Cavernous sinus syndrome: A prospective study of 73 cases at a tertiary care centre in Northern India.

OBJECTIVES: To study the clinical and etiological profile of patients with cavernous sinus syndrome (CSS) and identify factors which could determine the etiology and influence the outcome of these patients. PATIENTS AND METHODS: This prospective observational study included 73 consecutive patients satisfying the criteria of CSS (i.e. involvement of any 2 of the 3rd, 4th, 5th and 6th cranial nerves or any one of them with radiological evidence of cavernous sinus involvement). All these patients were subjected to detailed haematological, biochemical and radiological investigations and diagnosed and treated as per guidelines. The clinical and investigational data was recorded and analysed meticulously. RESULTS: A definitive etiological diagnosis of CSS could be achieved in 86% of patients. Tumours, fungal infections and Tolosa Hunt syndrome (THS) were most common causes. On univariate analysis, diabetes, severe vision loss (visual acuity of <3/60 in at least one eye), and presence of nasal discharge showed a significantly positive association with a fungal CSS. Evidence of paranasal sinusitis, bone erosion and ICA (internal carotid artery) involvement on Gadolinium enhanced MRI (magnetic resonance imaging) of brain were significantly associated with a fungal CSS (p=0.0001), whereas involvement of orbital apex had a negative association with a neoplastic etiology (p=0.014). On multiple logistic regression, orbital apex involvement on MRI was associated with diagnosis of THS (p=0.019, OR: 18.7; 95% CI: 1.6-217.4) while MRI evidence of paranasal sinusitis (p=0.014, OR: 45; 95% CI: 2.1-94.3) and bone erosion ((p=0.019, OR: 12.5; 95% CI: 1.5-103) correlated with diagnosis of fungal CSS. 65.2% of patients (fungal CSS- 70%) had a good prognosis at six months follow up. CONCLUSION: Most patients with CSS can be diagnosed accurately and managed properly with good outcomes.

Thyroid hormone binding protein abnormalities in patients referred for thyroid disorders.

BACKGROUND & OBJECTIVES: Thyroid hormone binding protein (THBP) abnormalities are the major cause of discordance in commonly performed total thyroxine (T4) and thyrotropin (TSH) estimations, though these do not interfere with thyroid hormone action. Determination of such abnormalities in patients showing discordant thyroid function tests (TFTs) is diagnostically important as it eliminates equivocal assessment of thyroid function and treatment especially where proper methodology for free T4 (FT4) estimation is not available. This study was undertaken to analyse the THBP abnormalities in the population attending thyroid clinic. Family members of affected patients were also screened to study the inheritance of quantitative TBG abnormalities. METHODS: Blood samples of 15000 consecutive patients over a period of 4 years (1994-1997) were tested for thyroid function. THBP abnormalities were studied using polyacrylamide gel electrophoresis autoradiography. Serum thyroxine binding globulin (TBG), free and total T4, total tri-iodothyronine (TT3) were assayed by radioimmunoassay methods. RESULTS: In our screening of 15,000 thyroid patients over a four year period, we found the presence of complete and partial TBG deficiency and TBG excess to be 1:2,500, 1:200 and 1:15,000 respectively. Our study on the families of three affected patients revealed X-chromosome linked inheritance pattern of TBG deficiency in two families and TBG excess in one family. INTERPRETATION & CONCLUSION: Our study suggests that it would be beneficial to rule out THBP abnormalities before interpreting results of TFTs, particularly when there is large discrepancy between T4 and TSH levels. In case of inherited THBP abnormalities, the family members of the affected individual should also be screened to avoid misdiagnosis and erroneous treatment in case they develop thyroid dysfunction in future.

Comparative evaluation of immunochemical methods for estimation of albumin in microalbuminuria.

Three immuno assays namely radioimmunoassay (RIA), radial immunodiffusion (RID) and rocket immunoelectrophoresis (RIE) were compared for their performance and utility. The accuracy limits of the methods were compared and also between methods using RIA as the reference. Urine samples, from known diabetic patients with albumin concentration ranging from 2.5 mg/l to 120 mg/l were analysed by the three methods. The mean differences were only 0.91 mg/dl and 0.5 mg/dl respectively for RID vs RIA and rocket vs RIA which is not statistically significant. Excellent correlation was seen between RIA and RIE (r = 0.98) and also between RIA and RID (r = 0.97). Compared to RID, RIE required less time and was more precise. RIA is suited for assaying large sample loads yet not suited for laboratories receiving samples occasionally. For a small pathological laboratory with limited facility rocket electrophoresis may be the most suitable method taking into consideration accuracy, time and cost.

Screening for microalbuminuria by RIA in 131I-treated thyroid cancer patients.

Thyroid cancer patients are treated with up to 9.9 GBq of 131I to ablate remnant thyroid tissue and/or any functioning metastases that may be present. Radioiodine therapy is repeated as often as required. However, only a small fraction of the 131I is taken up by remnant thyroid and metastases, the remainder being eliminated by the kidneys, which are therefore subject to irradiation. External radiation therapy to the kidneys is known to lead to nephritis and albuminuria. The study included 113 patients treated with one to four doses of 131I (1.1-9.9 GBq each dose) and followed up 1 month to more than 8 years later. Spot samples of urine were collected and microalbuminuria measured by in-house radioimmunoassay. Twelve patients had elevated levels (normal range up to 34 micrograms ml-1), but their clinical history revealed such predisposing factors as diabetes and/or hypertension and proteinuria before therapy commenced. The remaining patients had normoalbuminuria. Grouping the patients based on the total dose of 131I administered resulted in a median microalbuminuria of 2.4-12.9 micrograms ml-1. Hence, this study showed that the dose of 131I normally used in treating thyroid cancer does not increase microalbuminuria to any significant extent.