Infecto Flashcards
EBV - Overview
Most common signs and symptoms:
- Fever
- Pharyngitis
- Fatigue
- lymphadenopathy (mostly the posterior cervical chain)
- Splenomegaly
- Palatal petechiae
- Rash (maculopapular, urticarial or petechial)
EBV - Diagnosis
- Absolute or relative lymphocytosis
- Increased proportion of atypical lymphocytes
—– Elevated aminotransferases —– - Heterophile test (eg, the “Monospot” test, or Paul-Bunnell), although positivity can be delayed or absent in 10% of cases
(False positives for the Paul–Bunnell test are:
Hepatitis
Hodgkin lymphoma
Acute Leukaemia) - Diagnosis confirmed (if necessary) by EBV-specific antibodies, viral capsule antigen (VCA) antibodies—IgM, IgG and EB nuclear antigen (EBN-A)
! In addition, patients should also have a diagnostic evaluation for streptococcal infection by culture or antigen testing
EBV - resuming sports?
For athletes planning to resume noncontact sports, training can be gradually restarted three weeks from symptom onset.
For strenuous contact sports or activities associated with increased intraabdominal pressure, we suggest waiting for a minimum of FOUR WEEKS after illness onset
Q Fever - overview
Q fever is a zoonosis due to Coxiella burnetti.
Most common abattoir-associated infection in Australia and can also occur in farmers and hunters
Mode of infection – inhaled dust, animal contact, unpasteurised milk
Incubation: 1 to 3 weeks
Sudden onset fever, rigors and myalgia, muscle and joint pain, severe headache
photophobia.
Dry cough (may be pneumonia in 20%)
As the disease progresses, people can develop hepatitis (granulomatous), sometimes with jaundice.
Petechial rash(if persistant infection)
± Abdominal pain
If untreated, the acute illness usually lasts 1–3 weeks
Infection in pregnancy can result in fetal death, intrauterine growth restriction and premature delivery
TTX: doxycycline is the major treatment of choice for patients of any age with severe illness.
> Doxycycline 100 mg orally, 12-hourly for 14 days.
> If pregnant, SMT-TMP + Folic acid
Q Fever - vaccination?
Recommended for adolescents aged ≥15 years and adults who are at risk of infection with C. burnetii. These include:
abattoir workers
farmers
stockyard workers
shearers
animal transporters (of high-risk animals such as cattle, camels, sheep, goats and kangaroos)
veterinarians
wildlife and zoo workers who work with high-risk animals
Q fever vaccine is given SC, 0,5ml, as a single dose. Booster doses are not recommended.
People should receive serum antibody testing and a skin test before vaccination (together known as pre-vaccination testing).
Q Fever - fatigue syndrome and chronic form
Coxiella burnetii may cause chronic disease.
The most common complication in adults is subacute endocarditis.
Less common disease manifestations are caused by granulomatous lesions
About 10–15% of people who have had acute Q fever develop post–Q fever fatigue syndrome.
Tetanus - immunisation of adults
Tetanus toxoid as two doses 6 weeks apart with a third dose 6 months later.
Booster doses of tetanus toxoid are given every 10 years or at the time of major injury occurring 5 years after previous dose.
Tetanus prophylaxis after injury
- Tetanus immunoglobulin 250 U by IM injection - For non-immunised individuals or those of uncertain immunity IF wound is contaminated or has devitalised tissue.
(EVEN IF PREGNANT) - Tetanus toxois:
> Clean minor wounds: vaccine always if not completed before
> Contaminated wounds:
- If between 5-10y from last dose: toxoid again
- If <5y - nothing needed
! Any wound after 10y needs new toxoid
Cat-scratch disease - overview (clinical features, tx, symptoms)
Caused by a Gram negative bacterium Bartonella henselae.
An infected ulcer or papule pustule at bite site (30-50% of cases) after 3 days or so
1-3 weeks later: fever, headache, malaise regional lymphadenopathy (may suppurate) - painful
Intradermal skin test positive
Treatment is recommended in immunocompetent patients with:
- Unresolved lymphadenopathy (lasting more than 1 month);
- Lymphadenopathy associated with significant morbidity;
- Systemic disease with organ involvement (eg liver, eye, neurological); or
- Endocarditis.
eat with erythromycin or roxithromycin for 10 days OR azithromycin 500 mg on the first day and 250mg for 4 days.
Atypical pneumonia - overview
- Symptoms:
Fever, malaise
Headache
Minimal respiratory symptoms,
Non-productive cough - Findings:
Signs of consolidation absent
Chest X-ray (diffuse infiltration) - DxT: ‘flu’ + headache+ dry cough
Atypical pneumonia - most common ethiology
Mycoplasma pneumoniae (the commonest)
Adolescents and young adults: treat with roxithromycin (first line) or tetracycline (e.g. doxycycline 100 mg bd for 14 days)
Atypical pneumonia - less common ethiologies (OVERVIEW, TX)
> Legionella pneumophila (legionnaire disease)
Related to cooling systems in large buildings
Symptoms: Dry cough, influenza,
» REMEMBER: HIGH FEVER, CONFUSION AND/OR DIARRHOEA
Lymphopenia with marked leukocytosis;
Hyponatraemia
Ttx: Azithromycin (IV) or erythromycin (IV or O) plus ciprofloxacin or rifampicin for 21 days.
> Chlamydia psittaci (psittacosis)
Treat with doxycycline 100 mg 2x/D for 10 days
> Coxiella burnetti (Q fever)
EBV - Most common complications?
- Most common:
Antibiotic-induced skin rash
Thrombocytopenia
Ruptured spleen
- Other relevant:
Haematological: agranulocytosis, haemolytic anaemia, thrombocytopenia
Respiratory tract: upper airway obstruction(lymphoid hypertrophy)
Cardiac: myocarditis, pericarditis
Neurological:
cranial nerve palsies, especially facial palsy
Guillain–Barré syndrome
meningoencephalitis
transverse myelitis
Lyme Disease - cause and transmission?
A spirochaete: Borrelia burgdorferi (Borreliella)
Transmitted by Ixodes ticks
People living and working in the bush are susceptible.
Lyme Disease - clinical features (symptoms, dx, tx)
- Stage 1 (withing 1 month of the bite): erythema migrans, (characteristic pathognomonic rash, usually a doughnut shaped, well-defined rash about 6 cm in diameter at the bite site - bullseye)
+ flu-like illness (fever, chills, headache, fatigue, arthralgia) - Stage 2 (early disseminated): neurological problems such as limb weakness and cardiac problems, hearing loss
- Stage 3: arthritis (late Lyme disease)
-> Diagnosis
Clinical pattern especially rash of erythema migrans + serology and PCR of synovial fluid
-> Treatment
Remove tick
A typical regimen for adults is doxycycline 100 mg bd for 21 days or penicillin.
Rabies - overview of prophilaxy
> If exposure of intact skin to fluid - not needed
> If minor scratches without bleeding:
- Non - immune: 4 doses IM (0, 3, 7 and 14)
## - Vaccinated: 2 additional doses IM (0, 3)
> Trandermal bite or scratch OR contamination of mucous membrane or broken skin with saliva
- If vaccinated - ##
- Non-immune: HRIG (not beyong the 7th day after the dose 0 of vaccine) + Vaccine (0, 3, 7 and 14).
! If vaccinated domestic animal, observe for 15 days for signs of the disease.
! If wounded in head or neck, give Immunoglobulin even if vaccinated
Rabies - clinical overview
Causes by Lyssaviruses - single-stranded RNA viruses
Once a person is infected, the incubation period of rabies is usually 3–8 weeks. This can range from as short as 1 week to, on rare occasions, several years.
Initial symptoms: The prodromal phase lasts up to 10 days. During this phase, the person may experience non-specific symptoms such as: anorexia cough fever headache myalgia and fatigue
nausea and vomiting sore throat
Bite and clenched-fist injury - overview
For bites and clenched-fist injuries that are not infected, antibiotic therapy is usually not necessary for otherwise healthy individuals if the risk of wound infection is low (eg small wounds not involving deeper tissues that present within 8 hours and can be adequately debrided and irrigated). Give presumptive therapy if the risk of wound infection is high, including if:
presentation to medical care is delayed by 8 hours or more
the wound is a puncture wound that cannot be debrided adequately
the wound is on the hands, feet or face
the wound involves deeper tissues (eg bones, joints, tendons)
the wound involves an open fracture
the patient is immunocompromised (eg due to asplenia or immunosuppressive medications), or has alcoholic liver disease or diabetes
the wound is a cat bite.
TTX:
amoxicillin+clavulanate 875+125 mg orally, 12-hourly for 3 days
OR
procaine benzylpenicillin 1.5 g (child: 50 mg/kg up to 1.5 g) intramuscularly, as a single dose while awaiting oral therapy.
AND Start continuation therapy with oral amoxicillin+clavulanate (see dosage above) as soon as it is available.
! If infected wound at presentation: Amox-clav for 5 days
Toxoplasmosis - overview
Caused by Toxoplasma gondii
The definitive host is the cat (or pig or sheep)
The five major clinical forms are:
- Asymptomatic lymphadenopathy (the commonest)
- Lymphadenopathy with a febrile illness, similar to EBM
- Acute primary infection: a rash, myocarditis, pneumonitis, chorioretinitis and hepatosplenomegaly
- Neurological abnormalities - headache and neck stiffness, sore throat and myalgia
- Congenital toxoplasmosis - CNS and eye involvement - TRIAD : HYDROCEPHALUS + INTRACRANIAL CALCIFICATION + CHORIORETINITIS
Tetanus - clinical overview
Bacterial infection (Clostridium tetani)
Clinical features:
- Prodrome: fever, malaise, headache
- Trismus (patient cannot close mouth)
- Risus sardonicus
- Opisthotonos (arched trunk with hyperextended neck)
- Spasms, precipitated by minimal stimuli
Infective endocarditis without cardiac murmurs - most likely clinical scenario and pathogen?
- IV drug users who develop infection on the tricuspid valve.
- Staphylococcus aureus (causes 50% of acute form)
- Streptococcus viridans (50% of cases)
- Other responsible pathogens:
Streptococcus bovis
Staphylococcus epidermidis
Enterococcus faecalis
Candida albicans/Aspergillus
Coxiella burnetii (Q fever)
HACEK group (Gram -ve bacilli)
