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Postpartal sacral fracture without osteoporosis
Joint Bone Spine 2001 ; 68 : 71-3 © 2001 Éditions scientifiques et médicales Elsevier SAS. All rights reserved S1297319X01002627/SCO
CASE REPORT
Postpartal sacral fracture without osteoporosis Mickaël Rousière, André Kahan, Chantal Job-Deslandre* Service de rhumatologie A, hôpital Cochin, 27, rue du Faubourg-Saint-Jacques, 75014 Paris, France (Submitted for publication May 15, 2000; accepted in revised form October 24, 2000)
Summary – Stress fractures of the sacrum during pregnancy or the postpartum seem uncommon. We report a new case of nontrauma-related postpartal sacral fracture. Only four similar cases have been reported to date. The patient was 36 years of age and her fracture was diagnosed four weeks after her first delivery. Vitamin D levels were low, but there was no osteomalacia. Other standard laboratory tests were normal, as were absorptiometry measurements at the lumbar spine and femur. Rheumatologists should consider sacral fracture in pregnant or nursing patients with buttock pain. Magnetic resonance imaging is the diagnostic investigation of choice. Joint Bone Spine 2001 ; 68 : 71-3. © 2001 Éditions scientifiques et médicales Elsevier SAS fracture / nursing / osteoporosis / pregnancy / sacrum
Pain in the low back and sacrum is common during pregnancy and the postpartum [1] and usually due to mechanical lesions of the pelvic soft tissues or ligaments. Infections of the lumbar spine or sacroiliac joint and stress fractures of the pelvis account for a small number of cases. We report a new case of stress fracture of the sacrum during the postpartum in a woman without pregnancy-related osteoporosis. CASE-REPORT A 36-year-old woman sought medical advice for severe mechanical pain in her left buttock that had started 38 days after vaginal delivery of a 3460 g baby. The pain quickly became so severe that she had to use a crutch to walk. There was no history of trauma. The patient was primiparous, was breast-feeding her baby, and had a dietary intake of calcium of only 500 mg per day during her pregnancy. She denied pelvic or spinal pain during * Correspondence and reprints.
the pregnancy and had a negative personal and family history for significant medical or surgical problems. In particular, there was no history of osteoporosis. Her body temperature was normal. The left sacroiliac joint was excruciatingly painful to the slightest mobilization. Plain radiographs of the pelvis and thoracolumbar spine showed no osteoarticular abnormalities. Magnetic resonance imaging of the pelvis demonstrated a vertical fracture through the upper part of the left sacral wing (figure 1). Findings were normal for blood cells counts, tests for inflammation, serum and urinary levels of calcium and phosphate, renal function, thyroid function, and parathyroid function. Serum 25(OH)D3 was severely decreased (1.4 ng/L; normal > 10), and elevations were found in markers for bone turnover (osteocalcin and urinary excretion of deoxypyridinoline/ creatinine). There was no laboratory test evidence of osteomalacia (table I). Bone absorptiometry measurements obtained five months after the delivery showed normal bone mineral density values at the spine and femur (1.032 g/cm2
72
M. Rousière et al.
Figure 1. Magnetic resonance imaging of the pelvis (T2-weighted sequence, coronal sections): fracture through the left sacral wing.
yielding a T-score of + 0.3% and 0.719 g/cm2 yielding a T-score of + 0%, respectively). Management consisted in rest, analgesics, and supplements of calcium (1 g/day) and vitamin D (2 000 IU/ day). The clinical outcome was favorable within three months. There was no recurrence during follow-up, which was one year as of this writing. DISCUSSION Sacral fractures are rare during pregnancy and the postpartum: only six cases have been reported in the worldwide literature, four fatigue fractures and two insufficiency fractures. However, the prevalence is probably underestimated since lumbosacral pain is common
during delivery and usually resolves during the postpartal period, so that imaging studies are rarely performed to investigate this symptom. One cause of nontrauma-related fracture during pregnancy and the postpartum is osteomalacia due to vitamin D deficiency. Our patient had severe vitamin D deficiency. However, her serum levels of calcium, phosphate, and alkaline phosphatase were normal (in the absence of renal failure), making osteomalacia highly unlikely. A fracture can be the inaugural manifestation of osteoporosis of pregnancy or the postpartum. Fewer than 100 cases of this condition have been reported. Many of these patients were primagravidas who developed osteoporosis during the last trimester of pregnancy or shortly after delivery [2-4]. Vertebral fractures and fractures of the femoral neck, pelvis, ribs, and wrists have been reported. Absorptiometry findings have been variable, perhaps because of variations in the time between the diagnosis of the fracture and the absorptiometry study [5]. Osteoporosis or osteopenia was a common finding at the lumbar spine and femur: the mean Z-score decrease was 2.7% (0.02 to 4.6% at the lumbar spine and 1.5 to 4.6% at the femur). Few cases of sacral fracture revealing pregnancy-related osteoporosis have been published. In the case described by Breuil et al. [6], a fracture of the left sacral wing occurred at the seventh month of pregnancy in a patient on isocoagulant doses of heparin since the beginning of her pregnancy. Risk factors for bone loss in this patient were vitamin D deficiency and a smoking history of ten pack-years in the recent past [6]. In our patient, absorptiometry measurements showed no evidence of osteoporosis. Stress fractures can occur at the sacrum. In 1987, Lourie [7] described spontaneous osteoporotic frac-
Table I. Markers for calcium and phosphate metabolism. Markers Total serum calcium Ionized serum calcium Serum phosphate Serum alkaline phosphatase Serum albumin Serum creatinine 25(OH) vitamin D Serum parathyroid hormone Serum osteocalcin Urinary deoxypyridinoline/creatinine
Values at presentation 2.53 1.14 106 39 70 1.4 32 41 10.8
Values after 3 months
Normal values
2.44 1.27 1.05 ND ND 83 14 ND ND ND
2.25–2.55 mmol/L 1.19–1.30 mmol/L 0.8–1.55 mmol/L 40–135 UI/L 50–115 µmol/L 10–40 ng/mL 10–65 pg/mL 4–9 ng/mL 3.6–8.6 nmol/mmol
Postpartal sacral fracture without osteoporosis
tures of the sacrum in elderly patients. Risk factors for stress fractures of the sacrum are osteoporosis (usually due to menopause or glucocorticoid therapy) and sporting activities [8]. Only two well-documented cases in pregnant women have been reported [9, 10]. One of these patients [9] started experiencing pain at the seventh month of pregnancy. She gained 22 kg during her pregnancy. The pain became worse after delivery, which was by cesarean section. Imaging studies disclosed fractures through both sacral wings. No risk factors for osteoporosis were identified, and bone mineral density was normal at the lumbar spine and femur [9]. In the other case [10], the pain started at the end of the delivery, which lasted only 20 minutes. Computed tomography demonstrated a fracture through the right sacral wing. Absorptiometry findings were normal at the spine and femur [10]. Two other cases of pregnancyrelated sacral fracture have been described as stress fractures, although absorptiometry was not performed [11, 12]. One was a patient who performed aerobics during her pregnancy to limit her excessive weight gain (20 kg). The fracture occurred after an uneventful cesarean section [11]. The other patient had a fracture through the right sacral wing revealed by buttock pain during the last trimester of pregnancy [12]. Risk factors for sacral fracture during pregnancy and the postpartum probably include vaginal delivery of a high-birthweight infant, increased lumbar lordosis, excessive weight gain, and rapid vaginal delivery [13]. Fatigue fracture is the most likely diagnosis in our patient. The delayed onset of pain (38th postpartal day) coincided with resumption of strenuous physical activity, as in a previous case [9]. In all reported cases, the diagnosis was confirmed by magnetic resonance imaging and/or computed tomography. Computed tomography is both sensitive and specific and seems to be the investigation of choice for evaluating bone structure. However, computed tomography is not recommended during pregnancy. Magnetic resonance imaging has similar sensitivity and can be performed throughout pregnancy [14]. The fracture is seen as a low-signal line surrounded by an area of less severely decreased signal denoting edema of the surrounding bone. On T2-weighted sequences, the fracture line is seen as a moderate low signal or isosignal within the high signal produced by the edema. Our case illustrates the favor-
73
able outcome of these fractures. Because there is no risk of complications, medical treatment is sufficient. Analgesics and bed rest until resolution of the pain should be recommended. The pain resolves within three to eight weeks [8]. In conclusion, pregnancy-related sacral fractures are uncommon but should be considered by rheumatologists in the differential diagnosis of buttock pain during pregnancy or the early postpartal period. Magnetic resonance imaging usually provides the diagnosis. We believe that increased awareness of pregnancy-related sacral fractures through the publication of case reports will increase the number of diagnosed cases. REFERENCES 1 Heckman JD, Sassard R. Musculo-skeletal considerations in pregnancy. J Bone Joint Surg 1994 ; 76A : 1720-30. 2 Blanch J, Pacifici R, Chines A. Pregnancy-associated osteoporosis: report of two cases with long-term bone density follow-up. Br J Rheumatol 1994 ; 33 : 269-72. 3 Khovidhunkit W, Epstein S. Osteoporosis in pregnancy. Osteoporos Int 1996 ; 6 : 345-54. 4 Vandecandelaere M, Cortet B, Flipo RM, Duquesnoy B, Delcambre B. Ostéoporose de la grossesse : à propos de deux observations. Rev Med Interne 1997 ; 18 : 571-4. 5 Koeger AC, Oberlin F. Pathological phosphorus and calcium metabolism during pregnancy and breast-feeding. Rev Med Interne 1997 ; 18 : 546-52. 6 Breuil V, Brocq O, Euller-Ziegler L. Insufficiency fracture of the sacrum revealing a pregnancy-associated osteoporosis. Ann Rheum Dis 1997 ; 56 : 278-9. 7 Lourie H. Spontaneous osteoporotic fracture of the sacrum. An unrecognized syndrome of the elderly. JAMA 1982 ; 248 : 715-7. 8 Finiels H, Finiels PJ, Jacquot JM, Strubel D. Fractures of the sacrum caused by bone insufficiency. Meta-analysis of 508 cases. Presse Med 1997 ; 26 : 1568-73. 9 Schmid L, Pfirrman C, Hess T, Schlumpf U. Bilateral fracture of the sacrum associated with pregnancy. A case report. Osteoporos Int 1999 ; 10 : 91-3. 10 Sibilia J, Javier RM, Werle C, Kuntz JL. Fracture of the sacrum in the absence of osteoporosis of pregnancy: a rare skeletal complication of the post partum. Br J Obstet Gynaecol 1999 ; 106 : 1096-7. 11 Hoang TA, Nguyen TH, Daffner RH, Lupetin AR, Deeb ZL. Case report 491: stress fracture of the right sacrum. Skeletal Radiol 1988 ; 17 : 364-7. 12 Thienpont E, Simon JP, Fabry G. Sacral stress fracture during pregnancy. A case report. Acta Orthop Scand 1999 ; 70 : 525-6. 13 Leroux JL, Denat B, Thomas E, Blotman F, Bonnel F. Sacral insufficiency fractures presenting as acute low-back pain. Biomechanical aspects. Spine 1993 ; 18 : 2502-6. 14 Brahme SK, Cervilla V, Vint V, Cooper K, Kortman K, Resnick D. Magnetic resonance appearance of sacral insufficiency fractures. Skeletal Radiol 1990 ; 19 : 489-93.
CASE REPORT
Postpartal sacral fracture without osteoporosis Mickaël Rousière, André Kahan, Chantal Job-Deslandre* Service de rhumatologie A, hôpital Cochin, 27, rue du Faubourg-Saint-Jacques, 75014 Paris, France (Submitted for publication May 15, 2000; accepted in revised form October 24, 2000)
Summary – Stress fractures of the sacrum during pregnancy or the postpartum seem uncommon. We report a new case of nontrauma-related postpartal sacral fracture. Only four similar cases have been reported to date. The patient was 36 years of age and her fracture was diagnosed four weeks after her first delivery. Vitamin D levels were low, but there was no osteomalacia. Other standard laboratory tests were normal, as were absorptiometry measurements at the lumbar spine and femur. Rheumatologists should consider sacral fracture in pregnant or nursing patients with buttock pain. Magnetic resonance imaging is the diagnostic investigation of choice. Joint Bone Spine 2001 ; 68 : 71-3. © 2001 Éditions scientifiques et médicales Elsevier SAS fracture / nursing / osteoporosis / pregnancy / sacrum
Pain in the low back and sacrum is common during pregnancy and the postpartum [1] and usually due to mechanical lesions of the pelvic soft tissues or ligaments. Infections of the lumbar spine or sacroiliac joint and stress fractures of the pelvis account for a small number of cases. We report a new case of stress fracture of the sacrum during the postpartum in a woman without pregnancy-related osteoporosis. CASE-REPORT A 36-year-old woman sought medical advice for severe mechanical pain in her left buttock that had started 38 days after vaginal delivery of a 3460 g baby. The pain quickly became so severe that she had to use a crutch to walk. There was no history of trauma. The patient was primiparous, was breast-feeding her baby, and had a dietary intake of calcium of only 500 mg per day during her pregnancy. She denied pelvic or spinal pain during * Correspondence and reprints.
the pregnancy and had a negative personal and family history for significant medical or surgical problems. In particular, there was no history of osteoporosis. Her body temperature was normal. The left sacroiliac joint was excruciatingly painful to the slightest mobilization. Plain radiographs of the pelvis and thoracolumbar spine showed no osteoarticular abnormalities. Magnetic resonance imaging of the pelvis demonstrated a vertical fracture through the upper part of the left sacral wing (figure 1). Findings were normal for blood cells counts, tests for inflammation, serum and urinary levels of calcium and phosphate, renal function, thyroid function, and parathyroid function. Serum 25(OH)D3 was severely decreased (1.4 ng/L; normal > 10), and elevations were found in markers for bone turnover (osteocalcin and urinary excretion of deoxypyridinoline/ creatinine). There was no laboratory test evidence of osteomalacia (table I). Bone absorptiometry measurements obtained five months after the delivery showed normal bone mineral density values at the spine and femur (1.032 g/cm2
72
M. Rousière et al.
Figure 1. Magnetic resonance imaging of the pelvis (T2-weighted sequence, coronal sections): fracture through the left sacral wing.
yielding a T-score of + 0.3% and 0.719 g/cm2 yielding a T-score of + 0%, respectively). Management consisted in rest, analgesics, and supplements of calcium (1 g/day) and vitamin D (2 000 IU/ day). The clinical outcome was favorable within three months. There was no recurrence during follow-up, which was one year as of this writing. DISCUSSION Sacral fractures are rare during pregnancy and the postpartum: only six cases have been reported in the worldwide literature, four fatigue fractures and two insufficiency fractures. However, the prevalence is probably underestimated since lumbosacral pain is common
during delivery and usually resolves during the postpartal period, so that imaging studies are rarely performed to investigate this symptom. One cause of nontrauma-related fracture during pregnancy and the postpartum is osteomalacia due to vitamin D deficiency. Our patient had severe vitamin D deficiency. However, her serum levels of calcium, phosphate, and alkaline phosphatase were normal (in the absence of renal failure), making osteomalacia highly unlikely. A fracture can be the inaugural manifestation of osteoporosis of pregnancy or the postpartum. Fewer than 100 cases of this condition have been reported. Many of these patients were primagravidas who developed osteoporosis during the last trimester of pregnancy or shortly after delivery [2-4]. Vertebral fractures and fractures of the femoral neck, pelvis, ribs, and wrists have been reported. Absorptiometry findings have been variable, perhaps because of variations in the time between the diagnosis of the fracture and the absorptiometry study [5]. Osteoporosis or osteopenia was a common finding at the lumbar spine and femur: the mean Z-score decrease was 2.7% (0.02 to 4.6% at the lumbar spine and 1.5 to 4.6% at the femur). Few cases of sacral fracture revealing pregnancy-related osteoporosis have been published. In the case described by Breuil et al. [6], a fracture of the left sacral wing occurred at the seventh month of pregnancy in a patient on isocoagulant doses of heparin since the beginning of her pregnancy. Risk factors for bone loss in this patient were vitamin D deficiency and a smoking history of ten pack-years in the recent past [6]. In our patient, absorptiometry measurements showed no evidence of osteoporosis. Stress fractures can occur at the sacrum. In 1987, Lourie [7] described spontaneous osteoporotic frac-
Table I. Markers for calcium and phosphate metabolism. Markers Total serum calcium Ionized serum calcium Serum phosphate Serum alkaline phosphatase Serum albumin Serum creatinine 25(OH) vitamin D Serum parathyroid hormone Serum osteocalcin Urinary deoxypyridinoline/creatinine
Values at presentation 2.53 1.14 106 39 70 1.4 32 41 10.8
Values after 3 months
Normal values
2.44 1.27 1.05 ND ND 83 14 ND ND ND
2.25–2.55 mmol/L 1.19–1.30 mmol/L 0.8–1.55 mmol/L 40–135 UI/L 50–115 µmol/L 10–40 ng/mL 10–65 pg/mL 4–9 ng/mL 3.6–8.6 nmol/mmol
Postpartal sacral fracture without osteoporosis
tures of the sacrum in elderly patients. Risk factors for stress fractures of the sacrum are osteoporosis (usually due to menopause or glucocorticoid therapy) and sporting activities [8]. Only two well-documented cases in pregnant women have been reported [9, 10]. One of these patients [9] started experiencing pain at the seventh month of pregnancy. She gained 22 kg during her pregnancy. The pain became worse after delivery, which was by cesarean section. Imaging studies disclosed fractures through both sacral wings. No risk factors for osteoporosis were identified, and bone mineral density was normal at the lumbar spine and femur [9]. In the other case [10], the pain started at the end of the delivery, which lasted only 20 minutes. Computed tomography demonstrated a fracture through the right sacral wing. Absorptiometry findings were normal at the spine and femur [10]. Two other cases of pregnancyrelated sacral fracture have been described as stress fractures, although absorptiometry was not performed [11, 12]. One was a patient who performed aerobics during her pregnancy to limit her excessive weight gain (20 kg). The fracture occurred after an uneventful cesarean section [11]. The other patient had a fracture through the right sacral wing revealed by buttock pain during the last trimester of pregnancy [12]. Risk factors for sacral fracture during pregnancy and the postpartum probably include vaginal delivery of a high-birthweight infant, increased lumbar lordosis, excessive weight gain, and rapid vaginal delivery [13]. Fatigue fracture is the most likely diagnosis in our patient. The delayed onset of pain (38th postpartal day) coincided with resumption of strenuous physical activity, as in a previous case [9]. In all reported cases, the diagnosis was confirmed by magnetic resonance imaging and/or computed tomography. Computed tomography is both sensitive and specific and seems to be the investigation of choice for evaluating bone structure. However, computed tomography is not recommended during pregnancy. Magnetic resonance imaging has similar sensitivity and can be performed throughout pregnancy [14]. The fracture is seen as a low-signal line surrounded by an area of less severely decreased signal denoting edema of the surrounding bone. On T2-weighted sequences, the fracture line is seen as a moderate low signal or isosignal within the high signal produced by the edema. Our case illustrates the favor-
73
able outcome of these fractures. Because there is no risk of complications, medical treatment is sufficient. Analgesics and bed rest until resolution of the pain should be recommended. The pain resolves within three to eight weeks [8]. In conclusion, pregnancy-related sacral fractures are uncommon but should be considered by rheumatologists in the differential diagnosis of buttock pain during pregnancy or the early postpartal period. Magnetic resonance imaging usually provides the diagnosis. We believe that increased awareness of pregnancy-related sacral fractures through the publication of case reports will increase the number of diagnosed cases. REFERENCES 1 Heckman JD, Sassard R. Musculo-skeletal considerations in pregnancy. J Bone Joint Surg 1994 ; 76A : 1720-30. 2 Blanch J, Pacifici R, Chines A. Pregnancy-associated osteoporosis: report of two cases with long-term bone density follow-up. Br J Rheumatol 1994 ; 33 : 269-72. 3 Khovidhunkit W, Epstein S. Osteoporosis in pregnancy. Osteoporos Int 1996 ; 6 : 345-54. 4 Vandecandelaere M, Cortet B, Flipo RM, Duquesnoy B, Delcambre B. Ostéoporose de la grossesse : à propos de deux observations. Rev Med Interne 1997 ; 18 : 571-4. 5 Koeger AC, Oberlin F. Pathological phosphorus and calcium metabolism during pregnancy and breast-feeding. Rev Med Interne 1997 ; 18 : 546-52. 6 Breuil V, Brocq O, Euller-Ziegler L. Insufficiency fracture of the sacrum revealing a pregnancy-associated osteoporosis. Ann Rheum Dis 1997 ; 56 : 278-9. 7 Lourie H. Spontaneous osteoporotic fracture of the sacrum. An unrecognized syndrome of the elderly. JAMA 1982 ; 248 : 715-7. 8 Finiels H, Finiels PJ, Jacquot JM, Strubel D. Fractures of the sacrum caused by bone insufficiency. Meta-analysis of 508 cases. Presse Med 1997 ; 26 : 1568-73. 9 Schmid L, Pfirrman C, Hess T, Schlumpf U. Bilateral fracture of the sacrum associated with pregnancy. A case report. Osteoporos Int 1999 ; 10 : 91-3. 10 Sibilia J, Javier RM, Werle C, Kuntz JL. Fracture of the sacrum in the absence of osteoporosis of pregnancy: a rare skeletal complication of the post partum. Br J Obstet Gynaecol 1999 ; 106 : 1096-7. 11 Hoang TA, Nguyen TH, Daffner RH, Lupetin AR, Deeb ZL. Case report 491: stress fracture of the right sacrum. Skeletal Radiol 1988 ; 17 : 364-7. 12 Thienpont E, Simon JP, Fabry G. Sacral stress fracture during pregnancy. A case report. Acta Orthop Scand 1999 ; 70 : 525-6. 13 Leroux JL, Denat B, Thomas E, Blotman F, Bonnel F. Sacral insufficiency fractures presenting as acute low-back pain. Biomechanical aspects. Spine 1993 ; 18 : 2502-6. 14 Brahme SK, Cervilla V, Vint V, Cooper K, Kortman K, Resnick D. Magnetic resonance appearance of sacral insufficiency fractures. Skeletal Radiol 1990 ; 19 : 489-93.