What initial labs and imaging should I order for a 5-year-old with recurrent headaches over five months, two days of low-grade fever, and recent epistaxis?

Recurrent Headaches with Fever and Epistaxis in a 5-Year-Old

This child requires immediate evaluation for CNS infection with urgent blood work (complete blood count, blood cultures, hepatic transaminases, serum sodium) followed by MRI brain with and without IV contrast—do not delay empiric broad-spectrum antibiotics if the child appears ill or has any concerning neurological signs. 1, 2

Immediate Red-Flag Assessment

This clinical presentation demands urgent evaluation because:

• Fever combined with headache and vomiting constitutes the classic triad of CNS infection (meningitis/encephalitis) and must be ruled out first 1, 2
• Eight episodes of headache over five months represents a pattern of recurrent symptoms that, when combined with acute fever, raises concern for either recurrent infection or an underlying structural/hematologic problem 1
• Recent epistaxis in the context of recurrent headaches may indicate a coagulopathy, thrombocytopenia, or severe anemia—all of which can present with headache 3, 4
• Low-grade fever does NOT exclude serious intracranial pathology; bacterial meningitis can present with subtle temperature elevation initially 1, 2

Initial Laboratory Work-Up (Order Immediately)

Before any imaging or antibiotics:

• Complete blood count with differential to evaluate for anemia (which can cause headache and papilledema), thrombocytopenia (explaining epistaxis), or leukocytosis (suggesting infection) 1, 3, 4
• Blood cultures (must be drawn before antibiotics) 1, 2
• Hepatic transaminases and serum sodium (baseline for potential CNS infection) 1, 2
• Coagulation studies (PT/INR, PTT) given the epistaxis 3
• Reticulocyte count and peripheral blood smear if anemia is present, as severe anemia can cause increased intracranial pressure and headache 4

Critical Pitfall

Do NOT wait for laboratory results to initiate imaging or empiric antibiotics if the child has altered mental status, nuchal rigidity, photophobia, focal neurological deficits, or appears toxic 1, 2

Imaging Strategy

MRI brain with and without IV contrast is the mandatory initial imaging study for this presentation 5, 1, 2:

• MRI is superior to CT for detecting meningeal enhancement, encephalitis, brain abscess, subdural empyema, and epidural empyema 5, 1
• T2-FLAIR sequences detect vasogenic edema; diffusion-weighted imaging identifies cytotoxic edema; post-contrast T1 and FLAIR show meningeal enhancement 5, 1
• MRI can identify secondary causes of recurrent headache including posterior fossa tumors, hydrocephalus, or vascular malformations 1

If MRI is unavailable or the child requires emergent evaluation (altered consciousness, focal deficits, concern for herniation):

• Non-contrast CT head has 98% sensitivity for acute subarachnoid hemorrhage and can identify hydrocephalus, mass effect, or large abscesses 5, 1, 2
• CT with IV contrast should be performed if MRI cannot be obtained within a reasonable timeframe and infection is suspected 5

Additional imaging considerations:

• If initial MRI is normal but symptoms persist, obtain MR venography (MRV) to exclude cerebral venous sinus thrombosis, which can present with recurrent headaches and can be missed on routine MRI 5, 1
• CT paranasal sinuses (non-contrast) if sinusitis is suspected clinically as a source of recurrent headache or potential intracranial extension 5

Differential Diagnosis by Priority

Tier 1: Life-Threatening (Evaluate First)

• Bacterial meningitis/encephalitis: Fever + headache + vomiting is the classic presentation; altered mental status would confirm this 1, 2
• Brain abscess or subdural/epidural empyema: Often follows sinusitis or otitis media in children; can present with fever and recurrent headaches 5, 1
• Intracranial hemorrhage: Epistaxis may indicate coagulopathy predisposing to intracranial bleeding 1
• Acute hydrocephalus: Recurrent headaches with vomiting suggest intermittent increased intracranial pressure 1

Tier 2: Serious Conditions

• Cerebral venous sinus thrombosis: Can present with recurrent headaches and may have normal routine MRI—requires dedicated MRV 1
• Posterior fossa tumor: Progressive headaches over months with vomiting; fever would be atypical unless there is secondary infection 1
• Severe anemia with secondary increased intracranial pressure: Epistaxis suggests possible bleeding disorder; severe anemia can cause papilledema and headache 4

Tier 3: Less Urgent

• Recurrent sinusitis: Can cause recurrent headaches; epistaxis may be related to nasal inflammation 5
• Migraine variant: Recurrent pattern fits, but fever is NOT typical of primary migraine and should raise suspicion for secondary causes 1, 2

Empiric Treatment Protocol

If CNS infection is suspected based on clinical assessment:

• Do NOT delay empiric IV antibiotics while awaiting imaging or lumbar puncture if the child appears ill 1, 2
• Age-appropriate broad-spectrum coverage: ceftriaxone + vancomycin 1
• Add IV acyclovir if encephalitis is suspected (altered mental status, seizures, focal deficits) 1
• Administer IV anti-emetics and isotonic fluids for supportive care 1

When to Perform Lumbar Puncture

Defer lumbar puncture until AFTER neuroimaging if any of the following are present:

• Focal neurological deficits 1, 2
• Altered consciousness 1, 2
• Papilledema on fundoscopy 1
• Concern for increased intracranial pressure 1, 2

Risk of herniation with LP in these settings is significant 1

Disposition Criteria

Admit immediately if:

• Any red-flag features present (fever with headache, altered mental status, focal deficits) 1
• Abnormal neuroimaging 1
• CNS infection suspected 1, 2
• Severe anemia identified 4
• Coagulopathy with risk of intracranial hemorrhage 1

Critical Pitfalls to Avoid

• A normal initial MRI does NOT exclude cerebral venous thrombosis—dedicated MRV is required 1
• Never dismiss fever as "just viral" in a child with recurrent headaches without ruling out CNS infection 1, 2
• Do NOT attribute epistaxis to "dry air" without checking CBC and coagulation studies 3
• Recurrent headaches in a 5-year-old warrant investigation; this is NOT a typical age for primary headache disorders 1
• Never perform LP before imaging if focal signs, altered consciousness, or papilledema are present 1, 2