Cystic Fibrosis Flashcards

1
Q

Define cystic fibrosis

A

Severely life-shortening genetic disease resulting from abnormalities in the cystic fibrosis transmembrane conductance regulator (CFTR), a chloride channel found in cells lining the lungs, intestines, pancreatic ducts, sweat glands, and reproductive organs,

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2
Q

What is the aetiology of cystic fibrosis

A

Autosomal recessive
80% are due to delta F508 on the long arm of Chr 7
Mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) (anion/chloride channel found in the membrane of epithelial cells) - can be homo/heterozygous
→ abnormal salt transport by epithelial cells → thick, sticky secretions

Pancreas: blockage of exocrine ducts, early enzyme activation, autodestruction of the pancreas
Intestine: bulky stools → intestinal blockage
Lungs: Mucus retention, chronic infection, inflammation → lung tissue destruction

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3
Q

What are the common organisms implicated in respiratory tract infections in those with cystic fibrosis

A

Staph aureus
Pseudomonas aeruginosa
H. Influenzas
Burkholderia cepacia complex
Non-tuberculosis mycobacterium
Aspergillum fumigatus

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4
Q

What are the risk factors for cystic fibrosis

A

FHx CF
Known carrier status of both parents
Ethnicity: white
Genetic
- Cystic Fibrosis
- Ciliary dyskinesia or immotile cilia syndrome ± Kartagener’s syndrome

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5
Q

What is Kartagener’s syndrome

A

Autosomal recessive
Ciliary dyskinesia
Situs inversus
Chronic sinusitis

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6
Q

What are the symptoms of cystic fibrosis in young children

A

Pancreas (85%) and lungs most commonly affected

Neonatal Hx: Failure/delay to pass meconium, jaundice, bilious vomiting
Failure to thrive, poor weight gain, dropping percentiles
BUT voracious appetite
Cough (wet, prolonged, hard coughing spells, ± haemoptysis)
Recurrent infections
Chronic sinusitis and coryzal symptoms
Pale, fatty, foul-smelling, floating stools (steatorrhoea)
Gastro-oesophageal reflux

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7
Q

What are the symptoms of cystic fibrosis in older children

A

Hx pancreatitis: acute abdominal pain, nausea, vomiting
Symptoms of diabetes mellitus
Delayed puberty
Short stature due to malnutrition
Male infertility
Nasal polyps
Rectal prolapse due to bulky stools

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8
Q

What are the signs of cystic fibrosis on examination

A

General: ?malnutrition (protuberant abdomen, lack of SC fat, short stature)
Hands: clubbing
Resp: wheeze, increased AP diameter of chest
Abdominal exam
Testicular: ?genital abnormalities

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9
Q

What are the differentials for cystic fibrosis

A

Primary ciliary dyskinesia
Primary immunodeficiency
Asthma
GORD
Chronic aspiration
FTT
Coeliac disease
Protein-losing enteropathy

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10
Q

How is cystic fibrosis tested for in neonates

A

Heel prick testing at 5 days → elevated immunoreactive trypsinogen

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11
Q

What investigations should be done for cystic fibrosis

A

Bedside
Stool for faecal elastase: low
Stool for chymotrypsin: low
Stool for microscopy: fat globules seen

Other
Sweat test (pilocarpine iontophoresis): +ve (sweat chloride >60mmol/L, 30-59 = intermediate → CF centre referral)
Immunoreactive trypsinogen testing: +ve → follow with confirmatory testing (sweat)
Genetic testing: presence of mutation

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12
Q

In which patients should a sweat test be performed in

A

FHx CF
Congenital intestinal atresia
Meconium ileus
Symptoms and signs that suggest distal intestinal obstruction syndrome
Faltering growth (in infants and young children)
Undernutrition
Chronic sinus disease
Obstructive azoospermia
Rectal prolapse
Acute/chronic pancreatitis

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13
Q

What is the management for cystic fibrosis

A
  1. Refer to a CF centre

MDT management: Paediatrician | Nurse | physiotherapist | dieticians | pharmacists | clinical psychologists | social workers

  1. Respiratory
  2. Infection
  3. Nutrition
  4. Psychological
  5. General management
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14
Q

interventions done for patients with cystic fibrosis

A

Increased monitoring with spirometry and symptom watches
Physiotherapy 2x a day
- Airway clearance manoeuvres and devices
- Encouraging physical activity
- Manual chest physiotherapy
- Active cycle breathing
- Use of chest wall oscillators or PEP devices

Mucolytic therapy:
First line: rhDNase (Dornase alfa) nebs
Second line: rhDNase + hypertonic saline
Third line: Mannitol dry powder (INH)
Orkambi: Lumacaftor with Ivacaftor (potentiators and correctors) - useful for F508 mutation (78% of CF)

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15
Q

Describe the infection interventions done for patients with cystic fibrosis

A

Minimise contact with other patients with CF
Prophylactic antibiotics
- Flucloxacillin and azithromycin
- Moderate/severe → tobramycin and oxacillin
Inhaled bronchodilator e.g. salbutamol metered-dose inhaler
Rescue packs (for prompt IV Abx with any symptoms or signs of infection)
End stage CF disease → lung transplant*

*chronic infection with Burkholderia cepacia is an important CF-specific contraindication to lung transplantation

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16
Q

What nutritional therapy is recommended to those with cystic fibrosis

A

High calorie and high fat diet (150% of normal)
Fat soluble vitamin supplements (ADEK)
Pancreatic enzyme replacement with ever meal (lipase, protease, amylase) - CREON, pancreatin
Consider H2 antagonist of PPI to provide a more alkaline environment for the pancreatic enzymes
May be given a PEG to keep up with calorie intake

17
Q

What is the management for the following in cystic fibrosis:
Liver issues e.g. cirrhosis, portal HTN
Distal intestinal obstruction syndrome (DIOS)
Sterility

A

Liver issues → ursodeoxycholic acid therapy
Distal intestinal obstruction syndrome (DIOS) → oral laxatives
Sterility → ICSI

18
Q

What are the complications for cystic fibrosis

A

Underweight
Meconium ileus
Fat-soluble vitamin deficiencies
Distal intestinal obstruction syndrome
Male infertility (obstructive azoospermia)
Reduced female fertility
Upper airway complications: nasal polyps and sinusitis
Chronic liver disease
Urinary stress incontinence
Cystic fibrosis related diabetes
Reduce bone mineral density, rickets
Rare: arthritis, delayed puberty, renal calculi

19
Q

What is the prognosis for cystic fibrosis

A

There is no cure
Outlook has greatly improved, mean survival ahs risen from infancy to almost 40 years old