9. Cardiovascular Flashcards
What is intermittent bacteraemia?
Infection spilling into the blood from another source (e.g. pneumonia, pyelonephritis, meningitis, abscess) which results in bacteria levels rising and falling periodically when the immune system kicks in.
What is bacteraemia?
Presence of bacteria in the blood
bacteraemia + signs/symptoms of infection = bloodstream infection
Positive bacteria blood culture whenever bloods are taken. Associated with endocarditis, mycotic aneurysm, pacing lead infection.
Continuous bacteraemia.
What does a DTP of >2 diagnose?
differential time to positivity
CRBSI (catheter related blood stream infection)
DTP = time taken for blood culture from through-line catheter to become positive Vs. from peripheral vein.
if the time is much quicker at the catheter, then the catheter is the source of infection.
Most common bacterial cause of catheter infections?
Coagulase negative Staphylococcus
+ staphylococcus Aureus
Most common bacterial cause of infective endocarditis?
Staphylococcus Aureus
+ Streptococci viridans
+ Coagulase negative staphylococcus
What is a mycotic aneurysm?
Dilation of the vessel wall due to infection
staph. aureus, strep. spp, salmonella, E.coli
A medical emergency involving inflammation of the leptomeninges and CSF.
Meningitis
leptomeninges = inner layers i.e. arachnoid + pia matter
What is meningoencephalitis?
Inflammation of meninges AND brain parenchyma
Type of meningitis that is usually caused by bacteria and develops rapidly.
- Acute pyogenic
- Aseptic
- Bacterial
- Chronic
- Acute pyogenic
What are chronic causes of meningitis?
- Mycobacterium Tuberculosis
- Neurosyphilis
- Cryptococcus
Type of meningitis that is usually caused by virus.
- Acute pyogenic
- Aseptic
- Bacterial
- Chronic
Aseptic
Headache, photophobia, fever, neck stiffness are clinical features of what?
Meningitis
Most common cause of meningitis in neonates?
Streptococcus Agalactiae
Most common cause of meningitis in adults?
Streptococcus Pneumoniae
+ Neisseria meningitidis
Main cause of viral meningitis?
Enteroviruses: Coxsackie + Echovirus
+ HSV
Acute inflammation of the brain parenchyma usually caused by virus?
Encephalitis
Most common causes of viral encephalitis?
Herpes viruses (HSV1/2/VZV) Rabies
Acute progressive viral encephalitis that is almost always fatal unless vaccine is given quickly.
Rabies
from dog bites
What are the 4 stages of rabies?
- Prodromal phase - fever, nausea, fatigue
- Furious phase - seizures, twitching, hydrophobia
- Dumb phase - paralysed, disorientated, stuporous
- Coma/death
Please Fight Dogs
Tabes dorsalis is a symptom of what?
slow degeneration of nerve cells
Neurosyphilis
Brain abscess = pus in the brain parenchyma
What is the most common bacterial cause?
Streptococci
Staph Aureus most common after surgery/trauma.
Surgical drainage is the main treatment method for brain abscess’.
Which antibiotic is given in addition?
1. Penicillin
2. Gentamicin
Penicillin
gentamicin cant cross blood/brain barrier
What causes ischaemic heart disease?
Myocardial ischaemia due to coronary atherosclerosis and ventricular hypertrophy.
Does angina pectoris cause myocardial death?
No
MI causes myocardial death
What makes up acute coronary syndrome?
- MI
- Unstable angina (constant angina due to poor blood flow to heart muscle)
- Sudden cardiac death
Myocardial infarction affecting the inner 1/3rd of heart muscle.
Subendocardial
most susceptible to MI due to having less perfusion
Myocardial infarction affecting full thickness of heart muscle.
Transmural
Build up of fluid in the pericardial space.
Cardiac tamponade
Blood markers of ischaemic heart disease (IHD).
Troponins T + I
+ Creatine kinase MB
How does the artery of a patient with hypertension differ to a normal artery?
- Narrow lumen
- More smooth muscle
- very elongated nuclei
Outline the renin-angiotensin-aldosterone system.
The reactions?
Where the hormones come from?
Their effect?
- Renin (from kidneys) converts angiotensinogen (from liver) = angiotensin I
- ACE (from lungs) converts angiotensin I = angiotensin II
angiotensin II stimulates vasoconstriction, aldosterone release, vasopressin (ADH) release, cardiac/vascular hypertrophy - Angiotensin II stimulates aldosterone release (from adrenal glands) which stimulates salt + water reabsorption in kidneys.
Give 3 causes of secondary hypertension.
- Cushing’s syndrome
- Conn’s disease
- Pheochromocytoma (tumour of adrenal glands)
- Correction (narrowing of aorta)
- Renal artery stenosis
What BP is classed as malignant hypertension?
BP > 190/120 mmHg
sudden increase in BP, medical emergency, irreversible organ damage