05. AKT: Infection/Blood/MSK Flashcards
How long is a patient infectious for with measles?
Atleast 5 days after the onset of rash
How does measles present?
Prodrome:
- Fever, malaise, loss of appetite, followed by conjunctivitis, cough, coryza (blocked or runny nose)
- Koplik spots (blue-white spots on the inside of the mouth, opposite the molars) occur before the rash
Exanthem:
- Flat, red spots appear on 4-5th day
- Non-itchy rash that begins on the face and behind the ears, then spreads over the entire trunk and extremeties (palms and soles rarely involved)
- Onset of rash usually coincides with a high fever atleast 40C
Clinical definition of measles?
BOTH:
1. Generalised descending maculo-papular rash (persisting for 3 or more days)
2. Fever atleast 38C at the time of rash onset
AND atleast one of:
- Cough
- Coryza
- Conjunctivitus
- Koplik spots
Differentials for maculopapular rash?
- Measles
- Rubella
- Human Parvovirus B19
- Enterovirus
- HIV
- Adenovirus
- Arbovirus
- Roseola infantum
- Scarlet fever
- Drug reaction
- Kawasaki disease
What actions are needed if there is suspected measles?
- Urgent call to Public Health
- Lab testing: nose or throat swab for measles PCR AND urine PCR for measles (if within 3 weeks of rash)
- Measles IgM and IgG
- Isolate case immediately
Who are high risk groups when considering Group A strep infection?
- ATSI
- Maori and Pacific Islander people
- Personal history of rheumatic fever or rheumatic heart disease
- Family history of rheumatic fever or rheumatic heart disease
Red flags when assessing a sore throat?
- Unwell/toxic appearance
- Respiratory distress
- Stridor
- Trismus
- Drooling
- “Hot potato” voice (muffled voice associated with pharyngeal/peritonsillar pathology - sounding like they have a hot potato in their mouth)
- Torticollis - neck muscle spasm causing head turning
- Neck stiffness/fullness
What investigations would you order if there was a patient with sore throat + hepatosplenomegaly?
FBC, monospot +/- EBV serology
Most common causes of fever in travellers?
- Malaria
- Dengue fever
- Mononucleosis
- Rickettsial infection
- Typhoid
- Paratyphoid fever (enteric fever)
Characteristic features of malaria?
- Fever
- Malaise
- Nausea
- Vomiting
- Abdominal pain
- Diarrhoea
- Myalgia
- Anaemia
What should be done if there is clinical suspicion for malaria but the first diagnostic evaluation is negative?
Follow up testing should be performed each day for two more days.
Malaria is still possible even if an initial malaria smear is negative.
Features of dengue virus infection on history, exam and lab findings?
Symptoms:
- Headache
- Retro-orbital pain
- Marked myalgia and arthralgia
- Transient macular rash
Exam:
- Haemorrhagic features: petechiae, ecchymoses, vaginal or gastrointestinal bleeding
- Conjunctival injection
- Pharyngeal erythema
Lab findings:
- Leukopenia
- Thrombocytopenia
- Elevated aminotransferases
What is the primary purpose of malarial chemoprophylaxis?
Minimise the risk of dying from malaria when travelling to or residing in high-risk malaria areas
How long should malaria still be considered as a differential for cause of fever in a returned traveller?
Up to at least one year after visiting a malaria-risk area, regardless of whether chemoprophylaxis was taken
What can hand, foot and mouth disease look like?
- Small, oval white blisters on the palms, soles of the feet, as well as in the mouth
- A red skin rash with a brown scale on it
What is the most common cause of hand, foot and mouth disease?
Coxsackie virus
When is tetanus immunoglobulin indicated?
Children with a tetanus-prone wound (dirty or major wound) AND any of the following:
1. who are unimmunised
2. have had incomplete primary tetanus immunisation
3. uncertain tetanus immunisation history
How long should a postpartum woman wait after packed red blood cell transfusion if she also needs MMR booster?
6 months post PRBC to receive the MMR booster
Why should a woman wait after blood transfusion to get the MMR booster?
The PRBC may reduce the immune response to the MMR booster
What two tests are available for diagnosis of latent tuberculosis? Can they distinguish between latent and active TB?
- Mantoux test - tuberculin skin test
- Interferon-gamma release assay (IGRA)
No, they cannot distinguish between latent or active infection. They tend to remain positive indefinitely after infection or disease
Symptoms of active tuberculosis?
Especially if symptoms present for >3 weeks:
- Fever
- Cough
- Weight loss
- Lymphadenopathy
- What treatment for latent tuberculosis can be started in general practice if <35 years with normal liver function tests?
- What are its side effects?
- Isoniazid 10mg/kg, up to 300mg, daily PO. Co-prescription of vitamin B6 (pyridoxine) is generally offered
- GI upset, acne, hepatotoxicity, peripheral neuropathy
Ross River virus symptoms and signs?
- Joint pain
- Tiredness
- Fever
- Myalgia
- Rash
- Headache
- Joint swelling
- Depression
Most common manifestation is acute onset of joint pains +/- rash (maculopapular), fever, lethargy and myalgia
How is Ross River virus diagnosed?
- Diagnosis is confirmed by serology
- A blood sample should be collected within 7 days of symptom onset for IgM and IgG and another sample 10-14 days later tested in parallel by the same laboratory for IgG to confirm seroconversion. Diagnosis is confirmed by a 4 fold increase in IgG
Standard recommended management of bites and clenched-first injuries?
Thorough cleaning, irrigation, debridement, elevation and immobilisation
What factors indicate high risk of of wound infection in bite and clenched-first injuries, and therefore require presumptive antibiotic therapy?
- Presentation to medical care is delayed by 8 hours or more
- Puncture wound that cannot be debrided adequately
- Wound is on hands, feet or face
- Wound involves deeper tissues (e.g. bones, joints, tendons)
- Wound involves an open fracture
- Patient is immunocompromised
- Cat bite
When is air travel restricted in pregnancy?
- Domestic (more than 4 hours): after 36 weeks
- International: 32 weeks
What birth year range do you need to check for a completed 2 dose course of MMR vaccine?
Born between 1966 and 1994 (may not have received the complete 2 doses). Before this, measles was prevalent and would confer natural immunity.
What is the most common cause of erysipelas?
Streptococcus pyogenes (group A strep)
In cellulitis, what suggests strep pyogenes rather than staph aureus as the likely causative organism and what is first line treatment?
- Features: nonpurulent, recurrent or spontaneous, rapidly spreading
- Treatment: phenoxymethylpenicillin 500mg Q6hourly PO for 5 days
In cellulitis, what suggests staph aereus rather than strep pyogenes as the likely causative organism and what is first line treatment?
- Features: purulent, penetrating trauma, associated ulcer
- Treatment: Flucloxacillin 500mg Q6hourly PO for 5 days
Risk factors for superficial vein thrombosis?
- Intravenous cannulation
- Pregnancy
- Active cancer
- Varicose veins
Note: causes of venous stasis and venous trauma
What is a low risk superficial vein thrombosis?
- Caused by intravenous cannulation
- Located more than 3cm from the deep venous system
- Is shorter than 5cm
What is an intermediate risk superficial vein thrombosis?
- More than 3cm from deep venous system
- Is longer than 5cm
What is a high risk superficial vein thrombosis?
- Extends to within 3cm from the deep venous system
- Propagates despite anticoagulant therapy given for an intermediate risk superficial vein thrombosis
Management of low risk superficial vein thrombosis?
Symptomatic care with topical or oral NSAID therapy for 7 to 14 days
Management of intermediate risk superficial vein thrombosis?
Enoxaparin 40 to 80mg subcut daily for 45 days
Management of high risk superficial vein thrombosis?
Anticoagulant therapy for 3 months (similar to VTE treatment)
First line investigations for thrombocytopenia?
- FBC and peripheral blood film
- Fibrinogen, D-dimer, clotting factors
- Haemolysis screen: FBC and peripheral blood film, reticulocyte count, direct and indirect antibody test (Coombs), lactate dehydrogenase, haptoglobin, urinary haemosiderin, haemoglobin
- Vitamin B12 and folic acid levels
- Liver function tests
- HIV and hepatitis serology
- Stool for occult blood
- Renal function (deranged in thrombotic thrombocytopenic purpura/haemolytic uraemic syndrome)
- Platelet indices (size and volume): limited value
What level of thrombocytopenia may spontaneous bleeding occur?
- Platelet count < 20.
- Requires urgent referral to haematologist. If age >60, then urgent referral at platelet <30 is appropriate (risk of spontaneous bleeding increases with age)