Infectious Disease Flashcards

Question

How does chicken pox present and what is the Mx? characterise rash

Answer 1

Pyrexia, headache, abdo pain, malaise • Crops of vesicles appear over 3-5 days – head, neck, trunk (sparse on limbs) – itchy • Macular -> Papular → vesicle → crust – several stages at once Management: • Supportive, fluids, minimise scratching, analgesia • Antihistamines, emollients for pruritis • Acyclovir if immunocompromised or severe Isolate/no school from 5 days from onset of rash OR till lesions gone/crrusted over

Answer 2

* Most commonly due to Coxsackie A16 virus * Painful vesicular lesions on hands, foot, mouth, tongue, buttocks * Mild systemic features – fever, sore throat,spots in mouth → develop into ulcers * Disease subsides in a few days with fluids and analgesia do not need time off school (or isolation) - unless unwell

Answer 3

Viral are most common – most are self resolving • Bacterial may have severe consequences • Non-infectious causes: malignancy, AI disease

Answer 4

• Lethargy, loss of interest, drowsiness, coma, seizures, muscle pains, resp symptoms, * Headache, photophobia, neck stiffness, +ve Kernig sign * Non-blanching purpuric rash - meningococcal rash (doesnt necessarily mean meningitis is yet present) ↑cap refill (>2) * ↑ICP: ↓consciousness, abnormal pupillary response, abnormal posturing * Late signs – papilloedema, bulging fontanelle in infants, opisthotonus (hyperextension of head and back)

Answer 5

Basic obs - HR, RR, O2 sats, BP, temp, AVPU Bacterial meningitis workup a lot more * FBC (often ↑WCC) * Blood glucose and blood gas (acidosis) * Coagulation, CRP, U&Es, LFTs (check for CMV, EBV, Coxiella) * Blood culture, throat swab, urine, stool culture, nasopharyngeal aspirate if resp symptoms * Rapid antigen test for organisms (on blood, CSF or urine) * LP for CSF (full workup; glucose, protein, cultre, gram stain) - if viral, most important test * PCR of blood and CSF (for N meningitides) * CXR as part of febrile work up * Consider CT (if focal neuro signs or ↓ consciousness) Treat as bacterial if → ↑CRP, ↑WCC, abnormal CSF

Answer 6

Contraindications for LP: signs of ↑ICP (fluctuating consciousness, bradycardia, focal neuro signs, abnormal posturing, unequal pupils, papilloedema

Answer 7

Admit Bloods for culture then Empirical abx - based on age: • Immediate IV Ceftriaxone if > 3 months old • Use cefotaxime + amoxicillin/ampicillin if < 3 months old (abx is given to cover listeria) • Add vancomycin if recent travel outside the UK If signs of shock: Immediate fluid bolus of 20ml/kg saline over 5-10 mins If signs of shock persist, give a second bolus If signs persist after second bolus: • Give a first fluid bolus of 20ml/kg saline • Call for anaesthetic assistance for intubation and mechanical ventilation • Give vasoactive drugs: IV adrenaline or NA • Discuss with paediatric intensivist, consider more boluses Add 15 litre face mask O2 via reservoir breathing mask If > 3 months: give dexamethasone if suspected bacteria

Answer 8

Once cultures return: • Treat Hib with IV ceftriaxone for 10 days • Treat S pneumoniae with IV ceftriaxone for 14 days * Group B Strep with IV cefotaxime for > 14 days * L monocytogenes with IV amoxicillin/ampicillin (21), + gent (7) * G-ve bacilli with IV cefotaxime for 21 days

Answer 9

Offer a formal audiological assessment asap -Inflamm damage to cochlear Test for complement deficiency if: >1 episode of meningococcal disease, or meningococcal disease caused by serogroups other than B, or any serogroup plus a history of other recurrent or serious bacterial infections

Answer 10

Viral meningitis most commonly

Answer 11

Kernig's sign - ___? | Brudzinski's sign -?

Answer 12

Protein - normal - high Glucose - normal - low WCC - high

Answer 13

IVIG affects the efficacy of live virus vaccines, i.e. MMR (measles, mumps, rubella) and varicella (chickenpox) vaccines, and these should be delayed for 11 months after the last dose of IVIG is given or repeated after 11 months if given earlier.

Answer 14

ENCEPHALITIS

Answer 15

Encephalitis is defined as inflammation of the brain parenchyma associated with neurological dysfunction Medical emergency It is the result of direct inflammation of the brain tissue, as opposed to the inflammation of the meninges (meningitis), and can be the result of infectious or non-infectious causes. An aetiological agent is only identified in around 50% of cases. Most common causes; Herpes viruses: herpes simplex virus (HSV)-1, HSV-2, varicella zoster virus VZV, cytomegalovirus CMV, Epstein-Barr virus EBV, human herpes virus-6 HHV6, herpes B virus HSV is a rare cause of childhood encephalitis but can be devastating long term consequences Others include: bacterial, fungi, parasites, paraneoplastic, prion

Answer 16

acute onset of a febrile illness and altered mental status; altered state of consciousness, seizures, personality changes, cranial nerve palsies, speech problems, and motor and sensory deficits. meningismus - sx ; neck stiffness, photophobia, headache without meningeal inflammation parotitis lymphadenopathy optic neuritis - inflamed optic nerve -> pain with eye movement n temporary vision loss. acute flaccid paralysis

Answer 17

FBC Blood culture - reveals underline bacterial infection Ct head - hypodense lesions. Rest depends on aetiology MRI head - often hyperintense lesions. May see haemorrhage/ signs of oedema CSF culture n serology

Answer 18

Initially Viral - IV Aciclovir should be administered as soon as possible in all cases of suspected viral encephalitis. + supportive care ``` Once diagnosis confirmed: • If CMV suspected – add in ganciclovir and Foscarnet • If VZV – acyclovir/ganciclovir • EBV – acyclovir • Consider corticosteroids • Plus supportive care ``` Ongoing: Rehab

Answer 19

Complications include seizures, hydrocephalus, and neurological sequelae (e.g., behavioural disturbances, motor problems).

Answer 20

Spiramycin started ASAP once maternal infection is diagnosed * 10% have clinical manifestations → retinopathy, cerebral calcification, hydrocephalus, long term neuro disabilities, convulsions, spasticity * Infected newborns can be treated with pyrimethamine and sulfadiazine for 1 year

Answer 21

UPT | Serology for rubella - IgM - ELISA

Answer 22

Notify the local Health Protection Unit Refer urgently to obstetrician for risk assessment and counselling Rubella Infection <8-10 week GA → 90% of congenital rubella syndrome → deafness, congenital HD, cataracts, mental retardation risk of spontaneous abortion No effective tx for rubella in pregnancy. Discuss risk to fetus and let her know recommendation will be for a termination (at gynae)

Answer 23

Syphilis , as sex worker Serum Serology - syphilis Light field microscopy of swab of lesion

Answer 24

Treat with IM benzylpenicillin (IV only in neurosyphillis) + prednisolone More than 1 month away from birth so kid should be okay If congenital syphilis suspected eg mum still positive around birth or reactive treponema test on infant serum - IV benzylpen for neonate for 10 days.

Answer 25

Most common congenital infection → childhood disability and deafness neonate born with microcephaly, hearing loss, poor motor function Complications • When infant is treated; o 90% are normal with normal development o 5% have clinical features at birth – hepatosplenomegaly and petechiae with neurodevelopmental issues – sensorineural hearing loss o 5% develop problems later in life – mainly sensorineural hearing loss

Answer 26

• Infection in mother is usually asymptomatic or causes a mild non-specific illness • Amniocentesis 6w after maternal infection to confirm vertical transmission • Close surveillance for US abnormalities – intracranial and hepatic calcification Deranged LFTs, pp65 antiginaemia.

Answer 27

infects the majority of humans. Primary infection in individuals with normal immune function is usually asymptomatic. After primary infection, CMV establishes a state of lifelong latency in various host cells, with periodic sub-clinical re-activations Can get fever, malaise, diarrhoea

Answer 28

Infants born in high risk period should also receive VZIG and prophylactic acyclovir Mum - oral acyclovir

Answer 29

Sepsis !!! Cardiac Metabolic

Answer 30

Within 72 hours Bacteria from birth canal have ascended to invade amniotic fluid leading to secondary infection of foetus Can be caused by virus

Answer 31

Respiratory distress, apnoea, temperature instability, altered behaviour, altered tone (floppy baby), feeding difficulties, jaundice, seizures, signs of shock, oliguria, hypo/hyperglycaemia, metabolic acidosis

Answer 32

Septic screen → FBC, U&Es, LFT, blood cultures, CRP (note will take 12-24 hours to rise) o Sepsis 6: OUT → blood culture, lactate/FBC, urine o IN → O2, IV abx, fluids LP if stable CXR

Answer 33

Immediate abx – IV benzylpenicillin with gentamycin • Give for min 7 days, continue if still not recovered or micro advice • If meningitis suspected – IV amoxicillin with cefotaxime • Stop amoxicillin if later shown to be a G-ve infection

Answer 34

bacteraemia, with mild, influenza-like illness in mother characteristically meconium staining of the liquor, widespread rash, septicaemia, pneumonia, meningitis

Answer 35

Presentation up to 4 weeks of age with → localised herpetic lesions on eye/skin, encephalitis or disseminated disease Rare but high mortality acyclovir to neonate if exposed

Answer 36

Infants of mothers who are HBsAg positive should receive hep B vaccination (active Ig and passive vaccination) within 12 hours after birth to prevent vertical transmission

Answer 37

Treatment – notify public health England ``` - Severe/complicated ▪ Artesunate or Quinine - Uncomplicated ▪ ACT – artemisinin combo therapy - Consider chloroquinine if not falciparum ```

Answer 38

* Abx depending on region of travel | * Ceftriaxone, azithromycin or ciprofloxacin

Answer 39

Previously infected child has a subsequent infection with a different strain → severe capillary leak, hypotension, haemorrhagic manifestations

Answer 40

FBC (low wcc), LFTs (high), serum albumin (low) • Gold standard – viral antigen, nucleic acid detection and serology * Supportive – fluids, monitoring* * Intensive care if established warning signs and increased deterioration * may need blood transfusion

Answer 41

Has all the criteria of DHF plus circulatory failure as evidenced by: Rapid and weak pulse and narrow pulse pressure, or Age-specific hypotension and cold, clammy skin and restlessness.

Answer 42

Under 2s - ampicillin (due to listeria) Then cefoxatime Above - ceftriaxone

Answer 43

Severe viral and fungal infections in first months of life: Oral thrush, Pneumocystis jirovecii PCP, Failure to Thrive HIV, SCID, Di George Rx: For T-cell and neutrophil defects: § Co-trimoxazole to prevent PCP § Itraconazole or fluconazole to prevent other fungal infections

Answer 44

Severe bacterial infections inc pneumonia Brutons agammaglobulinaemia Selective IgA deficiency HyperIGM syndrome CVID Rx: § Antibiotic prophylaxis (e.g. azithromycin) to prevent recurrent bacterial infections

Answer 45

recurrent bacterial infections invasive fungal infections eg aspergillosis Chronic granulomatous disease For T-cell and neutrophil defects: § Co-trimoxazole to prevent PCP § Itraconazole or fluconazole to prevent other fungal infections

Answer 46

Lecuocyte function/adhesion deficiency: - Delayed umbilical cord separation - delayed wound healing - chronic ulcers Complement deficiency: - Reccurent menningococcal - recurrernt bacterial - SLE like sx

Answer 47

Major route is mother to child transmission – during pregnancy, at delivery and breast feeding Plus transmission by infected blood products, contaminated needles or sexual abuse (more uncommon)

Answer 48

• Children > 18 months old o HIV infection is diagnosed by detecting antibodies to the virus • Children < 18 months of age who are born to infected mothers → do HIV RNA PCR (standard) - All infants born to HIV positive mothers will be anti-HIV antibody positive for up to 18 months due to placental transfer of IgG - confirms exposure but not HIV infection • Two negative HIV RNA PCRs within the first 3 months of life, at least 2 weeks after completion of postnatal antiretroviral therapy, indicate the infant is not infected* *although this is confirmed by the loss of transplacental maternal HIV antibodies from the infant’s circulation after 18 months of age

Answer 49

If severe AIDS → opportunistic infections, Failure To Thrive, encephalopathy, malignancy

Answer 50

1. Breastfeeding - triangle: - Can, IF viral load is very LOW, otherwise no! - if breast healthy: no bleeding/mastitis - if baby does not have upset tummy/diarrhoea - if 1 of above is missing -> formula 2• Anti-retroviral therapy (ART) o Babies born to HIV-positive mothers receive zidovudine monotherapy within 4 hours of birth for 6 weeks - DO HIV RNA PCR test If high risk eg mum wasnt following precautions in pregnancy, give: • Combinations of 3 (or 4) drugs are used Tenofovir + Lamivudine + Nevirapine (2 NRTI with an INSTI) • Test infants HIV RNA PCR at day 1, week 6 and week 12 of age • Confirmatory test at 18 months - these are to screen to see if HIV has been developed --------------------------- • Immunisations v important • EXCEPT do not give live vaccines eg BCG • Consider additional vaccination -> influenza, hep A/B, VZV • Prophylaxis with co-trimazole for PCP (if +ve PCR/ high viral load mum) MDT: infectious disease team, St Mary's family planning clinic (advice on breastfeeding etc) FU: weight, growth, adherence, symptoms

Answer 51

1. Short&Sweet: Even if you are taking your HIV medication, your baby has double the chance of becoming infected with HIV if you breastfeed for 12 months rather than stopping before he or she is 6 months old. switch to bottlee/formula by 6 weeks. 2. Breast milk only If you choose to breastfeed, while your baby is under 6 months old, you should give breast milk only and no other food or drinks. This is known as exclusive breastfeeding. Giving breast milk and other foods may irritate the young (younger than 6 month old) baby’s tummy and increase the risk of HIV infection. http: //www.lhp.leedsth.nhs.uk/detail.aspx?id=177

Answer 52

Planned vaginal delivery can be offered ONLY if on HAART (so not just zidovudine monotherapy) and LOW viral load

Answer 53

Lymphoreticular malignancy. Drugs - particularly cytotoxic drugs and immunosuppressants. Viruses - eg, HIV. Malnutrition - the most common cause worldwide. Metabolic disorders - eg, renal disease requiring peritoneal dialysis. Trauma or major surgery. Protein loss - for example, due to nephrotic syndrome.

Answer 54

auto immunity

Answer 55

``` General: 4+ episodes Otitis in 1 year 2+ episodes pneumonia in 1 year FH immune deficiency Recurrent abscesses Adverse effect to BCG vaccine or other live vaccines Chronic diarrhoea (remember coealiac is autoimmune) Opportunistic infections ``` Condition specific: https://esid.org/Working-Parties/Clinical-Working-Party/Resources/Diagnostic-criteria-for-PID2