoracic pressure, causing transient cerebral circulatory arrest 3, 4
• This mechanism has been documented with transcranial Doppler showing complete cessation of cerebral blood flow during coughing episodes 4
• Typically affects patients with obstructive airway disease who generate extremely high intrathoracic pressures 3

Third Priority: Standard Syncope Workup

After excluding trauma and serious infection, proceed with systematic syncope evaluation:

Mandatory Initial Tests:

• 12-lead ECG (non-negotiable for all syncope presentations) 1, 5
• Orthostatic vital signs (blood pressure and heart rate supine and standing for 10 seconds each position) 1, 5
• Detailed history focusing on:
  • Exact circumstances before loss of consciousness 1
  • Witness account of the event (duration, movements, color changes) 1
  • Post-event recovery time and symptoms 1

Cardiac Risk Stratification:

Immediate specialist cardiovascular referral is indicated if any of the following are present 5, 6:

• Abnormal ECG suggesting arrhythmia (long QT, Brugada pattern, AV block) 5, 6
• Exertional syncope 1, 5
• Family history of sudden cardiac death before age 40 1
• Structural heart disease on examination 5, 6

Fourth Priority: Metabolic and Laboratory Evaluation

Essential Laboratory Tests:

• Complete blood count (infection, anemia) 2
• Comprehensive metabolic panel (electrolytes, glucose, renal function) 2
• Blood cultures if febrile 1, 2
• Inflammatory markers (CRP, procalcitonin if bacterial infection suspected) 1, 2

Consider Based on Clinical Context:

• Lumbar puncture with CSF analysis if meningitis/encephalitis suspected (especially if persistent altered mental status, fever, or meningismus) 1, 2
• CSF SARS-CoV-2 PCR if COVID-19 encephalitis is considered (one case report showed positive CSF despite negative nasopharyngeal swab) 1

Distinguishing Syncope from Seizure

Features Favoring Syncope in This Case:

• Brief duration of unconsciousness (syncope typically <30 seconds vs. seizures 74-90 seconds) 1, 7
• Rapid return to baseline mental status 1, 5
• Prodromal symptoms (if present: lightheadedness, nausea, visual changes) 1, 5

Features That Would Suggest Seizure:

• Lateral tongue biting (highly specific for seizure) 1, 7
• Prolonged post-ictal confusion (>5 minutes) 1, 7
• Eyes open during unconsciousness (more common in seizure) 1, 7
• Prolonged tonic-clonic movements 1, 7

Critical caveat: Brief myoclonic jerks during syncope should NOT be interpreted as epilepsy 1, 5. True seizure activity is typically longer and more organized 1, 7.

Diagnostic Algorithm Summary

1. Head CT immediately (unwitnessed fall with head trauma) 1, 2
2. Chest imaging + COVID-19/respiratory pathogen testing (5-day cough/fever prodrome) 1, 3
3. 12-lead ECG + orthostatic vitals (mandatory syncope evaluation) 1, 5
4. Laboratory workup (CBC, CMP, cultures if febrile) 2
5. Lumbar puncture (if encephalitis suspected based on persistent altered mental status) 1, 2
6. Cardiac specialist referral (if ECG abnormal or high-risk features) 5, 6

Common Pitfalls to Avoid

• Do not assume syncope caused the fall—trauma evaluation takes precedence 1
• Do not dismiss the infectious prodrome—COVID-19 and other viral infections can cause both respiratory symptoms and neurological complications including encephalitis 1
• Do not over-interpret brief myoclonic movements as seizure—these are common in deep syncope 1, 5
• Do not delay head imaging for other tests in patients with head trauma 2
• Do not miss cough syncope—this is a specific entity where treating the underlying cough eliminates the syncope 3, 4