1. Mahmoud Halawa M.D
Benha University, Egypt

2. Duchenne Muscular Dystrophy
(DMD)
 The most common cause of muscular dystrophy in children
 Prevalence: 1.3 to 1.8 per 10,000
 X-linked recessive
 Mutation of the dystrophin gene.

3.  Muscle weakness
 Progressive difficulty in walking
 Breathing difficulties
 Heart disease
 Learning difficulties (the IQ can be below 75)
 Intellectual disability
Symptoms usually appear between 2-3 y of age, the patient
become wheelchair bound by age 12 and death occurs by age 20

5. Diagnosis:
 Creatine phosphokinase (CPK)
 Electromyography (EMG)
 Electrocardiogram (EKG)
 Genetic analysis
 Muscle biopsy

6. Treatment:
 No curative treatment till now
 Gene therapy still under trial
 Corticosteroids
 ACE inhibitors
 Mobility aids
 Breathing assistance
 Surgery

7. Hospital Armand Trousseau, Paris, France.

8. The study
Study Objective: analyze the trend of a number of respiratory
parameters in patients with DMD to gain further information on the course of
the disease.
Study Design: Retrospective analysis
Subject Selection: 28 boys with DMD, age range between 6-19 year
old, who were followed between 2001 and 2011.
Methodology: Lung function, blood gases, respiratory mechanics, and
muscle strength were measured during routine follow-up over a 10 years.

9. All patients were treated with ACE inhibitors
None received corticosteroids
Patients with vertebral arthrodesis surgery were not
excluded
Only data before the initiation of NPPV were taken
into account

10. Lung Function and
Respiratory Muscle Tests
Non-
Invasive
Non-
Volitional
Volitional
Invasive
Non-
Volitional
Volitional
•FRC
•VT
•VE
•fR/VT
•FVC
•SNIP
•MIP
•MEP
•PEF
•CPF
•Sniff Pes
•Sniff Pdi
•Pgas cough
•TTdi
•TTes
•Pdi
• Pgas/ Pdi
•PTPes
•PTPdi
•CL dyn

11. Statistical analysis
 Mean + SD
 Median
 Range
 Decline in variables for each patient separately
 Mean decline in each variable for all patients

12. Results

13. Discussion
 This is the first study to report the natural evolution of a large
number of respiratory parameters.

14.  FVC may be more specific of disease
progression from age of 10y

15.  SNIP is very simple, feasible and reproducible to assess inspiratory muscle strength
 The decrease in SNIP% is very close to the decrease in MIP%
 SNIP values decline earlier compared to VC

16. Pgas cough was below normal in all the patients
It is also feasible and reproducible to asses expiratory muscle strength

17.  TTdi is useful to monitor the risk of developing diaphragmatic fatigue

18. The esophageal pressure time
product/minute remained within normal
values in the majority of patients
The diaphragmatic pressure time
product/minute values were higher with a
large intra- and inter-subject variability

19.  Respiratory surveillance is an essential component of the care
 Early involvement of the expiratory muscles
 Sniff and cough are easier tests and interesting
 PEF and CPF are simpler but less reliable
 FVC and EFV1 are correlated to CPF
 None of the non-volitional parameters was informative for the
follow up of the disease Except VE

20. The conclusion:
 SNIP and FVC are the most informative parameters to follow the
disease progression in DMD
 Pgas cough and TTdi are useful to monitor respiratory muscle
decline and the risk of muscle fatigue
 The monitoring of these parameters should be performed at an early
age in order to follow the time course of the respiratory muscle
decline
 These parameters is helpful to guide therapeutic trials in young
patients aiming at slowing disease progression

21. The main limitations:
 Retrospective data collection
 Low number of patients
 Difficulties in follow up in some patients