neurology

1. MITOCHONDRIAL ENCEPHALOMYOPATHIES
BY
Caroline Karunya Ponnarasi Kanagaraj
Group-IV

2. INTRODUCTION
The mitochondrial myopathies are a clinically
heterogeneous group of disorders with structural
mitochondrial abnormalities on skeletal muscle biopsy.
Their morphologic signature is the “ragged red fiber” seen
with the modified Gomori stain, containing accumulations
of abnormal mitochondria.
Patients may present with:
– Kearns-Sayre-Daroff syndrome
– myoclonic epilepsy [myoclonic epilepsy, ragged red fiber
syndrome, (MERRF)]
– mitochondrial myopathy, encephalopathy, lactic acidosis, and
stroke like episodes (MELAS).
These various syndromes are caused by separate
abnormalities of mitochondrial DNA.

4. VITAMINS
V-Vascular
I-Infection
T-Trauma
A-Autoimmune
M-Metabolic
I-Inherited
N-Neoplasm
S-Seizures

5. MELAS
Six different Point Mutation:
80% of cases have a A to G point mutation in the
tRNA (Leu) gene at bp 3243
7.5% of cases have a T to C point mutation in the
tRNA (Leu) gene at bp 3271
All of these mutations are heteroplasmic
Heteroplasmic= within a single cell,there is a mixture of
mitochondria,some containing mutant DNA and some
containing normal DNA.
This feature of mitochondrial diseases might offer a
solution to the varied rates of progression and onset of
the disease.

6. PATHOPHYIOLOGY
Abnormal Mitochondria do not metabolize pyruvate
Excess pyruvate is reduced to Lactic acid which
accumulates in blood and other fluids.
Large clumps of abnormal mitochondria form in the
walls of small arteries and capillaries in the brain and
muscles.

7. Symptoms
Short stature
External ophthalmoplegia (a rare symptom in
MELAS) Paralysis of the muscles that open eyelids, and
control eye movement Results in drooping of the
eyelids.
Musculoskeletal:
Overall muscle weakness
Exercise intolerance

8. Neurological:
Seizures
Recurrent severe headaches and migraines
Altered states of consciousness
Dementia (loss of intellectual ability)
Ataxia
Temporary local paralysis
Sensorineural hearing loss – damage to the nerve of the
inner ear, resulting in deafness

9. Other symptoms :
Vomiting
Loss of bowel control
Kidney dysfunction
Hormonal problems causing diseases like diabetes
mellitus
Cardiac conduction block – problems in the electrical
system of the heart that controls heartbeat

10. MERRF
MERRF – Myoclonic epilepsy with ragged red fibres
Myoclonus:
The sudden contraction of muscles, causing brief
jerking movements
Epilepsy:
The condition of having severe, recurrent seizures
Ragged red fibres :
Abnormal mitochondria accumulated under the
muscle membrane, appear as red strands in muscles,
when stained

11. CHARACTERSTICS
MERRF generally affects children and adolescents or
even adults at times, and almost always occurs after
normal development in infancy.
MERRF is very rare with prevalence being less than 1 in
100 000.
No ethnic or gender predisposition is found in MERRF.

12. SYMPTOMS
Neurological:
Myoclonus
Generalized Epilepsy
Ataxia
Dementia
Ocular:
Retinitis Pigmentosa – a group of diseases
characterized by
Swelling of cells in the retina
Vision loss in the night
Peripheral vision loss
Central vision loss

13. External ophthalmoplegia/ophthalmoperesis
Paralysis/weakness of the muscles that open eyelids
and move the eyes, resulting in restricted eye
movement and droopy eyes.
Physical appearance:
Short stature( may be present)
Other Symptoms:
Exercise intolerance
Cardiomyopathy – disease affecting the heart muscle,
which may lead to heart failure
Lipomas – benign tumours found beneath the skin, that
are composed of fatty tissue

14. Testing
Body fluids:
A high lactic acid and pyruvic acid (acids found in the
mitochondria) concentration in cerebrospinal fluid
(CSF) and blood
An increase in protein concentration in CSF
Muscle Biopsy:
Abnormal mitochondria from under the muscle tissue
membrane appear as “ragged red fibres” under a
microscope
•

16. Brain scans using MRI or CT reveal:
Abnormal signals from certain
brain areas, often from the
basal ganglia
scan of a healthy brain.

17. MRS testing reveals increase in lactate concentration in
the brain

18. TREATMENT
Medical care under the following specialists may be
required: neurologist, medical geneticist,
ophthalmologist and cardiologist.
There is no known treatment for the underlying disease,
which is progressive and fatal.
Patients are managed according to what areas of the body
are affected at a particular time.
Enzymes, amino acids, antioxidants and vitamins have
been used, but there have been no consistent successes
reported.

19. CONCLUSION
After coming to know about these diseases and the worst
thinking's of the mankind about a child ,I think you
would have got the motivation to live long and stay
strong for anything and you will realize that your life is
not that tough compare to those who are suffering from
an incurable diseases.
Till now doctors all around through world are still
finding medicine and ways to cure this diseases .
I wish that someone here in the classroom will be the
first one who finds the cure for this diseases which we
discussed now in the future and help kids like who are
undergoing these unwanted sayings.