Infectious Conditions Flashcards
3
What is meningitis?
Inflammation of the meninges (3 layers: dura mater, arachnoid mater and pia mater)
What are the causes of both bacterial and viral meningitis? What are some non-infective causes as well?
Bacterial:
* Neisseria meningitidis
* Streptococcus pneumoniae (pneumococcus)
* Haemophilus influenzae
* Listeria monocytogenes (particularly in neonates)
Viral:
* Enteroviruses (e.g., coxsackievirus)
* Herpes simplex virus (HSV)
* Varicella zoster virus (VZV)
Non-infective:
* Malignancies
* Certain drugs (i.e. NSAIDs)
* Systemic infl. disease (i.e. sarcoidosis, SLE)
Sx of meningitis
- Headache
- Stiff neck
- Fever
- Photophobia
- N+V
- Seizures
- Kernig’s sign
- Brudzinski sign
In children and neonates:
* Can present with non-blanching rash (when there is meningococcal septicaemia)
* Hypotonia and hypothermia
* Poor feeding
* Bulging fontanelle
- Kernig’s sign: Kernig’s sign is a test performed to evaluate the presence of meningeal irritation and stiffness in the hamstrings and lower back. To perform this test, the patient is positioned lying on their back with the hip and knee flexed at 90 degrees.
- Brudzinski’s sign: Brudzinski’s sign is another maneuver used to assess for meningeal irritation. This test involves passive neck flexion, where the examiner gently flexes the patient’s neck forward toward the chest while the patient is lying on their back.
Ix of meningitis?
Bloods: FBC, U&E, glucose
ABG
Blood cultures
CT head
Describe the differences in results of a lumbar puncture CSF for meningitis in both bacterial and viral.
Bacterial vs Viral
* Appearance: Cloudy vs clear
* Protein: High vs mildly raised/normal
* Glucose: Low vs normal
* WCC: High (neutrophils) vs High (lymphocytes)
* Culture: Bacteria vs -ve
Easy way to remember: Bacteria swimming in the CSF will release proteins and use up glucose. Viruses may release a small amount of protein and do not use up glucose. The immune system releases more neutrophils with bacteria and lymphocytes with viruses.
Tx of meningitis in:
* Bacterial meningitis (neonates and adults)
* Viral meningitis (neonates and adults)
Bacterial -
Adult:
* 2g of IV ceftriaxone BD + IV amoxicillin added in patients at age extremes for listeria coverage.
* Steroids - reduce severity of hearing loss
Neonates:
* If seen in primary care setting urgent dose of benzylpenicillin (IM or IV) while awaiting transfer to hospital
* Under 3 months – cefotaxime plus amoxicillin (amoxicillin is to cover listeria)
* Above 3 months – ceftriaxone
Viral -
Both:
* Aciclovir
Bacteria meningitis and meningococcal infection are notifiable diseases to the UK Health Security Agency. What is the post-exposure prophylaxis tx given by the local health protection team?
Single dose ciprofloxacin
What is encephalitis?
Inflammation of the brain parenchyma, also known as the “encephalon”.
The brain parenchyma refers to the functional tissue in the brain that is made up of the two types of brain cell, neurons and glial cells.
What are the causes of encephalitis?
Viral:
MC - herpes simplex virus type 1 (HSV-1)
Other -
* HSV-2
* CMV
* EBV
* VZV
* HIV
Sx of encephalitis
- Altered mental state
- Fever
- Flu-like prodromal sx
- Seizures
- Headache
- Behavioural changes
Ix for encephalitis
Bloods
CSF analysis w/viral PCR testing
CT scan - if lumbar puncture contraindicated
MRI scan
HIV testing
Contraindications to a lumbar puncture include a GCS below 9, haemodynamically unstable, active seizures or post-ictal.
Mx of encephalitis
Broadspectrum antimicrobial cover w/ 2g IV ceftriaxone BD and 10 mg/kg aciclovir TDS for two weeks.
Note: if CMV is the cause - ganciclovir
Aciclovir SE:
Generalised fatigue/malaise (common)
Gastrointestinal disturbance (common)
Photosensitivity and urticarial rash (common)
Acute renal failure
Haematological abnormalities
Hepatitis
Causes of brain abscess?
- Extension of sepsis from ear/sinuses
- Trauma to scalp
- Penetrating head injuries
- Embolic events i.e. IE
Sx of brain abscess?
- Raised ICP sx (i.e. nausea, seizures, papilloedema)
- Headache - dull + persistent
- Fever
- Focal neurology
Ix of brain abscess?
CT head
