Clinical record

A 37-year-old woman presented with a 2-month history of progressive restriction of movement of the left shoulder joint, associated with episodic pain over the region. She was unable to raise her left arm above the shoulder. The pain was mild, deep-seated, non-radiating and relieved by supporting the left elbow. She denied any weakness of the arm muscles.

The patient also complained of diminished pain and temperature sensation over the affected limb, as evidenced by painless scalds of the fingers of her left hand — the first about 4 years previously, and the second, 7 days before presentation. She had had mild pain in the left shoulder region infrequently for the previous 17 years, and had noticed enlargement of her left arm since childhood.

She had not noticed any lymphadenopathy. She had normal facial sensation and denied any history of diplopia, dysarthria, dysphagia, hoarseness, vertigo, sphincter abnormalities or weakness and ataxia of any extremity. There was no history of neck pain, trauma, radiation or prolonged fever. She had no hypertension or diabetes, and her family and obstetric history were unremarkable.

Examination: The patient’s left upper limb was larger than the right (Box, A). The other limbs appeared normal. Girth of the left upper limb was 51.6 cm at the shoulder (right, 46.5 cm); 35.8 cm at the mid-arm (right, 31.4 cm); and 29.1 cm at the forearm (right, 25.2 cm). Wrist and fingers also had wider girth on the left compared with the right, but were equal in length. The swelling of the left upper limb was painless, non-pitting, with no colour change or abnormal sweating. Temperature of the limb was normal. Apart from evidence of a recent scald injury, no other superficial skin changes, vascular prominences or nerve thickening were observed.

Loose bodies were present in the left shoulder joint, as evidenced by palpable crepitus. Left shoulder abduction was restricted beyond 90°. No hum, bruit or machinery murmur could be heard on auscultation in any part of the affected limb. The right breast was slightly larger than the left.

Neurological examination revealed that pain, temperature and tactile sensation were diminished on the left side from C2 to T6 dermatomes anteriorly, and from C2 to T4 dermatomes posteriorly. Position and vibration senses were well preserved in these segments. All modalities of sensation in other parts of the body were normal. The patient had normal speech and higher functions. The hairline was at C2 level and the height–neck ratio was 11.67 (reference range, < 13). No meningism or cranial or spinal deformities could be identified. Examination of the cranial nerves gave results within normal limits.

Apart from a mild weakness of the small muscles of the left upper limb, as evidenced by a positive card test and Grade 4/5 power in the left supraspinatus and deltoid muscles, the motor system appeared normal. Deep tendon reflexes in the left upper limb were present but grossly diminished. Plantar reflexes were bilaterally flexor, with preserved abdominal reflexes. The patient had normal coordination, stance and gait, with no evidence of nystagmus or Horner syndrome.

Investigations: Complete blood count and routine biochemistry tests gave normal results. Fasting blood glucose level was 5.4 mmol/L (reference range [RR], < 6.1 mmol/L), and results of oral glucose tolerance were in the reference range. A serum VDRL (Venereal Disease Research Laboratory) test was negative.

An x-ray of the left hand showed soft tissue swelling and a slight increase in the size of the metacarpals and proximal phalanges compared with the right (Box, B). X-ray of the left shoulder joint showed loss of normal architecture, multiple bony fragments and loose bodies (Box, C). Skeletal imaging showed no abnormalities of the skull, spine or other limbs. No abnormalities were seen in the affected limb on arteriovenous doppler examination, computed tomography, magnetic resonance imaging, angiography, lymphangiography and skin biopsy.

Magnetic resonance imaging of the brain and spine showed a fairly large (12 mm) cerebellar tonsil dipping in the posterior portion of the foramen magnum, with a large syrinx involving the whole of the cervical and thoracic spine to level T8 (Box, D).

Management: The patient was advised to undergo posterior fossa decompression, but was unwilling to have surgical intervention and is currently receiving regular follow-up.