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Unpredicted spontaneous extrusion of a renal calculus in an adult male with spina bifida and paraplegia: report of a misdiagnosis. Measures to be taken to reduce urological errors in spinal cord injury patients
© Vaidyanathan et al; licensee BioMed Central Ltd. 2001
Received: 26 November 2001
Accepted: 20 December 2001
Published: 20 December 2001
A delay in diagnosis or a misdiagnosis may occur in patients with spinal cord injury (SCI) or spinal bifida as typical symptoms of a clinical condition may be absent because of their neurological impairment.
A 29-year old male, who was born with spina bifida and hydrocephalus, became unwell and developed a swelling and large red mark in his left loin eighteen months ago. Pyonephrosis or perinephric abscess was suspected. X-ray of the abdomen showed left-sided staghorn calculus. Since ultrasound scan showed no features of pyonephrosis or perinephric abscess, he was prescribed a prolonged course of antibiotics for infection presumed to arise from the site of metal implant in spine. He developed a discharging sinus, following which the loin swelling and red mark subsided. About three months ago, he again developed a red mark and minimal swelling in the left loin. Ultrasound scan detected no abnormality in the renal or perinephric region. Therefore, the red mark and swelling were attributed to pressure from the backrest of his chair. Five weeks later, the swelling in the left loin burst open and a large stone was extruded spontaneously. An X-ray of the abdomen showed that he had extruded the central portion of the staghorn calculus from left kidney. With hindsight, the extruded renal calculus could be seen lying in the subcutaneous tissue of left loin lateral to the 10th rib in the X-ray of abdomen, which was taken when he presented with red mark and minimal swelling.
This case illustrates how mistakes in diagnosis could occur in spinal cord injury patients, and highlights the need for corrective measures to reduce urological errors in these patients. Voluntary reporting of urological errors is recommended to facilitate learning from our mistakes. In the patients who have marked spinal curvature, ultrasonography of kidneys and perinephric region may not be entirely reliable. As clinical symptoms and signs may be non-specific in SCI patients, they require prompt, detailed and occasionally, repeated investigations. A joint team approach by health professionals belonging to various medical disciplines, which is strengthened by frequent, informal and honest discussions of a patient's clinical condition, is likely to reduce urological errors in SCI patients.
A delay in diagnosis or a misdiagnosis may occur in the patients with spinal cord injury (SCI) or spinal bifida as typical symptoms of a clinical condition may be absent in these patients because of their neurological impairment. . Physicians may commit an error in diagnosis of a clinical condition as the symptoms and signs may be non-specific , or mistakes could occur during interpretation of medical images or histological appearances. Atypical decubital fibroplasia , which is a unique type of pressure sore displaying degenerative and regenerative features distinct from decubitus ulcer, may be misdiagnosed by pathologists and clinicians as a sarcoma. Epidemiology of medical errors showed that patients aged over 64 years have a greater risk of serious injury from adverse events than younger patients. . We believe that patients with spinal cord injury and spina bifida should be included in the high-risk group for possible occurrence of medical errors. We report an adult with spinal bifida and paraplegia, who presented with redness and minimal swelling in the loin. This was diagnosed initially as a pressure mark. Subsequently, a large renal calculus was extruded out of the loin swelling spontaneously.
Breatnach and associates  reported spontaneous extrusion of a staghorn calculus into the flank soft tissues, which was diagnosed by CT. The stone was demonstrable on CT as fragments of calciflc density appearing in the subcutaneous area. Breatnach and associates  stated that such a complication of renal calculus disease has not been reported previously. We failed to detect the calculus lying in the soft tissue of left loin in an abdominal X-ray (Figure 3), when this patient presented with redness and swelling in left loin. The ultrasound scan showed no abnormality in the kidney or perinephric region. Unfortunately, we did not evaluate the loin wall during this ultrasound examination. We attributed the swelling and redness to pressure caused by backrest of his chair, since SCI patients are highly susceptible to develop pressure sores. Instead of making a presumptive diagnosis of pressure mark, we should have persevered in our diagnostic efforts and should have reviewed the X-rays of abdomen, which were taken at different times. Obviously, there was an over reliance on the ultrasound scans. In hindsight, we realise that should have performed a CT of abdomen. Had we carried out a CT of abdomen, we would have detected the extruded stone lying in the subcutaneous tissue, and reached the correct diagnosis of spontaneous extrusion of renal calculus.
What should we do to reduce urological errors in the patients with spinal cord injury?
Some pertinent issues for minimising errors in spinal cord injury medicine are listed below.
♦ In SCI patients, renal calculi may be obscured by bowel gas shadows or by loaded colon in a plain X-ray of abdomen. Ultrasonography of kidneys and perinephric region may be unreliable in SCI patients who have marked spinal curvature. Even CT may be distorted by the patient's spinal and pelvic deformity and true axial images may not be obtained; this can make definition of soft tissue planes difficult.
♦ SCI patients are at increased risk for developing bladder cancer. When vesical malignancy occurs, SCI patients may not always present with the classical symptom of haematuria. Cystoscopy, when performed to screen for squamous cell cancer of the bladder in spinal cord injured patients with chronic or recurrent urinary tract infection, has been shown to result in an earlier stage at diagnosis and convey a survival advantage. 
♦ Histological interpretation of bladder biopsies in SCI patients may be difficult because of associated inflammatory changes. Immunohistochemistry of urinary bladder biopsy, in addition to routine haematoxylin & eosin staining, may be a useful diagnostic aid in selected SCI patients. Immunostaining with cytokeratin 14 may help in early detection of squamous metaplasia.
Immunostaining with Cytokeratin 20 is likely to facilitate the diagnosis of urothelial dysplasia. 
SCI patients require detailed and sometimes, repeated investigations as clinical symptoms may be vague and clinical signs could be completely non-specific. We missed an underlying renal pathology in a paraplegic patient, who presented twice with loin swelling and redness. There was a delay in making a correct diagnosis because of our total reliance on the report of ultrasound scans, which failed to detect the perinephric lesion in this paraplegic patient with spinal curvature. We learn from this case that ultrasonography of kidney and perinephric region may not be completely reliable in SCI patients, who have marked curvature of spine. A joint team approach by health professionals belonging to various medical disciplines, which is strengthened by frequent, informal and honest discussions of a patient's clinical condition, is likely to reduce urological errors in SCI patients and improve the quality of their care.
We thank the patient for providing written consent for publication of the clinical photograph.
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