MicrobiologyforMCEMST1

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					Microbiology for MCEM
Tetanus MCQ
   A. The incubation period is usually in excess of
       28 days

   B. Once the toxin is fixed to neurones,
       antitoxin is ineffective

   C. The mortality of established tetanus
       depends upon previous immunisation

   D. Patients with generalised tetanus present
       with trismus in 75%
Tetanus MCQ
   A.    The incubation period is usually in excess of 28 days
          FALSE
        Usually 4 - 14 days, median 7 days

   B.    Once the toxin is fixed to neurones, antitoxin is
          ineffective      TRUE
        Recovery depends on sprouting new terminals and
         synapses

   C.    The mortality of established tetanus depends upon
          previous immunisation TRUE
        6% with 1-2 doses of vaccine, 15% without any

   D. Patients with generalised tetanus present with
          trismus in 75% of cases TRUE
        Other presenting complaints include stiffness, neck rigidity,
         dysphagia, restlessness, and reflex spasms
Tetanus MCQ
   A.   The current recommendations for immunisation
         provide 6 doses by the age of 18

   B.   There is a small risk of immunisation causing a
         mild form of tetanus

   C.   Tetanus vaccine given at the time of a tetanus-prone
         injury may not boost immunity early enough to give
         additional protection within the incubation period of
         tetanus

   D.   Tetanus prone wounds mandate the
         administration of immunoglobulin
Tetanus MCQ
   A.    The current recommendations for immunisation
          provide 6 doses by the age of 18        FALSE
        Doses at 2,3,4 months, 3-5 years and 13-18 years

   B.     There is a small risk of immunisation causing a mild
           form of tetanus FALSE
        The vaccines are inactivated, do not contain live
         organisms and cannot cause the diseases against which
         they protect.

    C.    Tetanus vaccine given at the time of a tetanus-prone
          injury may not boost immunity early enough to give
          additional protection within the incubation period of
          tetanus TRUE

   D.     Tetanus prone wounds mandate the administration of
           immunoglobulin FALSE
        Only if wound is ‘high risk’ as long as patient fully
         immunised
Tetanus
   Clostidium Tetani is an obligate
    anaerobic gram positive bacillus

   Spore forming – resistant to heat,
    desiccation and disinfectants. Viable for
    years

   Found in soil, animal intestines and
    human faeces
Tetanus
   Tetanospasmin is released under anaerobic
    conditions, enters the nervous system
    peripherally at the myoneural junction and is
    transported centrally to neurons of the CNS.

   Inhibits neurotransmitter release (mainly GABA
    - inhibitory). Shorter nerves affected faster
    therefore facial/back stiffness first.
Tetanus prone wound is:
   Wounds or burn sustained >6 hours before
    surgical treatment.

   Any wound or burn with:
       A significant degree of devitalised tissue.
       Puncture wounds.
       Wounds having come in contact with soil or manure
        likely to harbour tetanus organisms.
       Clinical evidence of sepsis or compound fractures.
Tetanus
   High risk wound should always be treated with
    immunoglobulin
       Wound contaminated with horse manure / farmyard


   The preventative dose of human tetanus
    immunoglobulin is
       250iu im in most cases,
       500iu im if
          More than 24 hours have elapsed.

          Risk of heavy contamination.

          Burns.
Immunisation                 Clean Wound               Tetanus
   Status                                            prone wound

                                   Vaccine                 Vaccine             Immunoglobulin



Fully immunised            None required             None required             Only if high risk
i.e has received a total
of five doses at
appropriate intervals


Primary complete,          None required             None required             Only if high risk
boosters incomplete
but up to date


Primary incomplete or      Vaccine dose and          Vaccine dose and          Yes, one dose in a
boosters not up to         further doses to          further doses to          different site
date                       complete schedule         complete schedule


Not immunised or           Vaccine dose and          Vaccine dose and          Yes, one dose in a
status unknown             completion of full five   completion of full five   different site
                           dose course               dose course
Immunisation

   Once five doses of vaccine have been
    received at appropriate intervals, another
    dose of vaccine is not required following
    any type of wound.
Gastroenteritis MCQ
   A. Gastroenteritis is bacterial in origin in
       15-20% of cases

   B. Rotavirus is the leading cause of
       gastroenteritis in children

   C. Food poisoning is a notifiable disease

   D. Stool microscopy and culture is
       usually required
Gastroenteritis MCQ
   A. Gastroenteritis is bacterial in 15 - 20% of
       cases        TRUE
       Common organisms include Shigella, Salmonella, C
        jejuni Yersinia enterocolitica, E coli


   B. Rotavirus is the leading cause of
       gastroenteritis in children TRUE
       Viruses cause 50-70% of all cases of gastroenteritis
        in the UK. Other viruses include Norwalk,
        Caliciviruses, Adenovirus and Parvovirus
Gastroenteritis MCQ
   C. Food poisoning is a notifiable disease
       TRUE
       ‘A doctor who knows OR SUSPECTS the disease is
        obliged to notify the local Public Health department


   D. Stool microscopy and culture is usually
    required FALSE
       Unnecessary unless foreign travel, prolonged
        symptoms, severely ill, comes from an institution or is
        a food handler
Gastroenteritis - Dehydration

   Mild (<5%)
       Thirst, dry mouth, reduced urine output
   Moderate (5-10%)
       Tachycardia, tachypnoea, sunken eyes,
        sunken fontanelle in babies
   Severe (>10%)
       Reduced skin turgor, drowsiness, irritability
Gastroenteritis - Dehydration
   Rehydration formula
       Correction of deficit
          Degree of dehydration (%) X Weight (kg) X 10 =
           fluid loss in mls
          e.g. A 5% dehydrated 20kg child has lost
           1000mls. Goal is to replace this over 24 hours.

   Maintenance requirements
       4ml/kg/hr for the first 10 kg.
       2ml/kg/hr for the next 10 kg.
       1ml/kg/hr for any weight over 20 kg.
Food poisoning - Incubation periods

   Staph. aureus   1-6 hours
   E coli          1-2 days
   Shigella        1-3 days
   Campylobacter   1-3 days
   Rotavirus       1-7 days
Meningococcal MCQ
   A. Up to 25% of adolescents carry
       Meningococcus as commensals

   B. The peak incidence of meningococcal
       disease is in the 15-19 age group

   C. The overall mortality of meningococcal
       disease is around 10%

   D. Serogroup B infections are commoner
       than Serogroup C infections
Meningococcal MCQ
   A.    Up to 25% of adolescents carry
          Meningococcus as commensals
          TRUE
        Carriage is in the nasopharynx. 10% of adults also
         carry the organism.

   B.    The peak incidence of meningococcal
          disease is in the 15-19 age group FALSE
        Highest incidence is in children aged 1-5 with
         infants under 1 the next most commonly affected.
         Young people aged 15-19 is the next most affected
         group
Meningococcal MCQ
   C. The overall mortality of meningococcal
    disease is around 10% TRUE



   D. Serogroup B infections are commoner than
    Serogroup C infections TRUE
       Type C was slightly less common than Type B but the
        introduction of the MenC vaccine in Nov 1999
        reduced Type C infection enormously
Meningococcus
   Overall mortality remains around 10% in the UK

   Case fatality ratios increase with age and are higher in
    individuals with serogroup C than with serogroup B
    infections

   Mortality is higher in cases with septicaemia than in those
    with meningitis alone

   In those who survive, approximately 25% may experience a
    reduced quality of life, with 10–20% developing permanent
    sequelae

   The most common long-term effects are skin scars, limb
    amputation(s), hearing loss, seizures and brain damage
Meningococcus
   Benzylpenicillin is the antibiotic of choice for the general
    practitioner before transfer to hospital, unless there is a
    history of immediate allergic reactions after previous
    penicillin administration.

   The recommended dose is 1200mg for adults and children
    aged 10 years or over, 600mg for children aged one to nine
    years, and 300mg for those aged under one year.

   Although benzylpenicillin may reduce the chance of isolating
    the causative organism, this is outweighed by the benefit to
    the patient, and new techniques are available that facilitate
    the diagnosis of meningococcal disease even after
    antibiotics have been given.
Meningococcus
   Resuscitate!

   Give antibiotics ASAP when clinically suspicious,
    particularly if there is a petechial or purpuric rash

   In hospital:
       Cefotaxime 50mg/kg or 2g in adults
       Ceftriaxone (80mg/kg)

   Dexamethosone with / just before antibiotics
       Adults 0.15mg/kg
       Children 0.4mg/kg
Meningococcus
   Household contacts are at increased risk
    of developing the disease.

   Risk is highest in the first seven days
    following onset in the index case but
    persists for at least four weeks.

   Immediate risk can be reduced by the
    administration of antibiotic prophylaxis to
    the whole contact group.
Meningococcus
   Doctors, nurses, and paramedics who are directly exposed to
    nasopharyngeal secretions or pulmonary oedema from such
    patients, mainly during airway management (mouth to mouth
    resuscitation, intubation, and airway toilet), may be at some
    increased risk of meningococcal disease.

   Current guidelines in the United Kingdom advise offering
    antibiotic chemoprophylaxis only to those undertaking mouth to
    mouth resuscitation.

   In the United States chemoprophylaxis is recommended for
    healthcare workers who have had "intensive unprotected
    contact (without wearing a mask) with infected patients (eg
    intubating, resuscitating, or closely examining the oropharynx
    of patients)."
Meningococcus
   Rifampicin
       600mg every 12 hours for two days in adults
       10mg/kg dose for children over one year
       5mg/kg for children less than one year


   Ciprofloxacin as a single dose
       500mg is an alternative for adults
       250mg for children aged five to 12 years
       not yet licensed in the UK
Meningococcus

   Pregnant contacts
       Rifampicin 600mg twice daily for two days
       Intramuscular Ceftriaxone 250mg


   Unless the index case received
    Ceftriaxone treatment in hospital,
    chemoprophylaxis should also be given
    to the patient before discharge.
Notifiable diseases MCQ
   The following are notifiable diseases

   A. Tuberculosis

   B. HIV / AIDS

   C. Influenza

   D. Whooping Cough
Notifiable diseases MCQ
   The following are notifiable diseases

   A. Tuberculosis TRUE

   B. HIV / AIDS FALSE

   C. Influenza FALSE

   D. Whooping Cough TRUE
Diseases notifiable (to Local Authority Proper Officers)
under the
Public Health (Infectious Diseases) Regulations 1988

   Acute encephalitis                      Ophthalmia neonatorum
   Acute poliomyelitis                     Paratyphoid fever
                                            Plague
   Anthrax
                                            Rabies
   Cholera                                 Relapsing fever
   Diphtheria                              Rubella
   Dysentery                               Scarlet fever
   Food poisoning                          Smallpox
                                            Tetanus
   Leptospirosis
                                            Tuberculosis
   Malaria                                 Typhoid fever
   Measles                                 Typhus fever
   Meningitis                              Viral haemorrhagic fever
    meningococcal                           Viral hepatitis
    pneumococcal                             Hepatitis A
                                             Hepatitis B
    haemophilus influenzae                   Hepatitis C
    viral                                    other
    other specified                         Whooping cough
    unspecified                             Yellow fever
   Meningococcal septicaemia (without
    meningitis)                             Leprosy is also notifiable, but directly to the
                                             HPA, CfI, IM&T Dept
   Mumps
DoH ‘Green Book’
Immunisation against infectious
   disease
                                       Comprehensive
                                       Many notifiable
                                        diseases
Edited by
Dr David Salisbury CB FRCP FRCPCH
              FFPHM
Director of Immunisation               Regularly updated
Department of Health
                                       Includes clinical
                                        information
Dr Mary Ramsay BSc MB BS MRCP MSc
     MFPHM FFPHM
Consultant Epidemiologist
Health Protection Agency

Dr Karen Noakes BSc PhD
Principal Scientist
Immunisation
Department of Health

				
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