Infectious Diseases Flashcards
Meningitis - common symptoms and signs
Neck stiffness Headahce ↓ conciousness Seizures photophobia Kernig sign \+/- rash if meningococcal septicaemic
When do you not do an LO
Thrombocytopenia (bleeding risk) ↑ICP CV unstable, septic Coagulation problems Infection at LP site Neurolgy - focal symptoms
LP interpretation
Bacterial: Turbid, Cells: neutrophils, Glucose ↓: protein ↑↑
Viral: Cells: Lymphocytes, glucose normal, protein ↑
What factors to consider for causative organisms
Age (baby, young person, old person)
Immunosuppressed (HIV)
Common bacterial and viral causes
Bacterial Neiseeria meningitis S. pneumonia Listeria Haemophilus TB
Viral
HSV
Enterovirus: Coxsackie
< 1 month
Ampicillin and cefotamine
> 1 month and < 50 yrs
Ceftriaxone & vancomycin + dex
> 50 yeats
Ampicillin & vancomycin
Contacts
Ciprofloxacin, Rifampicim
Viral mgmt
Tx as bacterial until proven otherwise
Supportive
HSV or VZV aciclovir
CMV: Ganciclovir
Viral meningitis mgmt
Tx as bacterial until proven otherwise
Supportive
HSV or VZV aciclovir
CMV: Ganciclovir
Encaphilitis
Focal neurology Altered consciousness levels Seizures Personality changes Hx travel/animal bit
Prodromes →
rash cold sore
Conjunctivitis
Lymph nodes
Causes
Viral HSV2 CMV EBV VZV HHV6
Bacterial
Mgmt
Associated problems → mg seizures (phenytoin), electrolytes
Tx IV aciclovir
once got CSF results back tx with specific antivirals e.g. + ganciclovir for CMV
Toxplasmosis encephalitis - how does it show on CT
Multiple ring enhancing lesion
TB
Weight loss, night sweats, haemoptysis
Effusions, recent travel, crowded living environments
Primary TB
Spreading coughing
Primary Gohn focus in lungs
Secondary TB (latent)
Remains asymptomatic, non infectious 10% will reactive in their lifetime. (10% yearly for HIV)
1/3 of world population have latent TB
Secondary
Active TB, often due to ↓ host immunity (chemo) or re-infection.
Investigations for active TB
CXR Sputum samples - 3 1) culture → gold standard, takes 3 weeks 2) Microscopy: acid fast bacilli → fast 3) NAAT (PCR)
Latent TB - two tests.
For the first - describe the test and its limitations.
Mantoux test → intradermal TB injection of protein, look for size induration at 48-72 hours.
False positive → BCG, previous exposure, environmental mycobacteria
False negative → HIV, Sarcoid, lymphoma, current infection
IGRA - used if positive mantoux test - shows if positive due to BCG vaccine
Mgmt Tb - common side effects of the 4 drugs
Initial 2 months Rifampicin isonizid pyrozinamide ethambutol
Rifampicin SE
ORANGE urine
isonizid SE
sensory neuropathy
pyrozinamide SE
hepatits, arthralgia
ethambutol SE
Optic neuritis
Define MDR-TB
Resistant to any 2 of first line drugs
XDR-TB
Resistant to ++++
How to spot HIV in MCQ
Patient background
Seroconversion
Complications of HIV
Seroconversion - when does it happen and how does it present
2-3 weeks after first infection, non-specific flu like symptoms, rash malaise
Inv HIV a) point of care b) follow up
Point of care → ELISA (immnuoassay) - blood or saliva
Western blot - confirmation - must be a while after exposure
Viral PCR used in the window period - not common
Mgmt
2NRTIs + 1 other agent - regardless of CD4 count
NRTI - Zidovudine, Emtricitabine, Tenofovir
INSTI, NNRTI, PI
Monitoring of HIV mgmt
Load viral load - monitor 3-6 months or 2-3 months if more severe
Complications of HIV TB
risk of reactivation + disseminated disease
Complications of HIV pneumonia
Pneumocystic Jerovicci (co-trimoazole prophlyaxsis if lof CD4)
Complications of HIV - encephalitis
Toxoplasmossis
Complication of HIV - mouth/osephagus
Candidiais
Malaria in MCQs
High fever - cyclic every 2 or 3 days Recent travel (usually within 1 month) Headache Malaise Jaundice Anaemia Splenomegaly Seizure, metabolic acidosis, pulmonary oedema - if falciparum
Inv of malaria
Serial giesma stain thick and thin blood films
Types of malaria
a) Most common, most serious
b) less serious
a) Plasmodium falciparum
b) other ones (p. ovale, p malariae, p vivax)
Mgmt malaria
Depends on type and sensitivity (chloroquine sensitivity ↑- used to be common Tx)
Plasmodium falciparum → Artmether/lumefantrine - 6 oral doses over 2-3 days if uncomplicated
Prophylaxis
Depends on where you are going and sensitivity of region. Usually on required when p. falciaparum
Resistant areas: Atovaquone, malarone, doxycycline
Buzzword - dengue
Haemorrhagic fever Aedes Mosquitos Flushing face & neck Macuopapular rash Headache, arthalgia Bleeding gums Hepatospegauly and jaundice Confirmed on serology South & central america, Asia, africa
Buzzword typhoid
Faecol/oral Salmonella 3-21 days incubation Malaise, headache, cough, constipation High fever with relative bradycardia Dirrhoea after 1 week Rose spots (patch red) Tx Ceftoamine cipro
Buzzword Lyme
Borrelia burgdoferi
Tick bite
walkers
Early: erythema migrant - target lesion
Disseminated: malaise, arthritis, hepatitis
Late: focal neurology, myocarditis, heart block
Tx: Doxycyclin, IV benzlpen (complications)
Buzzword Rickettsia
Rocky mountain spotted fever
Tick
fever, N+V, conjucitivtis
Widespread rash, peripheral to central and more widespread
Buzzword Leptospirosis
Weil's disease Spread by infected rat urine Swimming, canoeing High fever cough +haemoptysis (pulmonary haemorrhage_ meningitis Jaunduce
Buzzword Brucellosis
Unpasteurised milk and chees Vets/farmers Undulant fever - peak in afternoon Sweats, malaise, anorexia Arthritis/ spine tenderness Rose bengal test Anti-o polysaccharide test
Buzzword Trypanosomiasis
African sleeping sickness Fly fever, riggers, headaches rash Meningoencaphilitis stage → weeks to months after confusion, agitation, conclusions, psychiatric changes 2 different types in W and E africa Thick and thin blood films
