===== 🧠 Postoperative Subdural Hematoma (SDH) =====

==== 📌 Definition ====
A **postoperative subdural hematoma** is an accumulation of blood between the **dura mater and arachnoid membrane** that occurs after cranial surgery. It may be **ipsilateral, contralateral, or bilateral**, and can be acute or delayed in onset.

==== ⚠️ Etiology and Mechanisms ====
  * Tearing of bridging veins during brain shift or retraction
  * Intraoperative injury to cortical veins
  * Coagulopathy (e.g., thrombocytopenia, anticoagulants, NSAIDs)
  * Overdrainage of CSF (ventricular or lumbar)
  * Sudden changes in intracranial pressure
  * Brain atrophy (elderly patients more vulnerable)

==== 🧪 Incidence ====
  * Less common than epidural hematoma but more frequent in elderly or anticoagulated patients
  * May present acutely (within 48 h) or subacutely/delayed (days to weeks)

==== 🩺 Clinical Presentation ====
  * Delayed awakening or deterioration of consciousness
  * Progressive headache
  * Hemiparesis or focal deficits
  * Dysphasia, seizures
  * Neurological worsening after initial improvement

==== 🖼️ Imaging Findings ====
  * **CT scan**: crescent-shaped, hypodense/isodense or hyperdense subdural collection
  * **MRI**: helpful in iso/hypodense cases or delayed diagnosis
  * May show midline shift or compression of ventricles

==== 🧠 Differential Diagnosis ====
  * Epidural hematoma
  * Postoperative infarct
  * Hygroma
  * Tension pneumocephalus

==== 🛠️ Management ====
  * **Surgical evacuation** if:
    - Mass effect present
    - Neurological symptoms worsen
    - Thickness >10 mm or midline shift >5 mm
  * Techniques:
    - Burr-hole drainage
    - Craniotomy in organized or solid hematomas
  * Reversal of anticoagulation or platelet transfusion if needed
  * Intensive monitoring (neuro ICU)

==== 📉 Prognosis ====
  * Depends on timing of diagnosis and neurological status at treatment
  * Good prognosis with early recognition and intervention
  * Delayed or missed SDH may lead to irreversible injury

==== 🧾 Prevention ====
  * Careful hemostasis and gentle brain retraction
  * Controlled CSF drainage during and after surgery
  * Avoid sudden intracranial pressure shifts
  * Close monitoring in high-risk patients (elderly, anticoagulated)
  * Early postoperative CT scan if symptoms or risk factors present