Infectious diseases

Question 1

Tonsillitis:
- Definition
- Risk factors (1)
- Pathophysiology
- Causes (5)
- Symptoms (6)
- Signs (3)
- Investigations
- Management
- DD (5)
- Complications (4)
- Extra facts: FeverPAIN or centor criteria

Answer 1

Tonsillitis:

• Definition: inflammation of palatine tonsils as a result of either bacterial/viral infection. Can occur with other areas of inflammation (tonsillopharyngitis), adenotonsillitis
• Risk factors: smoking
• Pathophysiology: In pharynx there is ring of lymphoid tissue and there is six areas (adenoid, tubal tonsils, palatine tonsils, lingual tonsil) (pic in word doc). At 4-8 years old tonsils are largest size
• Causes: viral (adenovirus, epstein barr virus), bacterial (strep pyrogenes, haem influ, moraxella catarrhalis)
• Symptoms: 5-7 days of odynophagia, fever, reduced oral intake, halitosis, snoring, sob
• Signs: red inflammed tonsils, white exudate/pus on tonsils, cervical lymphadenopathy
• Investigations: first history to determine if bacterial, bloods if admitted (fbc (neuts inc if bacterial), lfts (deranged if glandular fever), u+es (if dehyd/aki)
• Management: paracet/ibu, delayed prescription (2/3 days) and if not settled or fever rises come in. Admit if resp compromised (low sats, tachypnoea, use accessory m)/risk dehyd/abx not working. Abx IM benzylpenicillin (or oral penicillin V) 7-10 days (avoid coamox as if glandular fever will cause permanent skin rash), difflam (benzydramine) spray to reduce pain and allow swallowing, oral steroids, tonsillectomy if meets SIGN criteria (BIG BLEEDING COMPLICATION)
  7 or more episodes in 1 year. 5 or more per year in 2 years. 3 or more per year in 3 years
• DD: glandular fever (symptoms last longer), quinsy, malignancy, pharyngitis, epiglottitis
• Complications: recurrent = scarring/enlarged tonsils/time off school. Otitis media, peritonsillar abscess (spreads to peritonsillar space causing ear pain/tender neck, unable to open mouth, change in voice so needs incision + drainage + coamox), spreads to para/retropharyngeal spaces, post strep conditions (glomerulonephritis, rheumatic fever)
• Extra facts:
  Feverpain: Fever, Purulence, Attends rapidly (within 3 days), Severely inflammed tonsils, No cough/coryza. If 4-5 65% chance bacterial
  Centor: tonsillar exudate, lymphadenopathy, fever, no cough. If >3 then 40-60% likely bacterial

Question 2

Candidiasis:
- Definition
- Risk factors (6)
- Symptoms
- Investigations
- Management

Answer 2

Candidiasis:

• Definition: candida albicans yeast infection
• Risk factors: abx, oral corticosteroids, malnutrition, HIV, not changing wet nappies, humid
• Symptoms: pseudomembranous oral candidiasis (yellow white patches anywhere in mouth, itchy, burning, easily removed with red base), acute erythematous oral candidiasis (smooth tongue, assymp but burning/itching, most common), poor feeding, cracks in corner of mouth
• Investigations: clinical diagnosis, throat swab (but normal commensal in mouth)
• Management: miconazole oral gel 14 days if >4 months, if not tolerated nystatin suspension. If over 16 oral fluconazole. Advise sterilise bottles/dummies. Refer to paeds if recurrent or treatment not working as may be immunocompromised
  If on skin topical clotrimazole +/- hydrocortisone, highly absorbant nappies/change asap, don’t use sudocreme

Question 3

Toxic shock syndrome:
- Definition
- Causes (2)
- Risk factors (7)
- DD (3)
- Symptoms
- Investigations
- Manage

Answer 3

Toxic shock syndrome:

• Definition: sudden onset shock, multi organ failure and rush due to exotoxin mediated multisystemic illness
• Causes: staph aures, strep pyrogenes produce exotoxin which acts as superag and causes polyclonal T cell activation and massive cytokine release causing capillary leak
• Risk factors: diab, staph cellulitis, burns, alc, iv drugs, hiv, tampon use/gynae infections
• DD: meningococcal septicaemia, steve johnson syndrome, kawasaki disease
• Symptoms: early flu symptoms, N+V, diarrhoea. Progresses rapidly to high fever, widespread macular rash which can become erythrodermic and cover mucosal membranes. Then multi organ involvement where hypotension due to cardiac depression + confusion from encephalopathy
• Investigations: sepsis 6 (blood cultures, bloods (lfts, fbc, u+es, bone profile, crp, coag screen), throat swabs, wound swabs from suspected site
• Management: A-E, high flow oxy, aggressive fluid resus, abx clindamycin + ceftriaxone 10 days, can do surgical debridement or drainage, corticosteroids

Question 4

Mumps:
- Definition
- Symptoms
- Investigations
- Management
- Complications (4)

Answer 4

Mumps:

• Definition: paramyxovirus viral infection spread via resp droplets. 14-25 days incubation period. Lasts around 1 week. MMR vaccine 80% protection, 2 doses 1 at 1yr and other at 3-4 years
• Symptoms: initial flu like syndromes (prodrome) (fever, muscle aches, lethargy, reduced appetite, headache, dry mouth) then few days after parotid swelling (uni or bilat)
• Investigations: saliva swab for pcr testing + ab to virus
• Management: notify public health, supportive (rest, fluids, analgesia), avoid school 5 days after symptoms started
• Complications: abdo pain (pancreatitis), testic pain (orchitis), confusion/neck stiff/headache (mening/encephalitis), sensorineural hearing loss (unilat and transient)

Question 5

Kawasaki Disease:
- Definition
- Symptoms (6)
- Investigations (3)
- Management
- Complications (1)
- DD (4)

Answer 5

Kawasaki Disease:

• Definition: also known as mucocutaenous lymph node syndrome - systemic medium sized vessel vasculitis affecting children <5 common in asia
• Symptoms: CREAM: Conjunctivitis bilateral, Rash - widespread erythematous maculopapular, Erythema/ desquamation (skin peeling) palms/soles, Adenopathy cervical non tender, Mucosal involvement (strawberry tongue, cracked lips), persistent fever >38C for over 5 days
  Acute phase 1-2 weeks of fever/rash/lymphad
  Subacute 2-4 weeks of symptoms settle, peeling/arthralgia, inc risk aneurysms
  Convalescent 2-4 weeks return normal
• Investigations: bloods (fbc (anaemia, leukocytosis, thrombocytosis), lfts (hypoalbuminaemia, lfts enzymes elevated), esr inc), urine dip (leucocytes), echo
• Management: high dose aspirin to reduce thrombosis risk (usually avoided due to reyes syndrome), Iv immunoglobulins to reduce coron art aneurysm risk, echo follow up to check for aneurysms
• Complication’s: coron art aneurysm
• DD: scarlet fever, measles, drug reactions, toxic shock syndrome

Question 6

Cellulitis:
- Definition
- Causes
- Risk factors (4)
- Symptoms
- Investigations
- Complications (2)
- Management
- Red flags (5)

Answer 6

Cellulitis:

• Definition: bacterial infection of dermis and subcutaneous tissue
• Causes: staph aures, staph pyogenes
• Risk factors: skin trauma/bitr, eczema, diabetes
• Symptoms: spreading area of redness (erythema), warm to touch (calor), pain (dolor), swelling (tumour), fever, malaise, swollen lymph nodes near site
• Investigations: skin biopsy if skin broken and risk of uncommon pathogen
• Complications: sepsis, necrotising fasciitis
• Management: admit if <1 or immunocompromised. Fluids, paracet/ibu, elevate limb, oral flucloxacillin 5-7 days
  Advice: if cut clean immediately + cover, good hand hygeine
• Red flags: come back if mottled/pale/cold, blue lips, confused/floppy, increasing pain, drowsy, breathing problems, turns into rash which doesn’t disappear when pressure applied

Question 7

Conjunctivitis:
- Definition
- Symptoms - allergic and infective
- Causes
- Management

Answer 7

Conjunctivitis:

• Definition: allergic, viral, bacterial
• Symptoms:
• Causes: h influ, adenovirus
• Management: good hygeine, avoid rubbing, no contact lenses, bathing eyelids, if bacterial chloramphenicol abx eye drops, if allergic antihistamines, if <1 urgent opthal review as associated with gonococcal infection which can lead to sight loss + pneumonia

Question 8

Epiglottitis:
- Definition
- Causes (4)
- Pathophysiology
- Risk factors (3)
- Symptoms (8)
- DD (3)
- Investigations (4)
- Management
- Complications (3)

Answer 8

Epiglottitis:

• Definition: acute life threatening condition due to infection
• Causes: haem influ B, strep pneum, viral hsv, parainflu
• Pathophysiology: bacteria/virus (or thermal/trauma/chemical damage) invades epiglottis (designed to protect larynx) resulting in inflammation which can spread to aryepiglottic folds, the arytenoids and supraglottic larynx. VC are tightly bound to epithelium so restricts progression of swelling inc pressure causing airway obstruction (children’s epiglottis is more floppy/broader/longer/ angled more obliquely to trachea inc risk of acute airway obstruction.
• Risk factors: if children don’t get HiB vaccine at 8, 12, 16, 1 yr, male, immunosuppressed
• Symptoms: dyspnoea, dysphagia, drooling, dysphonia for <12 hours, no cough, signs of partial obstruction (rapid onset high fever, sore throat, dehydration), stridor (late sign), tripod position
• DD: croup, inhaled foreign body (sudden onset/ no fever), tonsillitis
• Investigations: don’t examine/calm, throat swabs on intubation, bloods (fbc, culture, crp), lateral neck xray (thumb print sign means swollen epig, thickened aryepiglottic folds, inc opacity larynx/vc)
• Management: secure airway (anaesthetist, ent), oxy, neb adrenaline (whilst awaiting definitive airway management it reduces oedema of upper airway mucosa), iv abx ceftriaxone, iv steroids reduce supraglottic inflammation
• Complications: meningitis, pneumonia, deep neck space infection

Question 9

Herpes simplex infection:
- Definition
- Symptoms (4)
- Management
- Complications (4)

Answer 9

Herpes simplex infection:

• Definition: HSV1 cold sores (opened blisters) passed on by direct contact (HSV2 is cold sores on genitals)
• Symptoms: cold sores, swollen lymph glands, drooling, fever
• Management: acyclovir. Hospital admission if unable to swallow. Paracet/ibup, ice compresses, avoid acidic foods. HSV1 takes 2-3 weeks to heal, cold sores 10-14 days to heal. Advise not to kiss babies if cold sore/ share utensils or anything with saliva
• Complications: poor fluid intake/food hence dehydration, if immunocompromised eczema herpeticum, encephalitis, painful gums/ulcers inside mouth = gingivostomatitis

Once sores have healed virus hides in nerve cells and come back from stress/tired/illness/poor diet/irritated skin

Question 10

Influenza:
- Symptoms (7)
- Investigations
- Management
- Complications (2)
- Vaccination

Answer 10

Influenza:

• Definition: influenza RNA virus A+B common, A responsible for outbreaks/epidemics
• Symptoms: come on 2 days after exposure, nasal discharge, cough, fever, D+V, fatigue. More complicated if CNS signs, LRTI
• Investigations: based on clinical signs, can do rapid testing if complicated signs
• Management: if <6 months zanamivir within 36 hours onset. Fluids, paracet/ibup, stay off school until symptoms go
• Complications: if 38-40C fever can have febrile seizures, pneumonia
• Vaccination: free up until 11yrs old, nasal spay from age 2 and takes 2 weeks to work (is a live attenuated vaccine which contains weak strain). Can’t have it if fever/blocked nose. Offered flu injection instead of spray 6 months - 2 yrs if at risk

Question 11

Measles:
- Definition
- Risk factors (1)
- Symptoms (5)
- Investigations
- DD (3)
- Management
- Complications (3)

Answer 11

Measles:

• Definition: highly contagious disease by measles morbillivirus RNA transmitted by droplets from nose, mouth, throat. Notifiable
• Risk factors: unvaccinated
• Symptoms: 10-14 days post exposure and last 7-10 days: fever >40, coryzal symptoms, conjunctivitis, rash 2-5 days after other symptoms start, koplik spots (grey spots on mucosal membrane pathognomonic of measles)
  Rash starts on face behind ears and spreads to rest of body. Erythematous macular rash with flat lesions
• Investigations: measles specific IgM/IgG serology 3-14 days after onset rash, measles RNA detection by PCR 1-3 days after rash onset
• DD: rubella, roseola, fifth disease
• Management: supportive, ibu/paracet, vit A if <2yrs, ribavirin may reduce symptoms. Stay off school for 4 days after rash started. Infectious 4 days before rash and 4 days after. Give MMR if not vaccinated and presenting within 72 hours
• Complications: (can become serious complications if unvaccinated), otitis media, pneumonia, encephalitis

Question 12

Rubella:
- Definition
- Symptoms (5)
- Investigations
- Management
- Complications (3)

Answer 12

Rubella:

• Definition: german measles, rubella togavirus and transmitted via resp droplets
• Symptoms: start 2 weeks after exposure: fever, coryza, arthralgia, post auricular lymphadenopathy, milder erythematous blanching rash which starts on face and moves down trunk sparing limbs for around 3 days
• Investigations: rubella specific IgM / IgG serology
• Management: supportive, ibu/paracet, notify public health. Avoid preg and stay off school 5 days after rash started.
• Complications: thrombocytopenia, encephalitis. Serious risk to preg esp in first 20 weeks otherwise can lead to congen rubella syndrome (cataracts (blindness), deafness, PDA, brain damage)

Question 13

Viral exanthemas:
- Definition
- Types (6)

Answer 13

Viral exanthemas:

• Definition: eruptive widespread rash
• Types

1. measles
2. Scarlet fever: Group A strep pyrogenes makes exotoxin which causes red/pink macular rough rash starting on trunks + spreading outwards, fever, lethargy, flushed face, sore throat, strawberry tongue, cervical lymphadenopathy. Can lead to rheumatic fever + post strep glomerulonephritis
   Manage: penicillin V/phenoxymethylpenicillin 10 days and don’t go to school until abx started. Notify public health
3. Rubella / German measles
4. Duke’s disease: no specific organism, no specific rash
5. Fifth disease/slapped cheek syndrome/erythema infectiosum: parvovirus b19 mild fever, coryza, muscle aches, lethargy, after 2-5 days diffuse bright red rash on cheeks and then a reticular rash spreads to trunk + limbs and is itchy/raised and lasts 1-2 weeks. Can lead to aplastic anaemia as suppresses bm, enceph/meningitis
   Manage: supportive, once rash forms no longer infectious so school ok after rash appears. If pt pregnant can lead to miscarriage or haematological conditions need serology testing (fbc, reticulocyte count)
6. Roseola infantum: human herpes virus 6 and sometimes 7. 1-2 weeks after exposure sudden high fever 3-5 days sore throat, swollen nodes, then disappears suddenly and 1-2 days rash mild erythematous macular across arms/legs/trunk/face not itchy. Can cause febrile convulsions, if immunocomp myocarditis, thrombocytopenia or GBS
   Manage: 1 week recovery