Microbiology infection Flashcards
Ddx: dysuria without pyuria or positive culture?
Non-infectious cause of discomfort
- urethral irritation due to sexual activity, tight clothing, vaginal hygiene products
- or a condition like interstitial cystitis: bladder inflammation without infection
What are likely causes of generalized rashes that involve the palms and soles? (3)
Drugs
Viral infections
Rickettsial infections
Syphillus
What indicates worse prognosis in a septic patient compared to fever?
Hypothermia
What is the exception to the normally significant bacterial growth?
Normal: 10^8 cfu/L
Exception: women with recognized uropathogen 10^6-7/L
What is the number of bacterial growth indicating significant growth?
10^8 cfu/L
What is a potential consequence of a UTI?
Septicaemia blood steam infection (BSI)
(aka “urosepsis”)
Value of fast urinalysis if organism later invades blood
What clinical presentation indicates endocarditis until proven otherwise?
Staphylococcus aureus meningitis without preceding CNS instrumentation
What is an unlikely cause of jaundice in a febrile patient?
Viral hepatitis
Investigation for paediatric patients with recurrent UTIs? (2)
Anatomical imaging
Proteinuria assessment
DDX for patients with unexplained neurological features (5)
tuberculosis
HIV
syphilis
Lyme disease
Whipple’s disease
What can severe muscle pain indicate?
Sepsis, even in the absence of fever
What does an early meningococcaemic rash resemble?
Non sepcific viral rash
- blotches, bumps or spots that may be itchy or not
When should DDX be UTI in paediatric patients
Febrile patient: UTI should be a DDX until proven otherwise
Specific IgM antibodies in pregnant patients
Due to changes in immunie response, IgM is a useful but unreliable marker of primary infections in pregnancy.
Clinical decisions should not be base solely on positive IgM.
When do you treat asymptomatic bacteriuria?
Pregnancy
Before urologic procedures
When can viral meningitis be diagnosed?
PCR
After patient recovery
Meaning, not everyone with aseptic meningitis has viral meningitis
Can you move a septic arthrititic joint?
Yes
What two structures should you examine with staphylococcal bacteraemia?
Heart and bones
What pathogen in the urine is a sign of bacteraemia until proven otherwise?
Staphylcoccus aureus
DDX = staphylococcal bacteraemia
List and describe different types of medical imaging for UTIs (3)
1 KUB ultrasound (kidney, ureter and bladder)
2 MCUG (micturating cystourethrogram)
3 Radioisotope nuclear imaging (DMSA - for kidneys)
DDX of patient presenting with fever and back pain
Vertebral osteomyelitis - bone infection
Can progress to epidural abscess
What needs to be excluded in a patient presenting with abdominal pain or back pain within weeks of an episode of diarrhoea
Bacterial aortitis
Microbiology: differentiate cystitis and urethritis
Cystitis: infection of bladder
- dysuria
- pyuria
Urethritis: infection of urethra
- dysuria
- mid stream pyuria but no growth
What is the DDX of an elderly patient with fever and multisystem disease until proven otherwise?
Living in tuberculosis-endemic setting, DDX = disseminated tuberculosis
What is a diagnosis that must be excluded from a febrile patient with recent travel hx
Travelling from malaria endemic countries, DDX = Malaria
Aid of paediatric bag urines (opportunistic catch) in ddx UTI
Can exclude but not confirm UTI due to high susceptibility of contamination
What pathogenic disease can masquerade as herpes simplex encephalitis?
Listeria monocytogenes meningoencephalitis
What symptom is unlikely to be associated with viral infections in the elderly?
And what symptom is not present in an elderly patient with sepsis?
Fever for both
What is the most likely cause of recurrent rigors?
Bacterial infection
