JRSM >
Volume 96, Number 6 >
Pp. 294-295
Department of Surgery, Papworth NHS Trust
1 Department of Oncology, Charing Cross Hospital, London
2 Department of Medicine, Hinchingbrooke Hospital, UK
Correspondence to: Dr Tjun Tang, 56 Hulatt Road, Cambridge CB1 8TH, UK E-mail: tjun{at}doctors.net.uk
Among the haemorrhagic complications of warfarin therapy, retroperitoneal bleeding into the psoas and iliacus muscles can be particularly difficult to diagnose and manage. Three case histories follow.
CASE HISTORIES
Case 1
A fit man of 75 with a mechanical aortic valve and bilateral hip
replacements was admitted with right hip pain and leg weakness, fatigue,
nausea and vomiting. He was on warfarin for thromboprophylaxis. He had been
seen five days earlier for the hip pain in the orthopaedic clinic, when lower
limb reflexes and hip X-ray were found to be normal. Nonsteroidal
anti-inflammatories were prescribed and he was listed for hip revision. On
admission he was also oliguric but haemodynamically stable. The right hip was
flexed with decreased movement, and he reported paraesthesia over the anterior
thigh. Right flank and thigh bruising were evident. Haemoglobin was 7.2g/dL,
urea 34.5 mmol/L, creatinine 264 µmol/L, and international normalized ratio
(INR) 11. CT demonstrated an iliacus haematoma. The warfarin was stopped, he
was given vitamin K, and nephrotoxic drugs were discontinued. Renal function
recovered and warfarin was cautiously restarted. One month later he had a limp
and walked with a stick but no prosthetic valve complications were evident on
echocardiogram.
Case 2
A woman aged 73 was admitted after a fall, complaining of a painful and
weak left leg. She had had mechanical mitral and aortic replacements for
rheumatic heart disease and was taking warfarin. On examination she was in
atrial fibrillation, with mitral and tricuspid systolic murmurs and pulsatile
hepatomegaly. Left knee movements were weak, the left knee jerk was absent and
there was bruising of the left thigh. Haemoglobin was 8.1 g/dL. INR was > 8
and liver function tests were abnormal. Ultrasound revealed a left psoas
haematoma extending under the inguinal ligament into the groin; the liver
appeared normal. She received fresh frozen plasma and three units of packed
red cells. On discharge, left leg weakness persisted.
Case 3
A woman of 69 was admitted after five days of nausea, vomiting and
right-sided abdominal pain. She had had two aortic valve replacements for
bacterial endocarditis and was on warfarin. Her general practitioner had
recently prescribed ciprofloxacin for a urinary tract infection. On
examination she was tender in the lower abdomen and unable to extend the right
hip. Her haemoglobin was 8.2 g/dL and INR was > 8. Blood and fresh frozen
plasma were given. CT scan showed a right psoas and iliacus haematoma and mild
right hydronephrosis. On discharge she had anterior thigh paraesthesia but no
residual weakness.
COMMENT
The therapeutic index of warfarin is narrow,1 and anticoagulant control is easily deranged by drugs (such as antibiotics) and co-morbid factors such as renal or hepatic dysfunction. Frequent INR measurement is the best way to avoid haemorrhagic complications.
The predilection for bleeding into the retroperitoneal space has not been fully explained but a unique weakness of the vascular and connective tissue has been suggested.2 Patients report lower abdominal or hip pain radiating to the groin or anterior thigh. Bleeding into the psoas muscle causes spasm and hip flexion and, as it extends, flank or thigh bruising may appear. Femoral nerve compression reduces quadriceps power and causes loss of the knee jerk and paraesthesia in the area of cutaneous supply. CT scan is the investigation of choice3 but ultrasound is also sensitive and is more rapidly available. The cases reported here show how bleeding is readily misdiagnosed as primary hip disease or ‘acute abdomen’. Delay in diagnosis is potentially fatal because severe haemorrhage can supervene. Locally the haematoma may cause ureteric obstruction and acute renal failure, or femoral nerve compression.4
Surgical treatment of this condition has been
proposed5 but we
would favour conservative management, with correction of the anaemia and
coagulation according to current
guidelines.6 The
patients above would not have been fit for surgery without such initial
measures and all recovered to a reasonable functional level. Haemophilic
patients treated for similar compressive femoral neuropathy have been shown to
make a good recovery without
surgery.7 Current
options for treatment of coagulopathy are vitamin K or fresh frozen plasma
(FFP), but neither is ideal. FFP (dose 15 mL/kg) corrects clotting rapidly but
its effect is short-lived and it carries a risk of infection; vitamin K
(
2.5 mg) takes longer to work and can result in prolonged anticoagulant
resistance, leaving patients with artificial heart valves at risk of
thromboembolic events and valve failure (patients with ‘tilting
disc’ valves and especially aortic valves may be able to tolerate short
periods without
anticoagulation8).
Overanticoagulation due to warfarin can be reversed completely and immediately
by infusion of a complex concentrate of factors II, VII, IX and
X.9 In cases of
severe haemorrhage, for example in the retroperitoneum, this would be the
treatment of choice for most patients. The likelihood of haemorrhage increases
with intensity and duration of anticoagulation, so patients with mechanical
heart valves on life-long warfarin are very likely to encounter it. After a
retroperitoneal bleed, the prescribing doctor will probably seek stricter
control but may also settle for more ‘gentle’ anticoagulation.
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