Ulnar Nerve Palsy/ Claw Hand

EXAMINATION
         •CLAW HAND
           WEAKNESS          •Hypothenar eminence
                                          •Abductor digiti minimi
                                          •Median 2 lumbricals (finger flexion)
                                          •All interrossei (adduction & abduction)
           WASTING              •Medial side of forearm
           SENSORY             •Medial 1 1/2 fingers
           SYMPATHETIC     •Sweating

CAUSES
         •# Dislocation @ elbow
         •Occupational (leaning on elbows)
         •OA
         •Mononeuritis multiplex

Fig 1: Claw Hand

The Ulnar Nerve

Fig 1: Claw Hand

The ulnar nerve (usually) supplies sensation to the skin of the fifth and the ulnar side of the fourth finger, front and back. There is sympathetic interruption, with absence of sweating in the affected area. The thenar muscles are supplied by the median nerve and are therefore spared. Although the fourth and fifth digits are held in the clawed position when the nerve is injured at the wrist, a high lesion paralyses the long flexors to these two fingers and results in the loss of this sign. A test for paralysis of the palmar interossei, supplied by the ulnar nerve, is the inability to adduct the fingers and thus to be unable to grip a sheet of paper between them. 

Causes of Chorea (Medical Mnemonics)

St. VITUS'S DANCE

St	Sydenham
V	Vascular
I	Increased RBC (Polycythaemia)
T	Toxins (CO, Mg, Hg)
U	Uraemia
S	SLE
'
S	Senile chorea
D	Drugs
A	Alpha syndrome
N	Neurodegenerative disorders (Huntington's disease, Neuroacanthocytosis, DPRLA)
C	Conception related (Pregnancy, OCP)
E	Endocrine (Hyperthyroidism, Hypo/ hyperglycaemia)

Fig 1: Sydenham Chorea

Further Reading

Myasthenia Gravis

Fig 1: Unilateral ptosis

•AI
•vs ACh receptors (NMJ postsynaptic memb)

SYMPTOMS
           •Facial weakness
           •Slurred speech
           •Dyspnoea
           •(Prox) Limb weakness
           •Worse @ end of day
            AUTONOMIC    •Nil

SIGNS
           CRANIAL      •Ptosis (episodic, unilateral, bilateral)
                                 •Ophthalmoplegia (episodic)
                                 •Dysarthria
                                 •Bulbar symptoms & nasal regurgitation
                                 •Head drooping (weakness of neck musculature)
            MOTOR        •Fatigable weakness of striated muscle
                                 •Respiratory muscle (ife-threatature)
                                 •n/↑ Reflexes

CAUSES
           •AI
           •Penicillamine

INVESTIGATIONS
           •90%Anti-ACh receptor antibody
           •Antistriated muscle antibody
           •80%Thymoma
            EMG                           •↓ Muscle action potential + rapid stimulation
                                               •Post activation exhaustion
            TENSILON TEST       •IV edrophonium (short acting anticholinesterase)
            CT THORAX               •?associated thymoma
            TFT                             •10%Thyrotoxicosis;

TREATMENT
           •Thymectomy
           •Steroids
           •Immunosuppression (Cyclophosphamide, Ciclosporin)
           •Plasmapheresis
           •IV Ig

Further Reading