I picked up the metal chart belonging to bed 15. The patient board merely said, “72-year-old man — extremity.” I could already hear myself calling our surgeons for the standard fare in our emergency department: the diabetic foot ulcer. I never anticipated calling them with a more ominous consult.
I found an expressionless man who appeared older than his stated age lying supine with the sheet pulled up. The patient and his daughter pointed to his right leg, claiming he had had pain for two months. My suspicion for acuity fell. Undoubtedly, a narrowed joint space or mechanical fall was starting to catch up to him. The daughter volunteered that the left lower extremity had bothered him but had improved. They denied any history of trauma. I became mildly annoyed, and asked why they came in that day, enduring our crowded waiting room. The daughter claimed the pain was now so intolerable her father could not walk. The thin man chimed in, “Es un ardor.”
“It is a burning pain,” his daughter said.
I ran through his list of comorbidities: diabetes, hypertension, and colitis. Nothing out of the ordinary. His medication list included several prescriptions from his hometown in Mexico. A review of systems revealed subjective fevers. I glanced at our documented temperature: 98.4. The remaining vital signs were normal. The patient lay comfortably in bed. I pulled back the sheet. Both lower extremities were normal. Intact skin, appropriate muscle tone, neutral alignment, and no edema. Dorsalis pedis pulses were strong and symmetric. The entire left lower extremity was nontender to palpation while passive range of motion of the hip and knee elicited no complaints.
I moved to the right lower extremity. I applied gentle pressure to the lateral and medial malleoli, the tibia and fibula, the gastrocnemius, the patella, and the joint line. So far, so good. I could range the knee without difficulty. As I palpated the femur and quadriceps, I heard a groan of pain. The entire right leg seemed to bother him. Ascending to the hip, I could-invoke no pain with flexion, extension, or internal and external rotation. To be sure, I applied an axial load, and remained convinced his hip joint was normal. On to the final test, one that would determine my disposition for this patient. I wanted to see him walk. Disconnected from the monitor, the daughter and I helped her father to his feet. He bore weight without difficulty. In fact, he walked better than some of our patients half his age. Back in the doctor's room, I presented the case to my attending. Although at a loss for a diagnosis, nothing fit my differential, and “discharge home” was written all over my face. My attending promised to examine the patient.
A few minutes later, he returned and asked me to order a CT scan of the patient's abdomen and pelvis. Huh? I stared at him blankly. He brought me to the bedside. His exam of the right lower extremity mirrored mine, although he localized the pain to the anterior thigh along the distribution of the femoral nerve. We then traced the course of the nerve proximally. He guided me just superior to the inguinal ligament where I felt an area of fullness not palpated on the left. This was the iliacus component of the powerful iliopsoas muscle. Something was affecting this muscle, and our clue had been pain from the compressed femoral nerve running along it. We progressed superiorly to the right lower quadrant. Palpation here produced a grimace of pain on the patient's face. I had missed this silent but visible expression of tenderness on my initial examination. My attending diagnosed the patient with an iliopsoas abscess.
The CT revealed a fluid collection of the iliopsoas muscle and an adjacent 15 mm perforated appendix as the source. We administered antibiotics, and admitted the patient to the general surgery service. He underwent CT-guided drainage of the abscess with placement of a pigtail drain. The patient did well, was discharged home, and was able to ambulate without pain in his right lower extremity.
The Absent Presentation
By Ravi Morchi, MD
“What do you have?” I asked.
“A 72-year-old gentleman with diabetes, hypertension, and two months of leg pain.”
She went on with a detailed history, obtained mostly through the patient's daughter. “His exam is unremarkable other than tenderness in his thigh. He ambulates pretty well.”
The patient doesn't speak English, and his daughter's interpretation is all we have. Filtered through her mind, the daughter's history may mislead us. We have to be mindful of what the body is saying.
His breathing is unlabored, and his pulse is neither bounding nor rapid. There is no distress to it. His point of maximal impulse is similarly calm and quiet. Rather than tenderness to the quadriceps muscles themselves, when you pinch the skin of his anterior thigh and lift it off the muscle below, you can isolate a sensation of hyperesthesia or even allodynia. This is a neuropathic problem. Over the anterior thigh, it must be the femoral nerve.
Palpating proximally to the fossa ovalis, I find no femoral lymphadenopathy and a normal femoral artery pulse. Just millimeters north of this runs a thickened, nontender inguinal ligament. And cephalad of this, the iliacus and psoas muscles diverge where the femoral nerve surfaces. He has tenderness, fullness, and guarding here.
Reflexive contraction of his abdominal muscles over the same locale and at the same depth every time, it is not distractable. Involuntary guarding from a parietal peritoneum antagonistic to being compressed against an inflamed iliopsoas below.
Oddly, he doesn't have the standard position: flexed at the hip and knee with resistance to passive range of motion, the favored presentation of an abscessed iliopsoas muscle.
This sign is absent in our patient. Maybe he has a rare sarcoma of the muscle itself and so no spasm? Whether zebra or horse, we have to image it to know. I head back to tell our resident.
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