Statistics from Altmetric.com
Answers on p 480.
Peripheral neuropathy is a common medical problem, with many potential aetiologies.1 One of the commonest systemic diseases to cause a peripheral neuropathy is diabetes mellitus.2,3 Patients with end stage renal failure are also prone to develop peripheral neuropathy, in part related to how well uraemic toxins are removed by renal replacement therapy.4
We present the case of a woman with diabetes, on dialysis treatment, who developed an acute severe peripheral neuropathy. There were unusual clinical and investigational findings that mandated further diagnostic work-up.
An overweight woman, born in Antigua in 1948, developed type II diabetes mellitus in 1979. From 1983 she required oral hypoglycaemic agents then insulin. In 1994 she developed heavy proteinuria and impaired renal function (inulin glomerular filtration rate 52 ml/min corrected for body surface area, n=125 ml/min/1.73 m2) and required retinal laser photocoagulation.
She was lost to follow up, but reappeared in 1998 no longer on insulin but metformin with a plasma creatinine of 250 μmol/l (normal range 52–116), a creatinine clearance of 25 ml/min, 11.8 g of urinary protein excretion per 24 hours, and a glycated haemoglobin (HbA1c) of 8.8%. By February 1999 she required renal replacement therapy by means of chronic ambulatory peritoneal dialysis. An adequacy test, soon after starting therapy, indicated she was well dialysed. In addition, there was some degree of improved glycaemic control back on insulin with a HbA1c of 8.1%. By May 2001 she was having major problems, with several weeks of a hoarse voice, a nodular itchy skin eruption, with profound distal muscle weakness and numbness, and an unsteady gait. On admission she was found to have severe distal muscle weakness, wasting, dysmetria and ataxia, and marked acral reduction in pinprick, pain, and vibration-sense. Deep tendon reflexes were absent. A chest radiograph showed bilateral hilar lymphadenopathy. Computed tomography of the chest showed normal lung parenchyma, but right paratracheal and bilateral mediastinal lymphadenopathy (see fig 1).
Flexible narendoscopy showed the right arytenoids overriding with right vocal cord paralysis. This is likely to have been secondary to compression of the right recurrent laryngeal nerve from the paratracheal lymph nodes. Laboratory investigations revealed raised plasma calcium 3.11 mmol/l (2.2–2.6), suppressed parathyroid hormone 5 nmol/l (10 – 65), raised total globulins at 46 g/l (20–35), raised IgG 24.6 g/l (5–18) with a polyclonal pattern on electrophoresis, and abnormal liver function tests alkaline phosphatase 375 IU/l (50–120) and γ-glutamyltransferase 113 IU/l (26–52). C-reactive protein was 16 mg/l (<5).
A comprehensive autoantibody screen was negative. A nerve conduction study showed a demyelinating symmetrical sensory motor polyneuropathy. The degree of slowing and the presence of partial conduction block in the ulnar nerve at the forearms were not consistent with diabetic or uraemic neuropathies.
This impressive collection of abnormal test results (hypercalcaemia; lymphadenopathy; polyclonal IgG increase; abnormalities of liver function; and the severity and type of motor sensory peripheral neuropathy) required two additional investigations to be performed, unifying the diagnosis.
What were these two diagnostic procedures?
What is the underlying diagnosis?
What treatment is there, and what is the prognosis?
Answers on p 480.