Infectious Disease Flashcards
what is sepsis?
it is a large immune response to systemic inflammation and affects the functioning of organs - cytokines affect the endothelial lining making it more permeable so there is a drop in intravascular volume, oedema and resultant hypoperfusion
what does hypoperfusion result in?
increased blood lactate leading to anaerobic respiration
what is the presentation of sepsis?
hypoxia, oliguria, AKI, thrombocytopenia, coagulation dysfunction, hypotension, high lactate, pyrexia, tachycardia, tachypnoea, low sats, rash, mottled skin, cyanosis, AF
what are the risk factors for sepsis?
extremes of age, chronic conditions, surgery, trauma, pregnancy, peri-partum, indwelling devices
how would you investigate sepsis?
FBC, U&Es, LFTs, CRP, clotting, cultures, ABG, dipstick, CXR, CT, LP
what is the management of sepsis?
within one hour - blood lactate, cultures, UO, IV fluids, IV ABx, O2
why is it important to look at clotting in sepsis?
activation of the coagulation system causes thrombocytopenia, haemorrhage and DIC
what is neutropenic sepsis?
it is when the neutrophils are less than 1x10^9/L. Caused by chemo, clozapine, methotrexate, carbimazole, infliximab, and usually treated with tazocin
what is the usual cause and some rarer causes of UTI?
E coli is usual
rare - Klebsiella, pseudomonas, staph, candida
how does UTI present?
dysuria, suprapubic pain, frequency, urgency, confusion, incontinence, loin or back pain, unwell, N&V, haematuria, renal angle tenderness, loss of appetite
what is the management of UTI?
LUTI women - 3d trimethoprim or nitrofurantoin
if immunocompromised, abnormal or impaired renal function - 5-10 days
male, pregnant or catheter - 7 days
how is UTI treated in pregnancy?
7d ABx, urine MC&S, nitro (avoid in third trimester), cefalexin, amoxicillin
avoid trimethoprim in first trimester
how is pyelonephritis treated?
refer if septic, 7-10d ABx, with cefalexin, co-amoxiclav, trimethoprim or ciprofloxacin
how does cellulitis present and what is the usual causes?
erythema, warmth, tense, oedematous, thickened, bullae, golden yellow indicates S Aureus - usual causes are S Aureus, GAS, GCS, MRSA
what is the Eron Classification?
severity of skin and soft tissue infections
I - no systemic symptoms
II - some systemic
III - significant systemic
IV - sepsis or life threatening
admit III and IV or if have comorbidities
what is the management of cellulitis?
flucloxacillin QDS PO if S Aureus, clarithromycin, clindamycin or co-amoxiclav
summarise bacterial tonsilitis?
usually caused by GAS or viral
CENTOR - bacterial - >3 give ABx - fever>38, tonsillar exudate, absence of cough, lymphadenopathy
treat with Pen V
summarise OM?
usually resolves in 3-7d without ABx - bulging red tympanic membrane, pain and then resolution means perforation, discharge - give amoxicillin, clari, erythro or coamox
summarise sinusitis?
self resolving in 2-3w without treatment - if >10d with no improvement then give 2w of high dose steroid nasal spray, if likely bacterial then pen V for 5 days
what is gastroenteritis?
it is inflammation of the stomach and intestines resulting in N,V&D - it is mostly viral and quickly spread (adeno, rota or noro)
describe the presentation of bacillus cereus?
it is a gram positive rod
from poor food hygiene
release cereulide toxin
cramping and vomiting within 5 hours and watery diarrhoea after eight hours - resolves in 24 hours
what gastroenteritis is azithromycin or ciprofloxacin used to treat?
campylobacter - travellers - 3-6d of abdo cramps, vomiting, some bloody diarrhoea, fever
shigella - bloody diarrhoea, abdo cramps
other than shigella what else releases the shiga toxin?
E coli - can result in HUS
how is giardiasis diagnosed and treated?
stool microscopy and treated with metronidazole
general management of gastroenteritis?
M,C&S, ORS or dioralyte, ABx
what are some differentials of septic arthritis?
gout, pseudogout, reactive arthritis, haemarthrosis
what is the presentation of septic arthritis?
hot, swollen, tender, red, stiff joint, reduced ROM and systemic sx
what is the management of septic arthritis?
joint aspiration, gram staining, crystal microscopy, culture and sensitives
washout or debridement
IV ABx for 3-6w (fluclox and rifampicin, vanco and rifampicin, clindamycin)
when does SBP present and how is it treated?
typically in liver failure and treated with pip taz, cephalosporins, levofloxacin and metronidazole
what is TB, how is it investigated and what are the risk factors?
it is a mycobacterium tuberculosis - small rod shaped
it is investigated with Ziehl Neelsen stain - bright red acid fast , Mantoux test, interferon gamma release assay, CXR, cultures (LN, sputum and mycobacterium)
risk factors - South Asian, immunocompromised, IVDU, known contact, immigrant, travel, homeless, alcoholic
what is the natural progression of TB?
active - latent - secondary - miliary
what is the presentation of TB?
lethargy, fever, night sweats, weight loss, cough and haemoptysis, erythema nodosum, lymphadenopathy, spinal pain
what is seen on CXR for TB?
patchy consolidation, pleural effusions, hilar lymphadenopathy, cavitations and miliary seeds
how is TB treated?
latent - isoniazid and rifampicin for 3m or isoniazid alone for 6m
acute - rifampicin 6m, isoniazid 6m, ethambutol 2m and pyrazinamide 2m
what are some AIDS defining illnesses?
Kaposki’s sarcoma, cytomegalovirus, candidiasis, PCP, TB
how is HIV screened and monitored?
screening - with any other infectious disease after 3m , antibody blood test, p24 antigen or PCR
monitoring - CD4 count (<200 is end stage), VL (<50 is undetectable)
how is HIV managed?
ARTs - 2 NRTIs (tenovir and emtricitabine - combination is known as Truvada) and 3rd agent
HAART - protease inhibitors, integrase inhibitors, (non) nucleoside reverse transcriptase inhibitors, entry inhibitors
prophylactic ABx for PCP, cervical smear annually, avoid live vaccines, keep up to date with vaccines
how does HIV impact birth?
usually a C section unless undetectable VL
baby to get 4weeks for ART and then tested
what is post exposure prophylaxis for HIV?
commenced in 72 hours use ART - truvada
what is post exposure prophylaxis for HIV?
commenced in 72 hours use ART - truvada and raltegravir for 28 days, test at presentation and at 3m and use protection until negative
what is the pathophysiology of malaria?
plasmodium protozoan - sporozoites are transferred to liver, can lie dormant as hypnozoites (ovale and vivax), mature to merozoites, and infect RBCs - burst every 48 hours
how does malaria present?
within 1-4 weeks for travel, spike fever every 48 hours, sweats, rigors, myalgia, malaise, headache, vomiting, pallor, hepatosplenomegaly, jaundice
how is malaria diagnosed?
blood film (EDTA) 3 samples over 3 days
what are the complications of malaria?
cerebral malaria, seizures, altered LOC, AKI, haemolytic anaemia, organ failure, death
what is the prevention of malaria?
education, spray, nets, barriers, medical advice if sx, antimalarials:
proguanil and atovaquone - OD 2 days before, during and 1w after
mefloquine - once weekly, 2w before, during and 4 week after
doxycycline - OF 2d before, during and 4 week after - risk of UV
how is malaria managed?
inform ID team
arthemeter and lumefantrine (riamet), proguanil and atovaquone (maladrone), quinine sulfate, doxycycline - all oral
IV - artesunate, quinine dihydrochloride
what is the presentation of meningitis?
fever, neck stiffness, vomiting, headache, LOC reduced, seizures, photophobia
how does meningitis present in neonates?
non specific
hypotonia, poor feeding, lethargy, bulging fontanelle, fever, unwell
what are Kernig and Brudzinski’s signs?
Kernig’s - flex hip and knee to 90 degrees, straighten knee - painful or resistance
Brudzinskis - head and neck tilt to chest - involuntary hip and knee flexion
what is the management of bacterial meningitis?
community - IM Ben Pen 1200mg adult
hospital - LP and CSF, PCR and DNA, <3m cefotaxime and amox, >3m ceftriaxone
if risk of resistance add vancomycin
steroids dex QDS 4d if needed
how does CSF present in viral v bacterial meningitis?
viral - clear, normal protein, normal glucose, increased WCC with lymphocytes, negative culture
bacterial - cloudy, increased protein, low glucose, increased WCC with neutrophils, positive culture
how is HSV meningitis managed?
supportive and acyclovir
what is the prophylaxis for contacts of meningitis?
single dose ciprofloxacin
what are complications of meningitis?
hearing loss, memory loss, seizures, CI
who gets vaccinated against flu?
> 65, healthcare, pregnancy, chronic conditions, young children
what are some complications of flu?
OM, sinusitis, bronchitis, viral / secondary bacterial pneumonia, febrile convulsions, worsening chronic conditions, encephalitis
what is the post exposure prophylaxis for influenza?
if within 48h - oseltamivir OD for 10d 75mg
how is influenza managed?
oral oseltamivir 75mg BD for 5 days, inhaled zanamivir 10mg BD for 5days within 48 hours of symptom onset
how does influenza present and how is it diagnosed?
fever, coryzal sx, lethargy, fatigue, anorexia, muscle and joint pain, headache, dry cough, sore throat
viral or nasal swabs for PCR to diagnose
