Psoas abscess diagnosis, cases

Psoas abscess is a rare disease with a worldwide incidence of 12 cases per year. The majority of cases reported in the literature are unique cases or short series. This infection can be primary (hematogenous or lymphatic spread) or secondary to the direct expansion of an infection or inflammatory process from surrounding organs (vertebrae, spinal discs, gastrointestinal tract, genitourinary tract). Psoas abscess is secondary in 39 to 83% of cases in developed countries and primary in 99% of cases in developing countries.

The classic symptoms described were fever, flank pain, and limitation of hip movement. However, psoas abscess can present with non-specific signs, an insidious evolution, and rare features in the clinical examination. These characteristics can delay the diagnosis, the treatment, and the management of the situation, leading to complications such as septic shock and death.

In this paper, we report a case of sudden death due to psoas abscess revealed at autopsy and we discuss the cause and manner of death.


Psoas abscess, known as psoatis, is a pyogenic infection of the iliopsoas muscle. It was described for the first time by Mynterin in 1881.

this disease is increasing due to advances of imaging technologies. It affected more frequently men than women

This disease can be classified as primary and secondary according to the mechanism of pathogenesis. Most cases of iliopsoas abscesses are secondary, primary iliopsoas abscesses are rare. Primary psoas abscess affected generally children and adults below the age of 30 years. While secondary psoas abscess is more common in adults over the age of 50 years old. The majority of cases showed a single organism. However polymcrobial origin is more frequent in abscess due to urinary or gastrointestinal origin. The most common organism implicated in primary abscesses is S. Aureus.

Enteric organisms are responsible for the majority cases of secondary psoas bascess. For gastrointestinal or genitourinary origin, EC is implicated in the majority of cases. M. tuberculosis is generally implicated in secondary abscesses (skeletal, genitourinary, or gastrointestinal origin). There are reported cases of primary psoas abscesses with M. tuberculosis. The origin of this infection is presumably a hematological spread from the respiratory system.

The typical clinical presentation is fever, back pain, and limp. This triad is presented only in 30% of cases. As our patient, the majority of cases

frequency–match check-text__match–highlight active” data-match-id=”0″>presented with non-specific symptoms such as loss of appetite, nausea, vomiting, abdominal pain, weight loss, malaise, …

In the present case, the patient was presented with mental confusion and a temperature of 38. There were no complaints of abdominal or back pain.

The non-specific signs can delay the diagnosis, taking over 45 days in the majority of cases.

In the current case, the diagnosis of psoas abscess didn’t was evocated because of unspecific signs and because of a history of psychiatric illnesses.

An accurate collection of the signs, their evolution, and thorough a depth clinical examination are essential to evoke the diagnosis of psoas abscess.

In many cases, the psoas abscess can be the manifestation of Crohn’s disease or immunosuppressed status (HIV infection for example).

(Iliopsoas abscess e A review and update on the literature)

Laboratory investigations including blood count, erythrocyte sedimentation rate, and C reactive protein are useful to refer to the diagnosis and to confirm the presence of inflammatory process.

In our case, there was leukocytosis, the C reactive protein was normal.

Imaging (sample abdominal radiography, ultrasound, CT scan, MRI) is so useful not only to confirm the diagnosis but also to plan the treatment.

CT scan has a high sensibility and specificity (sensibility of 76,7%and specificity of 91,4 %) which can reach respectively 100% and 81% in severe forms of soft tissue infection. (phlegmonous) In this case, the CT scan wasn’t performed at antemortem either postmortem. Other authors prefer the NMR to CT because it differentiates soft tissues and shows more accurate changes of the structures surrounding the abscess site.

In our case, the diagnosis was established at autopsy examination. No forensic pathology books are describing the examination of psoas muscle at autopsy. Some authors did not recommend cutting into it to avoid damaging the abdominal and pelvic vessels. In the present case, a longitudinal incision was made along the entire length of the muscle showing a large amount of green pus reaching the muscles of the thigh. The origin of the abscess a renal infection confirmed by the anatomopathological exam which schowed chronic and acute interstitial nephritis. Microbiological analysis of the pus presented in the psoas muscle and the left kidney showed the presence of Echershia Coli. This organism is reported to be the one of the most common pathogen responsible for this secondary psoas abscess. The death was attributed to septic shock due to psoas abscess which was the direct spread of kidney infection (). We concluded this mechanism because of fever, SIB, obnubilation, pale. In the first line the treatment should involves antibiotic with spectrum that cover the S.Aureus and also many source of primary origin of the psoas abscess. The aspiration of the abscess has changed. In the past surgical drainage was the treatment of choice. Now, authors recommend to manage small abscess with antibiotic only. For abscesses that need drainage, aspiration via ultrasound or CT guidance is sufficient in the majaority of cases.

Awareness of this condition should be increased to make early diagnosis and treatment and to improve prognosis.


Psoas abscess is a rare pathology with poor symptoms and features in the clinical examination, which delay the diagnosis and a high mortality rates. Our case is an alert for physicians as psoas abscess is deadly, presenting with non-specfic and polymorphic signs and miming others diseases. That’s why it requires the understanding of this entity to make rapidly the diagnosis and to grant an early treatment.