Ketamine-associated lower urinary tract destruction: a new radiological challenge

AIM

Ketamine is a short-acting dissociative anaesthetic whose hallucinogenic side effects have led to an increase in its illicit use amongst club and party goers. There is a general misconception amongst users that it is a safe drug with few long term side effects, however ketamine abuse is associated with severe urinary tract dysfunction. Presenting symptoms include urinary frequency, nocturia, dysuria, haematuria and incontinence.

MATERIALS AND METHODS

We describe the radiological findings found in a series of 23 patients, all with a history of ketamine abuse, who presented with severe lower urinary tract symptoms (LUTS). Imaging techniques used included ultrasonography (US), intravenous urography (IVU), and computed tomography (CT). These examinations were reviewed to identify common imaging findings. All patients with positive imaging findings had also undergone cystoscopy and bladder wall biopsies, which confirmed the diagnosis. The patients in this series have consented to the use of their data in the ongoing research into ketamine-induced bladder pathology.

RESULTS

Ultrasound demonstrated small bladder volume and wall thickening. CT revealed marked, generalized bladder wall thickening, mucosal enhancement, and perivesical inflammation. Ureteric wall thickening and enhancement were also observed. In advanced cases ureteric narrowing and strictures were identified using both CT and IVU. Correlation of clinical history, radiological and pathological findings was performed to confirm the diagnosis.

CONCLUSION

This case series illustrates the harmful effects of ketamine on the urinary tract and the associated radiological findings. Delayed diagnosis can result in irreversible renal tract damage requiring surgical intervention. It is important that radiologists are aware of this emerging clinical entity as early diagnosis and treatment are essential for successful management.

A comparison of aspiration and sclerotherapy with laparoscopic de-roofing in the management of symptomatic simple renal cysts

OBJECTIVES

To present the results of a minimally invasive treatment of symptomatic simple renal cysts, and to propose an algorithm for their management.

PATIENTS AND METHODS

Seventeen patients presenting with suspected symptomatic simple renal cysts were referred for trial aspiration; 16 presented with loin pain and one with a flank mass. If the cyst and symptoms recurred after a temporary response, they were managed by re-aspiration with sclerotherapy using 95% ethanol, or by laparoscopic de-roofing of the cyst.

RESULTS

Of the 17 patients referred, one failed to respond to aspiration and was excluded from further analysis. Three patients had sustained pain relief from simple aspiration alone, 13 required further treatment for symptom relapse, of whom six had aspiration and sclerotherapy, and seven had laparoscopic de-roofing. After a mean follow-up of 17 months, pain had recurred in all five patients originally presenting with pain and managed by sclerotherapy, and the patient who presented with a painless mass from a large cyst also developed pain after sclerotherapy. In contrast, the subsequent seven patients managed by laparoscopic treatment are pain-free at a mean follow-up of 17.7 months.

CONCLUSION

Evaluation including a diagnostic aspiration is essential to diagnose a symptomatic cyst. When treatment is indicated, laparoscopic de-roofing appears to be more effective than sclerotherapy.

Computerized strain-gauge plethysmography in the diagnosis of symptomatic and asymptomatic venous thrombosis

This study compares the results of a computerized strain-gauge plethysmograph with ascending lower limb venography in 94 patients with clinical deep venous thrombosis, and in 121 patients with asymptomatic legs being screened after total hip replacement. In the symptomatic patients, strain-gauge plethysmography had a sensitivity of 100%, an accuracy of 73%, a specificity of 64% and a negative predictive value of 100% for thrombosis above the popliteal confluence. In the screened patients, the figures were 38.1%, 55.4%, 60.0% and 81.1% respectively. Computerized strain-gauge plethysmography is a safe, non-invasive, reliable and portable method of excluding proximal thrombosis in a symptomatic patient. It avoids the need for urgent venography when anticoagulation therapy is reserved for those with proximal thrombosis. The device was not valuable as a screening tool after total hip replacement, since it had a low specificity and did not reliably detect the non-occlusive mural femoral thrombi which typically follow this procedure.

Laboratory investigation in the diagnosis of pulmonary thromboembolism

Laboratory findings were compared with lung scans in a prospective study of 260 patients undergoing ventilation-perfusion (V/Q) lung scanning for suspected pulmonary thromboembolism. The best discrimination between different lung scan results was obtained from the level of plasma cross-linked fibrin degradation products, every patient with a scan indicating a high probability of thromboembolism having detectable levels. An acute phase response was demonstrated in patients with pulmonary thromboembolism by a raised neutrophil count and elevated levels of plasma fibrinogen and serum C-reactive protein. A normal level of serum C-reactive protein and/or plasma cross-linked fibrin degradation productions in blood taken within 4 days of onset of symptoms virtually excluded the diagnosis of pulmonary thromboembolism. Detection of free plasma DNA was not helpful in discriminating between groups with different lung scan results. Discriminant analysis was used to assess the variables examined and to derive diagnostic models. An accuracy of 78 per cent was obtained with one model for classifying test patients according to the three lung scan classes of low, intermediate and high probability. A second model, for distinguishing patients with a low and a high probability of pulmonary thromboembolism on the basis of lung scans, and a third for predicting those with a low probability on lung scan, were accurate in 94.6 per cent and 83.5 per cent of patients respectively. Discriminant models could be used in the diagnosis of pulmonary thromboembolism, especially when diagnostic imaging is not available.

Impedance plethysmography and thrombo-embolic disease

This study compares the results of impedance plethysmography with lower limb venography in 68 patients referred for investigation of clinical deep vein thrombosis, and with the results of ventilation/perfusion isotope scans in 125 patients with suspected pulmonary embolism. Impedance plethysmography had a sensitivity of 100% and a specificity of 61% for the detection of thromboses involving popliteal or more proximal veins (30 patients), but a sensitivity of 90% and a specificity of 68% in the detection of thrombosis at any level, because of a low sensitivity in the detection of isolated calf vein thrombosis (60% in 10 patients). It is a non-invasive, portable and low-cost technique and, in centres where anticoagulation is only given to patients with popliteal or more proximal thrombosis, venography may only be necessary if impedance plethysmography is positive. It may also be of value in the assessment of patients with suspected pulmonary embolic disease and an indeterminate ventilation/perfusion lung scan.