Urine dipstick testing is frequently used in the ED. Which ONE of the following statements is INCORRECT?
Answer: A: The presence of nitrites on a urinary dipstick is highly specific (up to 95% specific) and not sensitive (45%) for diagnosis of a UTI. It detects bacteria that convert urinary nitrates to nitrites such as E. coli. Other bacteria such as Enterococcus, Pseudomonas and Acinetobacter are not detected by the nitrite test.
The accurate diagnosis of a UTI in a paediatric patient is important because a child with a UTI requires further investigations to exclude urinary tract abnormalities. A UTI can also lead to renal scarring that may cause significant morbidity later in life such as hypertension and renal impairment.
Many studies have lead to the conclusion that the bag urine sample is not suitable for detecting a UTI in a child. However, it may have some use in a child who is at a low to moderate risk for a UTI. If the bag specimen dipstick (+/− microscopy) is negative, then a UTI can be ruled out in such children. If it is positive then either a midstream clean catch or suprapubic aspiration or in-out catheter specimen should be taken. The bag specimen is also acceptable to use if only a chemical evaluation is required (glucose, ketones etc.).
Even when stored as per the manufacturer’s instructions a urine dipstick can lose its accuracy. There are many reasons why the test can be inaccurate and leaving the top off the container is one example. Many of the 10 tests on the stick are subject to interference by a variety of conditions or medications the patient is taking. Some of the examples are:
References:
Regarding haematuria, which ONE of the following statements is TRUE?
Answer: B: As little as 1 mL of blood in 1L of urine can cause gross haematuria. Both microscopic and gross haematuria are caused by similar disorders. The amount of blood in the urine does not always correlate to the severity or seriousness of the condition.
Causes of haematuria include:
While urothelial carcinoma is an important cause of macroscopic haematuria (especially in smokers), the most common cause of haematuria in males is BPH. Approximately 5–15% of patients with urolithiasis do not have haematuria. The presence of blood clots in the urine suggests a nonglomerular cause. Large clots suggest a bladder origin for the bleeding while stringy clots are more suggestive of a ureteric bleeding source. Brown muddy urine suggests a renal source of the bleeding.
Regarding Fourniers’s gangrene, which ONE of the following statements is TRUE?
Answer: C: Fournier’s gangrene is a polymicrobial, necrotizing infection of the perineum that predominately occurs in males. The infection originates from the skin, urethra or rectum. Risk factors include diabetes, immunosuppression, perianal trauma, perianal disease and UTIs. On examination, the patient may be extremely unwell with florid sepsis. There may be crepitus on palpation and areas of demarcated gangrene.
Fournier’s gangrene can progress extremely rapidly and can extend to involve the abdomen, back, thighs, genitalia and retroperitoenum.
The treatment involves fluid resuscitation, broad-spectrum intravenous (IV) antibiotics and prompt surgical debridement. Hyperbaric oxygen therapy can be considered as an adjunct to surgical debridement. Antibiotics should target anaerobic and gram-negative aerobic bacteria. An example of an empirical therapy regime is meropenem 1g IV 8-hourly and either lincomycin 600 mg IV 8-hourly or clindamycin 600 mg IV 8-hourly. This should continue until culture results are obtained.
Regarding diagnosis and treatment of genital infections, which ONE of the following statements is CORRECT?
Answer: A: Patient A most likely has gonococcal urethritis and should be treated with 500 mg IM ceftriazone but should also be covered with azithromycin 1g as a single oral dose to cover co-infection with Chlamydia. The presence of clue cells on a wet mount preparation of vaginal discharge is diagnostic of bacterial vaginosis caused by organisms such as Gardnerella vaginalis. Bacterial vaginosis causes grey/ white creamy discharge.
Trichomonas is a protozoa and is the most common non-viral sexually transmitted disease; trichomonads can be visualized on a wet mount. It causes vulvo-vaginitis, dysuria, itch and a yellow green thin offensive-smelling discharge. It is usually asymptomatic in males and is responsible for ~ 20% of cases of non-specific (non-gonococcal) urethritis. Trichomonas infection can be treated with metronidazole. Painful vesiculopustular lesions on an erythematous base on the perineum, which after several days ulcerate, is classical of herpes simplex infection. A first presentation of herpes can be treated with an antiviral such as acyclovir, valacyclovir or famcyclovir.
Patient D has prostatitis. At his age this may be sexually acquired or as a complication of bacterial lower UTI. The fluoroquinolone antibiotics have excellent prostatic penetration so ciprofloxacin or norfloxacin are the drugs of choice. Bactrim or trimethoprim are alternatives for bacterial prostatitis depending on culture results. Nitrofurantoin is not a good choice for prostatitis because it does not penetrate the prostate and it is bacteriostatic not bacteriocidal.
Reference:
Complications of a ureteric stent include all of the following EXCEPT:
Answer: D: Ureteric stents are well tolerated by most patients; however, patients with stents often present to the ED with complications. The most common complications of these devices seen in the ED include:
Ureteric stents cause a mild degree of hydronephrosis (not obstruction). Stents cause the ureter to dilate.
The upper urinary tract may remain obstructed despite insertion of a ureteric stent. This is particularly common with cases of extrinsic compression of the ureter where despite ureteric stenting the obstruction persists or returns. Ureteric stents do not cause low-grade fever.
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