PBL 37 Flashcards
Short term consequences of premature delivery
- Breathing problems - lack surfactant - RDS
- Heart problems - PDA and hypotension
- Brain problems
- Temperature control problems
- GI problems - immature GI system
- Blood problems - anaemia and jaundice
- Metabolism problems - hypoglycaemia
- Immune system problems
What is PDA and what can this lead to?
Persistent opening between the pulmonary artery and the descending aorta. This should close on its own but, if untreated, it can lead to too much blood flow through the heart and cause heart failure
Explain the reason infant jaundice can occur in premature babies
The liver may not be fully developed so the blood contains excess bilirubin
Long term complications of premature delivery
- Cerebral palsy - disorder of movement, tone or posture which can be caused by infection or inadequate blood flow or injury to a premature baby’s developing brain
- Impaired cognitive skills
- Vision problems -
- Hearing problems
- Dental problems
- Behavioural and psychological problems
- Chronic health issues - infections, asthma, SIDS
What is the cause of RDS?
A lung disorder in premature new-borns in which the air sacs in the lungs do not remain open because there is insufficient surfactant presence
What is the role of surfactant?
Coats the surface of air sacs, where it LOWERS surface tension, and it is this low surface tension that allows air sacs to remain open throughout the respiratory cycle
When does the foetus begin producing surfactant and by which time is there enough to allow the air sacs to remain open?
24wks
34/45wks
Risk factors for RDS
- Premature birth
- Mother who had diabetes whilst pregnant
- White male
- Mutation in certain genes that cause a deficiency of surfactant
Signs and symptoms of RDS
- Visibly laboured breathing
- Retractions (pulling in of chest muscles attached to the ribs and below the ribs during rapid breathing)
- Flaring of the nostrils during breathing in
- Grunting whilst breathing out
- Cyanosis (due to low O2 levels in blood)
How can we check to see if there is enough surfactant pre-birth?
Amniocentesis
- Measure the level of surfactant in amniotic fluid, this fluid is collected from the sac surrounding the foetus during a procedure called amniocentesis
When premature birth cannot be avoided, the mother is given injections of…
Corticosteroids - BETAMETHASONE
Treatment for RDS
- Synthetic surfactant therapy
2. Oxygen and measures to support breathing - CPAP
Bilirubin is a yellow substance formed when…
haemoglobin is broken down
Bilirubin is carried in the bloodstream to the … and processed so that it can be excreted out the … as part of …
Liver
Liver
Bile
Bilirubin is processed in the liver by a process called….
Conjugation
Where is bile made?
The liver
Explain how jaundice occurs
Bile is transported through the bile ducts to the small intestines (duodenum).
If bilirubin cannot be processed and excreted by the liver and bile ducts quickly enough, it builds up in the blood = hyperbilirubinaemia
The excess bilirubin settles in the skin, the whites of the eyes and other tissues, causing them to turn yellow
The most serious consequence of unconjugated bilirubin levels is…
Kernicterus
What is kernicterus?
Brain damage due to accumulation of bilirubin in the brain. It can lead to significant brain injury, resulting in developmental delay, cerebral palsy, hearing loss, seizures and even death
How can kernicterus be prevented?
Early diagnosis and treatment of hyperbilirubinaemia
Treatment of jaundice?
Phototherapy
Fluids
Causes of jaundice in new-borns?
- Physiologic jaundice (MOST COMMON)
- Breastfeeding
- Excessive breakdown of RBCs
What is physiologic jaundice?
RBCs in new-borns break down faster resulting in increased bilirubin production. Also, the new-born’s liver is immature and cannot process bilirubin / excrete it
How can breastfeeding cause jaundice?
- BREAST FEEDING JAUNDICE: New-borns who do not consume enough breast milk in the first few days, but it resolves in the first week
- BREAST MILK JAUNDICE: Occurs towards the end of the first week of life and may resolve by 2 weeks of age. It is caused by substances in breast milk that interfere with the liver getting rid of bilirubin from the body
How can haemolysis cause jaundice?
Haemolysis can overwhelm the new-born’s liver with more bilirubin than it can process.
What are the different types of haemolysis?
- Immune disorders
- They cause haemolysis when there is an antibody in the infant’s blood that attacks and destroys the infants’ RBCs. This can occur when the foetus’ blood type is not a match with the mothers (Rh or ABO) - Non-immune causes
- Hereditary G6PD deficiency and hereditary disorders such as alpha-thalassaemia cause excessive RBC breakdown
Less common causes of jaundice in new-borns?
- Severe infections
- Hypothyroidism
- Hypopituitarism
- Obstruction of bile flow from the liver
- Certain hereditary disorders
- Sepsis or UTIs
System error vs individual error
System error looks for explanation of its causes in the wider system i.e procedures, technology, communication, and the working culture
Individual error looks for explanations of its cause in people. Error can be traced back to the fault of an individual or individuals that make a wrong decision or were not paying attention
Two ways medical error comes about?
- Active failures
2. Latent errors
What are the different types of active failures?
- Unsafe acts committed by people in direct contact with patients
- Knowledge-based errors: forming wrong plans/diagnosis because of inadequate knowledge or experience
- Rule-based errors: Encounter relatively familiar problem but apply the wrong rule
- Skill-based errors: Attention slips and memory lapses
- Violations: people intentional break the rules
What are latent errors?
Develop over time and lay dormant until they combine with other factors or active failures to cause an adverse event. For example: working environmental conditions, training of staff and socio-cultural factors
How do you deal with latent errors?
- Report it - incident reporting systems
- Assess its seriousness
- Analyse why it occurred - root cause analysis
- Be open and honest with the affected patients and apologise - duty of candour
- Learn from the event and put in place actions to reduce the risk of repeat
How is gentamycin ototoxic?
Kills hair cells in the inner ear so it cannot respond to vibrations
Causes of deafness in general
- Damage to inner ear
- Ototoxic drugs: gentamycin
- Gradual build-up of ear wax
- Ear infection
- Abnormal bone growths or tumours
- Ruptured eardrum
- Menieres disease
What are muscular dystrophies?
A group of inherited muscle disorders in which one or more genes needed for normal muscle structure and function are defective, leading to muscle weakness of varying severity
What is DMD?
The second most common and most severe form of muscular dystrophy. Most are unable to walk by 12
What is the pattern of muscle loss in DMD?
First in upper legs and pelvis, followed by those of the upper arms
Cause of DMD?
Gene defect in the dystrophin gene which encodes the protein dystrophin
Absence of dystrophin permits excess calcium to penetrate the sarcolemma/cell membrane. Alterations in calcium and signalling pathway cause water to enter the mitochondria, which then burst.
In skeletal muscle dystrophy, mitochondrial dysfunction gives rise to an amplification of stress-induced cytosolic calcium signals and an amplification of ROS. Through an incompletely understood cascade, this oxidative stress within the cell damages the sarcolemma and results in cell death. Muscle fibres undergo necrosis and are replaced with adipose and connective tissue.
What is the inheritance pattern of DMD?
X-linked recessive
What is the role of the dystrophin protein?
- Important to maintain the muscle fibre cell membrane.
- It is responsible for connecting the cytoskeleton of each muscle fibre to the underlying basal lamina, through a protein complex.
Signs and symptoms of DMD
- Weakness of muscles, including the heart muscle and muscles for breathing
- Developmental delay: starting to walk, difficulty walking, running, jumping or climbing stairs
- Boys with DMD frequently fall
- Walking with a waddle
- Frequently walking on toes
- Difficulty rising from the floor
- Weakness in shoulder muscles usually follows and gets steadily worse
- Heart muscle gradually enlarges and weakens, causing issues with heartbeat and therefore can’t exercise…
- Arm and leg muscles usually contract around the joint, so the elbows and knees cannot fully extend. Eventually, scoliosis develops
Diagnosis for DMD
People with DMD have a high level of creatine kinase in their blood. This is because, in DMD, creatine kinase leaks out of muscle cells, causing levels in the blood to be abnormally high.
- High creatine kinase levels can also be caused by other means also, so they are not exclusive
Risk factors for DMD
- FHx
2. Male
Treatment for DMD
- Physical therapy and ankle/leg braces
- Ace inhibitors and b-blockers
- Drugs that increase dystrophin production
- Surgery
- Prednisone - after long-term use there are many benefits such as improving strength, allowing children to walk for a few more years, maintaining heart and lung functions, and increasing survival by 5-15yrs
- INCURABLE
Ethical issues around pre-natal screening
- Limitations of genetic testing, some tests do not identify all the possible gene mutations that may cause a particular condition, or they have limited predictive value, therefore couples may need to make difficult decisions without knowing the severity of the disorder
- Should the information be obtained if no treatment or intervention exists
- False positives and false negatives
- Genetic testing predicts increased risk, rather than certainty of disease
- Potential adverse personal or societal consequences - psychological harm, stigmatisation and discrimination
What is the age by which the majority of DMD patients are unable to walk?
12y/o
Sickle cell inheritance?
Autosomal recessive
Mutation in sickle cell disease?
GLU –> VAL in the Hbb gene found at the 11p chromosome
HBB gene encodes..
beta-globin
Mutation in HBB leads to…
Abnormal version of beta globin known as HbS
Normal RBC vs sickle cell RBC
Normal: flexible and biconcave
Sickle cell: rigid and crescent
Complications of sickle cell disease?
Anaemia, jaundice, sickle cell crises
Cystic fibrosis inheritance pattern?
Autosomal recessive pattern
What is CTFR involved in?
Production of sweat, digestive fluids and mucus
What happens when CTFR is not functional?
Secretions become thick, causing long term issues including breathing difficulty and coughing up mucus as a result of frequent lung infections
Thalassaemia inheritance pattern?
Autosomal recessive
Thalassaemias result in…
Abnormal formation of haemoglobin
The severity of thalassaemia depends on…
How many of the four genes for alpha globin or two genes for beta globin are missing
Effects of thalassaemia
Anaemia Bone problems Enlarged spleen Infections Heart problems
Where and when is the new-born physical examination carried out?
In the hospital and then again at 6-8 weeks
What is examined during the new-born physical examination?
- Baby’s eyes
- Heart sounds
- Hips to check the joints (DDH)
- Examine baby boys to see if their testicles have descended into the scrotum
Explain the new-born hearing screening process
- AOAE: automated otoacoustic emission test
- Soft-tipped earpiece is placed in baby’s ear and gentle sounds are played - AABR: automated auditory brainstem response
- If the AOAE does not work, this is used which involved placing 3 sensors on your baby’s head and neck. Soft sounds are played over your baby’s ears and gentle clicking sounds are played
Which conditions are looked out for in the new-born blood spot?
- Heel prick test
1. Sickle cell
2. Cystic fibrosis
3. Congenital hypothyroidism
4. Phenylketonuria
5. Medium-chain acyl-coA dehydrogenase deficiency (MCADD)
6. Classical galactosaemia
7. Glutaric aciduria type 1
8. Homocystinuria (HCU)
9. Maple syrup urine disease (MSUD)
