Use of various diagnostic methods in a patient with Gaucher disease type I

[Gaucher's disease in Tunisia (multicenter study)]

Gaucher's disease is one of the rare lysosomial disease that could receive substitutive enzymatic treatment which may improve considerably the prognosis of certain forms. The purpose of this work is to study the epidemiology of the disease in Tunisia, to highlight the diagnostic and therapeutic difficulties and also to precise our subsequent needs for substitutive medication.

PATIENTS AND METHODS

We have conducted a retrospective survey of the hospital wards that were susceptible to take care of patients having Gaucher's disease. These wards are the paediatric, neonatology, internal medicine, haematology, neurology and cardiology wards.

RESULTS

In this study we have observed 27 cases of Gaucher's disease over a period of 18 years (1983-2001). The age at onset ranges from birth to 73 years of age, with an average age of 14.5 years. According to the age at onset and the clinical presentation, we classify our patients into: 20 cases of type 1 (74%), three cases of type 2 (12%), and three cases of type 3 (12%), and one case of unspecified type.Gaucher's disease type 1: The age at onset ranged from 10 months to 73 years with an average of 19 years. The main clinical signs that we have observed were splenomegaly, hepatomegaly, pallor, haemorrhagic appearance and also osteoporosis and bone pain observed in 40% of the cases. The diagnosis was based on histology showing the Gaucher's cells in various tissues while the diagnosis obtained by the dosage of glucocerebrosidase took place only in 50% of the cases. The treatment has always been symptomatic (analgesics, transfusion). A splenectomy was performed in 47% of the cases and none of the patients received a specific treatment. The follow-up period ranged from 1 month to 18 years with an average follow-up of 4 years. Among the 12 patients having a follow-up of at least 1 year, we have noticed an improvement after splenectomy in three cases, a stability in three cases and two worsening cases dealing mainly with bone problems. One patient aged 73 died from respiratory problem and three were lost to follow-up. Gaucher's disease type 2: We have observed three cases of Gaucher's disease type 2 diagnosed at 1 day, 45 days and 3 months of age. The visceral manifestations were serious and the neurological features included seizures, hypertony, ocular-nerve palsies and psychometric decline. The three patients died. Gaucher's disease type 3: Three patients were probably suffering from Gaucher's disease type 3 with visceral manifestations observed at the ages of 9 months, 1 year and 3 years, and also neurological signs observed at respective ages of 2.5 and 3 years. Two patients died and the remaining one was lost to follow-up.

CONCLUSION

Gaucher's disease is not exceptional in Tunisia. Type 1 is by far the most common one. We have noticed some insufficiency in the diagnosis as the glucocerebrosidase enzymatic dosage was performed only in 50% of the cases as well as therapeutic insufficiency with no prescription of the specific treatment.

Imaging and quantifying skeletal involvement in Gaucher disease

Radiological imaging is used in patients with Gaucher disease to estimate the disease burden, to evaluate the presence of specific skeletal complications and to track response to therapy. MRI is currently the best technique for assessing bone marrow involvement in Gaucher disease. Gaucher cell infiltrated bone marrow is characterized by an abnormal low signal intensity on conventional T1- and T2-weighted spin echo sequences, owing to a reduction in fat marrow, which gives a high signal intensity. Enzyme replacement therapy results in a degradation of Gaucher cell deposits with a reconversion of marrow fat and consequently an increased signal on T(1)-weighted images. Conventional MRI also detects other skeletal complications in Gaucher disease, including oedema resulting from acute bone infarction, infection and trauma, avascular necrosis, pathological fractures and vertebral compression. The main drawback of conventional MRI is that it is not quantitative. Quantitative chemical shift imaging is the most sensitive quantitative method for evaluating bone marrow but is not widely available. Alternative MRI-based methods include calculation of the T1 relaxation constant and proton spectroscopy. Scoring of imaging changes detected on conventional MRI may be useful in estimating disease burden and risk of complications. Dual-energy X-ray absorptiometry (DXA) is sensitive to generalized osteopenia and changes in bone mineral density with extended enzyme replacement therapy. However, DXA is insensitive to local changes and cannot yet be used to predict fracture risk in these patients. Until the ideal quantitative technique is developed, conventional MRI will remain the best diagnostic modality for assessing skeletal complications in Gaucher disease and monitoring response to enzyme replacement therapy.

Bone and joint complications related to Gaucher disease

There is a broad spectrum of Gaucher disease-related skeletal complications, ranging from asymptomatic osteopenia to osteonecrosis (of the shoulders and hips) with secondary degenerative joint disease. Characterization of the pattern and severity of bone involvement in the individual patient requires the application of conventional and advanced radiographic techniques. The introduction of enzyme replacement therapy (ERT) for this inborn error of glycosphingolipid metabolism has focused great interest in determining the nature and extent of the bone responses with this mode of treatment. The multifactorial etiology of the bone complications necessitates a multifaceted approach, combining pharmacologic strategies with physical therapy and orthopedic intervention. As bone disease can lead to chronic pain and debility with a resultant adverse impact on quality of life, it is important that patients be monitored closely and that early intervention with ERT prior to established bone disease (infarction and fibrosis) be considered.