What are the potential causes and treatment options for severe headache, chills, and night sweats?

Severe Headache with Chills and Night Sweats: Differential Diagnosis and Management

The combination of severe headache, chills, and night sweats represents a medical emergency requiring immediate evaluation for life-threatening infectious causes, particularly bacterial meningitis, viral encephalitis, and systemic infections with CNS involvement. 1, 2

Immediate Life-Threatening Causes to Rule Out

Bacterial Meningitis

• Classic triad: Severe headache, fever with chills, and nuchal rigidity (meningismus) 1, 2
• Additional features: Altered consciousness, photophobia, nausea, and rapid clinical deterioration 2
• Diagnostic approach: Lumbar puncture showing elevated WBC (typically neutrophilic predominance), elevated protein, decreased glucose, positive gram stain or culture 1, 2
• Critical action: Start empiric IV antibiotics (ceftriaxone + vancomycin) and IV acyclovir immediately before LP if any delay in obtaining CSF, as delayed treatment dramatically increases mortality 2

Viral Encephalitis

• Presentation: Severe headache, fever, altered mental status, focal neurological deficits, or seizures 1, 2
• Key distinction: Encephalitis involves brain parenchyma inflammation, not just meninges, resulting in confusion, personality changes, or focal signs 2
• Workup: MRI brain with contrast (may show T2/FLAIR changes), CSF analysis with viral PCR panel (especially HSV), EEG to evaluate for subclinical seizures 1, 2
• Treatment: IV acyclovir 10 mg/kg every 8 hours should be started empirically until HSV is excluded 1, 2

Eosinophilic Meningitis (Tropical/Travel History)

• Angiostrongylus cantonensis (rat lungworm): Severe acute headache, meningism, visual disturbance, cranial nerve palsies with marked peripheral eosinophilia 1
• Incubation: 1-3 weeks after ingestion of undercooked snails, prawns, crabs, or frogs in SE Asia, Caribbean, or Hawaii 1
• Treatment: Prednisolone 60 mg daily for 14 days (mainstay), plus albendazole 15 mg/kg/day for 14 days 1

Neurocysticercosis (Cysticercal Meningitis)

• Presentation: Severe headache, meningism, altered consciousness, focal neurological signs, hydrocephalus common 1
• Geographic risk: South/SE Asia, Central/South America, Africa 1
• CSF findings: Lymphocytosis with eosinophilia in 20% of cases, positive CSF serology 1
• Treatment: Albendazole 400 mg twice daily for 14 days plus dexamethasone 4-12 mg/day (reducing after 7 days), ventricular shunting if hydrocephalus present 1

Neuroschistosomiasis (Acute Katayama Syndrome)

• CNS manifestations: Encephalitis or cerebral vasculitis with altered consciousness, severe headache, seizures, focal signs 1
• Risk factors: Recent freshwater exposure in endemic areas (Africa, SE Asia) 1
• Treatment: Corticosteroids alone initially to avoid neurological complications, followed by praziquantel 40 mg/kg twice daily for 5 days plus dexamethasone 4 mg four times daily (reducing over 2-6 weeks) 1

Systemic Infectious Causes

Brucellosis

• Classic presentation: Acute or insidious fever, night sweats, severe fatigue, headache, arthralgia 1
• Diagnosis: Blood culture for Brucella species or fourfold rise in agglutination titer between acute and convalescent sera 1
• Occupational/dietary risk: Unpasteurized dairy products, contact with livestock 1

Other Systemic Infections with Headache

• Influenza and viral syndromes: Severe headache with fever, chills, myalgias 3
• Rickettsial diseases: Headache, fever, night sweats with potential CNS involvement 3
• HIV/AIDS-related opportunistic infections: Cryptococcal meningitis, toxoplasmosis 3

Non-Infectious Secondary Causes

Temporal Arteritis (Giant Cell Arteritis)

• Age consideration: Primarily affects patients >50 years old 4
• Symptoms: Severe unilateral headache, jaw claudication, visual symptoms, scalp tenderness 4
• Laboratory: Markedly elevated ESR and CRP 4
• Emergency treatment: High-dose corticosteroids immediately to prevent blindness 4

Subarachnoid Hemorrhage

• Presentation: Thunderclap headache (sudden, severe, "worst headache of life"), may have fever/chills from meningeal irritation 1, 5
• Diagnosis: Non-contrast CT head (98% sensitive acutely), followed by LP if CT negative and suspicion high 1, 5

Diagnostic Algorithm

Step 1: Immediate Assessment

• Vital signs: Fever >38°C suggests infection; hypertension may indicate increased intracranial pressure 1, 2
• Neurological examination: Assess mental status, focal deficits, cranial nerves, nuchal rigidity, fundoscopy for papilledema 1, 4, 2
• Red flags requiring immediate imaging/LP: Altered consciousness, focal neurological signs, papilledema, immunocompromised state, recent head trauma 1, 2, 5

Step 2: Laboratory Evaluation

• Blood work: CBC with differential (leukocytosis, eosinophilia), ESR/CRP (inflammation), blood cultures (bacteremia), HIV testing if risk factors 1, 3
• Imaging: Non-contrast CT head before LP if concern for mass effect, abscess, or increased intracranial pressure 1, 2, 5
• Lumbar puncture: Opening pressure, cell count/differential, protein, glucose, gram stain, bacterial/viral cultures, viral PCR panel, consider fungal studies and cytology 1, 2

Step 3: Travel and Exposure History

• Geographic exposures: Recent travel to tropics (eosinophilic meningitis, malaria, dengue) 1, 3
• Food history: Undercooked seafood/snails (Angiostrongylus), unpasteurized dairy (Brucella) 1
• Animal exposures: Livestock, rodents, ticks 1, 3
• Freshwater exposure: Swimming in endemic areas (schistosomiasis) 1

Treatment Approach

Empiric Therapy (Before Diagnostic Confirmation)

• If meningitis/encephalitis suspected: IV ceftriaxone 2g every 12 hours + vancomycin 15-20 mg/kg every 8-12 hours + acyclovir 10 mg/kg every 8 hours 2
• If temporal arteritis suspected (age >50): Prednisone 60 mg daily immediately 4
• Symptomatic headache management: IV metoclopramide 10 mg plus IV ketorolac 30 mg for severe headache while awaiting diagnosis 6

Common Pitfalls to Avoid

• Delaying antibiotics for LP: If LP will be delayed >30 minutes in suspected bacterial meningitis, start antibiotics immediately after blood cultures 2
• Missing eosinophilic meningitis: Always check peripheral eosinophil count and ask about travel/dietary exposures in patients with aseptic meningitis 1
• Assuming viral syndrome: Night sweats are uncommon in simple viral upper respiratory infections and should prompt consideration of more serious systemic infections 1, 3
• Overlooking medication overuse headache: If patient has chronic headache history with recent escalation, consider MOH, but never assume this diagnosis in acute presentation with fever/chills 7

Disposition

• Admit for: Any suspicion of meningitis, encephalitis, or other CNS infection; altered mental status; focal neurological deficits; immunocompromised patients 1, 2, 5
• Outpatient workup: Only if completely normal neurological exam, no fever at presentation, no red flags, and reliable follow-up within 24-48 hours 5