infection Flashcards
(44 cards)
1
Q
Define malaria
A
infection with protozoan Plasmodium usually transmitted with female Anopheles mosquito bite.
2
Q
Life cycle of malarial parasite
A
- mosquito injects plasmodium (sporozoites) into bloodstream
- Invasion and replication of parasites in hepatocytes
- released into bloodstream and enter + infect RBCs to replicate (SYMPTOMS)
- => form Gametocytes taken up when another mosquito feeds and develops into sporozoites in mosquito gut
- then moves to salivary gland to be passed on to human the next bite
3
Q
Which populations have innate immunity to malaria
A
- sickle cell anaemia
- GP6D deficiency
- pyruvate kinase deficiency
- thalassemia
4
Q
presenting symptoms of malaria
A
symptoms are cyclical
- high fever (39+)
- headache
- flu-like symptoms (lethargy, fatigue)
- severe sweating
- shivering cold
*travel history (incubation period 1yr)
5
Q
features of severe malaria (e.g. cerebral malaria)
A
- impaired consciousness
- seizures
- altered respiration
6
Q
examination findings of malaria
A
- check for signs of severe malaria (impaired consiousness, seizures, altered respiration)
- basic obs (pyrexia)
- jaundice
- hepatosplenomegaly
- pallor (anaemia)
7
Q
investigations + findings for suspected malaria
A
- THIN/THICK blood film
- bloods (FBC, LFT, U&Es, ABG)
- urinalysis (check for blood/ protein)
8
Q
What groups are at risk of developing severe malaria?
A
- children
- pregnant women
- elderly (>65)
- immunocompromised (HIV)
9
Q
Management for malaria
A
- anti-malarial drugs (depending on plasmodium type)
- monitor other contacts for malaria (NOTIFIABLE DISEASE => to public health authorities)
10
Q
Define sepsis
A
Life threatening organ dysfunction caused by dysregulated host response to infection
11
Q
Causes of sepsis
A
Infection => stimulates immune response =>
Vasodilation + increased capillary refill => raised bp (usually respiratory/ UTI => CXR)
12
Q
Risk factors for sepsis
A
Immunocompromised
Diabetics
Elderly
Catheter
Open wound
IV drug user
13
Q
How to assess for SEPSIS? + symptoms
A
- less time to do history/ examination => treat immediately
- A=> E approach for initial assessment of SEPSIS
- Airway
- Breathing- cyanosed, high RR, low O2
- Circulation- febrile, warm/ cold peripheries, long capillary refill time
- Disability- confused
- Everything (fever, rashes, blood glucose, fever)
Other Symptoms:
- high resp rate (tachypnoea)
- low bp
- fever
- tachycardia (high HR)
- malaise/lethargy
- nausea/vomiting/ diarrhoea
- low urine output = marker of AKI
14
Q
How to diagnose sepsis? (Criteria)
A
QSOFA score - 2/3= SEPSIS
- Altered mental status (GCS<15)
- increased resp rate (>22)
- Low systolic bp (<100)
NEWS2 =/>5 = SEPSIS
15
Q
Investigations for sepsis
A
Bedside
- hourly urine output
- blood glucose
- ECG - rule out MI
- Urinalysis - check for UTI
Bloods:
- blood cultures
- Venous blood gas => serum Lactate (marker of severity/ tissue hypoperfusion)
- FBC- check for thrombocytopenia (worse prognosis)
- U&E- check for renal dysfunction
- LFT- high bilirubin (organ dysfunction)
- high CRP (not specific)
- Clotting screen- elevated PT/APTT
Imaging:
- CXR - check for Respiratory tract infection
16
Q
Treatment for SEPSIS (SEPSIS 6- give OAF, take LOB/ BUFALO)
A
- inform senior
1. Give 3 - oxygen- >94% (vasodilation in lungs)
-broadspectrum IV antibiotics- within hour - IV fluids- increase preload/stroke volume => increase O2/blood delivery to tissues
*over oxygenation => hyp
- Take 3
- blood cultures (give antibiotics before)
- lactate (see if they need ITU)
- urine output (measure fluid balance so not giving too much fluid)
17
Q
Define HIV
A
infection of the human immunodeficiency virus
18
Q
Transmission of HIV
A
- sexual contact (heterosexual mainly)
- blood contact (mother=>baby during intrauterine, breastfeeding), needle sharers, blood transfusions, organ transplantation.
19
Q
pathophysiology of HIV
A
- HIV binds to CD4+ T cells via gp120 receptors
- reverse transcriptase codes the viral genome => incoporates into hosts DNA
- HIV multiples => T cell death => depletion
20
Q
Presenting symptoms + signs of HIV
A
- Seroconversion (self-limiting)
- fever
- night sweats/ chills
- sore throat , encephalitis, diarhhoea
- SIGNS: lymphadenopathy, oral ulcers, rashes, - early/ asymptomatic
- quite well
- can get lymphadenopathy/ oral thrush/ weight loss - AIDS- syndrome of secondary diseases due to immunodeficiency
21
Q
Direct complications of HIV
A
- Neurological- polyneuropathy, dementia
- Lung- interstitial pneumonitis
- Heart- cardiomyopathy
- Haematology- anaemia
- GI- anorexia
- Eyes- cotton wool spots
22
Q
Secondary complications of HIV (from immunodeficiency)
A
- bacterial infection (TB, pneumococcal, skin)
- viral infection (HPV, VSZ)
- fungal infection (canadiadis, cryptococcus)
- protozoan (toxoplasmosis)
- tumours (kaposi sarcoma, SCC)
23
Q
Investigations + findings for HIV
A
- HIV test (HIV antibodies, PCR test for viral RNA, viral load, CD4 count)
- CXR- Pneumocystic pneumonia
- brain CT or MRI, LP - Cryptococcal meningitis
- colonoscopy and biopsy - CMV (colitis)
- brain CT or MRI- Toxoplasmosis
- stool microscopy- Cryptosporidia
24
Q
Management of HIV
A
Combo of Anti-retroviral therapies (ARTs)
- nucleoside reverse transcriptase inhibitor (NRTIs)
+ 1 of
- integrase inhibitor (INI)
- non-nucleoside reverse transcriptase inhibitor (NNRTI)
- boosted protease inhibitor (PI)
25
What should be given for potential/future exposure to HIV
pre-exposure prophylaxis (prEP) ARTs
26
Define infectious mononucelosis (glandular fever) and it's main cause
* infection mainly caused by **Epstein-Barr virus**
* aka kissing disease
* usually transmitted via saliva (kissing)/ sex
* mild in children, severe in adults
27
Presenting symptoms of infectious mononucleosis
* fever
* sore throat (pharyngitis)
* regional lymphadenopathy (tender, non-erythematous)
* malaise (unwell)
28
Examination findings of infectious mononucleosis
* **pyrexia**
* **regional lymphadenopathy**
* **splenomegaly**
* signs of hepatitis (jaundice, hepatomegaly)- adults more likely to have
29
Investigations for infectious mononucleosis
**_Bedside: Throat swab_**
* **positive heterophile antibodies** (Paul Bunnel test)- IgM AB agglutinate red cells of other animals(non-specfic)
* **EBV antibodies** (specific + sensitive)
Bloods:
* FBC- raised WCC, Hb-anaemia
* LFTs- raised AST,ALT (hepatitis)
Imaging
* Abdomen Ultrasonography - detect splenomegaly
* CT abdo - detect splenic rupture
30
Management of infectious mononucleosis
* hydration
* **analgesia** (paracetomol/ ibuprofen -NSAID)
* antipyretics
* Lifestyle - stop alcohol, **avoid physical contact with others** (kissing, sports =\> splenic rupture)
For severe disease:
Upper airway obstruction =\> corticosteroid (prednisilone)
Thrombocytopoenia =\> corticosteroid/ IV imunoglobulin
31
Why avoid giving antiboitics in infectious mononucelosis
* can cause antibiotoic induced rash
32
Complications of infectious mononucleosis
* **splenic rupture**
* Viral meningitis
* **thrombocytopeni**a - corticosteroids
* depression
* Guillan- Barre syndrome
* Burkitt's lymphoma (cancer)
33
define herpes simplex virus
sexually transmitted disease spread by direct contact
* HSV1(most common)
* HSV2
34
Types of herpes
* oral- ulcers on nose/lips (herpes labialis) or pharyngeal/oral mucosa (gingivostomatitis)
* genital- ulcers on external genetalia
* ocular- inflammation of eye usually blepharoconjuctivitis
* herpetic whitlow- infection o finger
35
symptoms of genital herpes
* usually asymptomatic
* fever, malaise
* multiple painful blisters around genetalia
* usually burst and leave ulcers
* urethral,vaginal discharge
36
symptoms of oral herpes
* fever, sore throat, lymphadenopathy
* painful, burning, itching
* blisters around the nose/mouth (herpes labialis)
* blisters in pharyngeal/oral mucosa (gingivostomatitis)
37
symptoms of ocular herpes
* mainly asymptomatic
* red, watery eye
* blurred/reduced vision
* hazy cornea
* irregular pupils (uveitis)
38
management of herpes
genital
* anaesthetic
* fluids to dilue urine
* oral acyclovir
ocular
* refer to opthamologist =\> topical anti-virals
oral
* analgesia
* oral acyclovir
* avoid triggers (stress, sunlight)- suncream lip balm
39
complications of herpes
* worse in immunocompromised individuals
* eczema herpetica
* erythema multiforme (target shaped lesions)
* herpetic whitlow
* eye disease
* meningitis/ encephalitis
40
define varicella zoster
* chicken pox is caused by infection of varicella zoster virus
* spread by direct contact/droplet infection
* incubation period of \<3 weeks
41
symptoms of varicella zoster virus
* fever, malaise, fatigue
* nausea, myalgia, headache, decreased appetitie
* followed by small, red itchy widespread rash which start on chest/face/back
* forms itchy blisters \<5 days
42
management of varicella zoster virus
* paracetamol
* topical calamine lotion (for itch)
* chlorophenamine (anti-histamine - for itch)
* fluids, soft clothes, short nails to avoid scratching
if severe complications/ pregnant/immunocompromised
* oral acyclovir
43
complications of varicella zoster virus
Children:
* bacterial skin infection (impetigo, cellulitis, erysipeles, necrotising fasciitis)
* neurological (Reye's, cerebellar ataxia, encephalitis, myelitis)
Adults (more severe complications/ hospitalised)
* hepatitis
* encephalitis
* pneumonia
Long term: VZV stays dormant in spinal ganglia =\> activated in adults as herpes zoster virus **_(shingles)_**
44
differentials for chicken pox
Widespread Rashes
* herpes zoster (painful unilateral blotchy rash)
* **_herpes simplex_**
* coxsacchie virus (hand,foot,mouth disease)
* **_drug induced_**
* **_contact dermatitis_**
* **_measles_** (fever/watery eyes=\> red blotchy rash first on forehead)
Other infection
* **_impetigo_** (yellow crusting in face, contagious)
* **_scabies_**- bite (itchy, red rash)
* syphillis -STI (cold sores =\> hair loss, sore throat, rash)
* TSS
Skin diseases
* guttate psoriasis (small, round scaly spots)
* erythema multiforme- allergy (symmetrical red raised lesions)
* dermatitis herpetiformis- coeliac disease (intense,itchy,blistering rash)
* steven johnson (rare)- allergy (fever =\> blistering rash =\> skin peels and heals)
* henoch-schonlein purpura - IgA vasculitis
