Steve Ritchie Flashcards by John Gibbins

What is the main cause of cystitis?

E. Coli

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What enables some E. Coli to invade to the kidney?

The E. Coli have fimbria that allow it to bind and flagella that allows it to move.

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How do you treat someone with cystitis?

Needs to be cleared by the kidneys, needs to be narrow spectrum (except in resistance).
Nitrofuratoin - 4 x a day
Trimethoprim - 1/day

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How do you treat someone with pylonephritis/

Gnetamycin - do blood and urine cultures

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How is hepatitis A virus transmitted?

Faecal oral route

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What does hepatitis A cause?

Acute hepatitis only - Higher rates of symptoms with age

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What are the symptoms of hepatitis B infection?

Usually asymptomatic in adults

Fever, malaise, jaundice, swollen liver, anorexia

30% of adults get an acute infection and less than 5% get chronic.

Children get chronic infection caught from mother during birth. Almost all don’t get an acute infection.

Can lead to cirrhosis and hepatocellular carcinoma -> death

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What are the symptoms of hepatitis C infection?

Usually asymptomatic in adults - 10-15% get acute

50-85% get chronic

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What sort of virus is hepatitis B and why is that important?

It is a DNA virus but it still uses reverse transcriptase, which is a drug target

It is incorporated into the nucleus and host DNA

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What causes damage to the liver cells in HBV infection?

Lymphocytes

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How do you identify HBV infection?

HBV virus releases a lot of HBSAg into the blood stream

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What are the targets of drugs with HCV?

Non-structural proteins from viral polymerase enzymes.

Does not enter host cell DNA.

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How do you detect HAV?

Detection of anti-HAV IgM antibodies in the blood.

IgM will be positive during the infection but IgG can also indicate previous infection

IgM -ve and IgG +ve indicates previous infection

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How do you detect HBV?

Detection of HBSAg in the blood

Hepatitis anti-HBS antibodies indicate vaccination
Hepatitis core antigen indicates infection (not present with vaccination)
Hepatitis b core antigen -ve but anti-HBS indicates protection indicates vaccination

Hepatitis b core antigen +ve, HBSAg negative and anti-HBS +ve indicates previous infection

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How do you detect HCV?

Detection of IgG antibody against HCV followed by PCR detection of HCV RNA in his blood.

If IgG present then either current infection or immunity, so check PCR. If both present then current infection.

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What is the most common for of HBV transmission?

Vertical transmission

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What are the symptoms of pneumonia?

Increase RR (70%)
Crackles (80%)
Consolidation - (30%)
Fever chills - 50%
Non-pulmonary (20%)

What are the risk factors for pneumonia?

<2 or .65 yo
Smoking
Chronic lung disease
Immune dysfunction

What are the main causes of pneumonia?

Streptococcus pneumonia
Haemophilius influenzae
Staphylococcus aureus
Viral pneumonia

What are the virulence factors of streptococcal pneumonia?

Polysaccharide capsule - prevents phagocytosis and complement
Pneumococcal surface protein A - binds to epithelial cells and prevents deposition of C3b
PspC - prevents activation of complement
Pneumolysin (toxin) lyses neutrophils and epithelial cells

What investigations do you do for someone with pneumonia?

Cheast X-ray is the primary investigation

Detect urine antigens - streptococcal urine antigens (high specificity low sensitivity).

Sputum sample - PCR for viruses and culture for bacteria

Blood cultures

Nasopharyngeal swab

What do you use to treat pneumonia?

Viral - no treatment

Streptococcus pneumonia is changing it’s transpeptidase - leading to reduced susceptability- less effective than S aureus

Treat Streptococcus pneumoniae with penicillin. May need a high dose if oral. I.V should be ok

How do macrolides work and what is some examples?

They interfere with bacterial ribosomes, which differ from human ribosomes. Interfere with transpeptidation (tRNA binding)

Azithromycin, erythromycin

Macrolids are broad spectrum, with limited activity against gram -ve bacteria.

Good for treatment of strep, staph and other causes of pneumonia. Treatment of chlamydia. Used in skin infection if allergic to penicillin

What are the adverse effects of macrolides?

erythromycin - agonist of motilin receptor - increase peristalsis - GIT upset

Azithromycin causes a prolonged Q-T interval and can cause arrhythmias.

What immune factor causes a fever and how?

IL-6 released from the innate immune cells acts on the hypothalamus -> releases factors to change temp. It also causes a change in behaiour.

What is the point of a fever?

Enhancing the function of the immune system. Particularly, neutrophils. They function better at this temp.

What is a cause of a non-blanching rash?

Septicoccal meningitis. Neisserria meningitidis

When should you investigate a fever?

Age <3 months Unwell Immunocompromised Duration >10 days

Should you treat a fever in an unwell child?

To make the child feel better

Where in the meninges does meningitis occur?

The subarachnoid space. This is where CSF is.

How is meningitis defined?

An increase in WBCs in the CSF.

What are the common causes of meningitis?

Virus - mild and no treatment required. Bacterial - neisseria meningitidis and streptococcus pneumonia - serious

What are the common symptoms of meningitis?

``` Headache Fever Photophobia Neck stiffness Drowsiness Rash (neisseria meningitidis) ```

How does neisseria meningitidis get into the CSF?

Usually an initial nasopharyngeal infection - from blood to CSF. Surgery directly to the subarachnoid space

How do you diagnose meningitis?

Clinical suspicion: Lift legs and then rais hear = stress on the meninges = pain in neck with meningitis. Kernigs sign. CSF assessment Blood cultures Throat swab Blood PCR

How do you differentiate between viral and bacterial meningitidis?

Viral - lymphocytes in the CSF, normal glucose, increased protein Bacterial - neutrophils in the CSF. decreased glucose.

What does the rash indicate in meningitis?

That it is caused by neisseria meningitidis

What are the virelence factors of neisseria meningitis?

Gram -ve bacteria. Main factors involve avoiding complement. Binds factor H, which prevents complement. Type N pili binds C4, which cleaves C3 convertase. Capsule prevents neutrophil recognition and complement binding. Blebs of LPS - super antigen

What does lots of LPS in the blood do?

Septic shock - neutrophils release NETS. -> clotting of capillaries. This causes fever, tachycardia, low blood pressure, SOB,

How do you treat bacterial meningitis?

IV antibiotics (penicillin) Take CSF and blood Pain relief Fluids Antibiotics to family members