Diseases Flashcards
Risk factors for CNS infection (3)
Immunodeficiency, chronic otitis media, cranial trauma
Contraindications of lumbar puncture (2)
cerebral SOL, ↑ ICP
Normal opening presure of CSF
<15~18 mmHg
Normal white cell count in CSF
<5 (<30 for 1-month-old infants)
Pathogenesis of meningitis (molecular mechanism)
- meningeal invasion –> replicate in subarachnoid space
- bacterial cell wall, LPS… –> inflammation & endothelial cell damage
- ↑ BBB permeability –> hydrocephalus + cell swelling –> cerebral oedema
- vasculitis –> cerebral ischaemia
- metabolic distrubances –> vasodilation
–> ↑ ICP
- neuronal injury
Kernig sign
knee extension is painful –> indicate meningitis
Brudzinski sign
passive neck flexion elicits hip & knee flexion –> indicate meningitis
Bacteria causing acute meningitis in infants <3 months (3)
Strep. agalactiae, E. coli (MC), Listeria monocytogenes
Bacteria causing acute meningitis in children >3 months (4)
Strep. pneumoniae, Neisseria meningitidis, Haemophilus influenzae, TB
Bacteria causing acute meningitis in adults (5)
Strep. pneumoniae (MC), Neisseria meningitidis, Listeria monocytogenes, TB, Strep. suis
MC bacteria causing acute meningitis in infants <3 months
E. coli
MC bacteria causing acute meningitis in adults
Strep. pneumoniae
Bacteria causing procedure-related acute meningitis (3)
S. aureus, S. epidermidis, GNR
Which pathogen commonly causes deafness as complication after acute meningitis?
Strep. suis
Empirical antibiotics for acute bacterial meningitis
IV cefotaxime
Which acute bacterial meningitis has the highest mortality?
Pneumococcal meningitis
If a patient with pneumococcal meningitis shows penicillin and cefotaxime resistant, which antibiotics should be prescribed? (2)
vancomycin + rifampicin
Which acute bacterial meningitis commonly shows petechiae / purpura?
Meningcoccal meningitis
Treatment for meningcoccal meningitis
Penicillin G (cefotaxime if resistant)
Treatment for HiB meningitis
ampicillin (amoxicillin-clavulanate, cefotaxime if resistant)
Which acute bacterial meningitis is acquired through zoonosis?
Strep. suis
Acute viral meningitis causative agents (5) (which MC?)
Enterovirus (MC), HSV2, VZV, HIV, mumps virus
Treatment for cryptococcal meningitis
IV amphotericin + flucytosine
[AIDS] lifelong fluconazole maintenance
Subacute / chronic meningitis causative agents (2)
TB, Cryptococcus neoformans
Diagnosis for cryptococcal meningitis
[CSF] India ink, LAT, culture
[Blood] culture & stain
Causative agents for acute encephalitis (4)
HSV1,2, Rabies, Japanese encephalitis, Toxoplasma gondii
Empirical antimicrobial for acute encephalitis
IV acyclovir
MC cause of sporadic encephalitis
HSV1,2
Diagnosis for herpes encephalitis
[Onset] CSF HSV PCR
[at day 7 from onset] MRI/ CT/ EEG
[at day 14] intrathecal HSV Ab
Prophylaxis for rabies
killed rabies vaccine + HRIG (post-exposure)
Vector for Japanese encephalitis
Culex mosquito
Which virus causes acute focal encephalitis?
HSV1,2
Which virus causes acute pan-encephalitis? (2)
Japanese encephalitis virus, Rabies virus
MC CNS infection in AIDS patients
Toxoplasma encephalitis
Which parasite causes acute focal encephalitis?
Toxoplasma gondii
Pathogen for subacute sclerosing encephalitis
Meales virus (reactivation after years)
Pathogen for progressive multifocal leukoencephalopathy
JCV
Transmission for poliovirus
faecal-oral route
Pathogenesis of poliovirus
direct infection of ventral horn of spinal cord
Presentations of poliomyelitis (3)
fever, flaccid paralysis, respiratory dysfunction
Vaccines for poliovirus (2)
IM inactivated / oral live
Pathogenesis of tetanus
tetanospasmin: retrograde axonal transport from PNS to CNS –> - inhibitory neurons –> spasm
Disease with risus sardonicus
tetanus
Diagnosis of tetanus
clinical diagnosis only
Management for tetanus (4)
Tetanus toxoid vaccine, Tetanus immunoglobulin, ABx on wounds, supportive (e.g. muscle relaxant)
Causative agents of Guillain-Barre Syndrome (2+3)
Campylobacter jejuni, Mycoplasma pneumoniae
EBV, VZV, Dengue
Presentations of Guillain-Barre Syndrome
ascending paralysis, paraesthesia
Management for Guillain-Barre Syndrome
IVIG
At which lobe does HSV mostly cause encephalitis?
Temporal lobe
Definition of uncomplicated UTI
adult non-pregnant female with no structural / neurological dysfunction
Risk factors for UTI (6)
- female
- male before 3m old
- indwelling catheter
- urinatry tract obstruction
- vesiculoureteral reflux
- DM
MC bacteria for UTI
E. coli
Bacteria causing UTI in young sexually active women
S. saprophyticus
Bacteria causing urethritis in male suspected to be STD (3)
Neisseria gonorrhoeae, Chlamydia trachomatis, Ureaplasma urealyticum
Bacteria causing UTI (8)
E. coli, Klebsiella, Proteus, Pseudomonas
S. saprophyticus, S. aureus, Enterococcus, MTB
Parasite causing UTI
Schistosoma haematobium
3 common urinary specimen and usages
First pass urine: for urethritis
Mid-stream urine (MSU): for cystitis
Terminal urine: for prostatitis
Reasons for negative urine culture
- true absence of UTI
- recent ABx use
- diuresis
- fastigious organisms / TB
Asymptomatic significant bacteriuria does not require ABx Tx except: (2)
- Pregnancy
- Prior to urogenital procedure
Significant bacteriuria definition for MSU
10^5 CFU/mL (colony forming unit)
Treatment for urethritis
IM Ceftriaxone once, followed by oral doxycycline / azithromycin
Antibiotics for cystitis (3)
PO Nitrofurantoin, Septrin, Augmentin
Treatment regimen for cystitis (uncomplicated vs complicated)
Uncomplicated: 3~5d
Complicated: 7d
Treatment for pyelonephritis
IV Augmentin / Tazocin until afebrile for 24~48h, followed by 14d PO
Antibiotics for prostatitis
PO Ciprofloxacin
MC cause for common cold / rhinitis
Rhinovirus
MC cause for pharyngitis / tonsilitis
Adenovirus
MC cause for epiglotitis
Haemophilus influenzae
MC cause for acute bacterial pharyngitis
Streptococcus pyogenes
Causes for infectious mononucleosis (or IM-like symptoms) (3)
EBV, CMV, HIV
MC causes for AECOPD
Haemophilus influenzae
Causes for hospital-acquired pneumonia (3)
Enterobacteriaceae, Pseudomonas aeruginosa, S. aureus
Routine workup for pneumonia
Blood test: CBC (esp. WCC & differential), LRFT, ESR, clotting profile…
Imaging: CXR
Microscopy:
1. Early morning sputum: microscopy, culture, gram stain, sensitivity, ZN stain for AFB, TB culture
2. NPA: PCR for atypicals and viruses
3. Blood: culture for bacteria, serology for atypicals & viruses
4. Urine: Pneumococcal Ag, Legionella Ag
Clinical triad of infectious mononucleosis + peripheral blood film findings
fever + tonsillar pharyngitis + lymphadenopathy
lymphocytosis, atypical lymphocytes
Which patient group is especially vulnerable to infectious mononucleosis and why?
X-linked lymphoproliferative syndrome
EBV in lymphocytes cannot be cleared
Diagnosis of EBV infectious mononucleosis
- Monospot test / Heterophile antibody test
- EBV IgM
Pathogen for upper respiratory tract infection + gray adherent membrane
Corynebacterium diphtheria
Management for diphtheria
antitoxin serum + penicillin
Empirical antibiotics for CAP (moderate & severe)
Moderate: PO / IV Amoxicillin-clavulanate + Macrolide
Severe: IV Ceftriaxone + Macrolide
Empirical antibiotics for HAP
IV Piperacillin-Tazobactem +/- Gentamicin
Empirical antibiotics for aspiration pneumonia
IV Ceftriaxone + Metronidazole
Managment for lung abscess / empyema
Metronidazole + drainage
Antibiotics for Streptococcus pneumoniae
Penicillin G [if susceptible]
Ceftriaxone, Fluoroquinolones
Vaccination for Streptococcus pneumoniae
PCV13, PPSV23
Pathogen for walking pneumonia
Mycoplasma pneumoniae
Pathogen for cold autoimmune hemolytic anaemia
Mycoplasma pneumoniae
Diagnosis of Mycoplasma pneumoniae
- Serology
- Cold agglutinin test
- PCR
Definition of nosocomial pneumonia
> 2d after admission / <2w after discharge
Micrological workup for enteric infections
Stool:
- Culture (XLD agar, TCBS agar, Skirrow’s medium +/- alkaline peptone-enhanced TCBS +/- sorbitol MacConkey agar)
- Multipex viral Ag detection (esp. Rotavirus) / PCR
- C. diffile toxin PCR
Blood (systemic involvement only)
Food (pandemic outbreak only)
What is the most common enteric microflora in small intestine?
Lactobacillus
Pathogens for bloody diarrhoea (5)
Shigella, amoeba, EHEC, Campylobacter, C. difficile
Pathogens associated with diarrhoea after eating eggs
Salmonella enteritidis
Pathogens associated with diarrhoea after eating poultry (2)
Salmonella, Campylobacter
Traveller’s diarrhoea: MC bacterial & parasitic cause
ETEC
Giardia lamblia
Strains for EHEC
O157:H7, O104:H4
Pathogen that causes HUS
EHEC
Pathogenesis of cholera infection
cholera toxin –> + adenylate cyclase –> ↑ intracellular cAMP –> ↑ Cl secretion –> ↓ Na absorption –> fluid & electrolyte loss
Pathogen for “rice water” stool
Vibrio cholerae
Screening for pseudomembranous colitis
GDH
Treatment for pseudomembranous colits
Oral vancomycin, metronidazole
Faecal microbiota transplant
Diagnosis of pseudomembranous colitis
- Clinical
- PCR for C. difficile toxins
- Colonoscopy
Workup for HBP infection
USG HBP
Biliary drainage + send specimen for microscopy, gram stain, C/ST
Blood culture, serology for parasites
Stool for parasites
Empirical antibiotics for HBP infection
Ampicillin + Cefuroxime + Metronidazole (triple antibiotics)
MC pathogen for bacterial liver abscess
Klebsiella
Treatment for Amoebic liver abscess
Metronidazole + Paromomycin
Complications of liver abscess
pulmonary spread, peritonitis, pericardial rupture
Presentations of bacterial liver abscess vs amoebic liver abscess
Onset: rapid; gradual
Fever: high; low
Association: /; hepatomegaly, cough, wheeze, crackles
Abscess: single / multiple; single
Vaccine type for HBV
recombinant subunit vaccine
Microbiological workup for CNS infection
CSF: gram stain, culture, ST, ZN stain, TB culture, India ink, HSV PCR
Blood culture
Empirical treatment for CNS infection
IV Cefotaxime [adults], IV Ampicillin + Gentamicin [neonates]
IV Acyclovir
Treatment for Streptococcus agalactiae
Ampicillin
Treatment for Listeria monocytogenes
Ampicillin
Treatment for E coli neonatal meningitis
Cefotaxime
Treatment for TB meningitis
3 HRZE + 9 HR
Common pathogens in bone infection (2+2+1)
S. aureus (90%), TB
[neonates] E. coli, Strep. agalactiae
[elderly] Pseudomonas
Workup for bone infection
Imaging
Inflammatory markers
Microbiology: culture of bone tissue, needle aspiration, blood
Treatment for bone infection (haematogenous, chronic)
Haematogenous: Cloxacillin 4~6w
Chronic: debridement of sequestrum (dead bone) + Cloxacillin >6w
Common pathogens in joint infection
S. aureus (MC)
[neonates] E. coli, Strep. agalactiae
[sexually active adults] Nesseria gonorrhoeae
Workup for joint infection
Imaging
Inflammatory markers, Rheumatoid factors
Joint aspirate: culture, gram stain
Treatment for joint infection
surgical drainage / lavage of joint + Cloxacillin 2~4w
Types of surgical wounds
Clean, clean-contaminated, contaminated, dirty
Antibiotic prophylaxis for clean-contaminated wounds
Cefazolin
Antibiotic prophylaxis for contaminated wounds
Cefuroxime + Metronidazole
Workup for soft tissue infections
- Gram stain & culture from:
- debrided tissues
- ulcer base / vesicle
- pus aspirate
- blood culture
General management of soft tissue infections (3)
incision & drainage of pus
debridement
antibiotics
Soft tissue infections that confine in epidermis only (2) (causative pathogens?)
Impetigo (S. aureus, Strep. pyogenes)
Ecthyma (Pseudomonas aeruginosa)
Disease with “honey crust” lesions
Impetigo
Treatment for impetigo
Cloxacillin / Vancomycin [MRSA] + Fusidic acid
Pathogen & treatment for erysipelas
Strep. pyogenes, Penicillin
Pathogen for folliculitis
S. aureus
Pathogens for cellulits
Strep. pyogenes, S. aureus
Treatment for cellulitis
Amoxicillin-clavulanate / Cloxacillin / Vancomycin [MRSA]
Pathogens for necrotizing fasciitis
Strep. pyogenes (MC), Vibrio vulnificus, S. aureus, anaerobes
Presentations of necrotizing fasciitis
- cellulits with haemorrhagic blisters
- progress to necrosis
- severe pain out of proportions
Subtype of necrotizing fasciitis that invades the scrotum and perineum
Fournier’s gangrene 佛尼爾壞死
Treatment for necrotizing fasciitis
aggressive surgical debridement + IV Piperacillin-Tazobactem / Meropenem + Metronidazole
4 Stages of decubitus ulcer
- Non-blanchable erythema of intact skin
- Partial-thickness skin loss
- Full-thickness skin loss
- Tissue loss
Pathogen associated with leeches bite
Aeromonas
Pathogens associated with human bite (4)
Streptococcus, S. aureus, Eikenella corrodens, anaerobes
Management of bite wounds (3)
Amoxicillin-clavulanate +/- debridement
Tetanous toxoid vaccine + Ig
Rabies vaccine + HRIG
Vesicular rash DDx (3)
VZV, HSV, Hand-foot-mouth disease…
Morbilliform rash DDx (8)
Rubella, measles, parvovirus B19, roseola
syphillis, meningococcal petechiae
Kawasaki disease, drug HSR
Haemorrhagic rash DDx (2)
Dengue, Chikungunya
Hyperplastic rash DDx (2)
Wart, pox (molluscum contagiosum)
Centripetal rash DDx (4)
Syphilis, rocky mountain spotted fever,
hand-foot-mouth disease, dengue
(start from extremities)
Numbered rashes 1~6
- Measles
- Scarlet fever
- Rubella
- SSSS
- Parvovirus B19
- Roseola
(Mysterious Skin Rash Seek Professional Relief)
Risk factors for infective endocarditis (5)
Valvular diseases, IVDA, prosthestic heart valve, poor dental hygiene, immunocompromised
MC pathogen for:
(a) Acute IE
(b) Subacute IE
(c) IE with prosthetic heart valve
(d) IE in IVDA
a) S. aureus
b) Strep. viridans
c) S. epidermidis
d) S. aureus
Antibiotic prophylaxis for IE (Which groups of patients are indicated?)
PO Amoxicillin
(prosthetic valve, previous IE, congenital heart disease)
Antibiotics for IE
Cloxacillin [MSSA] / Vancomycin [MRSA] / Penicillin [Streptococcus] / Ampicillin [Enterococcus] + Gentamicin
+ Rifampicin [prosthetic valve endocarditis]
Investigations for IE
> =2 bood cultures
Echocardiogram / TEE
ECG
Mechanisms of Janeway lesions in IE
Septicaemia triggers immune response –> formation of immune complex –> septic emboli which deposit bacteria –> form microabscesses
What is acute rheumatic fever?
an acute, immunological mediated multisystem inflammatory disease that follows group A Streptococcal pharyngitis after a few weeks