**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

In a 13-year-old male presenting with headache, consider the following differentials:

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

- **Secondary Headaches**
  - Viral or bacterial infections (e.g., sinusitis, upper respiratory tract infection, meningitis)
  - Medication overuse or withdrawal
  - Refractive errors (visual strain)
  - Trauma (concussion, subdural/epidural hematoma)
  - Intracranial mass lesion (tumor, abscess)
  - Idiopathic intracranial hypertension
  - Hypertension
  - Temporal arteritis (rare in this age group)
  - Dental or temporomandibular joint (TMJ) issues

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### 2. Recommended Diagnostic Tests

**Initial evaluation should be guided by history and physical examination.**  
Based on the limited information, consider:

- **Basic Assessment:**
  - Full neurological examination
  - Vital signs (including blood pressure)
  - Fundoscopy (to check for papilledema)
  - Sinus examination

- **Further Investigations (if indicated by history/exam):**
  - CBC, CRP/ESR (if infection or inflammation suspected)
  - Urinalysis (if systemic symptoms)
  - CT/MRI brain (if red flags present or abnormal neuro exam)
  - Lumbar puncture (if meningitis or subarachnoid hemorrhage suspected)
  - Vision assessment (if visual symptoms)

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### 3. Urgency Level

**Low to Medium** (based on current information)

- **Low** if headache is mild, intermittent, and not associated with red flags.
- **Medium to High** if any red flags or abnormal findings are present (see below).

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### 4. Key Observations and Clinical Notes

- **History is critical:** Onset, duration, character, location, associated symptoms (nausea, vomiting, photophobia, phonophobia, visual changes, fever, neck stiffness, recent trauma, etc.).
- **Family history:** Migraines, neurological disorders.
- **Medication history:** Recent changes, overuse.
- **Social/psychological factors:** School stress, sleep patterns.

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### 5. Red Flags to Watch For

Immediate further evaluation is warranted if any of the following are present:

- Sudden, severe ("thunderclap") headache
- Headache with fever, neck stiffness, photophobia (meningitis)
- Focal neurological deficits (weakness, vision loss, altered consciousness)
- Papilledema (suggesting raised intracranial pressure)
- Headache worsened by Valsalva, lying down, or in the morning
- Recent significant head trauma
- Headache with vomiting, especially projectile
- Change in headache pattern or progressively worsening headaches
- Immunosuppression or known malignancy

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**Summary:**  
A 13-year-old male with headache requires a thorough history and physical examination to distinguish between primary and secondary causes. Most headaches in this age group are benign, but red flags must be excluded. If any concerning features are present, urgent neuroimaging and specialist referral are indicated.

**Recommendation:**  
Encourage prompt evaluation by a healthcare professional for detailed assessment and management.