**Patient Information:**  
Name: Mr Patient  
Age: 13 years  
Gender: Male  
Medical History: Not specified (text appears non-informative)

**Current Symptom:**  
Headache

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### 1. Potential Differential Diagnoses

Given the limited information (isolated headache in a 13-year-old male), consider the following common and serious causes:

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

- **Secondary Headache Causes:**
  - Viral or bacterial infection (e.g., sinusitis, upper respiratory infection, meningitis)
  - Medication overuse or withdrawal
  - Dehydration
  - Vision problems (refractive errors)
  - Trauma (concussion, subdural hematoma)
  - Intracranial mass or increased intracranial pressure (rare but serious)
  - Hypertension
  - Dental issues (e.g., temporomandibular joint dysfunction)
  - Sleep disorders

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### 2. Recommended Diagnostic Tests

**Initial evaluation should be guided by history and physical examination.**  
If the headache is new, severe, or associated with concerning features, consider:

- **Basic Workup:**
  - Full neurological examination
  - Vital signs (including blood pressure)
  - Fundoscopic examination (for papilledema)
  - Sinus examination

- **Further Testing (if indicated by red flags or abnormal exam):**
  - CBC, CRP/ESR (if infection or inflammation suspected)
  - CT or MRI brain (if signs of increased intracranial pressure, focal neurological deficit, or trauma)
  - Lumbar puncture (if meningitis or subarachnoid hemorrhage suspected)
  - Vision assessment (if visual symptoms present)

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### 3. Urgency Level

**Medium**  
- Most pediatric headaches are benign, but the urgency increases if red flags are present (see below).
- If any red flags are present, escalate to **High** urgency.

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### 4. Key Observations and Clinical Notes

- Isolated headache in a 13-year-old is most commonly due to benign causes (migraine, tension-type).
- Lack of additional symptoms (fever, neck stiffness, vomiting, altered mental status, visual changes, trauma) makes serious causes less likely, but absence of information does not rule them out.
- Detailed history (onset, duration, character, associated symptoms, triggers, family history, medication use) and physical exam are essential for further risk stratification.

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### 5. Red Flags to Watch For

- Sudden, severe ("thunderclap") headache
- Headache with fever, neck stiffness, photophobia (meningitis)
- Altered mental status, confusion, or seizures
- Focal neurological deficits (weakness, vision loss, ataxia)
- Papilledema or signs of increased intracranial pressure (worse with lying down, vomiting)
- Headache waking from sleep or worse in the morning
- Recent head trauma
- Immunosuppression or known malignancy
- Persistent vomiting

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### 6. Confidence Level

**Confidence Level:** 70%  
- Confidence is moderate due to the very limited clinical information provided. A thorough history and physical examination are required for a more definitive assessment.

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**Note:**  
This analysis is based on the information provided. A face-to-face evaluation by a healthcare professional is essential for accurate diagnosis and management. If any red flags are present, seek urgent medical attention.