--- title: "Otogenic Brain Abscess" description: "ENT notes on Otogenic Brain Abscess - causes, pathology, clinical features, investigations, and treatment." source: "The ENT Resident" author: "Dr. Mausumi Das" canonical_url: "https://www.theentresident.com/ent-notes-lectures/otogenic-brain-abscess" categories: ["Otology"] video: "https://www.youtube.com/watch?v=gFHNT0qxoEc" image: "https://media.theentresident.com/og-images/otogenic-brain-abscess.png" --- # Otogenic Brain Abscess ENT notes on Otogenic Brain Abscess - causes, pathology, clinical features, investigations, and treatment. Watch the full video lecture on YouTube: https://www.youtube.com/watch?v=gFHNT0qxoEc ## 🧠 Otogenic Brain Abscess ### πŸ“Œ Definition of Otogenic Brain Abscess **Otogenic Brain Abscess** is a localized collection of pus in the brain parenchyma, usually occurring as a complication of **chronic suppurative otitis media (CSOM)** or **acute otitis media**. **Incidence:** - Accounts for **50% of brain abscesses in adults** - **25% of brain abscesses in children** are otogenic **Common Sites:** - Temporal lobe - Cerebellum >What is the most common site of otogenic brain abscess? **Age Distribution:** - **Bimodal peaks:** Pediatric age group and 4th decade **Sex Distribution:** - Male : Female = **3 : 1** --- ### 🧠 Causes of Otogenic Brain Abscess - **Children:** Most commonly due to **acute otitis media** - **Adults:** Most commonly due to **cholesteatoma** --- ### 🧬 Routes of Infection of Otogenic Brain Abscess - **Cerebral abscess:** - Direct spread via **tegmen** - **Retrograde thrombophlebitis** - **Cerebellar abscess:** - Spread through **Trautmann’s triangle** - Sometimes retrograde thrombophlebitis >What are the boundaries of Trautmann's Triangle? --- ### 🦠 Microbiology of Otogenic Brain Abscess - **Aerobes:** Staphylococcus, Streptococcus pneumoniae, Streptococcus haemolyticus, Proteus, E. coli, Klebsiella, Pseudomonas - **Anaerobes:** Peptostreptococcus, Bacteroides fragilis >Which is the most common microorganism seen in Otogenic Brain Abscess? --- ### πŸ”¬ Pathological Stages of Otogenic Brain Abscess 1. **Early Cerebritis (Day 1–3):** - Perivascular inflammation - Mild symptoms (headache, fever, malaise) 2. **Late Cerebritis (Day 4–9):** - Pus formation - Enlarged necrotic center - Cerebral edema 3. **Early Capsule Formation (Day 10–13):** - Capsule forms on cortical side - **Ring enhancement on CT/MRI** - Symptoms: Raised intracranial pressure, focal neurological signs 4. **Late Capsule Formation (Day 14+):** - Dense collagenous capsule, necrotic core - Reduced edema, gliosis outside capsule - Risk of rupture β†’ ventricles/subarachnoid space β†’ fatal meningitis --- ### 🩺 Clinical Features of Otogenic Brain Abscess **Due to Raised Intracranial Pressure** - Severe generalized headache - Nausea & projectile vomiting - Lethargy β†’ drowsiness β†’ coma - Papilledema - Bradycardia, subnormal temperature **Localizing Features** - **Temporal Lobe Abscess:** - Nominal aphasia - Contralateral homonymous hemianopia - Contralateral motor paralysis - Epileptic fits - Oculomotor palsy, pupillary changes - **Cerebellar Abscess:** - Suboccipital headache, neck rigidity - Spontaneous nystagmus - Ipsilateral hypotonia, ataxia - Past pointing, intention tremor - Dysdiadochokinesia --- ### πŸ§ͺ Investigations of Otogenic Brain Abscess - **Imaging:** - **CT Brain:** Ring-enhancing lesion (temporal lobe/cerebellum) - **MRI Brain:** More sensitive, detects early spread/ventricular rupture - **CT Temporal Bone:** To evaluate ear disease - **Lumbar puncture:** - Usually avoided (risk of coning) >What is the Investigation of choice (IOC) of Otogenic Brain Abscess? >What are the findings on performing lumbar puncture in Otogenic Brain Abscess? --- ### πŸ’Š Treatment of Otogenic Brain Abscess **1- Medical** - **Antibiotics:** - 3rd gen cephalosporins, chloramphenicol, metronidazole - Aminoglycosides if pseudomonas suspected - Guided by culture sensitivity of ear discharge - **Intracranial pressure control:** - Dexamethasone - Mannitol 20% >What is the dose of Dexamethasone and Mannitol for reducing intracranial pressure in Otogenic brain abscess? - **Ear discharge management:** Suction clearance, topical ear drops **2- Surgical** **Neurosurgery:** - Repeated aspiration via burr hole - Excision - Open drainage & evacuation **Otologic Surgery:** - Performed after neurological stabilization - **Acute OM cases:** Often resolve with antibiotics - **CSOM cases:** Require **radical mastoidectomy** --- ### ⚠️ Complications of Otogenic Brain Abscess - Ventriculitis - Status epilepticus - Respiratory failure - Motor/speech/visual deficits - Encephalitis - Septicemia --- ### 🩻 Differential Diagnosis of Otogenic Brain Abscess - Subdural empyema - Bacterial meningitis - Viral meningoencephalitis - Superior sagittal sinus thrombosis - Acute disseminated encephalomyelitis --- ## About This Note This free ENT note on Otogenic Brain Abscess was written by Dr. Mausumi Das and is paired with a corresponding video lecture. 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