Pathology Cheat Sheet
Read the Csf, Then the Vessel
Meningitis and stroke for NEET-PG: bacterial vs viral vs TB CSF, cryptococcal India ink, ischaemic infarct, hypertensive haemorrhage, and berry aneurysm SAH.
MedNext Academy | 3 min read
Read the Csf, Then the Vessel
Meningitis and stroke for NEET-PG: bacterial vs viral vs TB CSF, cryptococcal India ink, ischaemic infarct, hypertensive haemorrhage, and berry aneurysm SAH.
The pathology and CSF findings in meningitis and the types of cerebrovascular disease.
High-yield lines
- Acute bacterial meningitis causes a neutrophilic exudate, high protein, and low glucose in the CSF.
- Common causes of bacterial meningitis vary with age, including group B streptococcus in neonates and Streptococcus pneumoniae and Neisseria meningitidis in adults.
- Viral (aseptic) meningitis shows a lymphocytic CSF with mildly raised protein and normal glucose.
- Tuberculous meningitis shows a lymphocytic CSF with high protein and low glucose and a basal exudate.
- Fungal meningitis such as cryptococcal meningitis is seen in immunocompromised patients and shows encapsulated yeast on India ink.
- Ischaemic stroke results from thrombosis or embolism and produces liquefactive necrosis in the brain.
- The middle cerebral artery territory is the most common site of ischaemic stroke.
- Ischaemic infarcts evolve from red neurons to macrophage infiltration and finally a cystic cavity with gliosis.
- Intracerebral haemorrhage is most often caused by hypertension and typically affects the basal ganglia.
- Charcot-Bouchard microaneurysms of small penetrating arteries rupture in hypertensive haemorrhage.
- Subarachnoid haemorrhage is usually caused by rupture of a berry aneurysm of the circle of Willis.
- A lucid interval followed by deterioration suggests an extradural haematoma from middle meningeal artery rupture.
Mapped competency codes
- PA35.1
- PA35.3
Continue into the full chapter
This summary maps to PA35-central-nervous-system.
Frequently Asked Questions
How do CSF findings differ in bacterial and viral meningitis?
Bacterial meningitis shows neutrophils with high protein and low glucose, while viral meningitis shows lymphocytes with mildly raised protein and normal glucose.
What are the CSF findings in tuberculous meningitis?
A lymphocytic pleocytosis with high protein and low glucose, typically with a basal meningeal exudate.
What is the most common cause of intracerebral haemorrhage?
Hypertension, which causes rupture of Charcot-Bouchard microaneurysms, most often in the basal ganglia.
What causes non-traumatic subarachnoid haemorrhage?
Rupture of a berry (saccular) aneurysm of the circle of Willis, presenting with a sudden severe thunderclap headache.
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