College Answer

a) Applying SIRS criteria to pregnancy may be problematic as there is:
1. Leukocytosis
2. Body temperature is raised during pregnancy and labour
3. Tachycardia and tachypnoea are seen during normal labour

b)
1. Pyelonephritis
2. Chorioamnionits
3. Septic abortion
4. Episiotomy infections
5. Necrotising fasciitis
6. Septic thrombophlebitis
7. Aspiration pneumonia

c)
1. Gram negative more common than Gram positive agents
2. E.Coli
3. Group B Streptococcus
4. Can also be polymicrobial – E.coli, Klebsiella

d)
1. Tetracyclines
2. Chloramphenicol
3. Aminoglycosides
4. Metronidazole
5. Sulphonamides
6. Trimethoprim
7. Fluoroquinolones
8. Some macrolides
9. Nitrofurantoin
10. Isoniazid

Note: Some antibiotics in the above list are relatively rather than absolutely contra-indicated. The list is not exclusive and candidates giving other valid choices were given credit.

Discussion

a) Outline briefly the difficulties associated with the diagnosis of sepsis during late pregnancy and labour.

Problems of the obsolete definition of sepsis and SIRS:

• Neutrophilia is normal in pregnancy
• Inflammatory markers are normally slightly elevated
• The patient is normally slightly tachycardic, and may be slightly hypotensive, with a decreased SVRI. The circulation is normally hyperdynamic. They appear to be in early stages of vasodilated shock at the best of times.
• Tachypnoea is normal in pregnancy and labour (chronic respiratory alkalosis)
• The whole process of labour tends to obscure the findings one would normally associate with sepsis.
• Then, suddenly, they collapse (as they tend to compensate right up until the last minute, and then drop everything, given their increased susceptibility to lipopolysaccharide)

Other problems (stolen from the LITFL entry on this topic)

• Pneumonia may masquerade as the normal shortness of breath in pregnancy
• Abdominal pain due to visceral pathology may masquerade as contractions (or - more  confusingly - may co-present with labour)
• Appendicitis may be more difficult to diagnose, as the gravid uterus gets in the way of palpation.
• Nausea, vomiting, constipation - all of these may be routine for the pregnant woman, and a bowel obstruction may present disastrously late (eg. this case report by Khan et al, 2012).
• Abdominal pathology may be impossible to image, as everybody is going to freak out about the radiation exposure associated with a CT abdo/pelvis. This is in fact quite irrational, as the risks to a late-term foetus are quite small  (Chen et al, 2008). Instead, people should think about the foetal risk associated with remaining inside the septic abdomen of a critically ill mother whose source control is compromised by indecision about imaging. (In case anybody is interested, the dose from such a CT will total about 5 rads, which maxes out the recommended safe total foetal cumulative dose of 5-10 rads).
• Urinary sepsis may be asymptomatic (urinary frequency is pretty normal)

b) List the leading causes of sepsis in pregnant patients.

• Chorioamnionitis
• Urinary tract infections
• Pyelonephritis
• Endometritis
• Septic abortion

also...

• Episiotomy infections
• Necrotising fasciitis of the ceasarian wound
• Septic thrombophlebitis - especially pelvic vein thrombophlebitis
• Aspiration pneumonia

c) What are the common pathogens encountered in pregnancy-related sepsis?

Oh's Manual quotes the following bugs:

• Gram-negatives
• Streptococci (especially Group A, i.e. S.pyogenes)
• Bacteroides

To this, the Sanford Guide adds a few:

• Enterobacteriaceae
• Chlamydia trachomatis
• Ureaplasma urealyticum

(these are specific to chorioamnionitis and septic abortion)

d) List two antibiotics contra-indicated during pregnancy.

 The full list:

The college answer for Question 3.1 from the first paper of 2014 also lists nitrofurantoin, isoniazid and macrolides as drugs which are relatively contraindicated. This in fact, is not true: