Infection and Haematology in pregnancy

Question 1

GBS in pregnancy PPx?

Answer 1

• GBS commensal bacterium found in vagina or rectum in 25% of pregnant women - colonisation usually causes no symptoms.
• Can sometimes cause infection (sepsis, pneumonia, or meningitis) in neonate - early onset GBS disease of the newborn.
• Streptococci - gram positive cocci - alpha, beta, or gamma haemolytic groups - beta-haemolytic streptococci further divided into A, B, C, D, F, G and H groups. GBS pathogen is Streptococcus agalactiae.
• In addition to GBS disease of newborn - can also cause choriamnioitis or endometritis in the mother.

Question 2

Risk factors for GBS infection in neonate?

Answer 2

1) GBS infection in previous baby
2) Rupture of membranes >24 hours before delivery
3) Prematurity <37 weeks
4) Pyrexia during birth
5) Positive GBS test for mother
6) Maternal UTI during pregnancy found to be GBS

Question 3

Clinical features of GBS infection?

Answer 3

• Maternal or rectal colonisation does not cause symptoms but GBS that leads to infection may manifest in many ways.
  1) UTI - frequency, urgency, dysuria
  2) Chorioamnioitis - fevers, lower abdominal/uterine tenderness, foul discharge, maternal and/or foetal tachycardia (intrapartum)
  3) Endometritis - fevers, lower abdominal pain, intermenstrual bleeding, foul discharge

After delivery, neonatal infection symptoms:

1) Pyrexia
2) Cyanosis
3) Difficulty breathing and feeding
4) Floppy

Question 4

Investigations of GBS?

Answer 4

1) Detected using swabs - single for vagina then rectum (culture/PCR to detect on swabs)
2) Detected on urine cultures if woman is symptomatic for UTI

Only screened in high risk women:

1) Symptoms of chorioamnioitis/UTI during pregnancy
2) Previous STI symptoms pre-pregnancy
3) Previous GBS infected baby

Question 5

Prevention of GBS? Indications?

Answer 5

• HIGH DOSE INTRAVENOUS PENICILLINS - BENZYLPENICILLIN (Cefuroxime or Clindamycin in penicillin-allergy) throughout labour/

Indicated in:

1) GBS positive swabs
2) Previous GBS infected baby
3) UTI caused by GBS during this pregnancy
4) Pyrexia during labour
5) Labour <37 weeks
6) Rupture of membranes >18 hours

• If there is rupture of membranes in >37 weeks gestation in GBS positive woman - induce immediately and mimosa foetal exposure to infection.
• Antibiotics NOT INDICATED in planned caesarian sections.

Question 6

Anaemia in pregnancy PPx?

Answer 6

• Deficiency of Hb in blood - <110g/L in 1st trimester, <105g/L in 2nd and 3rd, <100g/L postpartum.
• During pregnancy both plasma volume and red blood cell mass increase - plasma volume increases disproportionately - haemodilution effect - predisposing anaemia.

Question 7

RF of anaemia in pregnancy?

Answer 7

1) Haemoglobinopathies (thalassaemia/sickle cell)
2) Increasing maternal age
3) Anaemia in previous pregnancy
4) Poor diet
5) Low socio-economic status

Question 8

Clinical features of anaemia in pregnancy?

Answer 8

1) DIZZINESS, FATIGUE, DYSPNOEA (also ft in normal pregnancy)
2) Sometimes asymptomatic and detected iN FBC
- O/E: pallor in mouth, koilonychia, angular cheilitis.

Question 9

Ddx of anaemia in pregnancy?

Answer 9

Anaemia has wide range of causes - Ddx can be categorised by mean corpuscular volume (MCV):

• Microcytic: Iron deficiency, thalassaemia, sideroblastic
• Normocytic: Anaemia of chronic disease, marrow infiltration, haemolytic anaemia, chronic kidney disease.
• Microcytic - B12 deficiency, folate deficiency, alcohol consumption, reticulocytosis, hypothyroidism

Question 10

Investigations of anaemia in pregnancy?

Answer 10

• FBC- assessing MCV AND HB LEVEL.
• Serum ferritin - not routine but only in areas of high haemoglobinopathies.
• Haemoglobinopathy screening: considered in patients with confirmed anaemia but unknown haemoglobinopathy status.
• Haemoglobin electrophoresis for sickle cell and beta-thalassaemia
• Serum Folate - folate deficiency
  Recommended all pregnant women are screened for anaemia at booking and 28 weeks gestation, in multiple pregnancies additional screening between 20-28wk.

Question 11

Management of anaemia in pregnancy?

Answer 11

If anaemia is microcytic or normocytic - most likely cause is iron deficiency:

1) TRIAL OF ORAL IRON (100mg-200mg) - 1st line tx and diagnostic - FBC after 2 weeks (should show increase in Hb)
2) IV Iron infusion of compliance is poor/malabsorption

Other:
Folate supplementation and blood transfusions as required (folate deficiency, beta thalassaemia, sickle cell)

Question 12

What is VTE in pregnancy?

Answer 12

• Venous thromboembolism is a collective term that describes deep vein thrombosis (DVT) and pulmonary embolism (PE).
• Leading cause of maternal mortality in UK (1/3rd of maternal deaths).
• Pregnancy major risk factor for VTE - 4-5x increased risk.
• Change in clotting proteins during pregnancy.
• Highest risk period - postpartum.

Question 13

Pre-existing risk factors for VTE?

Answer 13

1) Thrombophilia (APS)
2) Medical co-morbidities (cancer)
3) Varicose veins
4) Age >35 yrs
5) Parity >3
6) BMI >30 kg/m^2
7) Smoking
8) Immobile/paraplegia

Question 14

Obstetric risk factors for developing a VTE?

Answer 14

1) Multiple pregnancy
2) Cesarian section
3) Prolonged birth
4) Pre-term birth
5) Stillbirth
6) PPH
7) Pre-eclampsia

Question 15

Transient factors for VTE?

Answer 15

1) Any surgical procedure in pregnancy/puerpuriem
2) Dehydration (hyperemesis)
3) Ovarian hyperstimulation syndrome
4) Admission/immobility
5) Systemic infection
6) Long distance travel

Question 16

Clinical features of VTE?

Answer 16

• DVT:
  1) UNILATERAL LEG PAIN AND SWELLING
  2) Pyrexia, pitting oedema, tenderness, superficial veins prominent
  In pregnant women: usually - proximal veins, left leg mainly affected.

-PE:
1) SUDDEN ONSET DYSPNOEA
2) Pleural chest pain
3) Cough (rarely haemoptysis)
Clinically: tachycardia, tachypnoea, pyrexia or pleural rub/effusion (rare) - EXAMINE FOR DVT in PE PATIENT.

Question 17

DDx for VTE?

Answer 17

DVT - for unilateral leg pain and swelling - cellulitis, ruptured Baker’s cyst, superficial vein thrombophlebitis.
PE - Large number of possible diagnoses for sudden onset dyspnoea and chest pain. Acute coronary syndromes, aortic dissection, pneumonia and pneumothorax should be excluded.

Question 18

Investigations for VTE?

Answer 18

• In suspected DVT/PE basic set of bloods - FBC, U+Es and LFTs, as well as a COAGULATION SCREEN. Required before any treatment initiated.
• Raised D-dimer normal in pregnancy - testing not recommended.

DVT - COMPRESSION DUPLEX ULTRASOUND SCAN - if negative but clinical suspicion remain high, maintain anticoagulant treatment and repeat scan week later.

PE - ECG and CXR initially assessed.
CTPA (or V/Q scan) definitive diagnosis - V/Q scan associated with increased risk of childhood cancer, carries lower risk of breast cancer.

IF WOMAN PRESENTS WITH CLINICAL FT OF BOTH DVT AND PE - DUPLEX USS FIRST!!! If this is positive - CTPA or V/Q scan does not need to be performed - saves woman from unnecessary radiation exposure.

Question 19

Management of VTE?

Answer 19

• All women with VTE symptoms should have LMW HEPARIN started immediately (until diagnosis is excluded definitively).
• Confirmed VTE - Anticoagulation must be maintained throughout pregnancy until 6-12 weeks postpartum. Advised to omit dose 24 hours before any planned induction of labour/C-section, should not take if they think they are going into labour.
• LMWH anticoagulant of choice, alternatives include RIVAROXABAN, unfractionated heparin .
• WARFARIN IS TERATOGENIC.
• VTE at term - IV unfractionated Heparin should be considered. DISCONTINUED 6-hours before planned induction of labour or C-section (compared to 24hrs for LMWH).

Question 20

Cardiogenic shock secondary to massive PE?

Answer 20

• Resuscitated with ABCDE approach, consider immediate thrombolysis with IV unfractionated heparin.