Magnetic resonance imaging of pseudotumors of the craniovertebral junction in long-term hemodialysis patients

BACKGROUND/AIMS

Pseudotumors of the craniovertebral junction (PTCVJ) are observed in long-term hemodialysis (HD) patients. There are neither criteria for diagnosis nor guidelines for screening. We attempted to determine magnetic resonance imaging (MRI) findings that could be used to detect PTCVJ, to determine the prevalence of PTCVJ, and to evaluate whether destructive spondyloarthropathy (DSA) might be a yardstick for selection of patients for MRI examination for PTCVJ.

METHODS

MRI were examined in 19 DSA patients (8 males, 11 females, age 61.4 +/- 7.3 years, HD duration 17.0 +/- 4.4 years) and in 20 sex-, age-, and HD-duration-matched non-DSA patients (9 males, 11 females, age 57.5 +/- 6.6 years, HD duration 17.7 +/- 4.9 years). We evaluated MRI characteristics of PTCVJ according those which occur due to rheumatoid arthritis.

RESULTS

PTCVJ were characterized as follows: disappearance of fat pads in the upper region (supradental PTCVJ), intensity change of the 'predental triangle' in the anterior region (predental PTCVJ), and thickening of cruciform ligaments (retrodental PTCVJ). The prevalence of PTCVJ among patients undergoing HD more than 10 years was high (26 out of 39; 66.7%). The prevalence of PTCVJ was not different between DSA and non-DSA groups.

CONCLUSION

We verified that the above MRI findings might be helpful in the detection of PTCVJ. These findings were observed frequently and independently also in patients with DSA.

A common mutation of cholesteryl ester transfer protein gene in dialysis patients

BACKGROUND

In patients on maintenance hemodialysis, a decreased concentration of high-density lipoprotein cholesterol (HDL-C) is an apparent independent risk factor for vascular disease (VD). A common missense mutation of cholesteryl ester transfer protein (CETP) gene, D442G (Asp442 to Gly), increases HDL-C levels, but the mutation may also diminish the activity of reverse cholesterol transport.

METHODS

We compared the genotype distribution of the D442G polymorphism and postprandial serum lipid levels between patients with and without VD in 414 hemodialysis patients.

RESULTS

Serum levels of total cholesterol and HDL-C did not differ in patients with the mutation [group M (+)] and without the mutation [group M (-)] and in patients with and without VD. However, patients with below median HDL-C levels (< 45 mg/dl) had a significantly higher prevalence of VD than those with above median HDL levels (26.0 vs. 15.2%, P < 0.01). Moreover, in this low-HDL-C subgroup, group M (+) patients had a significantly higher prevalence of VD than group M (-) patients (54.5 vs. 24.4%, P < 0.05). In the subgroup, group M (+) patients with VD had higher levels of total cholesterol and a higher atherogenic index than those without VD, whereas group M (-) patients with VD had lower levels of total cholesterol and a lower atherogenic index than those without VD.

CONCLUSIONS

The D442G mutation may be a risk factor for atherosclerotic complications in dialysis patients with HDL-C levels below 45 mg/dl. Atherogenic lipid profiles may promote atherosclerosis in the patients with the mutation, but not in those with no mutation.

Hemodialysis-associated asthma in a renal failure patient

In a renal failure patient, asthma developed after 1 year hemodialytic treatment. The attack was exclusively associated with each hemodialysis. Skin test to the usual allergen such as house dusts or pollens was negative. The provocation test by inhaling acetate solution or oral intake of acetic acid was positive resulting in an increase in the pulmonary resistance, or asthmatic attack. This asthma disappeared completely after substitution of acetate in the hemodialysis by the use of a bicarbonate dialysate. Acetate might therefore precipitate the attack of asthma.

Effect of acetate upon arterial gases

Following infusion of sodium acetate, a significant fall in arterial oxygen tension (PO2) was observed (p less than 0.001). A rise in PCO2 or bicarbonate was also statistically significant. pH was however remained unchanged. Though a rise in PCO2, bicarbonate, pH was observed following infusion of sodium bicarbonate, no significant fall in PO2 was observed. These results suggest a role of acetate ion for the fall of arterial oxygen tension; the hemodialysis-induced hypoxemia.