What is the best approach to diagnose and manage a patient with fatigue, body aches, and severe headache for 5 days without neuro deficits?

Laboratory Workup for Patient with Fatigue, Body Aches, and Severe Headache without Neurological Deficits

The optimal laboratory workup for a patient with fatigue, body aches, and severe headache without neurological deficits should include a complete blood count, comprehensive metabolic panel, thyroid function tests, and inflammatory markers to rule out secondary causes before assuming a primary headache disorder. 1, 2

Initial Assessment and Red Flag Evaluation

• Assess for "red flags" that suggest a secondary headache disorder requiring urgent attention, including sudden onset/thunderclap headache, which may indicate subarachnoid hemorrhage 1
• Evaluate for headache that worsens when lying down or bending over, which may suggest increased intracranial pressure 1
• Check for new unexplained bruising or bleeding, which may indicate coagulopathy 1
• Assess for shortness of breath, leg swelling, or persistent abdominal pain, which may suggest thrombosis 1

Basic Laboratory Workup

• Complete blood count (CBC) to evaluate for anemia, infection, or thrombocytopenia 2
• Basic metabolic panel to assess for electrolyte disturbances, kidney function, and glucose levels 2
• Liver function tests to rule out hepatic causes that could contribute to fatigue and headache 2
• Thyroid function tests (TSH, free T4) as both hypothyroidism and hyperthyroidism can cause fatigue, body aches, and headaches 2
• Inflammatory markers (ESR, CRP) to screen for inflammatory or autoimmune conditions 2

Additional Laboratory Tests to Consider

• Serum calcium to evaluate for hyperparathyroidism which can present with fatigue and headache 2
• Urinary drug screen if substance use is suspected as a contributing factor 2
• Consider autoimmune panels if inflammatory or autoimmune processes are suspected based on clinical presentation 2

Neuroimaging Considerations

• Brain MRI with and without contrast is the preferred neuroimaging study if red flags are present or symptoms persist despite initial management 1, 2
• Non-contrast head CT as first-line imaging if there is concern for acute pathology 1
• Consider CT venography or MR venography if there is concern for cerebral venous thrombosis 1

Headache-Specific Evaluation

• If chronic migraine is suspected (≥15 headache days per month for >3 months, with ≥8 days having migraine features), document response to migraine-specific medications 3, 2
• Consider lumbar puncture if there are concerns for increased intracranial pressure, especially if papilledema is present on fundoscopic examination 2, 4

Diagnostic Considerations for Primary Headache Disorders

• Suspect migraine if patient has recurrent moderate to severe headache, particularly if pain is unilateral and/or pulsating, and when accompanied by photophobia, phonophobia, nausea and/or vomiting 3
• Consider chronic migraine in a patient with ≥15 headache days per month 3
• Evaluate for medication overuse headache if the patient is taking analgesics frequently 2
• Consider the relationship between fatigue and migraine, as studies show fatigue is significantly more common in chronic migraine than episodic migraine 5

Pitfalls to Avoid

• Don't assume primary headache disorder without ruling out secondary causes, especially with new or changing headache patterns 4, 6
• Avoid missing thyroid dysfunction, which can present with the triad of fatigue, body aches, and headache 2
• Don't overlook the possibility of medication overuse headache in patients with chronic headache 3
• Remember that fatigue can be both a symptom of the underlying condition and a comorbidity that requires separate evaluation and management 5

By following this systematic approach to laboratory workup, clinicians can effectively narrow the differential diagnosis and develop an appropriate management plan for patients presenting with fatigue, body aches, and severe headache without neurological deficits.