WEEK 5 Flashcards
Embryology of respiratory tract
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EMBRYONIC (3-8 WEEKS)
- Respiratory diverticulum (lung bud) develops from fetal foregut
- By ~5 weeks, two primary lung buds are visible, which later divide into lobar buds
- Cells lining lung buds derive from endoderm, blood vessels and connective tissue surrounding lungs are derived from mesoderm
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PSEUDOGLANDULAR (5-17 WEEKS)
- Rapid branching of airways
- 16-25 primitive segemental bronchi are formed
- Development of specialised cells such as cilia and mucous glands
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CANALICULAR (16-26 WEEKS)
- GAS EXCHANGE UNIT FORMATION
- FETUS CAN BE BORN PREMATURELY AT THE END STAGES OF CANALICULAR PHASE DUE TO FORMATION OF GAS EXCHANGE UNITS
- Lung develop from distal architecture
- includes terminal bronchioles, alveolar sacs and capillary blood vessels
- Type 1 and Type 2 pneumocytes (alveolar cells) form
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SACCULAR (24-38 WEEKS)
- Growth and formation of alveolar sacs which become alveoli after birth
- More surfactant produced
- Bronchioles continue to elongate, interstitial tissue between the sacs reduce and the alveolar walls become thinner which improves gas exchange
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ALVEOLAR (36 WEEKS - 2/3 YEARS)
- Cells at this stage are well differentiated and the pulmonary vasculature more developed forming the final alveolar
Define the term remodelling
Alteration of airway structure following external influence
- Environmental exposures
- Chronic diseases of childhood
- Infection
Leads to abnormalities due to interference of inter-cellular signalling
Seen in asthma and chronic lung disease of prematurity
What are the 3 upper congenital abnormalities affecting the respiratory tract
- Laryngomalacia
- Dynamic abnormal collapse of larynx
- Tracheomalacia
- Dynamic abnormal collapse of tracheal wall
- Traecho-oesphageal fistula
- Abnormal connection between trachea and oesophagus
What are the 2 lower congenital abnormalities affecting the respiratory tract
- Congenital pulmonary airway malformation (CPAM)
- Abnormal non-functioning lung tissue
- Congenital diaphragmatic hernia
- Diaphragm develops from multiple tissues around 7 weeks and closes by 18 weeks
Most common type of lung cancer
Adenocarcinoma
Sleep apnoea management
- Identify exacerbating factors
- Weight reduction
- Avoidance of alcohol
- Diagnose and treat endocrine disorders eg hypothyroidism
- Continuous positive airway pressure (CPAP)
- Mandibular repositioning splint
- Positional therapy devices
Presenting symptoms and signs of respiratory muscle weakness.
- SOB
- Orthopnoea (SOB while lying down)
- Ankle swelling (hypoxic cor pulmonale)
- Morning headache
- Recurrent chest infection
- Disturbed sleep
Investigations and management of respiratory muscle weakness.
INVESTIGATIONS:
- Lung function
- Lying and standing VC
- Mouth pressures/SNIP
- Assessment of hypoventilation
- Overnight oximetry
- Transcutaneous CO2 monitoring
MANAGEMENT:
- Treat underlying condition
- Oxygen therapy
- Tracheostomy ventilation
- Supportive treatment (not curative)
Other conditions causing excessive daytime sleepiness.
NARCOLEPSY
Chronic neurological disorder that affects the brains ability to control sleep-wake cycles
CLINCIAL FEATURES:
- Cataplexy
- Excessive daytime sleepiness
- Hypnagogic/hypnopompic hallucinations
- Sleep paralysis
INVESTIGATIONS:
- PSG
- MSLT
- LOW CSF orexin
TREATMENT:
- Modafinil
- Dexamphetamine
- Venlafaxine (for cataplexy)
- Sodium Oxybate (Xyrem)
Neurological conditions associated with respiratory muscle weakness.
CHRONIC VENTILATORY FAILURE
What is used to determine sleep apnoae
EPWORTH SLEEPINESS SCALE
It is scored out of 24, with a score of 11 or more regarded as abnormal
Define the principles of management of pulmonary vascular diseases.
- Oxygen
- Warfarin
- Direct Oral Anticoagulants
- RivaroXABAN
- ApiXABAN
- Thrombolysis
- Pulmonary embolectomy
Pulmonary hypertension causes, signs and treatment
CAUSES:
- Can be idiopathic
- Congenital heart disease (L to R shunt)
- HIV infection
- Secondary to left heart disease
- Secondary to chronic respiratory disease
- Chronic thromboembolic PH
- Miscellaneous
- Sarcoidosis
SIGNS:
- Elevated JVP
- Right ventricular heave
- Loud pulmonary second heart sound
- Hepatomegaly
- Ankle oedema
TREATMENT:
- Treat underlying condition
- Calcium channel antagonists
- Oxygen
- Anticoagulation
- Diuretics
Outline the management of pancreatic insufficiency and chest infection.
BOOSTING NUTRITION
- REPLACE ENZYMES: (CREON)
- DIET: High energy plus high calorie supplement drinks*Not low fat
- NUTRITIONAL SUPPLEMENTS: Fat-soluble vitamin and mineral supplements
Describe the genetics and presenting features of cystic fibrosis.
Occur when you inherit TWO MUTATED GENES, (one from each parent)
MOST COMMON AUTOSOMAL RECESSIVE DISORDER
Due to a mutation on the CFTR which is coded on chromosome 7
TWO COMMON PRESENTATIONS OF CF THROUGHOUT LIFE:
- PANCREATIC INFUFFICIENCY
a. The CFTR mutation also affects the pancreas.
b. The pancreas produces enzymes that digest food. Lack of enzymes causes:
- Malabsorption
- Abnormal stools - pale, offensive, float
- Failure to thrive
c. Importance of records, growth charts - RECURRENT CHEST INFECTIONS
- Pneumonia
- Bronchiectasis
- Scarring
- Abscesses
