Mitochondrial disease. NARP is an acronym for
neuropathy, ataxia, and retinitis pigmentosa. Other features include corticospinal
tract atrophy, developmental delay, dementia, seizures, cerebellar ataxia,
sensory neuropathy, and proximal neurogenic muscle weakness.
Unknown. Prevalence is estimated at 1:12,000 population.
NARP syndrome is maternally transmitted. A
T-to-G point mutation at the base pair nucleotide 8963 of mitochondrial DNA
is suspected. This MT ATP6 encodes for subunit 6 of mitochondrial adenosine
Defect of complex V of the respiratory chain
enzymes, with progressive loss of mitochondrial bioenergetic capacity.
Clinical and laboratory confirmation of elevated
pyruvate and lactate. Muscular biopsy shows ragged-red muscle fibers, and
the biochemical defect is often segmental on histochemistry. On
ophthalmoscopy, the retina reveals salt-and-pepper retinopathy.
Association of neuropathy, ataxia, and retinitis
pigmentosa leading progressively to blindness. Other clinical features
include mental retardation, progressive deafness, muscle weakness,
developmental delay, and sluggish pupils. Onset in young adulthood, with
normal development and language problems.
Diagnosis of mitochondrial disease
should be considered in any child with a multisystem neurologic disorder or
who is being investigated for hypotonia. Anesthesia-related morbidity and
mortality risk is essentially linked to the preoperative status of the
child, that is, the number and extent of organ dysfunction. The presence of
a mitochondrial disease is not considered a risk for malignant hyperthermia.
Avoid any elective anesthesia/surgery in the presence of infection or
temperature because the increase in cytokines (mainly tumor necrosis factor)
inhibits some complex of the respiratory chain. The following should be
checked: central nervous system (CNS) (seizures, myoclonus, strokes, swallowing problems; usual venous
or arterial concentration of lactates and glucose); muscles (hypotonia,
contractures, scoliosis); heart (even if the child is asymptomatic, ECG and
echocardiography to exclude conduction disorders and cardiomyopathy,
respectively; check functioning of pacemaker, if present); respiratory (frequent
infections, chronic lung aspiration, pulse oximetry breathing room air should be obtained,
obstructive and/or central apnea; reduced ventilatory drive is common, and
many patients have an abnormal response to both hypoxia and hypercarbia.
Deaths have been reported following sedation with chloral hydrate or
diazepam). Other organ involvement include: hepatic and renal function; nutritional status and diet (glucose and/or lipid rich; tolerance to fasting and
treatment [carnitine, vitamin Q, antiepileptic drugs]).
Usual treatment up to the day of
surgery. Preoperative fasting must be as short as possible. If fasting is usually
poorly tolerated, a glucose-containing solution should be started when the
fasting period begins. A sedative premedication is best avoided because of
the possible abnormal response to hypoxia/hypercarbia. Induction: According to the
anesthesiologist's choice. Sevoflurane is the best choice for inhalation
induction; propofol seems the best choice for IV induction, but a 2%
solution should be used to lessen the lipid load. Opiates: Dose should be carefully
titrated according to the patient's needs. Muscle Relaxant: Published data are
contradictory. Even in the absence of clinical myopathy, the patient's