About Me

My photo

I have completed bits of my EM training from India. Currently I am boarded with credentials from Christian Medical College, Vellore and also from the prestigious Royal College of Emergency Medicine, UK.  I am currently working in London as an A&E doctor, trying to appreciate the differences in the practise and culture of Emergency Medicine across different healthcare systems. I have always been an avid FOAMed supporter because FOAMed played an indispensable role during the days of my initial training. Through this blog, I aspire to disseminate knowledge and stay up to date with the EM literature. 

Monday, August 14, 2017

Overtesting and Misinterpretation - Urine Dip Pearls

Interpreting lab tests requires a considerable amount of knowledge and experience. One such test is urine dipstick which is often done in the ED to look for blood, evidence of infection, ketones etc. Since Emergency Departments across the globe are working under tremendous amount of time constraints, tests are now being done based of chief complaints (abdomen pain panel, pleuritic CP panel, Headache panel etc.) instead of clinical suspicion of a diagnosis. While this reduces the time to reach a conclusion, it makes evaluation and medical decision making very complex for a clinician. 

What are we supposed to do with a result that we never expected and we never wanted that to be sent at the first place? Positive hstroponin in a very low risk patient, positive d-dimer in a 16 year old who was hyperventilating or a positive urine dip for nitrites in an asymptomatic patient.

We know that we are overdiagnosing and over-treating UTIs. Rates of Misdiagnosis of UTI are up to 40%. Therefore, it is imperative to have have a pre-test probability before we order a urine dip or microscopy. And if it is already reported before you have actually seen the patient, be comfortable in disregarding the results if it does fit in the clinical scenario. 

Having a clinical questions can help. Ask yourself these two questions before you order any test (not just Urine Dip):

1.What are you looking for in the test. Is it Nitrites or blood or ketones? 
2. What is going to be your next step if the result is positive or negative?

Putting Urine Dip into a clinical context differentiates a clinician from other healthcare providers. Treating positive urine nitrites for UTI - Anyone can do that! 
But Medicine is not that simple!

Key points while interpreting a urine dip:

1. Bacteriuria does not equal UTI
If you send a culture on asymptomatic bacteriuria, you might get a positive culture but what if your patient never had any symptoms? The answer is - do not bother sending urine for testing in asymptomatic patients and do not treat asymptomatic bacteriuria (exceptions - Rx in pregnancy in those who are undergoing a urologic procedure). UTI is a clinical diagnosis, not a lab diagnosis. Colony counts and cultures are pointless without symptoms or clinical suspicion. 

2. Leucocyte Esterase (LE) is indicative of pyuria not UTI
Here is a list of things than can cause pyuria:
  • HIV
  • STDs
  • Appendicitis
  • Urolithiasis
  • Malignancy
  • Nephritis 
  • Dehydration
  • Diverticulitis
  • Indwelling catheters
Once again, results for LE needs to interpreted with a clinical context. In neutropenic patients, urine WBCs may be artificially low despite an infection

3. Nitrites 
Nitrates in the urine are converted to nitrites in the presence of Gram-negative bacteria such as E.coli. A positive nitrite test is a indirect marker of bacteriuria, not always a marker of infection (unless patient is symptomatic).

Nitrites are not produced by S. saprophyticus, Pseudomonas or enterococci, so a negative nitrites does NOT rule out UTI. Also watch your method of sample collection. Almost universally, urine is collected in a non-sterile fashion and thus interpretation should be always in the clinical context. Presence of Epithelial cells indicate a contaminated sample. 

Negative leukocyte esterase and nitrite negative almost rules out UTI

4. Elderly with Altered Mental State and UTI - Not always!
UTI is this scenario is pretty much a diagnosis of exclusion (Rule out Neuro and GI causes before labelling as UTI). Asymptomatic bacteriuria is extremely common in elderly. Rx them based on the history of symptoms and confirm your diagnose with a catheterised sample. When history is compromised due to cognitive issues - Look for fever, chills, elevated WCC, CRP, previous episodes of UTI to gauge your suspicion. If the look stable (normotensive, not tachycardia, no fever) then it is reasonable to hold Abx and convey this to the in-patient teams. 

5. He smells of urine, so we think it is a UTI
Anyone who is unkempt, not looked after well and urinates in his pants is going to smell bad. Bad smell is not always an indicator of Urine Infection. Do not prematurely close the diagnosis here. Smell can be affected by a number of factors such a your hydration status, concentration of urea, diet. Do a complete history and physical and then come to a conclusion. 

Take Home
  • Do not treat asymptomatic bacteriuria
  • Hold Abx if they look stable. Liaise with in-patient teams. 
  • Negative leukocyte esterase and nitrite negative makes UTI highly unlikely


Schulz L, Hoffman RJ, Pothof J, et al. Top ten myths regarding the diagnosis and treatment of urinary tract infections. J Emerg Med. 2016 Jul; 51(1): 25-30. 

Posted by:

     Lakshay Chanana
     Speciality Doctor
     Northwick Park Hospital
     Department of Emergency Medicine


Monday, August 7, 2017

Ulcerative Colitis - ED Management

Ulcerative colitis (UC) is a chronic inflammatory relapsing and remitting disease of the colon. The etiology is believed to be autoimmune with some genetic component. Peak incidence occurs in the second and third decades of life with characteristic symptom of bloody diarrhoea. The rectum is almost always involved in UC. 

Factors associated with an unfavourable prognosis include higher severity and extent of disease, a short interval between attacks, systemic symptoms, and onset of the disease after 60 years of age.

Clinical Presentation

Crampy abdominal pain, bloody diarrhea, and tenesmus are typical symptoms of UC. The disease is classified as mild, moderate, or severe depending on the clinical manifestations. 

Truelove and Witts criteria

Extra intestinal Manifestations 


ED diagnosis of ulcerative colitis rests on the following: 
History of abdominal cramps and diarrhea, mucoid stools, stool examination negative for ova and parasites, stool cultures negative for enteric pathogens, and confirmation of diagnosis by colonoscopy.


Mild to Moderate attacks
Most of these patients can be treated as outpatients. A combination of oral (2.4 grams/day) and topical mesalamine is used. Topical glucocorticoid enemas or Mesalazine enemas or suppositories (500 milligrams twice a day) are quite effective in distal proctosigmoiditis and have lower systemic side-effect profiles.

If topical therapy is unsuccessful, steroids (40-60md Prednisolone/day) are effective in inducing a remission in the majority of cases. Antidiarrheal agents are generally ineffective and may precipitate toxic megacolon.

Rx of UC based on severity of disease

Severe ulcerative colitis - Treat with IV steroids, fluids, correct electrolyte abnormalities, broad-spectrum antibiotics, melamine. IV cyclosporine (2-4 milligrams/kg per day) or infliximab (5 milligrams/kg) can be effective in fulminant colitis nonresponsive to IV steroids.

  • LGI Bleed (Most Common)
  • Toxic Megacolon The most feared complication of ulcerative colitis is the development of toxic megacolon. TM occurs as a result of extension of the inflammation beyond the submucosa, causing loss of contractility and dilated colon. Dilation of the colon is associated with a worsening of the clinical condition and development of fever and prostration. Patients with Toxic Megacolon appear toxic with distended, tender and tympanic abdomen. They typically present with fever, tachycardia and shock.

Plain radiography of the abdomen demonstrates a long, continuous segment of air-filled colon greater than 6 cm in diameter. Loss of colonic haustra represent bowel wall edema. Occasionally, features of toxic megacolon, such as leukocytosis, anaemia, dyselectrolytemia, hypoalbuminemia and peritonitis, can be masked in the patient taking corticosteroids.  

Antidiarrheal agents, hypokalemia, narcotics, cathartics, pregnancy, enemas, and recent colonoscopy have been implicated as precipitating factors in toxic megacolon. Rx with nasogastric suction, IV steroids, broad-spectrum antibiotics active against coliforms and anaerobes, and IV fluids. Get a surgical consultation ASAP.
  • Perforation
  • Bowel Obstruction (due to strictures)
  • Carcinoma Colon  (Advanced and prolonged disease)
  • Perirectal fistulas and abscesses 

Fulminant attacks of ulcerative colitis need hospitalization for fluid and electrolyte management and careful observation for the development of complications. Patients with complications such as GI Bleed, toxic megacolon, and bowel perforation should also be admitted. In addition to toxic megacolon, the indications for surgery include colonic perforation, massive lower gastrointestinal bleeding, suspicion of colon cancer, and disease that is refractory to medical therapy (large doses of steroids required to control the disease). 

Patients with mild to moderate disease can be discharged from the ED.  It is crucial to arrange close follow-up with gastroenterologist, and any adjustment in medical therapy should be discussed prior to discharge.

  1. https://clinicalgate.com/toxic-megacolon/
  2. Oxford Handbook of Clinical Medicine
  3. Tintinalli's textbook of EM - 8th Edition
  4. http://fromnewtoicu.com/blog/2016/12/28/toxic-megacolon-1
Posted by:

     Lakshay Chanana
     Speciality Doctor
     Northwick Park Hospital
     Department of Emergency Medicine