BRIEF HISTORY OF THE PATIENT AND HIS PROBLEMS IN ORDER OF PRIORITY:
18 year old male presented with:
Bilateral lower limb weakness since 1 month.Weakness in proximal and distal muscles.
History of wasting and thinning of muscles.
History of pain in the calf muscles while walking.
Weakness may be due to upper motor or lower motor neuron diseases.
PAST HISTORY:
Not a known case of DM/HTN/Epilepsy/CVA/CAD.
PERSONAL HISTORY:
Diet:mixed
Appetite:normal
Bowel and bladder movements:regular
History of alcohol consumption since 2 years:twice weekly
No history of smoking
FAMILY HISTORY:
No significant history.
NERVOUS SYSTEM EXAMINATION:
Higher mental functions-normal
Cranial nerves-intact
MOTOR SYSTEM:
RIGHT
LEFT
BULK
decreased
decreased
TONE:UL
normal
normal
LL
hypotonia
hypotonia
POWER:UL
4/5
4/5
LL
3/5
3/5
Deep tendon reflexes:
Biceps
present
absent
Triceps
absent
absent
Supinator
absent
absent
Knee
absent
absent
Ankle
absent
absent
SENSORY SYSTEM:normal
CEREBELLUM:normal
ANATOMICAL LOCALIZATION OF SITE OF LESION:
No upper motor neuron lesion signs are seen like spasticity,clonus,hyperreflexia,hypertonia and extensor plantar response.Therefore UMN lesion can be ruled out.
Hypotonia,absent deep tendon reflexes,muscle wasting suggest a lower motor neuron lesion.
SITES OF LOWER MOTOR NEURON LESION:
ANTERIOR HORN CELL
SPINAL NERVE ROOT AND PLEXUS
PERIPHERAL NERVE
NEUROMUSCULAR JUNCTION
MUSCLE
AHC lesions,radiculopathies and plexopathies often present asymmetrically.
NMJ problems show typical fatiguability,fluctuating weakness and ocular/pharyngeal musle involvement.
Myopathies are pure motor lesions,they also have a symmetrical muscle invovement but reflexes are intact.
Thus it is clear that the lesion is in the peripheral nerves.
ETIOLOGICAL DIAGNOSIS:
Peripheral polyneuropathies can be axonal or demyelinating.
Nerve conduction studies help in identifying the type of neuropathy.
AXONAL
DEMYELINATING
MOTOR NCS: CMAP
decreased
normal
Distal latency
normal
prolonged
Conduction velocity
normal
slow
Conduction blocks
absent
present
F wave and H reflex
normal/absent
prolonged/absent
NCS of the patient revealed bilateral common peroneal and sural axonal neuropathy.
Chronic alcohol consumption causes painful peripheral neuropathy.Associated nutritional deficiencies and direct toxic effect of alcohol results in alcoholic neuropathy.
PATHOPHYSIOLOGY OF ALCOHOLIC POLYNEUROPATHY:
Acetaldehyde is toxic to peripheral nerves.
Thiamine deficiency is common in chronic alcoholics.Cells cannot maintain the levels of ATP in the absence of thiamine.
Effects of alcohol depend on:frequency of drinking,quantity consumed,age of onset of drinking,duration of drinking,gender and genetic factors.