**Patient Analysis: Headache in a 13-year-old Male**

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**1. Potential Differential Diagnoses**

- **Primary Headache Disorders**
  - Migraine (with or without aura)
  - Tension-type headache
  - Cluster headache (less common in this age group)

- **Secondary Headache Causes**
  - Sinusitis
  - Viral or bacterial infections (e.g., upper respiratory tract infection, meningitis)
  - Medication overuse headache
  - Refractive errors (vision problems)
  - Trauma/concussion
  - Intracranial pathology (e.g., brain tumor, hydrocephalus, idiopathic intracranial hypertension)
  - Hypertension
  - Dehydration

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**2. Recommended Diagnostic Tests**

*Based on initial presentation of isolated headache, further history and physical examination are essential. Consider:*

- **Basic Workup**
  - Complete neurological examination
  - Vital signs (including blood pressure)
  - Fundoscopic exam (to assess for papilledema)
  - Assessment for sinus tenderness, neck stiffness

- **If Red Flags or Abnormal Findings:**
  - Brain imaging (MRI preferred, CT if urgent)
  - Lumbar puncture (if meningitis or subarachnoid hemorrhage suspected)
  - Laboratory tests (CBC, CRP/ESR if infection or inflammation suspected)
  - Vision assessment (refraction, fundoscopy)

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**3. Urgency Level**

- **Low to Medium** (based on current information: isolated headache, no red flags provided)
- **High** if any red flags or abnormal neurological findings are present (see below)

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**4. Key Observations and Clinical Notes**

- Age: 13 years (adolescent)
- Gender: Male
- Symptom: Headache (no further details provided)
- Medical history: Not contributory (no relevant history provided)
- *Critical missing information*: Onset, duration, frequency, severity, associated symptoms (nausea, vomiting, photophobia, phonophobia, visual changes, fever, neck stiffness, recent trauma, changes in consciousness), family history of migraine, medication use.

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**5. Red Flags to Watch For**

- Sudden, severe ("thunderclap") headache
- Headache with fever, neck stiffness, photophobia (meningitis/encephalitis)
- Focal neurological deficits (weakness, numbness, vision loss, ataxia)
- Altered mental status, confusion, seizures
- Papilledema (suggests raised intracranial pressure)
- Headache worse with lying down, coughing, or Valsalva
- Recent head trauma
- Persistent vomiting
- Headache awakening from sleep or worse in the morning
- Immunosuppression or cancer history

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**Summary:**  
This adolescent male presents with headache. In the absence of further details or red flags, primary headache disorders (migraine, tension-type) are most likely, but secondary causes must be considered. A thorough history and physical examination are essential. If any red flags are identified, urgent neuroimaging and further workup are warranted. Always recommend prompt evaluation by a healthcare professional for proper diagnosis and management.