Congenital, perinatal, neonatal infections

Question 1

Outline congenital toxoplasmosis

Answer 1

Protozoon toxoplasma gondii (parasite excreted in cat faeces, incubation period of 5-23 days)
* Transmission is faeco-oral route (from infected meat and cat faeces)
* Increased risk of vertical transmission with increasing gestational age (5% 1st, 80% 3rd trimester)
* Infection in 1st trimester- most likely to cause foetal damage but transmission rate is LOW (10%)
* In 3rd trimester- risk of foetal damage is low (10%) but transmission MUCH higher (85%)

Risk of congenital toxoplasmosis reduced with increasing gestational age (60-80% 1st, 5% 3rd)

 
Risk factors – household cats, increased incidence in rural areas and in France

Signs & symptoms:

• 60% asymptomatic at birth; may develop… deafness, low IQ, microcephaly
• 40% symptomatic at birth… CLASSIC TRIAD/ ‘the 4 C’s of toxoplasmosis’: 
  1. Chorioretinitis
  2. Convulsions
  3. Hydrocephalus (macrocephaly)
  4. Hepatosplenomegaly/jaundice
  5. Intracranial (‘tram-like’) calcifications- Scattered throughout the brain (unlike CMV, which is peri-ventricular)

Investigations:
* NOT USUALLY SCREENED - as very unlikely for babies to be affected
* Sabin Feldman Dye Test
* Bloods – IgM (active – may persist for months/years after), IgG (immunity)
* USS – foetal anomaly scan
* Other – amniocentesis and PCR to detect foetal infection (done if USS raises suspicion)

Management (mother should avoid eating raw/rare meat and handling cats and cat litter):

Pyrimethamine + Sulfadiazine + calcium folinate

For 1 year

Question 2

Syphillis

Answer 2

Syphilis is a systemic infection caused by the gram -ve spirochete (Treponema pallidum)

Aetiology – sexual contact, blood-borne, or vertical

Risk factors – young (age <29 years), African American, use of illicit drugs, infection with other STIs, sex worker

Signs & symptoms:

• congenital syphilis (PTL, still birth 25% if not treated, miscarriage):
  1. Rash on soles of feet and hands
  2. Bloody rhinitis
  3. Hepatosplenomegaly
  4. Glomerulonephritis
  5. ‘Hutchinson’s teeth’ (small, widely spaces, notched)
  6. Frontal bossing of skull, saddle-nose deformity
  7. ‘Saber’s shins (anterior bowing of shins)
  8. ‘Clutton’s joints’ (symmetrical knee swelling)

Investigations:

1. Microbiology – dark-ground (from chancre with dark-field illuminations),
2. PCR positive for T pallidum
3. Infant TP Syphilis IgM test is positive

Management

IV benzylpenicillin (10 day course)

Question 3

Hepatitis A, B, C

Answer 3

Jaundice, Hepatomegaly, Splenomegaly

Management

Babies born to chronically infected mothers or mothers with acute hepatitis B during pregnancy should receive:

• Vaccination (given at birth, 1 month, 6 months à serological test for HBV at 12 months)
• HBV IVIG (0.5mL within 12 hours of birth)

Hepatitis A virus usually resolves itself within six months

Hepatitis B or C viruses most likely will result in chronic liver disease
* Infants who develop cirrhosis will ultimately need a liver transplant.

Phototherapy/ exchange therapy depending on level of jaundice

Question 4

HIV

Answer 4

Aetiology: present in vaginal fluid, semen, blood, breast milk  transmission through sexual contact, BB, vertical

• Less transmission through vaginal mucosa than through anal mucosa
• Decision to treat with PEP based on guidelines (i.e. only ‘considered’ if penetrative vaginal intercourse)
• HIGHEST risk of transmission if mother is newly diagnosed at the beginning of pregnancy or near delivery (as viral load is extremely high in acute phase of infection)

Risk factors: vertical risk if high viral load, low CD4 count, prolonged rupture of membranes (>4h), breastfeeding, chorioamnionitis, preterm delivery
* Reduced transmission risk: low/ undetectable viral load at the time of delivery, ART, C-section delivery, XS formula feeding

Epidemiology: increasing prevalence as people are living longer, most prev in black-African heterosexual women in the UK

Signs & symptoms:
1. Recurrent infections
2. Severe infections
3. Unusual rash
4. Hepatomegaly
5. Splenomegaly

Management:

1. Cord clamped as soon as possible and baby bathed immediately after birth
2. Zidovudine monotherapy for 2-4w (low/medium risk) OR 4w PEP combination (high risk/confirmed)
3. Women not to breastfeed
4. Give all immunisations including BCG (unless a moderate-high risk of transmission)
5. Confirm or deny diagnosis of HIV in the neonate with direct viral amplification by PCR

(normally carried out at birth, on discharge, 6 weeks, and 6 months)

Question 5

 Cytomegalovirus (CMV)

Answer 5

DNA virus from the Herpes family

Types of HHV: Sites of latent infection:

• HHV-1, HHV-2 (HSV 1 and 2)
• HHV-3 (VZV) Dorsal root ganglia
• HHV-4 (EBV) B cells
• HHV-5 (CMV) Monocytes
• HHV-6 (Roseolovirus)
• HHV-7 (Roseolovirus)
• HHV-8 (Kaposi’s sarcoma-associated HV)

Most common congenital infection (0.5-1 in 1,000)

Aetiology – sexual contact, blood-borne, bodily fluids (saliva, urine), vertical

Risk factors – higher socioeconomic class (no childhood immunity), immunosuppression

Epidemiology – 50% immunity in pregnant women, 1% seronegative will contract CMV antenatally, most common congenital viral infection and most common cause of congenital deafness in the UK

Signs & symptoms:
Chorioretinitis is more common in congenital toxoplasmosis

Child (throughout life):

• 90% (birth) -> asymptomatic
• 10% develop SNHL

 
10% (birth) -> Congenital CMV
65% have SNHL

1. Peri-ventricular calcification
2. Chorioretinitis  cataracts
3. Jaundice ± ‘blueberry muffin’ rash
4. IUGR
5. Microcephaly
6. Hepatosplenomegaly

Investigations:

• Sample specimen (urine, blood or saliva) - PCR

Management:

• ganciclovir (IV) / valganciclovir (oral) for 6m + audiology follow-up + ophthalmology follow-up

Question 6

Herpes Simplex Virus

Answer 6

DNA virus

 
Two types: 1 (oral>genital) or 2 (genital>oral)

Spread to neonate – through direct contact with infected maternal secretions (transplacental possible), risk of neonatal transmission at vaginal delivery is 41% with primary lesion or 2% with recurrent lesions

 
Aetiology: physical/sexual contact; vertical

Risk factors: unprotected sex, immunosuppression, other STI

Factors influencing transmission:

• Type of maternal infection (primary or recurrent)
• Primary episode- 57% risk of neonatal infection
• First episode non-primary- 25% risk
• Recurrent episode(s)- 2% risk
• Presence of transplacental maternal neutralising antibodies
• Duration of rupture of membranes before delivery
• Use of foetal scalp electrodes/ integrity of mucocutaneous barriers
• Mode of delivery

Vaginal- increased risk

C-section- PREFERRED

Epidemiology: 2% of pregnant women

 
Signs & symptoms:

IU HSV infection

1. Microcephaly
2. Encephalomalacia
3. Hydranencephaly and/or intracranial calcification
4. Scarring, active lesions, hypo- and hyperpigmentation
5. Microphthalmia, retinal dysplasia, optic atrophy and/or chorioretinitis

 
Neonatal - 1 per 60,000 live births -> SEM, CNS ± SEM or disseminated infection:

Skin, Eye and Mouth (SEM) disease —- 45%
1. Blistering vesicular rash
2. Chorioretinitis

CNS disease ± SEM 30%——— Mortality 6% (high morbidity)
1. Seizures
2. Lethargy
3. Presents 10d-4w postpartum
4. Irritability
5. Poor feeding
6. Temperature instability
7. Bulging fontanelle

Disseminated infection involving multiple organs ———- 25%——— High mortality (30%)
1. Encephalitis (60-70%)
2. CNS (60-75%)
3. Hepatitis
4. Pneumonitis
5. No skin lesions (>20%)
6. DOC

 

Investigations:

Clinical diagnosis ± STI screen

PCR virus

 

Management:

IV aciclovir to child (14d if SEM disease  21d if CNS or disseminated)

+ monitor neutrophil count

 
Prognosis -> neonatal mortality from 2% (local disease) to 50% (disseminated disease)

Improved outcomes if early diagnosis and initiation of antiviral therapy

Question 7

Group B strep

Answer 7

Gram positive streptococcus characterised by presence of Group B Lancefield antigen – streptococcus agalactiae

• Gram +ve cocci in chains
• They can be classified into a, b, g haemolytic groups
• b-haemolytic streptococci are further divided into groups A, B, C, D, F, G and H
• Most common cause of early onset infection in neonates <7d old

 

Aetiology:

• Commensal bacterium of vagina and rectum carried by 25% women
• Majority of babies who come into contact are not affected (some become colonised, minority become ill)
• This is particularly dangerous if acquired around the time of delivery
• Transmission occurs between the time of rupture of membranes to delivery
• It is the most common cause of severe early-onset (within 7 days of delivery) infection in newborns 

 
Management:
Sepsis monitoring:

Postpartum – new-borns with…

• 1 risk factor  remain in hospital for at least 24 hours for observations
• ≥2 risk factors or one red flag  sepsis ABx + septic screen
  * GOSH ABx in neonate <72 hours = cefotaxime + amikacin + ampicillin

Red Flags:

Intrapartum ABx for confirmed/suspected sepsis (not GBS prophylaxis)

Respiratory distress starting >4 hours postpartum

Seizures

Nasal flaring

Jaundice

Need for mechanical ventilation in a term baby

Signs of shock

Sudden collapse

Tachypnoea

Poor tone

Question 8

Listeria

Answer 8

Gram-positive bacillus bacterium Listeria monocytogenes

 

Aetiology – found in soil, decayed matter and animals

People with reduced cell-mediated immunity (i.e. pregnant women, neonates) are most at risk

Faecal-oral transmission (soft cheese, pate, unpasteurised dairy products, unwashed salads)

Vertical (transplacental or during delivery (ascending route through the cervix))

 

Risk factors: pregnancy and immunosuppression increase risk of infection

Epidemiology: 1 per 20,000 pregnancies in the UK (rare)

 

Signs & symptoms:

• fever
• Lethargy
• Irritability
• Diarrhea
• poor feeding
• Vomiting
• respiratory distress
• skin rash - widely spread, small, pale nodules (granulomatosis infantiseptica)

 
Management -> IV ampicillin 2 g hourly for 14 days (or IV amoxicillin 6g/day) + gentamicin

If penicillin allergic: trimethoprim/ sulfamethoxazole or erythromycin

NOTE: trimethoprim/ sulfamethoxazole is contraindicated in the 1st trimester