Explanation:

• Acute SDH(Hyperdense on CT): <3 days
• Subacute SDH(Isodense on CT): 4-21 days
• Chronic SDH(Hypodense on CT): >21 days

Chronic SDH

• Chronic SDH: Collection of blood breakdown products that is more than 21 days old
• Chronic SDHs often occur in patients without a clear history of head trauma, as they may arise from minor trauma
• Alcoholics, the elderly, and patients on anticoagulation are at higher risk for developing chronic SDH
• Patients may present with headache, seizure, confusion, contralateral hemiparesis, or coma

Treatment

• A chronic SDH >1 cm or any symptomatic SDH should be surgically drained.
• Chronic SDH typically consists of a viscous fluid, with a texture and dark brown color reminiscent of motor oil.
• A simple burr hole can effectively drain most chronic SDHs.

Reference: Greenberg 9th Edition Chapter 55

Explanation:

• Acute SDH(Hyperdense on CT): <3 days
• Subacute SDH(Isodense on CT): 4-21 days
• Chronic SDH(Hypodense on CT): >21 days

Chronic SDH
• Chronic SDH: Collection of blood breakdown products that is more than 21 days old
• Chronic SDHs often occur in patients without a clear history of head trauma, as they may arise from minor trauma
• Alcoholics, the elderly, and patients on anticoagulation are at higher risk for developing chronic SDH
• Patients may present with headache, seizure, confusion, contralateral hemiparesis, or coma

Treatment
• A chronic SDH >1 cm or any symptomatic SDH should be surgically drained.
• Chronic SDH typically consists of a viscous fluid, with a texture and dark brown color reminiscent of motor oil.
• A simple burr hole can effectively drain most chronic SDHs.

Reference: Greenberg 9th Edition Chapter 55
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Explanation:

“Textbook” presentation with Lucid interval has following features (Only < 10%-27% have this classic presentation):

• brief posttraumatic loss of consciousness (LOC): from initial impact
• followed by a “lucid interval” for several hours
• then, obtundation, contralateral hemiparesis, ipsilateral pupillary dilatation as a result of mass effect from hematoma

Reference: Greenberg 9th Edition Chapter 55

Racoon eye or panda sign is periorbital ecchymosis that is seen in base of skull fracture. It is also seen in subgaleal haematoma, meningeal rupture and some cancers.  The blood seeps from base of skull and collects around the loose areolar tissue around the eyes.

Base of Skull Fractures are often missed on CT and plain skull x-rays. Clinical signs are usually more sensitive.

Signs of BSF may take several hours to develop and include cerebrospinal fluid (CSF), otorrhea or rhinorrhea, hemotympanum, laceration of the external auditory canal, postauricular ecchymosis (Battle’s sign) and periorbital ecchymosis with tarsal plate sparing (Raccoon eyes). Battle’s sign and unilateral blepharohematoma have the highest predictive value. Tarsal plate sparing is due to an anatomic structure called the orbital septum, which limits extravasation of blood beyond the tarsal plate . Indirect radiographic findings that suggest BSF include pneumocephalus and air-fluid levels within, or opacification of, an air sinus.

Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2850869/

• It’s not subconjunctival haemorrhage, its periorbital ecchymosis or bruising.
• Signs of Base of Skull fracture are –
  • Battle’s sign (bruising over the mastoid)
  • Racoon’ or ‘panda’ eyes (bilateral periorbital bruising).
  • Haemotympanum, or overt bleeding from the ear if the tympanic membrane has ruptured, and CSF rhinorrhoea or otorrhoea

Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2850869

Explanation:

Pseudomembranes in case of chronic SDH is derived from dura

Ref: Histopathological study of the outer membrane of the dura mater in chronic sub dural hematoma: Its clinical and radiological correlation- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4732239/

Explanation:

The most common histopathological type of membrane was the inflammatory membrane (Type II) seen in 42.30% of cases followed by hemorrhagic inflammatory membrane (Type III) seen in 34.62% of cases while scar inflammatory type of membrane (Type IV) was seen in 23.08% of cases. No case with noninflammatory type (Type I) was encountered.

Ref: Histopathological study of the outer membrane of the dura mater in chronic sub dural hematoma: Its clinical and radiological correlation- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4732239/

Explanation:

At least 50% of patients who die as a result of head injury do so because of uncontrolled increase in ICP

Explanation:

The most common indication for intubation was a Glasgow Coma Score (GCS) of less than 8, typically in the polytrauma patient with suspected head injury due to MVA.

Ref: Hardcastle TC, Goff T. Trauma unit emergency doctor airway management. S Afr Med J. 2007 Sep;97(9):864-7. PMID: 17985058.

Explanation:

Epidural Hematoma

• Source of bleeding: 85% = arterial bleeding (the middle meningeal artery is the most common source of middle fossa EDHs).
• Many of the remainder of cases are due to bleeding from middle meningeal vein or dural sinus.
• 70% occur laterally over the hemispheres with their epicenter at the pterion, the rest occur in the frontal, occipital, and posterior fossa (5–10% each).

“Textbook” presentation with Lucid interval has following features (Only < 10%-27% have this classic presentation):

• brief posttraumatic loss of consciousness (LOC): from initial impact
• followed by a “lucid interval” for several hours
• then, obtundation, contralateral hemiparesis, ipsilateral pupillary dilatation as a result of mass effect from hematoma

Other presenting findings:

• H/A, vomiting, seizure (may be unilateral), hemi-hyperreflexia + unilateral Babinski sign, and elevated CSF pressure (LP is seldom used any longer).
• Bradycardia is usually a late finding.
• In peds, EDH should be suspected if there is a 10% drop in hematocrit after admission.
• Contralateral hemiparesis is not uniformly seen, especially with EDH in locations other than laterally over the hemisphere.
• Shift of the brainstem away from the mass may produce compression of the opposite cerebral peduncle on tentorial notch which can produce ipsilateral hemiparesis (so called Kernohan’s phenomenon or Kernohan’s notch phenomenon),9 a false localizing sign.
• 60% of patients with EDH have a dilated pupil, 85% of which are ipsilateral. No initial loss of consciousness occurs in 60%. No lucid interval in 20%. NB: a lucid interval may also be seen in other conditions (including subdural hematoma).

Reference: Greenberg 9th Edition Chapter 55