Tutorial 4 Flashcards
(31 cards)
What are the typical features of acute bacterial and viral meningitis?
Clinical presentation and laboratory analysis of the CSF
Includes recognition of the characteristic gross and microscopic features of the brain in meningitis.
What are the protective membrane coverings of the CNS?
- Dura mater
- Arachnoid mater
- Pia mater
The pia and arachnoid are collectively referred to as the ‘leptomeninges’.
What is the role of cerebrospinal fluid (CSF) in the CNS?
Circulates in the vascularised subarachnoid space between the arachnoid and pia
Contamination of CSF by infective agents leads to meningitis.
What are the common causative bacterial agents of meningitis in neonates?
- Group B Streptococcus
- E. coli
- Listeria monocytogenes
This is part of a broader list of organisms that can cause meningitis.
What are the symptoms of meningitis?
- Fever
- Headache
- Lethargy
- Malaise
- Anorexia
Increased intracranial pressure may lead to severe headache, papilledema, nausea, vomiting, confusion, and loss of consciousness.
What CSF findings are characteristic of acute bacterial meningitis following a lumbar puncture?
- Colour: Purulent
- Pressure: Increased
- Cells: Increased neutrophils
- Protein: Increased
- Glucose: Decreased
Gram stain will be positive for organisms.
What is the histological feature of acute pyogenic meningitis?
Subarachnoid space is expanded and heavily infiltrated by acute inflammatory cells
Nuclei are multilobulated, indicating the presence of neutrophils.
What is a granuloma in the context of tuberculous meningitis?
A collection of activated macrophages surrounded by T lymphocytes
Granuloma formation is an example of Type IV Hypersensitivity.
What are the outcomes of viral meningitis?
Recovery is the rule. No gross changes seen in the brain
Most cases resolve without significant lasting effects.
What triggers the pathogenesis of septic shock in meningococcal septicaemia?
Presence of bacteria and their toxins in blood triggers a systemic inflammatory state
This results in endothelial cell activation and widespread thrombosis.
What characterizes Disseminated Intravascular Coagulation (DIC)?
Excessive widespread activation of coagulation and thrombi formation in microcirculation
Consumption of platelets and clotting factors leads to a hemorrhagic tendency.
Fill in the blank: The leptomeninges consist of the _______ and _______.
Arachnoid mater, Pia mater
True or False: Acute meningitis can be classified into acute pyogenic, acute aseptic, and chronic types.
True
What are the signs of meningeal irritation (Meningism)?
- Neck stiffness
- Photophobia
- Positive Kernig’s sign
- Positive Brudzinski’s sign
These signs can also occur in other conditions such as subarachnoid hemorrhage.
What is caseous necrosis in the context of tuberculous meningitis?
Necrosis in the centre of the granuloma that resembles cheese
It is a hallmark of granulomatous inflammation.
What complications can arise from delayed treatment of bacterial meningitis?
- Cranial nerve palsies
- Hydrocephalus
- Brain infarcts
- Epilepsy
Meningococcal infection can lead to meningococcal septicaemia and septic shock.
What does DIC stand for?
Disseminated Intravascular Coagulation
DIC is a serious condition characterized by the widespread activation of the clotting cascade.
In which condition is DIC commonly discussed in this context?
Meningococcal septicaemia
Meningococcal septicaemia is caused by the bacterium Neisseria meningitidis.
What are fibrin-rich microthrombi?
Thrombi formed in the glomerulus and other organs
These microthrombi can form in various organs including the brain, heart, lung, and gastrointestinal tract.
What is the significance of the glomerulus in relation to DIC?
It is a tuft of capillaries where fibrin-rich microthrombi can form
The formation of microthrombi can lead to renal complications.
What is the term for hemorrhagic spots larger than 1cm?
Ecchymoses
The singular form is echymosis.
What do you call pinpoint bleeds that are less than 1mm?
Petechiae
These are small red or purple spots on the body, caused by bleeding under the skin.
What syndrome is associated with adrenal necrosis and hemorrhage in meningococcal septicaemia?
Waterhouse-Friderichsen Syndrome
This syndrome is characterized by bilateral adrenal hemorrhage and insufficiency.
What causes adrenal gland stress during shock?
Increased demand for corticosteroids and catecholamines
The adrenal glands respond to stress by producing these hormones.
