A 15-year-old girl was brought to the emergency department (ED) by friends; she was at a party and began to feel unwell with a headache and fever. By the time she arrived she had deteriorated significantly and was obtunded, requiring intubation and aggressive fluid resuscitation. She has been transferred to the intensive care unit (ICU) with a working diagnosis of meningococcaemia. You contact public health authorities to initiate contact tracing.
Who of the following should receive clearance antibiotics?
Answer: A: The rationale for clearance antibiotics after an individual case of invasive meningococcal disease is to prevent secondary cases. Antibiotics are used to eliminate carriage in the asymptomatic carrier who was responsible for transmission of the meningococcus to the index case, therefore preventing transmission to other susceptible individuals in the carrier’s close contact network. Clearance antibiotics are therefore indicated for the following contacts of the index case:
The index case themselves is a poor transmitter of the meningococcus that is causing their illness. However, there is a small but definite risk of transmission of meningococci from a case to an HCW, therefore, clearance antibiotics are indicated under circumstances as mentioned above. Otherwise, saliva and low-level salivary contact is not important in the transmission of meningococcus. Therefore, contacts who have shared food, drinks, water bottles, cigarettes, bongs, lip balm, wind instruments, communion cups, referee’s whistles and even dummies do not require antibiotics. Contacts of the case who attended classes, sporting events, parties and night clubs, childcare (unless as described above) or shared modes of travel within 7 days of the case’s illness also do not require clearance antibiotics but should be provided with information on invasive meningococcal disease.
Reference:
An 18-year-old male has presented to the ED with a rapid-onset febrile illness associated with myalgia. You consider meningococcaemia as a potential diagnosis.
Which ONE of the following is INCORRECT regarding meningococcaemia?
Answer: D: Neisseria meningitidis, a gram-negative intracellular diplococcus, is classified into serogroups according to their capsular polysaccharides. Groups B and C cause the greatest disease in Australia but group C more commonly causes cases, compared with group B in most developed countries. There is a vaccine against group C. Cases occur when organisms are transmitted to a susceptible individual from the nasopharynx of a carrier; carriers often have some immunity from invasive disease caused by the organisms they carry.
Clinical disease typically takes the form of meningitis or meningococcaemia; the two may coexist. Meningococcal disease has a wide spectrum of presentation including nausea, vomiting, myalgias, abdominal pain, leg or joint pain, pharyngitis, septic shock, pneumonia, myopercarditis and DIC. The rash associated with meningococcal infection may be petechial or purpuric, but also may be urticarial, macular or maculopapular, particularly early in the disease. Patients with meningococcaemia without meningitis have a greater mortality than those with meningitis.
References:
A 42-year-old female presents to the ED with a cough and a fever of 38.9°C; she is found to have mild community-acquired pneumonia.
Which ONE of the following is correct regarding blood cultures in this patient?
Answer: D: Blood cultures are a relatively expensive investigation with a low yield and high contamination rate that rarely changes management in the ED. The primary determinant in detecting bacteraemia is the volume of blood taken; adult cultures should contain at least 10 mL of blood. The yield is also improved when the sample is collected at the onset of fever, and more than one set is taken over several hours. Contamination is usually from skin organisms (coagulase negative Staphylococci, Corynebacterium spp., or Propionibacterium, or cultures where multiple bacteria are isolated). Blood cultures are not recommended in immunocompetent patients with community-acquired pneumonia (CAP) who are treated as outpatients (however, they are recommended for inpatients).
Cultures are positive in 1–40% of patients with CAP but only change management in 1 in 500 patients. Anaerobic cultures are not warranted in patients with CAP, and should be reserved for patients with suspected abdominal and pelvic sources of infection. The most common organism isolated on culture in patients with CAP is Streptococcus pneumoniae.
A 57-year-old woman presents to the ED in Cairns with symptoms of pneumonia. She has no medical history, medications or allergies. She is a non-smoker and drinks 35 standard drinks per week. Her observations are: respiratory rate 32, heart rate 122, blood pressure (BP) 100/56 mmHg, SaO2 90% on 15l O2/min, temperature 38.2°C, Glasgow Coma Scale (GCS) 14. Chest X-ray (CXR) confirms a right middle lobe (RML) and right lower lobe (RLL) pneumonia.
What is the most appropriate initial regime of antibiotics for this patient?
Answer: D: This patient’s examination and X-ray findings are consistent with severe pneumonia as calculated by two pneumonia severity scoring systems used in CAP in Australia (CORB score >2, SMART-COP score of 5). In addition, she lives in a tropical area and is at risk of Burkholderia pseudomallei and Acetinobacter baumanii infection due to her heavy alcohol consumption. She should therefore receive broadspectrum antibiotics which cover B. pseudomallei and A. baumanii plus S. pneumonia, Legionella pneumophilia and enteric gram-negative bacilli. Therapeutic guidelines recommend the use of meropenem and azithromycin for patients living in tropical areas with risk factors for B. pseudomallei and A. baumanii infection; these risk factors include diabetes, chronic lung disease, chronic renal failure and heavy alcohol consumption.
Severe CAP in patients from non-tropical regions and in patients in tropical regions who don’t have risk factors for infection with B. pseudomallei and A. baumanii should again be treated with broadspectrum antibiotics. Azithromycin should be given with ceftriaxone, cefotaxime or benzylpenicillin plus gentamicin; if the patient has an immediate/severe penicillin allergy they should receive moxifloxacin with azithromycin. (Choices A, B and C are therefore all correct choices, depending on drug allergies, for such a patient).
A 26-year-old female who is 39 weeks pregnant presents to a rural ED with an itchy vesicular rash of 24 hours’ duration. She has no past history and this is her first pregnancy, which has, so far, been uncomplicated. You diagnose chickenpox and find that this patient has not been immunised or exposed to varicella in the past.
What should you do prior to discharging her?
Answer: C Women who develop chickenpox infection within 2 weeks of likely delivery present the greatest risk to the fetus of developing neonatal varicella, which presents with a fever and vesicular rash plus potential visceral disease including pneumonia, meningoencephalitis and hepatitis. The mortality of neonatal varicella is 25% and is higher in premature babies and those whose mothers developed or were exposed to varicella zoster virus within 5 days of delivery. This patient should receive acyclovir to reduce her risk of complications of varicella infection such as varicella pneumonia; however, treatment does not reduce the risk of transmission of varicella to the fetus. If delivery occurs within 5 days of the patient developing a rash, the neonate should receive varicella-zoster immune globulin as PEP.
Congenital varicella syndrome usually occurs in infants whose mothers were infected between 8 and 20 weeks’ gestation, but the transmission risk is low (2%) compared with the risk of other viruses.
The risk of viral transmission during delivery is not greater than at other times during pregnancy; therefore a caesarean section will not reduce the risk of neonatal varicella infection. If in a rural centre it would be prudent to discuss the case with the referral obstetrics and paediatric service prior to delivery.
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