9) Maternal Medicine: Respiratory Flashcards
Most common chronic condition in pregnancy
Asthma
Incidence of asthma in pregnancy
10%
Effect of pregnancy on asthma
1/3 improve, 1/3 worsen, 1/3 unchanged
Severe disease more likely to deteriorate than mild disease - 60%/10%
When are asthma exacerbations most common?
24-36 weeks
Risks of pregnancy with asthma?
Higher risk of PIH/PET.
If poorly controlled, risk of low birthweight.
May have increased risk of CS.
Most women with well controlled asthma no or minimal risks.
Medical management of stable asthma
1: Short acting B2 agonist PRN
2: Inhaled steroid
3: Long acting B2 agonist
4: Increase steroid dose. Add montelukast (leukotriene receptor antagonist), SR theophylline or B2 agonist tablet.
5: Oral steroids.
Which asthma drug requires levels monitoring in pregnancy?
Theophylline
What percentage of women with asthma experience exacerbations during labour?
<20% (severe/life threatening exacerbations rare)
Which drugs associated with labour/delivery should be avoided in women with asthma?
Prostaglandin F2 = haemobate
Labetalol.
NSAIDs.
Ergometrine may cause bronchospasm but can be used during PPH (give syntocinon for routine 3rd stage).
Prostaglandin E2 = prostin is fine to use.
Risk of asthma exacerbations postpartum
None
Criteria for moderate acute asthma exacerbation
Increasing symptoms
PEFR 50-75%
No severe features
Criteria for severe acute asthma exacerbation
PEFR 33-50%
RR >25
HR >110
Inability to complete sentences
Criteria for life threatening acute asthma exacerbation
PEFR <33% SpO2 <92% PaO2<8 Normal PaCO2 4.6-6 Altered conscious level Exhaustion Arrhythmia Hypotension Cyanosis Silent chest Poor respiratory effort
Criteria for near fatal asthma
Raised PaCO2 and/or requiring mechanical ventilation with raised inflation pressures
Treatment of acute exacerbation of asthma
O2 to maintain sats 94-98%
Steroids (40-50mg)
B-agonists (nebuliser if severe/life-threatening)
Ipratropium (if severe/life threatening or poor response to B agonists)
IV MgSO4 (1.2-2g IV over 20 mins)
ABG if sats<92% or any other life threatening feature
CXR if life threatening or suspect another pathology.
Incidence of TB in pregnancy in UK
4.2 per 100,000
Proportion of women with TB asymptomatic
1/2 to 2/3
Extrapulmonary TB in pregnancy - how common compared to pulmonary TB?
As common
What proportion of non-respiratory TB is CNS?
5%
What proportion of maternal deaths is CNS TB responsible for?
2/3
Most common site of extra pulmonary TB
Lymph nodes
Investigation to establish latent TB infection
Mantoux test
What can cause false positive Mantoux test?
Other mycobacteria, previous BCG
What is the gold standard for diagnosis of TB?
Culture
TB on pregnancy
If not treated can cause increased PET, PPH, PTL, IUGR, Perinatal mortality.
How does congenital TB present?
2nd or 3rd week
Hepatosplenomegaly, respiratory distress, fever, low weight gain, irritability
(Very rare)
Standard regimen for treatment of TB in pregnancy
Rifampicin + Isoniazid + Ethambutol (+ Pyrazinamide if resistance suspected)
+ Pyridoxine to protect against isoniazid neuropathy.
Duration of treatment of TB
Standard treatment 6 months
Extrapulmonary TB 12 months
Drug resistant TB 2 years
What to do if TB diagnosed in the 2 weeks following delivery?
Infant needs prophylactic isoniazid (+vit B6) and tuberculin test 6-12w
BCG if tuberculin negative.
What is the risk of streptomycin in pregnancy?
Fetal ototoxicity
Most common bacterial pneumonia
Strep. pneumonia
When to suspect influenza?
Fever + two or more other symptoms (myalgia, arthralgia, cough, headache, sore throat, blocked or runny nose, vomiting or watery diarrhoea)
Fetal risks associated with influenza
Preterm birth
Perinatal mortality
Risk factors for admission with flu
Obesity
Asthma
Multiple pregnancy
Other medical problems
Benefit of tamiflu
If started within 2 days reduces risk of critical care admission
Incidence of aspiration syndrome after CS and after VD
CS: 1 in 1500
CS: 1 in 6000
How does aspiration syndrome present?
Severe inflammation over 8-24 hours. CXR can show complete “white out”. Clinical improvement 2-3d.
When does bacterial aspiration pneumonia occur?
Symptoms 2-3 days after aspiration
How does the CXR finding in bacterial aspiration pneumonia differ from aspiration syndrome?
More localised
Organism involved in bacterial aspiration pneumonia
Mixed anerobes
Where is the mutation in CF?
CFTR (Chloride channel) gene on chromosome 7
What is the incidence of CF carriers?
1 in 25
Clinical features of CF
Pancreatic insufficiency - diabetes, malabsorption
Respiratory - recurrent infections with pseudomonas, staph aureus, burkholderia
Subfertility in men (not women)
Median survival with CF
31 years
What to do in pregnancy if one partner is a carrier or affected?
Offer partner testing
What is the chance of being a carrier if test is negative?
1 in 250
What to do if both partners carriers/affected?
Offer counselling and PGD
How many women per year with CF embark on pregnancy?
30-40
Live birth rate for mothers with CF
70-90%
Effect of CF on rate of miscarriage
No change
Effect of CF on rate of congenital anomalies
No change
Risk of PTB with CF
25%
What FEV1 is associated with the lowest risk of complications in CF patients?
> 70%
Effect of pregnancy on maternal survival
None
What percentage of mothers with CF are not still alive for their child’s 10th birthday?
20%
Management of pregnancy in a mother with CF
Folic acid Growth scans Nutritional input + physio input **GTT (first trimester and 24-26)** Monitoring of respiratory function
Mode of delivery in CF
Dependent on maternal condition.
Epidural recommended in labour to facilitate passive time in 2nd stage and avoid GA if CS.
How long after heart/lung transplant should CF patients wait before conceiving?
2-3 years
What is the risk of rejection/graft loss with heart/lung transplants compared to other solid organ transplants?
Higher
Breast feeding with CF
Breast milk is of normal composition so should be encouraged. May struggle to keep up calorie requirements.
Contraception in CF
Avoid deep due to BMD.
