A 52-year-old man undergoes spinal anesthesia for lower limb orthopedic surgery. During the procedure, he develops sudden onset severe headache, neck stiffness, and photophobia. Which is the most common cause of this complication?

Explanation

## Most Common Cause of Post-Operative Headache After Spinal Anesthesia **Key Point:** Post-dural puncture headache (PDPH) is the most common neurological complication of spinal anesthesia, occurring in 10–50% of patients depending on needle size and technique. ### Pathophysiology of PDPH 1. CSF leakage through the dural puncture site 2. Decreased CSF pressure and volume 3. Traction on pain-sensitive meningeal structures 4. Typically occurs 24–48 hours post-procedure (can be immediate to 7 days) ### Clinical Features of PDPH | Feature | PDPH | Meningitis | Subdural Hematoma | | --- | --- | --- | --- | | **Onset** | 24–48 hrs | 12–24 hrs | Variable (acute/chronic) | | **Headache character** | Positional (worse upright) | Non-positional, severe | Gradual onset | | **Neck stiffness** | Absent or mild | Prominent, rigid | Absent | | **Photophobia** | Mild or absent | Marked | Absent | | **CSF findings** | Normal | Elevated WBC, protein | | **Fever** | Absent | Present (usually) | Absent | | **Risk factor** | Large needle gauge | Traumatic tap | Coagulopathy | **High-Yield:** PDPH is self-limited in 70–80% of cases; conservative management (bed rest, hydration, analgesics, caffeine) resolves symptoms within 1–2 weeks. Epidural blood patch (EBP) is the gold standard for refractory cases. ### Risk Factors for PDPH - **Needle gauge:** 25G needle → 1–2% incidence; 22G → 5–10%; 18G → 10–15% - **Needle bevel orientation:** Pencil-point (Sprotte, Whitacre) < cutting bevel (Quincke) - **Number of puncture attempts:** Each additional attempt increases risk - **Patient factors:** Female, young age, low BMI, pregnancy - **Technique:** Multiple dural punctures, high CSF pressure **Clinical Pearl:** The hallmark of PDPH is **positional nature** — headache worsens within 15 minutes of sitting/standing and improves within 30 minutes of lying flat. This distinguishes it from meningitis (non-positional) and other causes. ### Management Algorithm ```mermaid flowchart TD A[Suspected PDPH]:::outcome --> B{Severity & Disability?}:::decision B -->|Mild, self-limited| C[Conservative: Bed rest, hydration, analgesics, caffeine]:::action B -->|Moderate to severe| D[Caffeine 500 mg IV/oral]:::action D --> E{Response in 24–48 hrs?}:::decision E -->|Yes| F[Continue conservative care]:::action E -->|No| G[Epidural Blood Patch]:::action G --> H[Relief in 70–90% of cases]:::outcome ``` **Mnemonic:** **PDPH** = **P**ositional **D**ural **P**uncture **H**eadache — the positional component is diagnostic.