Peripheral neuropathy- Neurology/IM Flashcards
Definition of Peripheral neuropathy
It’s inflammation or degeneration of the peripheral nerves and/or the cranial nerves resulting in impairment of their conductivity leading to motor, sensory and autonomic manifestations.
Causes of mononeuropathy
1) Trauma
2) Infective: leprosy, herpes zoster.
3) Vascular: polyarteritis nodosa.
4) Metabolic: DM.
Causes of polyneuropathy
Hereditary
1) Hereditary motor and sensory neuropathy
2) Hypertrophic interstitial polyneuropathy.
3) Hereditary disorders of lipid metabolism
Symptomatic
1) Infective
2) Toxic
3) Nutritional
4) Metabolic
5) Autoimmune
6) Endocrinal
7) Drug-induced
8) Inflammatory diseases
9) Malignant disease
10) Others: electric shock, radiation.
Causes of autonomic neuropathy
- Diabetes mellitus.
- Alcoholics.
- Nutritional.
- Amyloidosis.
- Uremia.
- Guillian-barre syndrome.
- Familial.
Clinical picture of polyneuropathy
A. Motor:
- Weakness or paralysis of lower motor neuron (LMN) nature (wasting, hypotonia, hyporeflexia)
- The weakness in the extensors of the distal group of muscles leads to bilateral foot drop and/or wrist drop.
- Lost Ankle reflex with preserved Knee reflex.
- The cranial nerves may be affected specially CN3, 6, 7 and 10.
- High steppage gait due to the foot drop.
B. Sensory:
- Subjectively there is pain and paresthesia in the limbs, specially distally.
- Objectively there are:
1) Superficial sensory impairment:
▪ Hypoesthesia
▪ Paraesthesiae
▪ Dysesthesia
▪ Hyperesthesia
▪ Allodynia
▪ Hyperalgesia
2) Deep sensory loss especially distally with absence of deep reflexes.
C. Autonomic:
-Vasomotor: coldness and cyanosis of the limbs.
-Cutaneous: loss of hair, brittle nails, rough skin, trophic ulcers, loss of SC fat. Hyperhidrosis later anhidrosis, dependent edema, early warmth, and hyperemia later coldness and pallor.
-CVS: orthostatic hypotension, resting tachycardia.
-Genito-urinary: impotence & loss of testicular sensations.
-GIT: gastroparesis, diarrhea, or constipation.
-Unawareness of hypoglycemia in DM.
Clinical picture of diabetic neuropathy
-Early diabetes: Mononeuritic type
-Frank diabetes: Polyneuretic type
-Polyneuropathy is mainly sensory (Pain, paranesthesia or superficial sensory loss). It starts in LL from toes upwards may affect hands from fingers upwards as well = Stock and glove hypoesthesia.
- Deep sensations lost
- Motor weakness
- Autonomic manifestations:
▪ Impotence and lost testicular sensation.
▪ Sensory, motor, or autonomic bladder.
▪ Postural hypotension resting tachycardia.
▪ Silent myocardial infarction.
▪ Gastroparesis diabeticorum: indigestion and delayed gastric emptying.
▪ Hyperhydrosis or anhydrosis.
▪ Trophic skin changes: ulcers, loss of hair, brittle nails, and Charcot’s neuropathic joint.
Treatment of diabetic neuropathy
1)Optimal glucose control (Most effective)
2) Vasodilators
3) Vitamins B1, B6, B 12 daily & ATP
4) For the neuropathic pain:
a) Anticonvulsants:
▪ Pregabalin
▪ Gabapentin
▪ Carbamazepine and Oxcarbazepine
b) Antidepressants:
-Duloxetine-Venlafaxine
- tricyclic antidepressants (Amitriptyline, Nortriptyline).
5) Physiotherapy if motor weakness is present.
Short note about refsums disease
- This is a hereditary lipid storage disease.
- Onset is during the 1st and 2nd decades.
- There is hypertrophic neuropathy associated with night-blindness, cerebellar ataxia, retinitis pigmentosa, ichthyosis (scaly skin) nerve deafness and skeletal deformities.
- Phytanic acid accumulation in the liver and other tissues due to lack of the enzyme phytanic acid hydroxylase, which is necessary to metabolize phytanic acid, as a result serum phytanic acid is markedly elevated.
Treatment:
Plasmapheresis and restriction of phytanic acid in diet (found in dairy products, beef, lamb, and some seafood).
Short note about charcot marie tooth disease
- Hereditary motor and sensory neuropathy appearing during the 1st and 2nd decades.
▪ It has a gradual onset and a very slow progressive course over many years.
▪ The wasting and weakness start distally in the lower limbs in the peronii muscles then the anterior tibial group, then ascend to involve the muscles of the lower half of the thigh resulting in the inverted champagne-bottle appearance.
▪Despite the marked degree of wasting there is mild weakness (i.e., discrepancy between the degree of wasting and the degree of motor weakness).
▪ Sensations are impaired specially the vibration sense which is markedly diminished.
▪ Skeletal deformities are usually present e.g., pes cavus or hammer toe.
▪ It may be associated with herido-familial ataxia.
Clinical picture of GBS
1) Febrile stage: it starts with an influenza-like attack with fever, headache, malaise, and pains all over the body with no nervous symptoms.
2) Latent stage: the above symptoms disappear, and the patient is free for 1-4 weeks.
3) Paralytic stage:
-There is acute severe weakness or paralysis with numbness and tingling starting in the LL and ascending to involve the trunk and sometimes respiratory muscles, followed by the UL muscles.
-Contrary to other types of polyneuropathies, weakness is proximal more than distal.
-Despite severe degree of paralysis, wasting is not present early in the disease.
-Sensory impairment may occur resulting in stock and glove hypoesthesia& deep sensory loss.
-Early in the disease there is tenderness of the calves.
-The cranial nerves are usually involved specially CN 7 and 10 resulting in bilateral facial paralysis and bulbar symptoms.
-Autonomic instability is common with hypotension or hypertension.
-CSF shows cyto-albuminous dissociation (↑ protein & normal cell count).
ttt of GBS
Should begin as soon as possible, preferably within the first 7-10 days.
1) Absolute bed rest till heart rate reaches below 100/min. (i.e., return of the vagal tone).
2) Care of the bulbar muscles by:
▪ Frequent suction of secretions from the pharynx.
▪ Tube feeding in case of pharyngeal paralysis.
3) Care of the respiratory muscles by:
▪ Suction to keep a patent airway.
▪ Tracheostomy may be needed.
4) Specific treatment:
Gamma-globulins (IVIG) and plasma exchange (PE): the most effective treatment (Both are equally effective).
5) Vitamins B1, B6, B12 IM daily.
6) Antibiotics to guard against 2ry infection.
7) Physiotherapy: Massage, passive and active exercises, proper positioning, and electrical stimulation.
Clinical picture of diphtheritic neuropathy
Symptoms and signs occur 2-8 weeks after the appearance of diphtheria.
- Two main types of neuropathies may occur:
1) Localized type: affecting CN3,7 and 10. The vagal paralysis results in bulbar symptoms with lost palatal and pharyngeal reflexes.
2) Generalized type: affecting the peripheral nerves.
clinical picture of leprotic neuropathy
- The neuropathy may be of the mono-or polyneuritic types.
- The commonest nerves affected are the lateral popliteal, ulnar, greater auricular, trigeminal, and facial nerves.
- There is irregular thickening of the affected nerves.
- Neuropathy is mainly sensory.
- There are 3 clinical types:
1) Nodular (lepromatous) leprosy: cutaneous nodules over the face and neck which ulcerate and heal by fibrosis leading to the leonine faces, usually associated with fever and lymphadenopathy.
2) Maculo-anaesthetic (tuberculoid) leprosy: maculo-anaesthetic skin patches with frequent trophic changes in the limbs (ulceration, gangrene).
3) Mixed type.
ttt of leprosy
1) Treatment of leprosy:
a. Tuberculoid leprosy: Dapsone and rifampin (both for 6 months).
b. Lepromatous leprosy: Dapsone, rifampin with clofazimine (all for 1-2 y or until the skin smear is zero).
2) Treatment of neuropathy.
clinical picture of pellagra
Characteristic Dermatitis, Diarrhea, Dementia (3D) and neuropathy in the setting of malnutrition
I. Skin manifestations:
●They start as a bilateral and symmetrical dermatitis followed hyperkeratosis (rough, scaly and desquamated skin) and pigmentation.
●The lesions involve the exposed areas (face, neck, dorsum of the hands and feet) and over bony prominences (trochanters, elbows, knees, heels).
II- GIT manifestations:
●Mouth: stomatitis, glossitis with atrophy of the papillae (glazed tongue).
●Stomach: dyspepsia, nausea, vomiting, epigastric pain.
●Intestines: colic, diarrhea.
●Hepato-splenomegaly may be present.
III. Neuropsychiatric manifestations:
●Peripheral neuropathy mainly sensory due to PN degeneration.
●Paraparesis or quadriparesis (systemic paraparesis) due to pyramidal tract degeneration (pellagral lateral sclerosis).
●Mentality changes as anterograde amnesia, depression, dementia and suicidal tendencies due to cerebral cortex degeneration.
