Measles in pregnancy

Abstract

Measles is becoming more prevalent; it can be difficult to diagnose, with severe complications in pregnancy. We report a case of measles in a 27-year-old, parainfluenza virus type 2-infected woman who was 32 weeks pregnant. She presented with fever, tachycardia, sore throat and a pruritic rash. She never had the measles, mumps, rubella vaccine. Serology showed raised inflammatory markers with lymphopoenia. Throat swab showed parainfluenza virus. Chest radiography was normal. Despite appropriate antimicrobial therapy, she developed worsening respiratory failure requiring premature delivery via caesarean section.

Postoperatively, she was transferred to a tertiary centre for extracorporeal membrane oxygenation. She was decannulated and made a full recovery. Meanwhile, her husband was diagnosed with measles. She was then tested and measles was confirmed. The baby did not develop congenital measles.

This case emphasises the importance of vaccine histories at booking of pregnancy and early multidisciplinary team input to facilitate delivery in rapidly deteriorating pregnant women.

Background

Measles is more prevalent in the UK today than it was 20 years ago, likely due to a drop in uptake of the measles, mumps, rubella (MMR) vaccine in children in the early 2000s.¹ Public Health England confirmed 267 cases of measles in 2017, following multiple outbreaks. As of March 2018, a further 265 cases had been laboratory confirmed.^2–4

Measles in pregnancy is associated with severe maternal complications and an increased risk of preterm delivery. Measles can present in a non-specific similar way to many viral illnesses and can be difficult to diagnose. Although treatment is supportive, in the pregnant patient an early diagnosis can aid decisions about preterm fetal lung protection, fetal neuroprotection and delivery. Here, we present a case of measles with severe complications during pregnancy.

Case presentation

A 27-year-old woman presented with fever, tachycardia, sore throat and a pruritic rash at 32+0 weeks of pregnancy. The rash had appeared at least 2 days prior to admission, initially on the palms of her hands and then spreading to her face. She denied any other infective symptoms. On examination, the rash was maculopapular and blanching. She had no Koplik spots or cervical lymphadenopathy. Her temperature was 38.0°C and her heart rate was 101 bpm. The rest of her examination findings were normal.

There were no maternal medical complications in this pregnancy. Booking bloods were normal, including screening for HIV, hepatitis and syphilis. She had two previous spontaneous vaginal deliveries at term and had a medical history of anxiety, depression and dyslexia. She smoked five cigarettes a day and her booking body mass index was 30.65 kg/m². She had a penicillin allergy and did not have the MMR vaccine.

Investigations

Biochemical and haematological investigations showed raised inflammatory markers with a lymphopoenia; white blood cell count 6.6×10⁹/L, lymphocytes 0.7×10⁹/L, C reactive protein 42 mg/L and lactate was 0.9 mmol/L. Initial blood, urine, throat and vaginal flora cultures did not grow any bacteria. Chest radiography was normal.

Differential diagnosis

Viral infection was the suspected diagnosis, specifically influenza. With a lack of typical morbilliform rash and atypical progression, measles was lower down on the list of possible diagnoses. We could not rule out group B streptococcus sepsis at this point.

Treatment

While awaiting full bacterial culture and viral swab results, clindamycin, metronidazole and oseltamivir were initiated. The patient deteriorated 24 hours after admission, and at this time arterial blood gas showed a respiratory alkalosis, with pH 7.35, partial pressure of oxygen (pO₂) 10.2 kPa and partial pressure of carbon dioxide3 kPa. Examination revealed spread of the rash to her trunk and back, as well as reduced air entry and crepitations in the right lower lung base. Within a few hours she deteriorated further and became hypoxic; repeat arterial blood gas showed a pO₂ of 10.0 kPa on 5 litres of 100% oxygen. After discussion with the microbiology team, ciprofloxacin and gentamicin were started. She was transferred to intensive care for high-flow nasal oxygen therapy after review by the physicians and anaesthetists. After 5 days of progressive severe respiratory failure with increasing pulmonary infiltrate, she developed respiratory acidosis with hypercapnia.

Intermittent fetal cardiotocography during admission showed a persistent rise in baseline rate (170 bpm) which was in line with maternal tachycardia, normal variability, accelerations present and no decelerations. This indicated that the fetus was coping well despite poor maternal condition. Intramuscular steroids were given to promote fetal lung maturity in the event of preterm delivery.

On day 5 of her admission, after joint discussion between physicians, intensivists, obstetricians and neonatologists, the decision was made for delivery by emergency caesarean under general anaesthesia, due to maternal compromise. This decision was made after considering the risk of long-term morbidity in the fetus, including risk of cerebral palsy and encephalopathy, due to chronic maternal hypoxia and acidosis.^{5 6}

Outcome and follow-up

In the immediate postnatal period, the patient was transferred to a tertiary unit for extracorporeal membrane oxygenation (ECMO) due to severe respiratory failure and acute respiratory distress syndrome (figure 1). The viral throat swab had tested positive for parainfluenza virus by this point, so the differential diagnosis was parainfluenza pneumonia. She was decannulated on day 10 postpartum.

On day 7 postpartum, the patient’s partner developed fever, fever and morbilliform rash and was admitted for treatment of suspected measles. Measles oral fluid IgM and PCR were sent and came back as positive for both the patient and her partner. She recovered well without further intervention and was discharged on day 16 postpartum. The baby did not develop congenital measles and there were no other neonatal complications.

To prevent the spread of measles, the patient was sequestered in a single room throughout her care, and her partner was not permitted to visit the ward.

Discussion

Measles is a highly contagious infection caused by an RNA virus from the paramyxovirus family. Transmission is airborne, and measles hosts are infective for 4 days prior to and after the onset of rash.

Measles is reported to cause severe complications in the immunocompromised state of pregnancy. During normal pregnancy, progesterone suppresses Th-1 cells, thereby causing a reduction in the cell-mediated immune response. It may be harder to diagnose measles in immunocompromised patients as the hallmark morbilliform rash can be absent.⁷ Moreover complications, most commonly pneumonia, are more likely to develop and more often require hospital admission. Mortality due to complications of measles is also thought to be raised. A study from 1993 of 58 American pregnant women with measles reported that 60% were hospitalised, 26% were diagnosed with pneumonia and 3% died due to measles complications.^8–10 A recent report of 61 cases in Sudan revealed a prenatal mortality rate of 13.1%.¹¹ In the 2009–2011 outbreak of measles in France, five pregnant women were affected, all of whom recovered without the need of mechanical ventilation.⁷ One woman required caesarean delivery at 38 weeks due to fetal growth restriction, a known complication of measles. Other reported complications include hepatitis, miscarriage, preterm labour and intrauterine death.^{12 13} Unlike rubella, congenital measles is not thought to cause congenital defects in the fetus, however it is associated with an increased risk of subacute sclerosing panencephalitis and neonatal death.^{14 15}

Where measles is suspected, IgG and IgM should be tested; if both are positive this indicated acute infection.¹⁶ Testing for IgM in oral fluid is more sensitive and specific than using serum. It is of note that viral throat swabs will test positive for parainflueza virus in someone infected with measles. Measles is a notifiable disease and cases should be referred to Public Health England to be confirmed with viral PCR.

Treatment of measles is supportive only, alongside treatment of complications.¹⁰ Pneumonia can lead to the complication of acute respiratory distress syndrome, as in this case. This occurs when inflammation causes alveolar oedema due to an increase in microvascular permeability, thereby fatally impeding gaseous exchange. Factors such as increased serum sodium and increased circulating blood volume in pregnancy may contribute to its development. ECMO has been used with some success to treat acute respiratory distress in pregnancy caused by influenza.⁵

Public Health England recommends taking a thorough vaccination history at booking, and it is important that this is revisited in pregnant women presenting with rash and suspected viral illness.^{10 16} During preconception counselling, immunisations should form part of the discussion to help prevent infection in pregnancy. The MMR vaccine containing live, attenuated viruses has a theoretical risk to the fetus, however, there are no known adverse effects to women who are vaccinated shortly before or during pregnancy.¹ Current UK guidelines recommend giving human normal immunoglobulin as post-exposure prophylaxis for pregnant women who have been exposed to measles, although its efficacy in pregnancy is unknown.¹⁷

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