38. Pathology of Prematurity Flashcards
Define prematurity.
How does the placenta affect the baby in pre-eclampsia, and what is the foetus’s response?
What are some short and long term pulmonary diseases of the newborn?
Babies born before 37w gestation.
Superficial implantation and deficient spiral artery-trophoblast invasion; SA retain SM so impaired blood flow to baby -> releases biochemical signals resulting in the woman developing hypertension and pre-eclampsia so the fetus can benefit from a greater amount of maternal circulation of nutrients due to increased blood flow to impaired placenta.
Short term: respiratory distress syndrome, pneumonia, apnoea of prematurity, lung haemorrhage. Long term: bronchopulmonary dysplasia.
What is RDS? (Diagnosis, presentation).
HMD histology is found with RDS. What is HMD?
What are some acute complications of HMD?
Caused by lack of surfactant in premature baby (prod from about 35w onwards). Dx: clinical, radiological, post-mortem (purple lungs, liver-like consistency, PDA). Presentation: tachypnoea, expiratory grunting, recession, onset within 48h of birth. Differential: infection.
Hyaline membrane disease - manifestation of acute lung injury. Damaged vascular integrity allows fluid leak into air spaces. Partial reabsorption leaves proteinaceous material. If v preterm: necrosis of surface epithelium and epithelial plugs. Macrophages in 2-3days. Re-epithelialisation of terminal airways.
Air leaks due to increase in pressure to inflate lungs, pneumothorax if air leaks through pleura, pulmonary interstitial emphysema = increases RDS due to parenchyma compression.
What condition is this and what are the features?
HMD. Collapsed air spaces, distal airways lined by necrotic material later by eosinophilic hyaline membranes, dilation of septal lymphatics, oedema and focal haemorrhage, capillary thrombi.
What are some chronic complications of HMD?
What are the features of bronchopulmonary dysplasia?
How can RDS be prevented?
Continued ventilatory support >28d. Disease due to interruption of normal lung function.
Reduced numbers of alveoli and septa, larger alveoli, arrest in pulmonary alveolar and vascular development, abnormalities in vascular endothelial growth factor, abnormal alveolar capillary distribution, thickened muscular layer of pulmonary arteries.
Antenatal steroids, avoid intrauterine hypoxia, prophylactic surfactant treatment, keep warm, avoid acidosis.
What is pulmonary haemorrhage?
What is necrotising enterocolitis? (+ risk, presentation, tx, complications).
Acute bleeding from the lung, upper respiratory tract, trachea, and alveoli. [Pic] Common if episode of hypoxia. Can be hard to clinically distinguish from HMD.
Acute bowel invasion/inflammation/necrosis of bowel with gas formation in bowel wall (pneumatosis). Risk: prematurity, hypoxia, infection, enteral feeding. Presentation: abdo distension, tenderness, discolouration, blood in stools, generalised collapse. Tx: stop feeds, give abx +/- surgery. Complications: death, short gut from resection, strictures, late obstruction.
What condition is this?
Necrotising enterocolitis.
Dilation of involved segments, dusky serosal surface, deeply congested mucosa, patchy/diffuse ulceration, perforations often multiple.
What condition is this, and what features can you see?
Necrotising enterocolitis.
L: pneumatosis (gas cysts in bowel wall), epithelial regrowth and granulation tissue, fibrosis of muscularis propria.
R: mucosal necrosis, vascular congestion, oedema and inflammation, focal haemorrhage.
What conditions is the preterm central nervous system susceptible to?
What are some risk factors of PVH?
What are some complications of intracerebral bleeding?
Periventricular haemorrhage (PVH) (germinal matrix in floor of lateral ventricles is very vascular due to active glial and neuronal proliferation -> poor control of brain perfusion). Periventricular leucomalacia (PVL) (ischaemia of periventricular white matter).
Prematurity, RDS, pneumothorax, hypercapnia, acidosis, hypotension, instability and handling, severe bruising at birth.
Collapse and death, loss of brain parenchyma tissue with cyst development, blockage of CSF circulation leading to hydrocephalus.
What is this condition?
Intraventricular haemorrhage.
Usually 20 to bleeding in the germinal matrix. Haemorrhage can occur at one/several sites. Blood may fill entire ventricle system. When ventricles overdistended, blood dissects into parenchyma.
What are the risk factors for intraventricular haemorrhage?
What are the stages of IVH classification?
What are some sequelae of grades III and IV IVH?
Prematurity, conditions that disturb cerebral blood flow (HMD with hypoxia, hypothermia, hypercapnia and acidosis, BP instability).
Stage I: haemorrhage in the germinal matrix. Stage II: IVH without ventricular dilation. Stage III: IVH with enlarged ventricles. Stage IV: IVH with parenchymal haemorrhage.
Post-haemorrhagic hydrocephalus, general brain atrophy, multicystic encephalopathy.
What is periventricular leucomalacia (PVL)?
How might hypoxic brain damage affect term infants’s brains?
What might be seen on the brain of a full term infant with hypoxic-ischemic encephalopathy?
What would a combination of hypoxia and increased venous pressure due to placental abruption cause?
Necrosis of white matter, anoxic-ischaemic brain damage in border zones between arterial territories, occurs mainly in preterm infants.
Swollen with flattened convolutions, marked cortical pallour, congested sub-cortical white matter. [Pic]
Bilateral damage to cortical grey matter in watershed areas in depth of sulci, shinkage and gliosis, cellular necrosis and apoptosis, capillary proliferation and mineralisation of necrotic neurones, multifocal ischaemic necrosis.
Interruption of venous return with backward increase in venous pressure and intracranial and intrathoracic haemorrhages.
What condition is this?
Periventricular leucomalacia.
Oedema and lack of grey and white matter differentiation.
