Infectious Diseases Flashcards
1
Q
Note:
A
Aerobic bacteria require oxygen whereas anaerobic bacteria do not. GRAM POSITIVE bacteria have a thick peptidoglycan cell wall that stains with crystal violet stain. GRAM NEGATIVE bacteria don’t have this thick peptidoglycan cell wall and don’t stain with crystal violet stain will stain with other stains. ATYPICAL BACTERIA cannot be stained or cultured in the normal way.
Also rod shaped bacteria are called bacilli and circular shaped bacteria are called cocci.
2
Q
Note:
A
Nucleic acid is an essential component of bacterial DNA
Ribosomes are where bacteria proteins are synthesised within the bacterial cell.
Folic acid is essential for the synthesis and regulation of DNA within the bacteria. Folic acid cannot be directly imported into the cell and requires a chain of intermediates to get in. This chain starts with para-aminobenzoic acid (PABA), which is directly absorbed across the cell membrane and into the cell. PABA is converted to dihydrofolic acid (DHFA), which is converted inside the cell to tetrahydrofolic acid (THFA), then folic acid.
3
Q
Note:
A
A gram stain is used as a quick way to check a sample under a microscope to look for bacteria. It involves two main steps:
Add a crystal violet stain, which binds to molecules in the thick peptidoglycan cell wall in gram positive bacteria turning them violet.
Then add a counterstain (such as safranin) which binds to the cell membrane in bacteria that don’t have a thick, peptidoglycan cell wall (gram negative bacteria) turning them red/pink
4
Q
Gram positive cocci ?
A
Staphylococcus
Streptococcus
Enterococcus
5
Q
Gram positive rods ?
A
Use the mnemonic “corney Mike’s list of basic cars”:
Corney - Corneybacteria
Mike’s - Mycobacteria
List of - Listeria
Basic - Bacillus
Cars - Nocardia
6
Q
Gram positive anaerobes ?
A
CLAP
C - Clostridium
L - Lactobacillus
A - Actinomyces
P - Propionibacterium
7
Q
Gram negative bacteria ?
A
Neisseria meningitidis
Neisseria gonorrhoea
Hameophilia influenza
E. coli
Klebsiella
Pseudomonas aeruginosa
Moraxella catarrhalis
8
Q
Definition of an atypical bacteria ?
A
Bacteria that cannot be cultured in the normal way or detected using a gram stain.
9
Q
Atypical are most often implicated in what ?
A
Pneumonia
10
Q
Atypical bacteria that cause atypical pneumonia ?
A
“Legions of psittaci MCQs”
Legions - Legionella pneumophila
Psittaci - Chlamydia psittaci
M - Mycoplasma pneumoniae
C - Chlamydophilia pneumoniae
Qs - Q fever (coxiella burnetii)
11
Q
Which type of antibiotics is MRSA resistant to + give examples?
A
Beta-lactam antibiotics such as penicillins, cephalosporins and carbapenems.
12
Q
People are often colonised with MRSA bacteria and have them living harmlessly on their skin and respiratory tract. If these bacteria become part of an infection they can be difficult to treat. Pts being admitted for surgery or inpatient treatment are screened for MRSA infection by taking nose and groin swabs, so that extra measures can be taken to try and eradicate them and stop their spread. Eradication involves a combination of what ?
A
Chlorhexidine body washes and antibacterial nasal creams
13
Q
Antibiotic treatment options for MRSA are ?
A
Doxycycline
Clindamycin
Vancomycin
Teicoplanin
Linezolid
14
Q
What are extended spectrum beta lactamase bacteria (ESBLs) ?
A
Bacteria that have developed resistance to beta-lactam antibiotics. They produce beta lactamase enzymes that destroy the beta-lactam ring on the antibiotic. They can be resistant to a very broad range of antibiotics.
15
Q
ESBLs tend to be + what do they usually cause
A
E. coli or klebsiella and typically cause UTIs but can also cause other infections such as pneumonia
16
Q
What are ESBLs sensitive to ?
A
Carbapenems such as meropenem or imipenem.
17
Q
What do bacteriostatic antibiotics do ?
A
They either stop the reproduction or growth of bacteria
18
Q
What do bactericidal antibiotics do ?
A
They directly kill bacteria
19
Q
TOM TIP:
A
In your OSCEs questions about treating infections can always be answered with “treat with antibiotics according to the local antibiotic policy”
20
Q
Antibiotics that inhibit cell wall synthesis ?
A
Antibiotics with a beta-lactam ring:
-Penicillin
-Carbapenems such as meropenem
-Cephalosporins
Antibiotics without a beta-lactam ring:
-Vancomycin
-Teicoplanin
21
Q
Antibiotics that inhibit folic acid metabolism ?
A
-Sulfamethoxazole blocks the conversion of DHFA to THFA
-Trimethoprim blocks the conversion of THFA to folic acid
-Co-trimoxazole is a combination of the two.
22
Q
Metronidazole ?
A
The reduction of metronidazole into its active form only occurs in anaerobic cells. When partially reduced, metronidazole inhibits nucleic acid synthesis
23
Q
Antibiotics that inhibit protein synthesis by targeting the ribosome ?
A
-Macrolides such as erythromycin, clarithromycin and azithromycin
-Clindamycin
-Tetracyclines such as doxycycline
-Gentamicin
-Chloramphenicol
24
Q
TOM TIP:
A
When taking an allergy history always ask what reaction pts have with that medication. If they report diarrhoea for example, this is a side effect rather than an allergy and means if necessary (for example in life threatening sepsis) they can still receive that medication
25
Stepwise process of escalating antibiotic treatment ?
Start with AMOXICILLIN which covers streptococcus, listeria and enterococcus
Switch to CO-AMOXICLAV to additionally cover staphylococcus, haemophilus and e. coli
Switch to TAZOCIN to additionally cover pseudomonas
Switch to MEROPENEM to additionally cover ESBLs
Add TEICOPLANIN or VANCOMYCIN to cover MRSA
Add CLARITHROMYCIN or DOXYCYCLINE to cover atypical bacteria
26
What is sepsis ?
A condition where the body launches a large immune response to an infection that causes systemic inflammation and affects organ function
27
Pathophysiology of sepsis ?
Pathogens are recognised by macrophages, lymphocytes and mast cells. These cells release vast amounts of cytokines like interleukins and tumour necrosis factor to alert the immune system to the invader. These cytokines activate other parts of the immune system. This immune activation leads to further release of chemicals such as nitrous oxide that causes vasodilation. The immune response causes inflammation throughout the body.
Many of these cytokines cause the endothelial lining of blood vessels to become more permeable. This causes fluid to leak out of the blood into the extracellular space, leading to oedema and a reduction in intravascular volume. The oedema around blood vessels creates a space between the blood and the tissues, reducing the amount of oxygen that reaches the tissues.
Activation of the coagulation system leads to deposition of fibrin throughout the circulation, further compromising organ and tissue perfusion. It also leads to consumption of platelets and clotting factors as they are being used up to form the clots. This leads to thrombocytopenia, haemorrhages and an inability to form clots and stop bleeding. This is called disseminated intravascular coagulopathy (DIC).
Blood lactate rises due to anaerobic respiration in the hypo-perfused tissues with inadequate oxygen. A waste product of anaerobic respiration is lactate.
28
What is septic shock ?
It is defined when arterial blood pressure drops resulting in organ hypo-perfusion. This leads to a rise in blood lactate as the organs begin anaerobic respiration. This can be measured as either:
-Systolic blood pressure less than 90 despite fluid resuscitation
-Hyperlactaemia (lactate > 4 mmol/L)
29
Management of septic shock ?
Should be treated aggressively with IV fluids to improve the BP and tissue perfusion. If IV fluid boluses don't improve the BP and lactate level the pt should be escalated to the HDU or ICU where they can use inotropes (such as noradrenaline) that help stimulate the CVS and improve BP and tissue perfusion.
30
What is severe sepsis ?
It is defined as when sepsis is present and results in organ dysfunction, for example:
-Hypoxia
-Oliguria
-AKI
-Thrombocytopenia
-Coagulation dysfunction
-Hypotension
-Hyperlactaemia (>2 mmol/L)
31
Risk factors for sepsis ?
Any condition that impacts the immune system or makes the pt more frail or prone to infection is a risk factor for developing sepsis:
-Very young or old pts (under 1 or over 75 years)
-Chronic conditions such as COPD and diabetes
-Chemotherapy, immunosuppressants or steroids
-Surgery, recent trauma or burns
-Pregnancy or peripartum
-Indwelling medical devices such as catheters or central lines
32
Presentation of sepsis ?
The national early warning score (NEWS) is used in the UK to pick up the signs of sepsis. This involves checking physical observations and consciousness level:
-Temperature
-Heart rate
-Respiratory rate
-Oxygen sats
-BP
-Consciousness level
33
Other signs on examination that could indicate sepsis ?
-Signs of potential sources such as cellulitis, discharge from a wound, cough or dysuria
-Non-blanching rash can indicate meningococcal septicaemia
-Reduced urine output
-Mottled skin
-Cyanosis
-Arrhythmias such as new onset atrial fibrillation
34
Key points to be aware of in regards to the presentation of sepsis ?
-Tachypnoea is often the first sign of sepsis
-Elderly pts often present with confusion, drowsiness or simply "off legs"
-Neutropenic or immunosuppressed pts may have normal observations and temperature despite being life threateningly unwell
35
Investigations for sepsis (include possible extra investigations)?
Arrange blood tests for pts with suspected sepsis:
-FBC - to assess cell count including white cells and neutrophils
-U&Es - to assess kidney function and look for AKI
-LFTs to assess liver function and for possible source of infection
-CRP - to assess inflammation
-Clotting - to assess for DIC
-Blood cultures to assess for bacteraemia
-Blood gas to assess lactate, pH and glucose
Additional investigations that can be helpful in locating the source of the infection:
-Urine dipstick and culture
-CXR
-CT scan if intra-abdominal infection or abscess is suspected
-Lumbar puncture for meningitis or encephalitis
36
Septic pts should be assessed and have treatment initiated within 1 hour of presenting with suspected sepsis. This involves performing the sepsis six, what is this ?
BUFALO
B - Blood cultures
U - Urine output
F - IV fluids
A - Empirical broad spectrum (A)ntibiotics
L - Blood (L)actate level
O - Oxygen
37
What is neutropenic sepsis ?
A very important medical emergency. It is sepsis in pts with a low neutrophil count of less than 1 x 10(to the power of 9)/L
38
Neutropenia is usually the consequence of anti-cancer or immunosuppressant treatment. Name some medications that may cause neutropenia ?
-Anti cancer chemotherapy
-Clozapine (schizophrenia)
-Hydroxychloroquine (rheumatoid arthritis)
-Methotrexate (RA)
-Sulfasalazine (RA)
-Carbimazole (hyperthyroidism)
-Quinine (malaria)
-Infliximab (monoclonal antibody use for immunosuppression)
-Rituximab (monoclonal antibody use for immunosuppression)
39
Note:
Have a low threshold for suspecting neutropenic sepsis in pts taking immunosuppressants or medications that may cause neutropenia. Treat any temperature above 38°C as neutropenic sepsis in these pts until proven otherwise. They are at high risk of death from sepsis as their immune system cannot adequately fight the infection. They need emergency admission and careful management.
40
Each local hospital treatment will have a neutropenic sepsis policy. Treatment is with what (include an example)
Immediate broad spectrum antibiotics such as piperacillin with tazobactam (tazocin).
The other aspects of management are essentially the same as for sepsis, however extra precaution needs to be taken. Time is precious so don't delay antibiotics while waiting for investigation results.
41
Antibiotic choice for chest infections in the community ?(include initial antibiotics, alternatives and what you would use to treat atypical bacteria)
An appropriate initial antibiotic in the community would be:
-Amoxicillin
Alternatives
-Erythromycin/ clarithromycin
-Doxycycline
To treat atypical bacteria:
-Macrolides such as clarithromycin
-Quinolones such a levofloxacin
-Tetracyclines such as doxycycline
42
Note:
The main source of bacteria for UTIs is from the faeces, where the normal intestinal bacteria such as E. coli can easily make the short journey to the urethral opening from the anus. Sexual activity is a key method for spreading bacteria around the perineum. They are also very common in women where incontinence or hygiene are a problem.
Urinary catheters are a key source of infection and catheter associated UTIs tend to be more significant and difficult to treat.
43
Presentation of a lower UTI ?
-Dysuria
-Suprapubic pain or discomfort
-Frequency
-Urgency
-Incontinence
-Confusion is commonly the only symptom in older more frail pts
44
Presentation of pyelonephritis ?
-Fever
-Loin, suprapubic or back pain. This may be bilateral or unilateral
-Looking and feeling generally unwell
-Vomiting
-Loss of appetite
-Haematuria
-Renal angle tenderness on examination
45
Urine dipstick note (relating to UTIs):
Nitrites - gram negative bacteria (such a E. coli) break down nitrates, a normal waste product in urine, into nitrites. The presence of nitrites suggest bacteria in the urine.
Leukocytes - There are normally a small number of leukocytes in the urine but a significant rise can be the result of an infection or other cause of inflammation. Urine dipsticks test for leukocyte esterase, a product of leukocytes that gives an indication to the number of leukocytes in the urine.
NITRITES are a better indication of infection than LEUKOCYTES. If both are present the pt should be treated as a UTI. If only NITRITES are present it is worth treating as a UTI. If only leukocytes are present the pt should not be treated as a UTI unless there is clinical evidence they have one.
If nitrites or leukocytes are present, the urine should be sent to the microbiology lab. If neither are present the pt is unlikely to have a UTI.
Send a MSU sample to the microbiology lab to be cultured and have sensitivity testing.
46
Most common cause of UTIs + other causes ?
Most common cause is E. coli. This is a gram negative, anaerobic baccilus that is part of the normal lower intestinal microbiome. It is found in faeces and can easily spread to the bladder.
Other causes:
-Klebsiella pneumoniae (gram negative anaerobic rod)
-Enterococcus
-Pseudomonas aeruginosa
-Staphylococcus saprophyticus
-Candida albicans (fungal)
47
Antibiotic choice for a UTI ?
An appropriate initial antibiotic in the community would be:
-Trimethoprim
-Nitrofurantoin
Alternatives:
-Pivmecillinam
-Amoxicillin
-Cefalexin
48
Duration of antibiotics for a UTI ?
-3 DAYS of antibiotics for a simple lower UTI in women
-5-10 DAYS of antibiotics for women that are immunosuppressed, have abnormal anatomy or impaired kidney function
-7 DAYS of antibiotics for men, pregnant women or catheter related UTIs
It is worth noting that NICE recommend changing the catheter when someone is diagnosed with a catheter related urinary tract infection
49
UTIs in pregnancy increase the risk of pyelonephritis, PROM and pre-term labour. How are UTIs managed in pregnancy + when are nitrofurantoin and trimethoprim avoided ?
-7 days of antibiotics (even with asymptomatic bacteriauria)
-Urine for culture and sensitivities
-First line: nitrofurantoin
-Second line: cefalexin or amoxicillin
Nitrofurantoin is generally avoided in the third trimester as it is linked with haemolytic anaemia in the newborn.
Trimethoprim is generally considered safe in pregnancy but avoided in the first trimester or if they are on another medication that affects folic acid (such as anti-epileptics) due to the anti-folate effects.
50
Management of pyelonephritis ?
Referral to hospital if there are features of sepsis
NICE recommend following first line antibiotics for 7-10 days when treating pyelonephritis in the community:
-Cefalexin
-Co-amoxiclav
-Trimethoprim
-Ciprofloxacin
51
What is cellulitis ?
An bacterial infection of the dermis and subcutaneous fat.
52
When a pt presents with cellulitis you should look for what + what could this be due to ?
A breach in the skin barrier and a point of entry for the bacteria.
This may be due to skin trauma, eczematous skin, fungal nail infections or ulcers.
53
Presentation of cellulitis ?
-Erythema (red discolouration)
-Warm or hot to touch
-Tense
-Thickened
-Oedematous
-Bullae (fluid filled blisters)
-A golden-yellow curst can be present and indicates a staphylococcus aureus infection
54
Causes of cellulitis ?
Most common causes are:
-Staph aureus
-Group A streptococcus (mainly strep pyogenes)
-Group C streptococcus (mainly strep dysgalactiae)
MRSA is another cause that needs to be considered
55
Assessment of the severity of cellulitis + when should pts be admitted?
Eron classification:
Class 1 - no systemic toxicity or comorbidity
Class 2 - systemic toxicity or comorbidity
Class 3 - significant systemic toxicity or significant comorbidity
Class 4 - sepsis or life threatening infection
Admit the pts for IV antibiotics if they are class 3 or 4. Also consider admission for frail, very young or immunocompromised pts
56
Treatment of cellulitis ?
Antibiotics:
Flucloxacillin is very effective against staph infections and also works well against other gram positive cocci. It is usually the first choice in treating cellulitis and can be give orally or IV.
Alternatives:
-Clarithromycin
-Clindamycin
-Co-amoxiclav
57
Bacterial tonsillitis is most commonly caused by what ?
Group A streptococcus (GAS) infections, mainly streptococcus pyogenes
58
Otitis media, sinusitis and tonsillitis not caused by GAS are most commonly caused by ?
Strep pneumoniae
59
Other causes of otitis media, sinusitis and tonsillitis ?
Haemophilus influenzae
Moraxella catarrhalis
Staph aureus
60
Tonsillitis is most commonly viral and does not require antibiotics. What is the Centor criteria used for ?
It is used to estimate the probability that tonsillitis is due to a bacteria infection and requires antibiotics.
61
What are the components of the Centor criteria and what score indicates that it is appropriate to offer the pt antibiotics ?
-Fever ≥ 38 degrees celsius
-Tonsillar exudates
-Absence of cough
-Tender anterior cervical lymph nodes
Score of 3 or more indicates it is appropriate to offer antibiotics.
62
Treatment if a pt scores 3 or more on Centor criteria ?
Penicillin V for a day 10 day course is typically first line.
Alternative antibiotics for a broader specrum of activity:
-Co-amoxiclav
-Clarithromycin
-Doxycycline
63
It is difficult to distinguish between bacterial and viral otitis media. It presents with ear pain. Examination will reveal a bulging red tympanic membrane. If the ear drum perforates there can be discharge from the ear.
Otitis media usually resolves 3 to 7 days without antibiotics. If systemically unwell consider admission.
Which antibiotics would you prescribe if appropriate ?(include initial antibiotic in the community, alternatives if penicillin allergy and second line if not responding to amoxicillin after 2 days)
An appropriate initial antibiotic in the community:
-Amoxicillin
Alternatives to penicillin:
-Clarithromycin
-Erythromycin
Second line if not responding to amoxicillin after 2 days:
-Co-amoxiclav
64
Sinusitis can be bacterial or viral. NICE recommend providing an antibiotic if the pt is systemically very unwell, however most pts do not require antibiotics. Sinusitis usually last 2-3 weeks and resolves without treatment.
Management of sinusitis ?
NICE guidelines suggest the following management:
-Symptoms for less than 10 days: no antibiotics
-No improvement after 10 days: 2 weeks of high-dose steroid nasal spray
-No improvement after 10 days and likely bacterial cause: consider delayed or immediate prescription antibiotics
Penicillin V for a 5 day course is typically first line. Co-amoxiclav is used second line if they do not respond after at least 2-3 days.
Alternatives:
-Clarithromycin
-Erythromycin (pregnancy)
-Doxycycline
65
Common causes of intra-abdominal infections ?
-Anaerobes (e.g. bacteroides and clostridium)
-E. coli
-Klebsiella
-Enterococcus
-Streptococcus
66
Note:
When treating intra abdominal infections a broad spectrum of antibiotic cover is required unless culture results are available. It needs to cover gram positive, gram negative and anaerobic bacteria. Always follow the local guidelines as these are frequently changed based on local resistance and infection control issues.
67
Antibiotics for intra-abdominal infections ?
CO-AMOXICLAV:
This provides good gram positive, gram negative and anaerobic cover. It does not cover pseudomonas or atypical bacteria.
QUINOLONES
Ciprofloxacin and levofloxacin provide reasonable gram positive and gram negative cover and also cover atypical bacteria however they don't cover anaerobes so are usually paired with metronidazole when treating intra-abdominal infections
METRONIDAZOLE
This provides exceptional anaerobic cover but does not provide any cover against aerobic bacteria
GENTAMiCIN
This provides very good gram negative cover with some gram positive cover particularly against staphylococcus. It is bactericidal, so works to kill the bacteria rather than just slowing it down.
VANCOMYCIN
This provides very good gram positive cover including MRSA. It is often combined with gentamicin (to cover gram negatvies) and metronidazole (to cover anaerobes) in pts with penicillin allergy.
CEPHALOSPORINS
These provide good broad spectrum cover against gram positive and gram negative bacteria but are not very effective against anaerobes. They are often avoided due to the risk of developing C. difficile infection.
TAZOCIN AND MEROPENEM
Piperacillin/tazobactam (tazocin) and meropenem are heavy hitting antibiotics that cover gram positive, gram negative and anaerobic bacteria. They don't cover atypical bacteria or MRSA and tazocin doesn't cover ESBLs, but they cover almost everything else. They are usually reserved for very unwell pts.
68
Common regimes for intra-abdominal infection ?
-Co-amoxiclav alone
-Amoxicillin plus gentamicin plus metronidazole
-Ciprofloxacin plus metronidazole (penicillin allergy)
-Vancomycin plus gentamicin plus metronidazole (penicillin allergy)
Note:
Antibiotics can be given orally when an oral version is available, for example in mild diverticulitis, or IV in more serious infections.
A stat dose of GENTAMICIN is often added to regimes not including gentamicin if the pt is severely septic to provide strong initial bactericidal gram negative action.
69
Management of spontaneous bacterial peritonitis ?
-Piperacillin and tazobactam (tazocin) is often first line
-Cephalosporins such as cefotaxime are often used
-Levofloxacin plus metronidazole is a common alternative in penicillin allergy.
70
What is septic arthritis ?
When an infection occurs in a joint.
Notes:
-This can be in a native joint or in a joint replacement
-It is a medial emergency
-Has a mortality rate of around 10%
71
Septic arthritis is a common and important complication of what ?
Joint replacement.
72
Presentation of septic arthritis ?
It usually only affects a single joint. This is often a knee. It presents with a rapid onset of:
-Hot, red, swollen and painful joint
-Stiffness and reduced range of motion
-Systemic symptoms such as fever, lethargy and sepsis
73
Most common causative organism of septic arthritis + other bacteria ?
Staph aureus is the most common causative organism.
Other bacteria:
-Neisseria gonorrhoea (gonococcus) in sexually active individuals
-Group A Streptococcus (most commonly Streptococcus pyogenes)
-Haemophilus influenzae
-E. coli
74
Tom tip:
In a young pt presenting with a single acutely swollen joint always consider gonococcus septic arthritis until proven otherwise. Gonorrhoea infection is common and delaying treatment puts the joint in danger. In your exams it might say that the gram stain revealed a "gram negative diplococcus". The pt may have urinary or genital symptoms to trick you into thinking of reactive arthritis but remember that it is important to exclude gonococcal septic arthritis first as this is a more serious condition
75
Differential diagnoses of septic arthritis ?
-Gout (fluid shows urate crystals that are negatively birefringent of polarised light)
-Pseudogout (fluid shows calcium pyrophosphate crystals that are rod shaped intracellular crystals positively birefringent of polarised light)
-Reactive arthritis typically triggered by urethritis or gastroenteritis and associated with conjunctivitis
-Haemarthrosis (bleeding into the joint)
76
Management of septic arthritis ?
Have a low threshold for treating a pt for septic arthritis until it has been excluded with examination of the joint fluid. Be particularly cautious with immunosuppressed pts.
There will be a local hot joint policy at your hospital to guide what team admits the pt (orthopaedics, rheumatology or infectious diseases), what antibiotics to use and for how long.
Aspirate the joint prior to antibiotics and send the sample for GRAM STAINING, CRYSTAL MICROSCOPY, CULTURE and ANTIBIOTIC SENSITIVITIES. The joint fluid may be purulent. The gram stain will come back quite quickly and may give a clue about the organism. The full culture will take longer.
Empirical IV antibiotics should be given until the sensitivities are known. Antibiotics are usually continued for 3 to 6 weeks in total. Choice of antibiotic depends on the local guidelines. Example regimes are:
-Flucloxacillin plus rifampicin is often first line
-Vancomycin plus rifampicin for penicillin allergy, MRSA or prosthetic joint
-Clindamycin is an alternative
77
Is influenza a DNA or RNA virus ?
RNA virus
78
How many types of influenza are there + what are they called
Three types: A, B and C
79
Which type of influenza has different H and N subtypes ?
Type A
80
Who can receive the influenza vaccine free on the NHS ?
-Aged 65 and over
-Young children
-Pregnant women
-Chronic health conditions such as asthma, COPD, HF and diabetes
Healthcare workers and carers
81
Presentation of influenza ?
-Fever
-Coryzal symptoms
-Lethargy and fatigue
-Anorexia (loss of appetite)
-Muscle and joint aches
-Headache
-Dry cough
-Sore throat
82
Diagnosis of influenza ?
Viral nasal or throat swabs can be sent to the local virology lab for PCR analysis. This will confirm the diagnosis and also provide data to public health so that they can monitor the number of cases of influenza.
83
Management of influenza ?
Public health monitor the number of cases of flu and provide guidance on when there is enough flu in the area to justify treating pts with suspected flu.
Healthy pts that are not at risk of complications do not need treatment with antiviral medications. The infection will resolve with self care measures such as adequate fluid intake and rest.
These are two options for treatment in someone AT RISK of complications of influenza:
-Oral oseltamivir (Tamiflu) 75mg twice daily for 5 days
-Inhaled zanamivir 10mg twice daily for 5 days
Treatment needs to be started within 48 hours of the onset of symptoms to be effective.
Post-exposure prophylaxis can be given to higher risk pts, such as those with chronic diseases or immunosuppression, within 48 hours of close contact with influenza. This aims to minimise the risk of developing flu and complications.
Options for post-exposure prophylaxis are:
-Oral oseltamivir (Tamiflu) 75mg once daily for 10 days
-Inhaled zanamivir 10mg once daily for 10 days
84
Complications of influenza ?
-Otitis media, sinusitis and bronchitis
-Viral pneumonia
-Secondary bacteria pneumonia
-Worsening of chronic health conditions such as COPD and heart failure
-Febrile convulsions (young children)
-Encephalitis
85
What is gastroenteritis + how does it present ?
Inflammation all the way from the stomach to the intestines and presents with nausea, vomiting and diarrhoea.
86
Note:
The most common cause of gastroenteritis is viral.
It is essential to isolate the pt in a healthcare environment such as a hospital ward as they can easily spread it to other pts.
87
Viral gastroenteritis is common. It is highly contagious. Causes are ?
-Rotavirus
-Norovirus
-Adenovirus is a less common cause and presents with a more subacute diarrhoea.
88
E coli is a normal intestinal bacteria. Only certain strains cause gastroenteritis. How is it spread ?
Through contact with infected faeces, unwashed salads or contaminated water.
89
Which strain of E. coli produces the shiga toxin ?
E. coli 0157.
90
What symptoms does the shiga toxin produced by E. coli 0157 cause + what else does it do/what does this lead to ?
This causes:
-Abdominal cramps
-Bloody diarrhoea
-Vomiting
It destroys blood cells and leads to haemolytic uraemic syndrome (HUS).
91
Note:
The use of antibiotics increases the risk of hameolytic uraemic syndrome, therefore antibiotics should be avoided if E. coli gastroenteritis is considered
92
Campylobacter is a common cause of travellers diarrhoea. It is a gram negative bacteria. It is spread by ?
-Raw or improperly cooked poultry
-Untreated water
-Unpasteurised milk
93
Campylobacter:
-How long is intubation?
-How long do symptoms take to resolve?
-Symptoms are ?
Intubation is usually 2 to 5 days. Symptoms resolve after 3 to 6 days.
Symptoms are:
-Abdominal cramps
-Diarrhoea often with blood
-Vomiting
-Fever
94
When can antibiotics be considered for gastroenteritis caused by campylobacter jejuni + which antibiotics could be used ?
Where pts have severe symptoms or other risk factors such as HIV or heart failure. Popular antibiotic choices are azithromycin or ciprofloxacin
95
How is Shigella spread ?
By faeces contaminating drinking water, swimming pools and food.
96
Incubation period + time for symptoms to resolve from shigella infection causing gastroenteritis ?
Incubation period is 1 to 2 days.
Symptoms usually resolve in a week without treatment.
97
Presentation of gastroenteritis causing by shigella ?
-Blood diarrhoea
-Abdominal cramps
-Fever
98
Note:
Shigella can produce the Shiga toxin and cause HUS
99
Treatment of severe cases of gastroenteritis caused by Shigella ?
Azithromycin or ciprofloxacin
100
How is Salmonella spread ?
By eating raw eggs or poultry and food contaminated with the infected faeces of small animals.
101
Incubation period + time for symptoms to resolve for gastroenteritis caused by salmonella ?
Intubation is 12 hours to 3 days
Symptoms usually resolve within 1 week.
102
Symptoms of gastroenteritis caused by salmonella + when are antibiotics required to treat?
-Water diarrhoea that can be associated with mucus or blood
-Abdominal pain
-Vomiting
Antibioitics are only necessary in severe cases
103
What type of bacteria Bacillus cerues, how is it spread and what food is it typically found on?
It is a gram positive bacillus that is spread through inadequately cooked food. It grows well on food not immediately refrigerated after cooking. The typical food is fried rice left out at room temperature.
104
Which toxin does bacillus cereus produce + what symptoms does this cause (include time frames) + how long for symptoms to resolve
Whilst growing on the food it produces a toxin called cereulide that causes abdominal cramping and vomiting within 5 hours of ingestion. When it arrives in the intestines it produces different toxins that cause a watery diarrhoea. This occurs more than 8 hours after ingestion. All of the symptoms usually resolve within 24 hours.
105
TOM TIP:
The typical exam pt with bacillus cereus develops symptoms soon after eating leftover fried rice that has been left at room temperature. It has a short incubation period after eating the rice and they then recover within 24 hours. Examiners like this question because the course of bacillus cereus is easy to distinguish from other causes of gastroenteritis.
106
Which type of bacteria is Yersinia Enterocolitica ?
Gram negative bacillus
107
How is Yersinia Enterocolitica spread ?
Pigs are key carriers of Yersinia and eating raw or undercooked pork can cause infection. It is also spread through contamination with the urine or faeces of other mammals such as rats and rabbits.
108
Yersinia most frequently affects children causing which symptoms ?
-Watery or bloody diarrhoea
-Abdominal pain
-Fever
-Lymphadenopathy
109
Incubation period and length of symptoms with gastroenteritis caused by Yersinia ?
Incubation is 4 to 7 days.
Illness can last longer than other causes of enteritis with symptoms lasting 3 weeks or more.
110
Older children or adults with Yersinia can present with right side abdominal pain due to mesenteric lymphadenitis and fever, which can give the impression of what ?
Appendicitis.
111
When are antibiotics required to treat Yersinia ?
They are only necessary in severe cases and guided by stool culture and sensitivities
112
Staph aureus can produce enterotoxins when growing on food such as eggs, dairy and meat. When eaten these toxins cause small intestine inflammation. What symptoms does this cause, how long after ingestion do these symptoms start, how long before they settle and what actually causes the enteritis ? (i.e. bacteria or toxin)
Symptoms:
-Diarrhoea
-Perfuse vomiting
-Abdominal cramps
-Fever
These symptoms start within hours of ingestion and settle within 12 to 24 hours.
It is not actually the bacteria causing the enteritis but the staphylococcus enterotoxin.
113
Giardia lamblia is a type of what + where does it live ?
It is a type of microscopic parasite. It lives in the small intestines of mammals.
114
How is Gardia lamblia spread ?
It releases cysts in the stools of infected mammals. The cysts contaminate food or water and are eaten, infecting a new host. This is called faecal-oral transmission.
115
What symptoms does Gardiasis cause, how to you diagnose it and how do you treat it ?
Infection may not cause any symptoms or it may cause chronic diarrhoea.
Diagnosis is made by stool microscopy.
Treatment is with metronidazole.
116
Principles of gastroenteritis management:
-When pts develop symptoms they should immediately be isolated to prevent spread
-A sample of faeces can be tested with microbiology, culture and sensitivities to establish the causative organism and antibiotic sensitivities
-Always assess a pt for dehydration. IV fluids can be given if oral fluids are not tolerated.
-Advise people to stay off work or school for 48 hours once symptoms have resolved.
-Antidiarrhoeal and antiemetic medication are generally not recommend but may be useful for mild to moderate symptoms.
117
Name some post-gastroenteritis complications ?
-Lactose intolerance
-Irritable bowel syndrome
-Reactive arthritis
-Guillain-Barre syndrome
118
Note:
Neisseria meningitidis is a gram negative diplococcus bacteria. They are cocci that occur in pairs (diplo-). It is commonly known as meningococcus.
119
What is meningococcal septicaemia, what does it cause and what does this indicate ?
When the meningococcal bacterial infection is in the bloodstream. It causes the classic non-blanching rash. this indicates the infection has caused DIC and subcutaneous haemorrhages.
120
Most common causes of bacterial meningitis in adults and children ?
Neisseria meningitidis (meningococcus) and streptococcus pneumoniae (pneumococcus)
121
Most common cause of bacterial meningitis in neonates + how is it usually contracted?
Group B Streptococcus (GBS).
It is usually contracted during birth from GBS bacteria that often live harmlessly in the mother's vagina
122
Presentation of meningitis ? Presentation if meningococcal septicaemia ?
-Fever
-Neck stiffness
-Vomiting
-Headache
-Photophobia
-Altered consciousness
-Seizures
When there is meningococcal septicaemia children can present with a non-blanching rash.
Note: Other causes of bacterial meningitis do not usually cause the non-blanching rash.
123
How else can meningitis present in neotnates & babies + what do NICE recommend ?
Neonates and babies can present with very non-specific signs and symptoms such as hypotonia, poor feeding, lethargy, hypothermia and a bulging fontanelle. For this reason NICE recommend lumbar puncture as part of the investigations for all children:
-Under 1 months presenting with fever
-1 to 3 months with fever and are unwell
-Under 1 years with unexplained fever and other features of serious illness
124
There are two special tests you can perform to look for meningeal irritation. What are they ?
KERNIG'S TEST
-This involves lying the pt on their back, flexing one hip and knee to 90 degrees and then slowly straightening the knee whilst keeping the hip flexed at 90 degrees. This creates a slight stretch in the meninges and where there is meningitis it will produce spinal pain or resistance on this movement.
BRUDZINSKI'S TEST
-This involves lying the pt flat on their back and gently using your hands to lift their head and neck off the bed and flex their chin to their chest. A positive test is when this causes the pt to involuntarily flex their hips and knees.
125
Pts seen in the community with suspected meningitis AND a non blanching rash should receive an injection of what ?
IM or IV benzylpenicillin:
-Under 1 year: 300mg
-1-9 years: 600mg
-Above 10 years and adults: 1200mg
Note: This shouldn't delay transfer. Where there is a true penicillin allergy transfer should be the priority rather than other antibiotics.
126
Management of bacterial meningitis in hospital ?
-Ideally a blood culture and a lumber puncture should be performed prior to starting antibiotics however if the pt is acutely unwell antibiotics should not be delayed.
-Send blood tests for meningococcal PCR if meningococcal disease is suspected (This can give a quicker result than a blood culture depending on local services and will still be positive after the bacteria has been treated with antibiotics
-There should be a low threshold for treated suspected bacterial meningitis. Typical antibiotics are:
-Under 3 months = cefotaxime + amoxicillin (to cover listeria potentially contracted during pregnancy)
-Above 3 months = ceftriaxone
-Vancomycin should be added to these if there is a risk of penicillin resistant pneumococcal infeciton.
-Dexamethasone is used if the LP is suggestive of bacterial meningitis to reduce the frequency and severity of hearing loss and neurological damage.
127
People that have had close prolonged contact to a pt who has contracted meningitis should recieve what prophylaxis if they were in close contact within the 7 days prior to the onset of the illness ?
A single of ciprofloxacin.
128
Most common causes of viral meningitis ?
HSV, enterovirus and VSV
Note: A sample of the CSF from the lumbar puncture should be sent for viral PCR testing.
129
Viral meningitis tends to be milder than bacterial and often only requires supportive treatment. Aciclovir can be used to treatment meningitis caused by what virus ?
HSV
130
Where is a LP normally done and why ?
The L3-L4 intervertebral space as the spinal cord ends at the L1-L2 vertebral level.
131
Tom TIP:
Interpreting LP results is a common exam question. It is easier to think about what will happen to the CSF with bacteria or viruses living in it rather than trying to rote learn the results. It makes sense that bacteria swimming in the CSF will release proteins and use up the glucose. Viruses don't use glucose but may release a small amount of protein. The immune system releases neutrophils in response to bacteria and lymphocytes in response to viruses.
132
Complications of meningitis ?
-Hearing loss is a key complication
-Seizures and epilepsy
-Cognitive impairment and learning disability
-Memory loss
-Focal neurological deficits such as limb weakness or spasticity.
133
TB is an infectious disease caused what ?
The mycobacterium tuberculosis
134
What shape is mycobacterium tuberculosis, does it gram stain/ why and what is this property called ?
-It is a small rod shaped bacteria (a bacillus)
-It does not gram stain in the normal way as it has a waxy coating that makes gram staining ineffective
-This property is called acid-fastness
Therefore the TB bacteria are described as acid-fast bacilli.
135
How can TB bacteria be stained + what colour do they turn ?
They require a special staining technique using the Zeihl-Neelsen stain. This turns TB bacteria bright red against a blue background.
136
Note:
TB is more prevalent in non-UK born pts (i.e. from South Asia), those who are immuncompromisded and those with close contacts with TB. Multi-Drug Resistant TB (MDR TB)) are strains that are resistant to more than one TB drug, making them very difficult to treat.
137
Disease course of TB:
The TB bacteria are very slow dividing with high oxygen demands. This makes them difficult to culture and treat. They are mostly spread by inhaling saliva droplets from infected people. It then spreads through the lymphatics and blood. Granulomas containing the bacteria form around the body.
ACTIVE TB is where there is active infection in various areas of the body. In the majority of cases the immune system is able to kill and clear the infection. The immune system may encapsulate sites of infection and stop the progression of the disease and this is referred to as LATENT TB. When latent TB reactivates this is known as SECONDARY TB. When the immune system is unable to control the disease this causes a disseminated, severe disease and is referred to as MILIARY TB.
138
The most common site for TB infection is in the lungs, where they get plenty of oxygen. Extrapulmonary TB is where it infects other areas such as ?
-Lymph nodes - a "cold abscess" is a firm painless abscess caused by TB, usually in the neck. They do not have the inflammation, redness and pain you would expect from an acutely infected abscess.
-Pleura
-CNS
-Pericardium
-GI system
-GU system
-Bones and joints
-Cutaneous TB affecting the skin
139
Name 5 RF's for TB ?
-Known contact with active TB
-Immigrants from ares of high TB prevalence
-People with relatives or close contacts from countries with a high rate of TB
-Immunocompromised due to conditions like HIV or immunosuppressant medications
-Homeless people, drug users or alcoholics
140
What does the BCG vaccine involve + what does it offer protection against + what is it less effective against ?
An intradermal infection of live attenuated TB. It offers protection against severe and complicated TB but is less effective against pulmonary TB
141
Prior to the BCG vaccine pts are tested with what, why and what else are they assessed for ?
The mantoux test. They are only given the vaccine if the test is negative. They are also assessed for the possibility of immunosuppression and HIV due to the risks related to a live vaccine.
142
Note:
The BCG vaccine is offered to pts that are at higher risk of contact with TB:
-Neonates born in areas of the UK with high rates of TB
-Neonates with relatives from countries with a high rate of TB
-Neonates with a FH of TB
-Unvaccinated older children and young adults (under 35) who have close contact with TB
-Unvaccinated children or young adults that recently arrived from a country with a high rate of TB
-Healthcare workers
143
TB usually presents with a history of chronic, gradually worsening symptoms. Most cases are of pulmonary TB (around 70%) but they often have systemic symptoms. Typical signs and symptoms of TB include ?
-Lethargy
-Fever and night sweats
-Weight loss
-Cough with or without haemoptysis
-Lymphadenopathy
-Erythema nodusum
-Spinal pain in spinal TB (also known as Pott's disease of the spine)
144
There are two tests for an immune response to TB caused by previous, latent or active TB. What are they ?
In pts where active TB is suspected which two tests are used to support the diagnosis ?
Mantoux test & Interferon-gamma release assay
CXR and cultures.
145
What is the Mantoux test used to look for + what would a positive test indicate ?
A previous immune response to TB.
A positive test would indicate possible previous vaccination, latent or active TB.
146
What happens in the Mantoux test (include what would indicate a positive result) + what happens if there is a positive result
The test involves injecting tuberculin into the intradermal space on the forearm. Tuberculin is a collection of TB proteins that have been isolated from the bacteria. It does not contain any live bacteria.
Injecting the tuberculin creates a bleb under the skin. After 72 hours the test is "read". This involves measuring the induration of the skin at the site of the injection. NICE suggest considering an induration of 5mm or more a positive result. After a positive result they should be assessed for active disease
147
What happens in the interferon-gamma release assay test + what is it used for
The test involves taking a sample of blood and mixing it with antigens from the TB bacteria. In a person that has had previous contact with TB the WBCs have become sensitised to those antigens and they will release IG as part of an immune response. If IG is released from the WBCs this is considered a positive result.
The IGRA is used to confirm latent TB in pts with a positive Mantoux test but no active disease
148
What would the different types of active TB show on a CXR ?
-PRIMARY TB - may show patch consolidation, pleural effusions and hilar lymphadenopathy
-REACTIVATED TB - may show patchy or nodular consolidation with cavitation (gas filled spaces in the lungs) typically in the upper zones
-DISSEMINATED MILIARY TB - give a picture of "millet seeds" uniformly distributed throughout the lung fields.
149
Note:
Performing a TB bacterial culture and collecting a sample of the TB bacteria is very useful prior to starting treatment. This allows testing of the bacteria for resistance to antibiotics. Unfortunately cultures can take several months to grow an organism. Treatment is usually started whilst waiting for the culture results.
150
How is TB bacteria collecting for culturing ?
-SPUTUM - 3 samples should be collected and tested. If they are not producing sputum hypertonic saline can be used to induce sputum production. They might require bronchoscopy with lavage to collect sputum samples
-MYCOBACTERIUM BLOOD CULTURES
-LYMPH NODE ASPIRATION or BIOPSY
151
Why would a nucleic acid amplification test be used when testing for TB ?
It provides information about the bacteria faster than a traditional culture but is only used where having this information would affect treatment or they are at higher risk of developing complications (i.e in HIV).
152
Management of latent TB ?
Otherwise healthy pts do not necessarily need treatment for latent TB. Pts at risk of reactivation of latent TB can be treated with either:
-Isoniazid and rifampicin for 3 months
-Isoniazid for 6 months
153
Management of active pulmonary TB ?
RIPE
R - Rifampicin for 6 months
I - Isoniazid for 6 months
P - Pyrazinamide for 2 months
E - Ethambutol for 2 months
154
Other management considerations for active TB ?
-Test for other infectious diseases (HIV, Hep B & C)
-Test contacts for TB
-Notify Public Health of all suspected cases
-Pts with active TB should be isolated to prevent spread until they are established on treatment (usually 2 weeks). In hospital negative pressure rooms are used to prevent airborne spread. Negative pressure rooms have ventilation systems that actively remove air to prevent it spreading on to the ward.
-Management and followup should be guided by a specialist MDT
-Treatment is slightly different for extrapulmonary disease and often includes using corticosteroids
-Individualised drug regimes are required for multidrug-resistant TB
155
Side effects of TB treatment ?
-Rifampicin ("red-an-orange pissin") can cause red/orange discolouration of secretions like urine and teras. It is a potent inducer of cytochrome P450 enzymes therefore reduces the effect of drugs metabolised by this sytem. This is important for medications like the contraceptive pill
-Isoniazid ("I'm so num azid") can cause peripheral neuropathy. Pyridoxine (vitamin B6) is usually co-prescribed prophylactically to reduce the risk of peripheral neuropathy
-Pyrazinamide can cause hyperuricaemia resulting in gout
-Ethambutol ("eye-thambutol") can cause colour blindness and reduced visual acuity
Rifampicin, isoniazid and pyrazinamide are all associated with hepatotoxicty
156
What type of virus is HIV ?
What is the most common type of HIV ?
What does the virus do to the body ?
How does the disease progress ?
-It is a RNA virus.
-HIV-1 is the most common type. HIV-2 is rare outside West Africa.
-The virus enters and destroys CD4 T helper cells
-An initial seroconversion flu like illness occurs within a few weeks of infection. The infection is then asymptomatic until it progresses and the pt becomes immunocompromised and develops AIDS defining illnesses and opportunistic infections potentially years later.
157
Transmission of HIV ?
HIV can't be spread through normal day to day activities including kissing. It is spread through:
-Unprotected anal, vaginal or oral sexual activity
-Mother to child at any stage of pregnancy, birth or breastfeeding. This is referred to as vertical transmission.
-Mucous membrane, blood or open wound exposure to infected blood or bodily fluids such as through sharing needles, needle-stick injuries or blood splashed in an eye.
158
There is a long list of AIDS defining illnesses associated with end stage HIV infection where the CD4 count has dropped to a level that allows for unusual opportunistic infections and malignancies to appear. Name some examples ?
-Pneumocystis jirovecii pneumonia (PCP)
-Cytomegalovirus infection
-Candidiasis (oesophageal or bronchial)
-Lymphomas
-TB
159
In hospital who should we screen for HIV ?
Practically everyone admitted to hospital with an infectious disease
160
How long can antibody tests for HIV be negative following exposure ?
3 months. Therefore repeat testing is necessary if an initial test is negative within 3 months of a potential exposure.
161
3 methods of testing for HIV with a a description of each ?
-Antibody blood test - this is the typical test used in hospitals to screen for HIV. There is an option for pts to self sample by requesting a kit online and posting a sample of their blood to get tested for the antibody.
-PCR testing for the p24 antigen - tests directly for this HIV antigen in the blood. It can be positive before the antibody test.
-PCR testing for the HIV RNA levels - tests directly for the quantity of the HIV virus in the blood and gives a viral load.
162
Monitoring of HIV pts (include description and ranges) ?
CD4 count
-This is a count of the number of CD4 cells in the blood. These are the cells destroyed by the HIV virus. The lower the count the higher the risk of opportunistic infection:
-500-1200 cells/mm3 is the normal range
-Under 200 cells/mm3 is considered end stage HIV / AIDS and puts the pt at high risk of opportunistic infection
Viral load
-Viral load is the number of copies of HIV RNA per m of blood. "Undetectable" refers to a viral load below the lab's recordable range (usually 50 - 100 copies/ml). The vial load can be in the hundreds of thousands in untreated HIV.
163
BHIVA guidelines recommended starting a regime of what for treating HIV ?
2 NRTIs (e.g. tenofovir and emtricitabine) plus a third agent
164
Highly Active Anti-Retrovirus Therapy (HAART) medication classes ?
Protease inhibitors (PIs)
Integrase inhibitors (IIs)
Nucleoside reverse transcriptase inhibitors (NRTIs)
Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
Entry inhibitors (EIs)
165
Additional management of HIV ?
-Prophylactic co-trimoxazole (Septrin) is given to pts with a CD4 under 200 cells/mm3 to protect against PCP
--HIV infection increases the risk of developing CVD.
Close monitoring of CV RF's and blood lipids and appropriate treatment e.g. stains to reduce their risk of developing CVD.
-Yearly cervical smears for women. HIV predisposes to developing cervical HPV infection and cervical cancer
-Vaccinations should be up to date including annual influenza. Pts should avoid live vaccines.
166
Post exposure prophylaxis in HIV :
Post exposure prophylaxis can be used after exposure to HIV to reduce the risk of transmission. It is not 100% effective and must be commenced with a short period (less than 72 hours).
It involves a combination of ART therapy. The current regime is Truvada (emtricitabine / tenofovir) and raltegravir for 28 days.
HIV tests should be done initially but also a minimum of 3 months after exposure to confirm a negative result
167
Malaria is an infectious disease caused by ?
Members of the plasmodium family of protozoan parasites.
168
What is the most severe and dangerous member of the plasmodium family ?
Plasmodium falciparum
169
Malaria is spread through ?
Bites from the female Anopheles mosquitoes that carry the disease.
170
Types of malaria parasites ?
Plasmodium falciparum
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
171
Life cycle of malaria ?
1. Malaria is spread by female Anopheles mosquitoes, usually at night.
2. Infected blood is sucked up by the feeding mosquito. The malaria in the blood reproduces in the gut of the mosquito producing thousands of sporozoites.
3. When that mosquito bites another human or animal the sporozoites are injected by the mosquito. These sporozoites travel to the liver of the newly infected person. They can lie dormant as hypnozoites for several years in P. vivax and P. ovale.
4. They then mature in the liver into merozoites, which enter the blood and infect RBCs.
5. In RBCs the merozoites reproduce over 48 hours, after which the RBCs rupture, releasing loads more merozoites into the blood and causing haemolytic anaemia. This is why people infected with malaria have high fever spikes every 48 hours.
172
Suspect malaria in someone who lives or has travelled o an area of malaria. The incubation period is 1 to 4 weeks after infection with malaria although it can lie dormant for years. Non specific symptoms + signs of malaria ?
Non specific symptoms:
-Fever, sweats and rigors
-Malaise
-Myalgia
-Headache
-Vomiting
Signs
-Pallor due to anaemia
-Hepatosplenomegaly
-Jaundice as bilirubin is released during the rupture of RBCs
173
Diagnosis of malaria ?
-Diagnosis can be made using a malaria blood film
-Three blood samples are sent over 3 consecutive days to exclude malaria. This is due to the 48 hour cycle of malaria being released into the blood from RBCs
174
Management of malaria ?
Oral options for uncomplicated malaria:
1. Artemether with lumefantrine (Riamet)
2. Proguanil and atovaquone (Malarone)
3. Quinine sulphate
4. Doxycycline
IV options in severe or complicated malaria
1. Artesunate. This is the most effective treatment but is not licensed
2. Quinine dihydrochloride
175
Name some complications of plasmodium falciparum infection ?
-Cerebral malaria
-Seizures
-Reduced consciousness
-AKI
-Pulmonary oedema
-DIC
-Severe haemolytic anaemia
-Multi-organ failure and death
176
Prophylactic antimalarial options ?
Proguanil and atovaquone (malarone)
-Most expensive
-Best side effect profile
Mefloquine
-Can cause bad dreams and rarely psychotic disorders or seizures
Doxycycline
-Broad spectrum antibiotic therefore it causes side effects like diarrhoea and thrush
-Makes pts sensitive to the sun causing a rash and sunburn
