ANSWER 10
This woman has the symptoms and signs of acute pyelonephritis. Acute pyelonephritis is
much more common in women than men, and occurs due to ascent of bacteria up the urin-
ary tract. Pregnancy, diabetes mellitus, immunosuppression and structurally abnormal uri-
nary tracts increase the likelihood of ascending infection.
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Pyelonephritis causes loin pain which can be unilateral or bilateral. The differential
diagnoses of loin pain include obstructive uropathy, renal infarction, renal cell
carcinoma, renal papillary necrosis, renal calculi, glomerulonephritis, polycystic
kidney disease, medullary sponge kidney and loin-pain haematuria syndrome.Differential diagnosisFever may be as high as 40°C with associated systemic symptoms of anorexia, nausea and
vomiting. Some patients may have preceding symptoms of cystitis (dysuria, urinary fre-
quency, urgency and haematuria), but these lower urinary tract symptoms do not always
occur in patients with acute pyelonephritis. Many patients will give a history of cystitis
within the previous 6 months. Elderly patients with pyelonephritis may present with non-
specific symptoms and confusion. Pyelonephritis may also mimic other conditions such as
acute appendicitis, acute cholecystitis, acute pancreatitis and lower lobe pneumonia. There
is usually marked tenderness over the kidneys both posteriorly and anteriorly. Severe
untreated infection may lead on to septic shock.
The raised white cell count and CRP are consistent with an acute bacterial infection.
Microscopic haematuria, proteinuria and leucocytes in the urine occur because of inflam-
mation in the urinary tract. The presence of bacteria in the urine is confirmed by the
reduction of nitrates to nitrites.
This woman should be admitted. Blood and urine cultures should be taken, and she should
be commenced on intravenous fluids and antibiotics, until the organism is identified, and
then an oral antibiotic to which the organism is sensitive can be used. Initial therapy
could be with gentamicin and ampicillin, or ciprofloxacin. She should have a renal ultra-
sound scan to exclude any evidence of obstruction. In patients with obstructive uropathy,
infection may lead to a pyonephrosis with severe loin pain, fever, septic shock and renal
failure. If there is evidence of a hydronephrosis in the context of urinary sepsis, a nephro-
stomy should be inserted urgently to prevent these complications.
Patients with an uncomplicated renal infection should be treated with a 2-week course of
antibiotics, and then have a repeat culture 10–14 days after treatment has finished to con-
firm eradication of infection. In patients with infection complicated by stones, or renal
scarring, a 6-week course of treatment should be given.
- Acute pyelonephritis may present with or without preceding lower urinary tract
symptoms. - Renal ultrasound should be performed within 24 h of admission to exclude urinary tract
obstruction. - Antibiotics should be continued for at least 2 weeks in cases of acute pyelonephritis to
minimize the risk of relapse.