Intracranial Complications of CSOM

🧠 Intracranial Complications of CSOM

Chronic suppurative otitis media (CSOM), especially when associated with cholesteatoma, can lead to life-threatening intracranial complications due to proximity of the middle ear and mastoid to the cranial cavity.

These complications often coexist, may be silent initially, and require early diagnosis and aggressive management.

Intracranial Complications of CSOM are :-

1. Extradural Abscess
2. Subdural Abscess
3. Meningitis
4. Otogenic Brain Abscess
5. Sigmoid Sinus Thrombosis
6. Otitic Hydrocephalus

🟡 Extradural Abscess

📖 Definition of Extradural Abscess

Extradural abscess is a collection of pus between the bone and the dura mater.

• Occurs as a complication of:

  • Acute otitis media
  • CSOM with cholesteatoma

• Often coexists with other intracranial complications

• May act as a precursor to brain abscess

What is the other name for Extradural abscess?

🧬 Pathology of Extradural Abscess

Two mechanisms of spread:

1. Direct bone erosion

2. Thrombophlebitic spread

Describe the two pathways of spread of Extradural abscess.

What are the sites of Extradural Abscess?

🩺 Clinical Features of Extradural Abscess

• Often asymptomatic
• Frequently discovered incidentally during mastoidectomy
• Most important symptom:
  • Persistent localized headache
  • Headache relieved by free flow of pus from ear
  • Spontaneous abscess drainage
• Others:
  • Severe otalgia
  • Malaise
  • Low-grade fever
  • Pulsatile purulent ear discharge

🔍 Investigations of Extradural Abscess

• Contrast-enhanced CT / MRI
  • Shows dural elevation

🩻 Treatment of Extradural Abscess

• IV antibiotics (pre- and post-operative)
• Mastoidectomy
  • Remove bone till healthy dura is seen
  • If suspicion persists → remove intact tegmen tympani / sinus plate
• Close post-operative monitoring
  • To prevent meningitis, brain abscess, sinus thrombosis

🔴 Subdural Abscess

📖 Definition of Subdural Abscess

Subdural abscess is a collection of pus between the dura mater and arachnoid mater.

🧬 Pathology of Subdural Abscess

• Spread via:
  • Bone + dura erosion
  • Thrombophlebitic spread (bone intact)

🩺 Clinical Features of Subdural Abscess

Hallmark presentation:

• Sudden, unusually severe headache
• Fever and vomiting
• Rapid deterioration

Symptoms due to:

1. Meningeal irritation

2. Cortical venous thrombophlebitis

3. Raised intracranial tension

What are the symptoms of meningeal irritation seen in Subdural abscess?

What is Kernig's sign?

What are the symptoms of Cortical venous thrombophlebitis seen in Subdural abscess?

What are the signs and symptoms of Raised intracranial tension seen in Subdural abscess?

🔍 Investigations of Subdural Abscess

• MRI with contrast (investigation of choice)

  • Differentiates extradural vs subdural abscess
  • Shows multiple lobulated subdural collections

• Lumbar puncture is contraindicated

Why is Lumbar Puncture contraindicated in Subdural Abscess?

🩻 Treatment of Subdural Abscess

🚨 Neurosurgical emergency

• High-dose IV antibiotics
• Burr hole drainage
• Radical mastoidectomy
  → Performed after intracranial abscess is controlled

🟠 Meningitis

📖 Definition of Meningitis

Meningitis is inflammation of the leptomeninges (pia + arachnoid) with bacterial invasion of CSF.

🧬 Etiology in Otogenic Meningitis

• Infants & children → Acute otitis media
• Adults → Cholesteatoma
• Others:
  • Temporal bone fracture
  • CSF leak
  • Ear & mastoid surgeries

What are the different Routes of Spread in Meningitis?

🩺 Clinical Features of Meningitis

Early symptoms:

• Fever with chills and rigors
• Headache
• Projectile vomiting
• Photophobia
• Irritability, restlessness

Classical signs:

• Neck rigidity
• Kernig sign
• Brudzinski sign

Others:

• Seizures (infants)
• Cranial nerve palsies
• Hemiplegia
• Initially exaggerated reflexes → later absent
• Papilledema (late)
• Altered consciousness → coma

What is Kernig's sign?

What is Brudzinski sign?

🔍 Investigations of Meningitis

• HRCT temporal bone
• MRI brain
• Fundoscopy → papilledema
• Lumbar puncture (after imaging)

What findings are seen in Lumbar puncture in Meningitis?

🩻 Treatment of Meningitis

⚠️ Medical treatment takes precedence

• IV third-generation cephalosporins (7–10 days)
• Modify antibiotics as per culture
• Corticosteroids → reduce neuro-audiological sequelae
• Surgery:
  • Only after stabilization
  • AOM → myringotomy ± cortical mastoidectomy
  • CSOM → radical / modified radical mastoidectomy

🔵 Otogenic Brain Abscess

📖 Definition of Otogenic Brain Abscess

A localized collection of pus in brain parenchyma secondary to otitis media.

What is the most common site of Otogenic Brain Abscess?

• Bimodal age distribution:

  • Pediatric age group
  • Fourth decade

• Male predominance

• Children → AOM

• Adults → Cholesteatoma

🧠 Stages of Brain Abscess of Otogenic Brain Abscess

1. Early cerebritis (Day 1–3)
2. Late cerebritis (Day 4–9)
3. Early capsule formation (Day 10–14)
4. Late capsule formation (> Day 14)

Describe the progression of Otogenic brain abscess through it's different stages.

🩺 Clinical Features of Otogenic Brain Abscess

1. Raised ICT:

• Headache
• Vomiting
• Lethargy
• Papilledema
• Bradycardia
• Subnormal temperature

1. Localizing signs involving either Temporal lobe or Cerebellum

What are the Localizing signs seen when Temporal lobe is involved and when Cerebeluum is involved?

🔍 Investigations of Otogenic Brain Abscess

• CT / MRI brain

  • Ring-enhancing lesion

• CT temporal bone

• Lumbar puncture contraindicated

🩻 Treatment of Otogenic Brain Abscess

1. Medical

   • IV antibiotics
   • Mannitol / dexamethasone

2. Neurosurgical

   • Burr hole aspiration
   • Excision
   • Open drainage

3. Otologic

   • AOM → antibiotics
   • CSOM → radical mastoidectomy

🟣 Sigmoid Sinus Thrombosis

📖 Definition of Sigmoid Sinus Thrombosis

Inflammation of the lateral venous sinus wall with formation of an intraluminal thrombus

What are the other synonyms of Sigmoid Sinus Thrombosis?

🧬 Pathology of Sigmoid Sinus Thrombosis

1. Perisinus abscess
2. Endophlebitis
3. Mural thrombus
4. Intrasinus abscess
5. Proximal & distal extension

Describe the different stages of Sigmoid Sinus Thrombosis.

🩺 Clinical Features of Sigmoid Sinus Thrombosis

• Picket-fence fever with chills & rigors
• Headache
• Progressive anemia
• Emaciation
• Griesinger sign
• Papilledema
• Jugular vein tenderness
• Positive Tobey Ayer & Crowe Beck tests

What is Picket fence fever? What is the mechanism behind it?

What is Griesinger sign?

How would you perform and interpret Tobey Ayer test?

How would you perform and interpret Crowe Beck test?

🔍 Investigations of Sigmoid Sinus Thrombosis

• Peripheral smear (rule out malaria)
• Blood culture
• Lumbar puncture → ↑ pressure
• CECT brain → Delta sign
• MRI

🩻 Treatment of Sigmoid Sinus Thrombosis

• IV antibiotics
• Mastoidectomy + sinus exposure
• Rare:
  • Internal jugular vein ligation
  • Anticoagulation

🟤 Otitic Hydrocephalus

📖 Definition of Otitic Hydrocephalus

→ Raised intracranial pressure with normal CSF findings

What is the other name of Otitic Hydrocephalus?

🩺 Clinical Features of Otitic Hydrocephalus

• Severe headache
• Diplopia
• Blurred vision
• Nystagmus

🔍 Investigations of Otitic Hydrocephalus

• Lumbar puncture:
  • CSF pressure > 300 mm H₂O
  • Normal CSF contents
• MRI brain

🩻 Treatment of Otitic Hydrocephalus

• Reduce intracranial pressure:
  • Mannitol
  • Acetazolamide
  • Corticosteroids
  • Diuretics
• IV antibiotics
• Surgical:
  • Repeated lumbar puncture
  • Lumbar drain
  • Lumboperitoneal shunt
  • Mastoidectomy

📌 Exam Pearls

• Extradural abscess is often silent
• Subdural abscess = neurosurgical emergency
• LP contraindicated in subdural abscess & brain abscess
• Meningitis → medical treatment first
• Temporal lobe abscess = most common otogenic abscess
• Picket-fence fever = sigmoid sinus thrombosis
• Normal CSF + raised ICP = otitic hydrocephalus

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