Infections of the Urinary Tract

Question 1

What is pyelonephritis?

What is its most common cause?

Answer 1

• Infective inflammatory disease of the renal parenchyma, calyces and pelvis.
• Can either be acute, recurrent or chronic.
• Usually due to an infection ascending from the bladder.

Question 2

What are the common causative organisms of pyelonephritis?

Answer 2

• Usually caused by gram negative bacteria.
  
  • ​E. coli in 60-80% of cases
  • Klebsiella in ~20% of cases
  • Proteus mirablis in ~15% of cases
• Some other organisms can be implicated:
  
  • Pseudomonas species
  • Enterobacter species

Question 3

What are the risk factors for developing pyelonephritis?

Who commonly gets it?

Answer 3

• Can occur at any age. Peak incidence in women aged 15-20.
• Also common in people >65.
• Risk factors:
  
  • ​Urinary tract structural abnormalities
  • Recent instrumentation of the urethra
  • Pregnancy
  • Immunocompromisation

Question 4

Describe the presentation of pyelonephritis.

Answer 4

• LUTS
  
  • Frequency
  • Hesitancy
  • Dysuria
• Also symptoms of uper urinary infection:
  
  • Flank pain
  • Fever
  • Also possibly:
    
    • Rigors
    • Nausea and vomiting
• Patients look unwell
• Might elicit costovertebral angle tenderness when palpating the back.
• Suprapubic tenderness

Question 5

What investigations would you do if querying pyelonephritis?

Answer 5

• There is no set definitive diagnostic criteria. Diagnosis is made on clinical picture and investigation results.
• MSU (or catheter specimen if px has indwelling catheter) before starting ABx therapy.
• Dipstick may help in some situations (NOT useful in those patients with indwelling catheter or those >65).
• Bloods and culture, based on clinical picture if you consider it necessary (look at WBCs and CRP).

Question 6

Describe the treatment of pyelonephritis.

Answer 6

• Start empirical ABx treatment before the cultures and sensitivities are back.
• In Fife, guidelines for pyelonephritis:
  
  • start Co-trimoxazole in men and non-pregnant women.
  • If px has impaired renal function, start co-amoxiclav.
  • In a pregnant patient, use cefalexin.
• Important to prescribe analgesia.
• Think about hydration also.

Question 7

When should a patient with pyelonephritis be admitted?

Answer 7

• If the patient presents in primary care you should consider admission to hospital depending on clinical picture.
• For example:
  
  • septic patients
  • unable to have oral fluids
  • high risk of complications

Question 8

What are the complications of acute pyelonephritis?

Answer 8

• Sepsis
• Perinephric abscess
• Renal damage leading to either AKI or CKD
• In pregnancy - associated with premature labour
• Some patients get recurrent pyelonephritis – can lead to renal scarring and complications. If this is the case, you may wish to refer to urology to look for structural abnormalities or any longstanding damage from the recurrent pyelonephritis.

Question 9

What is urethritis?

What is the main cause?

Answer 9

• Inflammation of the urethra.
• Can occur in males and females; occurs mostly in males.
• Mostly due to infective cause - usually STI.

Question 10

What are the non-infective causes of urethritis?

Answer 10

• Trauma (especially catheterisation)
• Chemical irritation (such as spermicide or washing with something irritant)
• Urethral foreign body
• Urethral stricture

Question 11

What are the main symptoms of urethritis?

Answer 11

• Urethral discharge
• Dysuria
• Genital discomfort (penile)

Question 12

How is urethritis diagnosed?

Answer 12

• First stage in diagnosis is making a slide up for microscopy.
  
  • To do this: 5mm plastic loop or cotton-tip swab. Place it ~1cm into urethra. Rub it along glass slide.
• If gram-negative intracellular diplococci are seen, the likely cause of urethritis is gonorrhea.
• If it is NOT gonorrhea, it is called non-gonococcal urethritis (NGU).
  
  • We make a presumptive diagnosis of that – if we look at the microscope and see >5 polymononuclear polymorphs in 5 or more fields on the microscopy slide.

Question 13

What are the main causative organisms in non-gonococcal urethritis (NGU)?

Answer 13

• Chalmydia 11-50%
• Mycoplasma genitalium 6-50%
• To a lesser extent
  
  • Uroplasma
  • Trichomonas
  • Adenovirus
  • HSV

Question 14

How is urethritis investigated if gonorrhea is the likely causative organism?

Answer 14

• If we think urethritis is caused by gonorrhea, want to do NAAT and first-pass urine.
• Think about any other sites of sexual exposure – pharynx and rectum.
• Also want to take swabs for culture because we want to grow the gonorrhea to see what it is sensitive to (especially with increasing ABx resistance).

Question 15

How is urethritis investigated if gonorrhea is NOT the likely causative organism?

Answer 15

• If we think urethritis is due to another STI (not gonorrhea), should do NAAT which tests for chlamydia (look at relevant sites and think about where we need to test from).
• May also want to do other relevant tests: obtain MSU If ?UTI.
• Anything else you think is clinically relevant.

Question 16

How is urethritis treated if due to gonorrhea?

Answer 16

IM Ceftriaxone 1g

Question 17

How is urethritis treated if NOT due to gonorrhea?

Answer 17

Doxycycline 100mg BD for 7 days

Question 18

What advice should a patient with urethritis due to an STI be offered?

Answer 18

• Avoid all sexual contact.
• If due to gonorrhea, patient should abstain until they have had a negative test of cure (usually at 14 days).
• If a particular cause is not found, the patient should avoid sex while treatment is continuing and while symptoms persist.
• If, despite treatment, symptoms still persist, encourage the patient to re-present.

Question 19

What are the complications of urethritis?

Answer 19

• Complications depend on the cause of the urethritis. They include:
  
  • Epididymitis
  • Sexually-acquired reactive arthritis
  • In women, PID because this is a potentially ascending infection

Question 20

What is epididymo-orchitis?

Answer 20

A clinical syndrome characterised by pain and swelling of the epididymus and the testes.

Question 21

What are the causes of epididymo-orchitis?

Answer 21

• Usually caused by infection:
  
  • Either from an ascending STI such as chlamydia, gonorrhea or mycoplasma genitalium.
  • Or, from a coliform enteric bacterium, either acquired in MSM during insertive anal sex or by UTIs (coliforms such as E.coli, Klebsiella or proteus).
• When associated with a UTI, it is usually due to urinary tract structural abnormality such as urinary obstruction or urethral instrumentation (such as catheterisation).
• Other microorganisms can also cause epididymo-orchitis. Other infective organisms include:
  
  • Mumps (epididymo-orchitis appears in the background of ~20% of men with mumps)
  • Leprosy
• There are several non-infective causes:
  
  • Bechet’s disease
  • Sarcoidosis
  • Side effect of Amiodarone
  • Due to granulomatous orchitis

Question 22

What are the clinical features of epididymo-orchitis?

Answer 22

• Typical presentation is unilateral scrotal pain and swelling.
• May have pyrexia.
• There may be urethritis if it is sexually-acquired.
• There may be UTI symptoms.
• There may be erythema or oedema.

Question 23

How is epididymo-orchitis investigated?

Answer 23

• Mainstay of testing is gram stain of urethral smear. This is even if there are no urethral symptoms. Looking for any micro-organisms.
• Might look for STIs by NAAT and first pass urine.
• May look for UTIs by taking MSU.
• Might do bloods (elevated CRP or ESR would support a diagnosis of epididymo-orchitis).
• Also think about sexual risk – offer other sexual health screening as you see fit based on the sexual hx.
• Think also about testing for the other possible causes – if mumps, IgM and IgG serology.
• USS may have a role if acute onset; there are lots of other important causes of testicular and pain and swelling which you DO NOT WANT TO MISS.
  
  • For example, testicular torsion (acute surgical emergency).

Question 24

Describe the treatment of epididymo-orchitis.

Answer 24

• You can start empirical treatment depending on what you think the cause is:
  
  • If you think it is likely due to a sexually-transmitted organism, first-line is doxycycline 100mg BD for 14 days, PLUS ceftriaxone 500mg IM as a one off.
  • If you think gonorrhea is a likely cause, you may also want to add Azithromycin 1g stat.
  • If you think it may be due to an enteric organism, you can also think about ofloxacin.
• When you start Abx, improvement should be seen within ~3 days.
• Incredibly uncomfortable – use NSAIDs (unless contraindicated) and perhaps scrotal support.
• Also advise to avoid sex while Abx therapy is going on.
• If no improvement with ABx you may need to rethink the diagnosis and perhaps refer to urology to consider other causes of testicular pain and swelling – testicular abscess, tumour etc.

Question 25

What are the complications of epididymo-orchitis?

Answer 25

• Up to 10% develop a hydrocele.
• 3% may develop an abscess.
• Up to 15% develop chronic epididymo-orchitis.
• ?Infertility - thought to be linked but this is inconclusive and poorly understood.