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Thursday, August 1, 2013

presentation of nephrolithiasis

history

Patients with urinary calculi may report pain, infection, or hematuria. Small nonobstructing stones in the kidneys only occasionally cause symptoms. If present, symptoms are usually moderate and easily controlled. The passage of stones into the ureter with subsequent acute obstruction, proximal urinary tract dilation, and spasm is associated with classic renal colic.

Acute onset of severe flank pain radiating to the groin, gross or microscopic hematuria, nausea, and vomiting not associated with an acute abdomen are symptoms that most likely indicate renal colic caused by an acute ureteral or renal pelvic obstruction from a calculus. Renal colic pain rarely, if ever, occurs without obstruction.

Patients with large renal stones known as staghorn calculi (see the image below) are often relatively asymptomatic. The term "staghorn" refers to the presence of a branched kidney stone occupying the renal pelvis and at least one calyceal system. Such calculi usually manifest as infection and hematuria rather than as acute pain.
Asymptomatic bilateral obstruction, which is uncommon, manifests as symptoms of renal failure.

Important historical features are as follows:

Duration, characteristics, and location of pain
History of urinary calculi
Prior complications related to stone manipulation
Urinary tract infections
Loss of renal function
Family history of calculi
Solitary or transplanted kidney
Chemical composition of previously passed stones
Location and characteristics of pain
Most calculi originate within the kidney and proceed distally, creating various degrees of urinary obstruction as they become lodged in narrow areas, including the ureteropelvic junction, pelvic brim, and ureterovesical junction. Location and quality of pain are related to position of the stone within the urinary tract. Severity of pain is related to the degree of obstruction, presence of ureteral spasm, and presence of any associated infection.

Stones obstructing the ureteropelvic junction may present with mild-to-severe deep flank pain without radiation to the groin, due to distention of the renal capsule. Stones impacted within the ureter cause abrupt, severe, colicky pain in the flank and ipsilateral lower abdomen with radiation to the testicles or the vulvar area. Intense nausea, with or without vomiting, usually is present.

Pain from upper ureteral stones tends to radiate to the flank and lumbar areas. On the right side, this can be confused with cholecystitis or cholelithiasis; on the left, the differential diagnoses include acute pancreatitis, peptic ulcer disease, and gastritis.

Midureteral calculi cause pain that radiates anteriorly and caudally. This midureteral pain in particular can easily mimic appendicitis on the right or acute diverticulitis on the left.

Distal ureteral stones cause pain that tends to radiate into the groin or testicle in the male or labia majora in the female because the pain is referred from the ilioinguinal or genitofemoral nerves.

Stones lodged at the ureterovesical junction also may cause irritative voiding symptoms, such as urinary frequency and dysuria. If a stone is lodged in the intramural ureter, symptoms may appear similar to cystitis or urethritis. These symptoms include suprapubic pain, urinary frequency, urgency, dysuria, stranguria, pain at the tip of the penis, and sometimes various bowel symptoms, such as diarrhea and tenesmus. These symptoms can be confused with pelvic inflammatory disease, ovarian cyst rupture, or torsion and menstrual pain in women.

Calculi that have entered the bladder are usually asymptomatic and are passed relatively easily during urination. Rarely, a patient reports positional urinary retention (obstruction precipitated by standing, relieved by recumbency), which is due to the ball-valve effect of a large stone located at the bladder outlet.

Phases of acute renal colic attack
The actual pain attack tends to occur in somewhat predictable phases, with the pain reaching its peak in most patients within 2 hours of onset. The pain roughly follows the dermatomes of T-10 to S-4. The entire process typically lasts 3-18 hours. Renal colic has been described as having 3 clinical phases.

The first phase is the acute or onset phase.The typical attack starts early in the morning or at night, waking the patient from sleep. When it begins during the day, it tends to start slowly and insidiously. The pain is usually steady, increasingly severe, and continuous, sometimes punctuated by intermittent paroxysms of even more excruciating pain. The pain may increase to maximum intensity in as little as 30 minutes after onset or may take up to 6 hours or longer to peak. The typical patient reaches maximum pain 1-2 hours after the start of the renal colic attack.

The second phase is the constant phase. Once the pain reaches maximum intensity, it tends to remain constant until it is either treated or allowed to diminish spontaneously. The period of sustained maximal pain is called the constant phase of the renal colic attack. This phase usually lasts 1-4 hours but can persist longer than 12 hours in some cases. Most patients arrive in the ED during this phase of the attack.

The third phase is the abatement or relief phase.During this final phase, the pain diminishes fairly quickly, and patients finally feel relief. Relief can occur spontaneously at any time after the initial onset of the colic. Patients may fall asleep, especially if they have been administered strong analgesic medication. Upon awakening, the patient notices that the pain has disappeared. This final phase of the attack most commonly lasts 1.5-3 hours.

Other symptoms
Nausea and vomiting occur in at least 50% of patients with acute renal colic. Nausea is caused by the common innervation pathway of the renal pelvis, stomach, and intestines through the celiac axis and vagal nerve afferents. This is often compounded by the effects of narcotic analgesics, which often induce nausea and vomiting through a direct effect on gastrointestinal (GI) motility and an indirect effect on the chemoreceptor trigger zone in the medulla oblongata. Nonsteroidal anti-inflammatory drugs (NSAIDs) can often cause gastric irritation and GI upset.

The presence of a renal or ureteral calculus is not a guarantee that the patient does not have some other, unrelated medical problem causing the GI symptoms.

In some cases, a stone may pass before the definitive imaging procedure has been completed. In these cases, residual inflammation and edema still may cause some transient or diminishing obstruction and pain even without any stone being positively identified.

physical examination

The classic presentation for a patient with acute renal colic is the sudden onset of severe pain originating in the flank and radiating inferiorly and anteriorly. The pain is usually, but not always, associated with microscopic hematuria, nausea, and vomiting. Dramatic costovertebral angle tenderness is common; this pain can move to the upper or lower abdominal quadrant as a ureteral stone migrates distally. However, the rest of the examination findings are often unremarkable.

Abdominal examination usually is unremarkable. Bowel sounds may be hypoactive, a reflection of mild ileus, which is not uncommon in patients with severe, acute pain. Peritoneal signs are usually absent—an important consideration in distinguishing renal colic from other sources of flank or abdominal pain. Testicles may be painful but should not be very tender and should appear normal.

Unlike patients with an acute abdomen, who usually try to lie absolutely still, patients with renal colic tend to move constantly, seeking a more comfortable position. (However, patients with pyonephrosis also tend to remain motionless.) The classic patient with renal colic is writhing in pain, pacing about, and unable to lie still, in contrast to a patient with peritoneal irritation, who remains motionless to minimize discomfort.

Findings should correlate with the reports of pain, so that complicating factors (eg, urinary extravasation, abscess formation) can be detected. Beyond this, the specific location of tenderness does not always correlate with the exact location of the stone, although the calculus is often in the general area of maximum discomfort.

Approximately 85% of all patients with renal colic demonstrate at least microscopic hematuria, which means that 15% of all patients with kidney stones do not have hematuria. Lack of hematuria alone does not exclude the diagnosis of acute renal colic. Tachycardia and hypertension are relatively common in these cases, even in patients with no prior personal history of abnormal cardiac or blood pressure problems.

Fever is not part of the presentation of uncomplicated nephrolithiasis. The presence of pyuria, fever, leukocytosis, or bacteriuria suggests the possibility of a urinary infection and the potential for an infected obstructed renal unit or pyonephrosis. Such a condition is potentially life threatening and should be treated as a surgical emergency.

In patients older than 60 years presenting with severe abdominal pain and with no prior history of renal stones, look carefully for physical signs of abdominal aortic aneurysm (AAA)

complications

The morbidity of urinary tract calculi is primarily due to obstruction with its associated pain, although nonobstructing calculi can still produce considerable discomfort. Conversely, patients with obstructing calculi may be asymptomatic, which is the usual scenario in patients who experience loss of renal function due to chronic untreated obstruction. Stone-induced hematuria is frightening to the patient but is rarely dangerous by itself.

Serious complications of urinary tract stone disease include the following:

Abscess formation
Serious infection of the kidney that diminishes renal function
Urinary fistula formation
Ureteral scarring and stenosis
Ureteral perforation
Extravasation
Urosepsis
Renal loss due to long-standing obstruction
Infected hydronephrosis is the most deadly complication because the presence of infection adjacent to the highly vascular renal parenchyma places the patient at risk for rapidly progressive sepsis and death.

A ureteral stone associated with obstruction and upper UTI is a true urologic emergency. Complications include perinephric abscess, urosepsis, and death. Immediate involvement of the urologist is essential.

Calyceal rupture with perinephric urine extravasation due to high intracaliceal pressures occasionally is seen and usually is treated conservatively.

Complete ureteral obstruction may occur in patients with tightly impacted stones. This is best diagnosed via IVP and is not discernible on noncontrast CT scan. Patients with 2 healthy kidneys can tolerate several days of complete unilateral ureteral obstruction without long-term effects on the obstructed kidney. If a patient with complete obstruction is well hydrated and pain and vomiting are well controlled, the patient can be discharged from the ED with urologic follow-up within 1-2 days.

Ditulis Oleh : Unknown // 4:34 PM
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