 |
|
Figure 5. Pes cavus |
| High-arched
foot results from a chronic imbalance of
intrinsic foot muscles in
Charcot-Marie-Tooth disease. |
|
Table 1. Mono- and
Generalized Neuropathies Commonly
Encountered in Clinical Practice
|
|
Mononeuropathies |
Generalized neuropathies |
Cranial
neuropathies:
- Trigeminal neuralgia
- Bells
palsy
- Diabetic cranial neuropathies
Carpal tunnel syndrome (median nerve)
Cubital tunnel syndrome (ulnar nerve)
Sciatic nerve damage following hip
replacement
Diabetic mononeuropathy/mononeuropathy
multiplex
Amyloidosis |
Diabetic
neuropathies:
- Generalized sensorimotor
polyneuropathy
- Autonomic neuropathy
- Polyradiculopathy
Hereditary neuropathies:
- Charcot-Marie-Tooth disease
- Amyloid polyneuropathy
- Dejerine-Sottas disease
- Refsums
disease
Inflammatory/autoimmune neuropathies:
- Guillain-Barré syndrome (GBS)
- Chronic inflammatory demyelinating
polyneuropathy (CIDP)
Toxic/metabolic/infectious diseases:
- Various toxin-induced neuropathies
- Alcoholic neuropathy
- HIV neuropathy
- Lyme neuropathy
- Uremia
- Porphyria
Systemic/malignancy-related neuropathies:
- Paraneoplastic
- Dysproteinemia
|
|
Table 7. Key Findings
from History and Physical Examination:
Pattern Recognition for Generalized
Neuropathies
|
|
Pattern |
Classification/possible diagnoses |
Comments |
| Symmetric
proximal and distal weakness with sensory
loss |
Inflammatory demyelinating polyneuropathy
Guillain-Barré syndrome (GBS)
Chronic inflammatory demyelinating
polyneuropathy |
Patient
complaints include: difficulty raising arms
to brush teeth and comb hair, problems
climbing stairs, difficulty rising from a
seated position, sensory loss, and sensory
ataxia |
| Symmetric
distal weakness with sensory loss |
Metabolic
disorders (e.g., amyloidosis, diabetes,
Sjögrens
syndrome)
Drugs (amitriptyline, chloroquine, dapsone)
and toxins
Hereditary neuropathies (Charcot-Marie-Tooth
disease, amyloidosis) |
Underlying conditions may be axonal or
demyelinating;
therefore, laboratory investigations (e.g.,
fasting blood sugar, hemoglobin
A1C, vitamin B12
levels, molecular genetic blood tests) are
recommended based on initial suspicions |
|
Asymmetric distal weakness with sensory loss |
Vasculitis
Hereditary neuropathy with predisposition to
pressure palsies
Infectious diseases (leprosy, Lyme, HIV)
Sarcoidosis
Compression and entrapment neuropathies |
Vasculitis is the most common diagnosis when
multiple nerves not normally subject to
compression are involved. Compressive
mononeuropathy, radiculopathy should be
considered with single nerve/region
involvement. |
|
Asymmetric distal weakness without sensory
loss |
Upper-motor-neuron disease
Generalized: multifocal motor neuropathy
(MMP) |
Bulbar
findings (i.e., slurred or nasal speech,
drooling, nasal regurgitation of liquids,
difficulty whistling, swallowing),
fasciculations,and hyperreflexia suggest
upper-motor-neuron disease, and are rare
with MMP |
|
Asymmetric proximal and distal weakness with
sensory loss |
Polyradiculopathy
Plexopathy (brachial or lumbar)
Meningeal carcinomatosis or lymphomatosis |
In
diabetic plexopathy, pain typically precedes
weakness |
| Symmetric
sensory loss without weakness |
Cryptogenic sensory polyneuropathy (CSPN)
Metabolic derangements (diabetes, alcohol),
drugs, toxins |
CSPN is
primarily observed in older adults. Diabetic
and alcoholic neuropathies may present with
few or no motor signs. |
|
Asymmetric proprioceptive sensory loss
without weakness |
Sensory
neuropathy (ganglionopathy)
Paraneoplastic syndrome
Sjögrens
syndrome
Idiopathic sensory neuropathy
Drug (e.g., cisplatin and its analogues) or
vitamin B6 toxicity
HIV sensory neuropathy |
Primarily
affects large fibers. May warrant a cancer
workup. |
| Autonomic
symptoms |
Generalized - diseases affecting small
fibers: e.g., acute dysautonomia, familial/
primary amyloidosis, GBS, diabetes, Chagas
disease, porphyria, HIV-related autonomic
neuropathy, idiopathic pandysautonomia |
Typically
associated with other types of neuropathy.
Conduct autonomic testing (e.g., Valsalva
heart rate response to pressure changes).
May be an early or sole presentation of
alcoholic or diabetic neuropathy. |
|
Based on Barohn [6], Kowalske [13]. |
|
Table 8. Assessment
of Muscle-Group Weakness
|
|
Symptoms |
Likely source of weakness |
Slurred/nasal speech
Drooling
Nasal regurgitation of liquids
Difficulty whistling, smiling
Difficulty swallowing, weight loss |
Bulbar
muscles |
Diplopia
Ptosis |
Extraocular muscles |
Trouble
reaching
Difficulty holding razor, comb, hair dryer
Difficulty placing things in high cabinets |
Proximal
upper-extremity muscles |
Difficulty opening jars, doors, using keys,
silverware
Trouble buttoning clothing |
Distal
upper-extremity muscles |
Trouble
rising from chairs, sofas
Trouble getting out of car, bath, or off
toilet
Difficulty climbing stairs |
Proximal
lower-extremity muscles |
Tripping
Sprained ankles |
Distal
lower-extremity muscles |
|
Table 9. Principal
Motor Innervation of Peripheral Nerves:
Localizing Muscle Weakness
|
|
Nerves |
Muscles |
Action |
| Axillary |
Deltoid |
Shoulder
abduction |
|
Musculocutaneous |
Biceps,
brachialis |
Flexion
of elbow |
|
Median |
Flexor
carpi radialis |
Radial
flexion of wrist |
| Flexor
digitorum sublimis |
Flexion
of middle phalanges (digiti II-V) |
| Flexor
digitorum profundus (lateral half) |
Flexion
of distal phalanges (digiti II, III) |
| Pronator
teres, pronator quadratus |
Pronation
of forearm |
| Abductor
pollicis brevis |
Abduction
of thumb |
| Opponens
pollicis brevis |
Opposition of thumb |
| Flexor
pollicis longus |
Flexion
of distal phalanx of thumb |
| Flexor
pollicis brevis |
Flexion
of proximal phalanx of thumb |
|
Ulnar |
Flexor
carpi ulnaris |
Ulnar
flexion of wrist |
| Flexor
digitorum profundus (medial half) |
Flexion
of distal phalanges (digiti IV, V) |
| Abductor
digiti minimi |
Abduction
of digiti V |
| All other
intrinsics of hand |
Finger
abduction/adduction |
|
Radial |
Triceps |
Extension
at elbow |
|
Brachioradialis |
Flexion
of forearm |
| Extensor
carpi radialis/ulnaris |
Extension
at wrist with radial/ulnar deviation |
| Supinator |
Supination of forearm |
| Extensor
pollicis brevis |
Extension
of thumb (proximal) |
| Extensor
pollicis longus |
Extension
of thumb (distal) |
| Extensor
indicis proprius |
Extension
of index (proximal) |
| Extensor
digiti V proprius |
Extension
of little finger (proximal) |
| Extensor
digiti communis |
Extension
of digits (II-V, proximal) |
|
Femoral |
Iliopsoas |
Flexion
of thigh at hip |
|
Quadriceps |
Extension
of leg at knee |
| Obturator |
Adductor
longus, adductor brevis, adductor magnus |
Adduction
of thigh at hip |
| Superior
gluteal |
Gluteus
medius, gluteus minimus, gluteus maximus |
Abduction
of thigh at hip |
| Sciatic |
Biceps
femoris, semitendinosus, semimembranosus |
Flexion
of leg at knee |
|
Sciatic branches: fibular (deep) |
Tibialis
anterior |
Dorsiflexion of foot |
| Extensor
digitorum longus |
Extension
of toes |
| Extensor
hallucis longus |
Extension
of great toe |
| Sciatic
branches: fibular (superficial) |
Peroneus |
Everts
foot |
|
Tibial |
Gastrocnemius, soleus |
Plantar
flexion of foot |
| Flexor
digitorum longus |
Flexion
of distal phalanges (II-IV) |
| Flexor
hallucis longus |
Flexion
of distal phalanges (I) |
| Flexor
digitorum brevis |
Flexion
of middle phalanges (II-V) |
| Flexor
hallucis brevis |
Flexion
of middle phalanges (I) |
| Pudendal |
Perineal
and sphincters |
Closure
of sphincters, contraction of pelvic floor |
|
From Ronthal [14]. |
