**Patient Information:**  
Name: Mr Patient  
Age: 13 years  
Gender: Male  
Medical History: Not specified (entry "dfgdfg" is not interpretable)

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

**Secondary Headache Causes:**
- Viral or bacterial infection (e.g., sinusitis, upper respiratory tract infection, meningitis)
- Medication overuse or withdrawal
- Dehydration
- Vision problems (e.g., refractive errors)
- Trauma (concussion, subdural hematoma)
- Intracranial pathology (e.g., tumor, hydrocephalus, idiopathic intracranial hypertension)
- Dental or temporomandibular joint (TMJ) issues

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### 2. Recommended Diagnostic Tests

**Initial Evaluation:**
- Detailed history (onset, duration, character, location, associated symptoms, triggers, relieving factors, family history, medication use, trauma, recent infections)
- Physical examination (vital signs, neurological exam, fundoscopic exam, ENT and dental exam)

**Further Investigations (if indicated by history/exam):**
- CBC, CRP/ESR (if infection or inflammation suspected)
- Lumbar puncture (if meningitis/encephalitis suspected)
- Brain imaging (CT/MRI) if:
  - Abnormal neurological findings
  - Sudden, severe ("worst ever") headache
  - Signs of raised intracranial pressure
  - Headache worsening over time
  - Headache with vomiting, visual changes, or altered consciousness

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### 3. Urgency Level

**Medium**  
- Most headaches in this age group are benign, but a thorough assessment is needed to rule out serious causes.
- **Urgency increases to High** if any red flags (see below) are present.

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### 4. Key Observations and Clinical Notes

- Isolated headache in a 13-year-old is most often due to benign causes (migraine, tension-type).
- Lack of associated symptoms (fever, neck stiffness, vomiting, visual changes, altered consciousness) in the provided information.
- No trauma or significant medical history provided.
- Detailed history and examination are essential to guide further workup.

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### 5. Red Flags to Watch For

- Sudden onset, severe ("thunderclap") headache
- Headache with fever, neck stiffness, photophobia (meningitis/encephalitis)
- Headache with vomiting, especially in the morning or with position changes (raised intracranial pressure)
- Focal neurological deficits (weakness, vision changes, altered consciousness)
- Headache worsening over time or with exertion/coughing/straining
- Headache after trauma
- Headache with papilledema on fundoscopic exam
- Immunosuppression or known malignancy

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**Summary:**  
A 13-year-old male presents with headache. Most likely causes are primary headache disorders, but secondary causes must be excluded, especially if red flags are present. Initial workup should focus on detailed history and examination, with further tests guided by findings. Urgency is medium unless red flags are identified, in which case urgent evaluation is warranted.

**Recommendation:**  
Advise prompt clinical assessment by a healthcare professional to obtain a full history, perform a physical and neurological exam, and determine the need for further investigation.