Infectious diseases Flashcards
What are some causes of atypical pneumonia?
legionella pneumophilia
Mycoplasma pneumonia
Chlamydia
What are causes of atypical pneumonia in HIV patients?
Aspergillus
Pneumocystis jiroveci
What are causes of atypical pneumonia in CF patients?
Pseudomonas
Burkholderia
How are atypical pneumonias treated?
Clarithromycin
What are causes of typical pneumonia
strep pneumoniae
h. influenzae
staph aureus
klebsiella pneumoniae
how is typical pneumonia treated?
amoxicillin if mild
co-amoxiclav and macrolide e.g. erythromycin if moderate or severe
what type of organism is strep pneumoniae?
gram positive diplococcus
when is staph aureus pneumonia common?
post influenza
what makes up a bacterial cell wall?
peptidoglycan
what electrolyte imbalance does legionella pneumophiliacause?
low sodium
what is the motor response in GCS?
- Obeys commands
- Localises to pain
- Withdraws from pain
- Abnormal flexion to pain (decorticate posture)
- Extending to pain
- None
what is the verbal response in GCS?
- Orientated
- Confused
- Words
- Sounds
- None
what is the eye response in GCS?
- Spontaneous
- To speech
- To pain
- None
what investigation needs to be done if you suspect legionella pneumonia?
urinary antigens
sputum culture and PCR for chlamydia or mycoplasma differential
CXR
what are the potential complications of legionella pneumonia?
sepsis hyponatraemia renal failure pleural effusion abscesses
what is legionella pneumonia associated with?
colonises water tanks e.g. holidays/air con
what drug should be given before results of urinary antigens come back in atypical pneumonia?
tazocin
tx of legionella is erythromycin/clarithromycin but give broad spec before confirmation
Ix in meningitis?
full blood count CRP coagulation screen blood culture whole-blood PCR blood glucose blood gas
immediate management if meningococcal septicaemia suspected?
IM benzylpenicillin
what is initial empirical therapy aged > 50 years for meningococcal septicaemia?
Intravenous cefotaxime + amoxicillin
amoxicillin is for listeria cover, only if >50
what is meds used for meningitis caused by listeria?
Intravenous amoxicillin + gentamicin
what is the treatment of meningitis if penicillin allergic?
chloramphenicol
if amoxicillin allergic- cotrimoxazole
what is also given in meningitis to reduce neurological sequale?
dexamethasone
what is the rash expected in meningococcal septicaemia?
non-blanching purpura
when couldn’t you do a LP?
raised ICP
don’t need to do if the patient has a rash
name some bacterial causes of meningitis? (>6 years)
Neisseria meningitidis (meningococcus) Streptococcus pneumoniae (pneumococcus)
name some bacterial causes of meningitis in neonates to 3 months?
Group B Streptococcus: usually acquired from the mother at birth. More common in low birth weight babies and following prolonged rupture of the membranes
E. coli and other Gram -ve organisms
Listeria monocytogenes
name some bacterial causes of meningitis in 3 months to 6 years?
Neisseria meningitidis (meningococcus) Streptococcus pneumoniae (pneumococcus) Haemophilus influenzae
what are classic signs and symptoms of meningitis?
headache fever nausea/vomiting photophobia drowsiness seizures
Signs:
neck stiffness
purpuric rash
what are the CSF finding in bacterial meningitis?
cloudy
high protein
low glucose
10 - 5,000 polymorphs/mm³
what are the CSF finding in viral meningitis?
clear
normal/raised protein
high glucose
lymphocytes
what are the CSF findings in TB meningitis?
slightly cloudy
high protein
low glucose
lymphocytes
who needs to informed if a diagnosis of bacterial meningitis?
Public health england
name some viral causes of meningitis?
Viral enterococcus
HSV
what is prophylaxis of close contacts of meningitis?
ciprofloxacin (recommended)or rifampicin
name the species of malaria?
P.falciparum (most common and severe)
P.vivax
P.ovale
P.malariae
how is malaria transmitted?
by the bite of the female anopheline mosquito
what are the features of malaria?
severe headache fever/ cold/ sweating splenomegaly dry cough myalgia D&V
what is a protective factor for malaria?
sickle cell trait (HbS)
Ix for malaria
3 x thick and thin blood films (thick= diagnostic) (thin= species) bloods inc coag screen and LFTs RDT (antigen test)
mx of falciparum malaria?
most are resistant to chloroquine
- IV artesunate if severe
- ACTS if uncomplicated
- fluids and ITU support
mx of other strains of malaria?
quinine
artemisinin-based combination therapy (ACT) or chloroquine
complications of severe malaria?
DIC multi-organ failure seizures and coma death ARDS shock sepsis
malarial prophylaxis drugs?
doxycycline- 2 weeks prior and 4 weeks after
malarone- 2 days before and 7 days after
methequine- taken weekly
SEs of doxycycline?
sunlight hypersensitivity, nausea and diarrhoea
SEs of methequine?
neuropsychiatric SEs- anxiety and hallucinations
common causes of gastroenteritis?
Viral- Rotavirus
Norovirus
Adenovirus
Bacterial- E.coli, Campylobacter jejuni, shigella, salmonella, bacillus cereus, giardia, staph aureus
what are the 4C’s that are associated with C.diff infection?
clindamycin, cephalosporins, co‐amoxiclav and ciprofloxacin
what condition can C.diff infection lead to?
pseudomembranous colitis
features of C. diff infection?
diarrhoea
abdominal pain
a raised white blood cell count is characteristic
if severe toxic megacolon may develop
diagnosis of C.diff
is made by detecting Clostridium difficile toxin (CDT) in the stool
mx of C.diff
1st line- metronidazole
2nd line- vancomycin
features of E.coli infection?
most common cause of GE travellers watery stools abdo pains nausea It is spread through contact with infected faeces, unwashed salads or water. E. coli 0157 produces the Shiga toxin- can lead to haemolytic uraemic syndrome no ABX tx
features of giardia infection?
prolonged, non bloody diarrhoea
tx= metronidazole
features of cholera?
profuse, watery diarrhoea
hypoglycaemia
severe dehydration resulting in weight loss
travellers
features of shigella infection?
bloody diarrhoea
vomiting and abdo pain
Shigella is spread by faeces contaminating drinking water, swimming pools and food.
Shigella can produce the Shiga toxin and cause haemolytic uraemic syndrome. Treatment of severe cases is with azithromycin or ciprofloxacin.
features of campylobacter infection?
flu-like prodrome followed by crampy abdo pains, fever and diarrhoea which may be bloody
may mimic appendicitis
It is spread by:
Raw or improperly cooked poultry
Untreated water
Unpasteurised milk
what typically causes bacillus cereus infection?
rice
features of amoebiasis infection?
gradual onset bloody diarrhoea
abdo pain and tenderness which may last for several weeks
mx of campylobacter?
Clarithromycin
mx of salmonella and shigella
ciprofloxacin
what else needs to be done with infective GE?
The ‘Proper Officer’ at the Local Health Protection Team needs to be notified. They in turn will notify the Health Protection Agency on a weekly basis
how to tell if cellulitis has progressed to necrotising fasciitis?
pain disproportionate to injury
Ix for cellulitis?
bacterial= black swabs
blood cultures
what is HIV?
a single stranded RNA virus
causes host cells to produce virions which infect new cells with CD4 receptor
transmission of HIV?
needlestick sex IVDU blood products vertical transmission
diagnosis of HIV?
serology
detect antibodies and antigens of the virus
(can have false negative results up to 4 weeks post infection)
markers of disease progression in HIV?
CD4 cells
viral load
what does U=U mean?
undetectable viral load= untransmittable
what is at risk once CD4 count <200?
opportunistic infections e.g. PCP and toxoplasmosis
what is at risk once CD4 count <50?
MAI- mycobacterium avium intracellulare
CMV
when is AIDS diagnosed?
CD4 count <200
what are AIDs defining illnesses?
Kaposi’s sarcoma Pneumocystis jirovecii pneumonia (PCP) Cytomegalovirus infection Candidiasis (oesophageal or bronchial) Lymphomas Tuberculosis
Ix of PCP?
CD4 count and viral load
CXR
bronchio-alveolar lavage
sputum culture
TX of PCP?
IV cotrimoxazole (oral when well) for 21 days steroids
tx of HIV?
antiretroviral therapy-
2NRTIs plus PI or NNRTI
what is post-exposure prophylaxis for HIV?
zidovudine- within 72 hours of exposure
do pregnancy test before
prophylaxis of CMV?
gancyclovir
prophylaxis of PCP?
co-trimoxazole
differentials of jaundice in the UK?
hepatitis EBV CMV ascending cholangitis typhoid TB malaria leptospirosis
transmission of hep A?
faco-oral transmission (shellfish)
features of hep A?
Acute
self-limiting jaundice and abdo pain
IgM
tx of hep A
supportive vaccine
RFs of hep B?
IVDU multiple sexual partners blood products vertical transmission typically prisons, homeless, overcrowding
features of hep B?
acute- jaundice, malaise, abdo pain, N&V
Ix of hep B?
various antibodies
PCR for viral load
LFTs- high bilirubin, high ALT/AST, high ALP
histology- ground glass hepatocytes
signs of previous vaccination
HBsAb
signs of chronic infection
HBcAb, HBs Ag, HBV-DNA
signs of infection cleared after exposure
HBsAb, HBcAb
tx of Hep B infection?
Screen for other blood born viruses (hepatitis A and B and HIV) and other sexually transmitted diseases
Refer to gastroenterology, hepatology or infectious diseases for specialist management
Notify Public Health (it is a notifiable disease)
Stop smoking and alcohol
Education about reducing transmission and informing potential at risk contacts
Testing for complications: FibroScan for cirrhosis and ultrasound for hepatocellular carcinoma
Antiviral medication- tenofevir or entecavir
Liver transplantation for end-stage liver disease
prognosis of Heb B?
80% full recovery
10% chronic hepatitis
10% carriers
what to use as prophylaxis for transmission
HBIG
give within 24 hours of birth if vertical, followed by full vaccination course
transmission of Hep C?
blood products and sexually
IVDU most common
toothbrushes and razors
features of Hep C?
majority are asymptomatic
10-15% have jaundice and other general symptoms
who needs to be screened for hep C?
any patient with a persistently elevated ALT
diagnosis of hep C?
serology- HCV antibody PCR- HCV PCR LFTs FBC U&Es
clinical assessment of the liver?
Fibroscan- assesses liver stiffness
if advanced fibrosis- 6 monthly AFP and liver USS for screening of HCC
OGD if gastric or oesophageal varices
features of liver failure?
coagulopathy- prolonged PT time
splenomegaly
varices
tx of hep C virus?
DAAs- direct acting antiviral drugs
monitor FBC, U&E and LFTs every 4 weeks and viral load
what is defined as cure for Hep C?
undetectable HCV RNA in the blood 12 weeks after the end of treatment
RFs for TB?
HIV overcrowding IVDU ethnic minorities homeless immunosuppression
what is the pathophysiology of TB?
mycobacterium tuberculosis -> engulfed by macrophages -> form granumoas -> GHON focus -> latent phase -> MTB enters bloodstream-> extra-pulmonary TB
features of TB?
pulmonary- cough +/- haemoptysis
SOB
fever, night sweats, weight loss, fatigue, lymphadenopathy
extra pulmonary- TB meningitis, pericarditis, arthritis etc (anywhere in body)
test for latent TB?
Mantoux
quantiferon gold test
test for active TB?
CXR
sputum microscopy for acid fast bacilli (Ziehl-Neelson stain)
Tx of TB and tests to do beforehand?
Rifampicin
Isoniazid
Pyrazinamide
Ethambutol
U&Es, LFTs, FBC, vision testing
SE of rifampicin?
nausea, anorexia, red urine, hepatotoxicity
SE isoniazid?
N&V, constipation, peripheral neuropathy
SE pyrazinamide?
hepatoxicity, N&V, arthralgia, sideroblastic anaemia
increased uricaemia causing gout
SE ethambutol?
optic neuritis
prevention of TB?
notifiable disease
prophylaxis of contacts
BCG vaccine
what is infectious mononucleosis?
glandular fever
causes of glandular fever?
EBC
CMV
HHV-6
features in glandular fever?
sore throat, pyrexia and lymphadenopathy
also splenomegaly, hepaitis
diagnosis of glandular fever?
monospot test and FBC
how long do you have to avoid playing contact sports in glandular fever?
8 weeks
cause of syphilis?
spirochaete e.g. treponema pallidum
primary features of syphilis?
chancre- painless ulcer at site of sexual contact
local non-tender lymphadenopathy
secondary infection in syphilis?
6-10 weeks after primary infection fevers, lymphadenopathy rash on trunk, palms and soles buccal ulcers condylomata lata
tertiary features of syphilis?
gummas
ascending aortic aneurysms
Argyll Robertson pupil
tabes dorsalis
Ix of syphilis?
rological tests can be divided into: cardiolipin tests (not treponeme specific) e.g. VDLR treponemal-specific antibody tests
tx of syphilis?
benzathine penicillin 1st line IM
alternative- doxycycline
what rash is sometimes seen following syphilis tx?
Jarisch-herxheimer
what disease is common in warm fresh water in the tropics? e.g. canoeing/sailing holidays
leptospirosis, leptospira interrogans
tx= doxycycline
complication of leptospirosis?
Weil’s disease- jaundice occurs about 1 week after the onset of symptoms
causes renal failure and major haemorrhage
characteristics of lyme disease and cause?
tick bite
target-shaped rash, an erythematous macule spreads slowly from the centre
can have joint involvement with a mono- or oligoarthritis
how to diagnose PCP?
bronchoalveolar lavage
CXR- bilateral perihilar shadowing
Cysts and trophozoites on microscopy of the sputum
Exercise induced desaturations
tx of PCP?
Co-trimoxazole
+ steroids if hypoxic
neurocomplications of HIV/
Cerebral toxoplasmosis - tx is sulfadiazine
Cryptococcus meningitis
Primary CNS lymphoma
NHL
CMV encephalitis
Progressive multifocal leukoencephalopathy
Ix of viral hepatitis?
LFTs and clotting Hep B and C serology Alpha fetoprotein US scan of the liver Liver biopsy
what 2 STIs can present with a chancre?
syphilis
gonorrhoea
girl comes back from India with rigors, RUQ pain referred to shoulder and diarrhoea. Stool culture and microscopy shows cysts. What is the cause?
amoebiasis with liver abscess
ID that can cause gross eosinophilia?
parasitic worm infections due to pulmonary eosinophilia
complications of meningitis?
hearing loss
seizures and epilepsy
cognitive impairment
memory loss
post gastroenteritis complications
Lactose intolerance
Irritable bowel syndrome
Reactive arthritis
Guillain–Barré syndrome
GE management?
Stool MC&S
Assess dehydration- fluid challenge
Diaoralyte if necessary (rehydration)
Advise them to stay off work or school for 48 hours after symptoms have completely resolved
Antibiotics should only be given in patients that are at risk of complications and once the causative organism is confirmed.
how long do newborns of HIV positive mothers need treatment for?
4 weeks
can only be delivered by vagina if undetectable load
