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Flashcards in Common infections Deck (25):
1

Classical presentation of acute pneumonia

   Fever - due to inflammation Shortness of breath Increased sputum production Pleuretic chest pain Dullness to percussion Bronchial breathing   

2

CURB65

Used for estimating prognosis of pneumonia. Score over 2 = hospital, over 3=ITU

Confusion

Urea >7mmol/l

Respiratory rate >30/min

Blood pressure SBP>90 or DBP <60

Age over 65

 

 

3

Organisms that cause acute pneumonia

Typical:
Streptococcus pneumoniae
Haemophilus influenzae
Staphylococcus aureus

Atypical:
Mycoplasma pneumoniae
Chlamydophila pneumoniae
Legionella sp.
Respiratory viruses
TB

4

Atypical pneumonia

Pneumonia caused by organisms which do not respond to penicillin or are non-culturable e.g. leigionella, M. pneumoniae, viruses.

Can't differentiate clinically

Detect with serology (rising Ab levels or urine antigen detection)

5

What investigations would you carry out in a patient with suspected pneumonia

Blood cultures, sputum if productive cough

Serology (2 samples, 7 days apart, may confirm atypical infection, useful in outbreaks)

Antigen testing (urine)

Pleural fluid sampling (to differentiate other causes of lung disease)

6

Why would you test a sputum sample in a patient with suspected pneumonia?

If the suspected cause was not a normal commensal of the body e.g. M. pneumoniae, Mtb, Pneumocytis,

7

Parapneumonic effusion

Pleural effusion associated with bacterial pneumonia, lung abscesses or trauma which introduces organisms into the chest wall.

Pleural inflammation results in exudate forming in the pleural cavity. This has a high neutrophil content.

Pleural effusions are normally sterile but if the bacteria invade the pleural space, inflamation and fibrogenesis result in abscess formation.

Fluid is resorbed and fibroblasts proliferate forming a scar.

8

Treatment of acute pneumonia

Increased survival if antibiotics given <4hrs

Amoxycillin for mild infection

Clarithromycin for atypical/hospital infection

Severe pneumonia broad spectrum (co-amoxiclav) + clarithromycin

Oxygen, IV fluids (treatment for sepsis)

9

Gastroenteritis

Inflammation of the stomach and intestinal epithelium

10

Diarrhoea

passage of liquid stool or frequent passage of normal stool

11

Food poisioning

vomiting/diarrhoea caused by eating food contaminated with bacteria, bacterial toxins or other substances

12

Dysentery

Bloody diarrhoea with mucus, tenesmus, pain and fever

13

Signs of hypovolemia

thirst, dry mucus membranes

low venous pressure

tachcardia

hypotension

14

Signs of colitis

Abdominal tenderness

bowel sounds

distension

15

In what patients would investigation of diarrhoea be indicated?

Bloody diarrhoea

Dehydrated patients

If diarrhoea is persistent

Abdominal pain

Fever

Immunocompromised

Risk of C.diff (>60, recent admission, antibiotics)

16

What investigations would you do in a patient with diarrhoea?

Blood tests

Stool sample (selective agar, grown in selective conditions)

17

Causes of non-inflammatory diarrhoea

Enteroadherent E. coli
Staph aureus
Bacillus cereus
Clostridium perfringens
Cholera

normally due to the relsease of toxin, rapid onset

18

Causes of inflammatory diarrhoea

Clostridium difficile (antibiotic related)
Shigella
E. coli
Salmonella
Campylobacter

19

Common food-borne causes of diarrhoea

Salmonella (poulty/eggs)

Campylobacter (poultry)

E.coli (faecall contaminated food)

20

Characteristic of cholera

Rice water stool

Rapid loss of fluid 

21

Common causes of viral gastroenteritis

Norovirus

Rotavirus

 

Detected by EM, Elisa or PCR

22

Giardia

Caused by giardia lamblia

Causes diarrhoea due to fat malabsorption, atrophy of intestinal villi and loss of disaccharides

Diagnosis my microscopy for cysts or immunoassay

Treat with metronidazole

23

Subacute endocarditis

Slow progressing endocarditis caused by bacteria from the mouth and GI tract

Progression is subtle

Vasculitic lesions are normally first indication e.g. splinter haemorrhages

24

Acute endocarditis

Caused by S. aureus

Rapid deterioration, results in valve failure

25

Investigations for a patient with endocarditis

Blood culture

Echocardiogram (valve lesion or vegetation)

Duke criteria for assessing severity

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