Recognising Haematuria Mimics?
You are a paramedic working as part of an ambulance crew on a 1200-0000 shift. After your first call of the shift, you have cleared from the hospital and finished restocking when control passes you a Category 3 call.
You are attending an 8-month-old girl with blood in her urine. The family are from out of area and has been unable to make their own way to a treatment centre, so 111 has passed the call to the ambulance service for a face-to-face assessment.
As you arrive on scene, you are met by the infant’s mother. She shows you to the living room, where 8-month-old Sophie crawls on the floor, playing with her toys. Sophie’s mother has noticed blood in her nappies twice this afternoon. She had phoned her GP for advice and was advised to call 111 as they are on holiday away from home.
Sophie appears happy and pain-free. There are no concerning signs when assessed using the Paediatric Assessment Triangle. You complete a set of observations:
Pulse: 118
SPO2: 99% on room air
Temperature:36.5
Respiratory Rate 30
Blood Glucose 5.6
Sophie’s mum then shows you a urine sample she got while waiting.
You look at the sample, slightly perplexed. It appears red, but when you perform a urine dip, it comes back clear, and Sophie seems so good in herself.
You wonder what could be causing this and what you should do next.
The presence of blood in children’s urine can be concerning for both families and clinicians, with a wide range of potential causes requiring assessment and management.
Alongside these causes, clinicians should be aware of some ‘mimics’ that can present with pink or red urine in a healthy individual and no blood identified on urinalysis.
Pharmacological Causes of ‘Haematuria’
Abnormal colouring of urine is a side effect of several medications, which occurs due to metabolites of these medications being readily excreted through the urinary system.
Particular medications to be aware of include sulfonamides (e.g. sulfadiazine, sulfasalazine, co-trimoxazole), nitrofurantoin, and senna.
Clinicians should be aware of any recent infections which were managed with antibiotics in the community or any over-the-counter management of constipation.
As some medications have an elimination time of over 24 hours, coloured urine may present for a day or so after treatment is finished, so parents may report that their child is recovering from a UTI but are concerned that there is blood in the urine despite finishing their antibiotics.
When a red urine colour is the only symptom, parents should be advised to finish the treatment course and follow up with their GP if other symptoms develop or if the abnormal colouring remains 48 hours after completion.
Dietary Causes of ‘Haematuria’
From the age of 6 months, parents are encouraged to introduce solid foods to their child’s diet. Over the following months, parents are advised to introduce various foods to the infant to encourage a balanced diet and build familiarity with various flavours and textures.
As with medications, several food metabolites can also be excreted in the urine, resulting in abnormal urine colour. Foods known to colour urine include blackberries, rhubarb, beetroot, and foods with large amounts of added colouring.
Beeturia, the process of passing red urine after consuming beetroot, occurs in approximately 14% of the population. The cause of this has been disputed, with some authors suggesting a genetic trait making individuals more susceptible and some suggesting this to be a symptom of allergy.
A trial conducted by Watson et al. noted a significant increase in beeturia in those with iron deficiency anaemia compared to a healthy cohort, suggesting that the mechanism for beeturia was associated with the rate of iron absorption. No studies have discussed beeturia as a diagnostic test for anaemia. Because of this, consider whether any other symptoms (fatigue, shortness of breath, pallor, etc) are present.
Isolated beeturia doesn’t warrant follow-up in an otherwise well infant. Because beeturia is a benign presentation, little research has been undertaken since the 1960s. Parents of children presenting with this should be reassured that it is a harmless presentation and should clear up within 48 hours.
Haematuria Mimics in Newborns
It is normal for a baby to pass very concentrated urine in the first few days of life. This concentrated urine can appear red/brown or pink in the nappy, which can alarm new parents. This colour change is due to the formation of urate crystals, which can be seen in approximately 22% of newborns and are completely harmless.
The presence of urate crystals for more than three days or in babies over one week old can be a sign of poor hydration, kidney, or metabolic disorders. These individuals should be taken to the hospital for further investigation by a paediatrician.
False menses can also be a haematuria mimic in newborn girls. This is due to the rapid decline in hormone levels which the infant had been exposed to in utero. This leads to blood-tinged discharge being passed from the vagina. It usually resolves within ten days of birth. As with urate crystals, this can be alarming for parents, but they should be reassured that this presentation is normal. With vaginal bleeding in a newborn, clinicians should also examine the external genitalia to check for signs of trauma that may arise from non-accidental injury.
Having gathered a thorough history, you establish that Sophie has not had any recent infections, is not taking any medications, and hasn’t been on any recently.
Sophie’s mother advises that they had been trying to introduce new food to her diet and that she had enjoyed beetroot for her dinner.
There are no signs of injury or illness, and you are happy that you have identified the likely source of the discoloured urine.
You advise Sophie’s parents that this is harmless but not to give more beetroot for the next couple of days. You signpost the family to the local urgent care centre and leave with Sophie’s parents, who are reassured and grateful for your advice.
References
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