1977, British Journal of Radiology, 50, 757-760
OCTOBER 1977
Case reports
containing contrast medium is used. Water soluble contrast opacifies the amniotic fluid and this may be detected on early films. Myodil coats the skin on delayed films (the fetogram) because it is taken up by the vernix and will not coat before 32 weeks or in lesions which are covered by meninges only. In this case, the thin layer of Myodil covering the lesion suggested that the defect was covered by skin and this was in fact so. The covering of the meninges by skin may account for the fact that the alpha-fetoprotein was normal.
anomaly is 1:20 and increases to 1:10 if two previous siblings had the defect. Amniocentesis early in the second trimester with the detection of raised levels of alpha-fetoprotein would be an indication to terminate pregnancy.
CONCLUSION
LODGE, T., SAMUEL, R. G., and HEAP, S. W., 1965. Cranio-
The value of early antenatal diagnosis does not radically change the obstetrical management, but enables early surgical consultation and a prepared approach to the post-natal infant care. The risk of a subsequent child having a neural tube defect after the birth of a child with this
REFERENCES MATSON, D. D., 1969. Neurosurgery of Infancy and Childhood, 2nd edn, p. 65. SHAUB, M., WILSON, R., and COLLEA, J., 1976. Fetal cystic
lymphangioma (cystic hygroma)—prepartum ultrasonic findings. Radiology, 121, 449-450. MACRAE, D. L., 1966. Observation on craniolacunae. Acta Radiologica, 5, 55-64. lacunae in relation to hydrocephalus and spinal dysraphism. Proceedings of the Xlth International Congress of Radiology, London. Excerpta Medica, 640-645. RUSSELL, J. G. B., 1969. Radiology in the diagnosis of fetal abnormalities. Journal of Obstetrics and Gynaecology of the British Commonwealth, 76, 345-350. RUSSELL, J. G. B., 1973. Radiology in Obstetrics and Antenatal Paediatrics, p. 14 (Butterworths).
Classical acute osteomyelitis with a negative bone scan By E. S. Garnett, M.B., B.S., F.R.C.P., F.R.C.P.(C), W. P. Cockshott, M.B., Ch.B., M.D., M.R.C.P., F.R.C.P.(C), F.R.C.R., and J. Jacobs, M.R.C.S., M.B., B.S., D.C.H., M.D., M.R.C.P., F.R.C.P.(C) Departments of Radiology and Paediatrics, McMaster University Medical Centre, Hamilton, Ontario, Canada {Received January, 1977 and in revised form April, 1977)
Clinically and pathologically acute haematogenous osteomyelitis displays the characteristics of a typical inflammatory reaction. Local blood flow is increased, the capillaries are dilated and become leaky. These vascular features favour the development of a positive scintiscan following the introduction of a boneseeking radiopharmaceutical (Van Dyke et al., 1965; Garnett et al., 1975). Clearly, the vascular changes will precede any radiologically detectable alterations in bone structure. Accordingly, skeletal scintigraphy is now recommended as a sensitive test to help in the early diagnosis of osteomyelitis (Duszynski et al., 1975; Gilday et al, 1975; Majd and Frankel, 1976; Treves et al., 1976). The purpose of this report is to draw attention to the fact that proven severe acute osteomyelitis in a major long bone need not be associated at a preradiographic stage with a greater than normal accumulation of bone-seeking radiopharmaceutical either in the bone itself or in the surrounding soft tissue.
CASE REPORT
Clinical findings A previously healthy, 11 -year-old boy developed a "flu"like illness with malaise, diarrhoea and fever. On the second day of his illness he complained of throbbing pain in his right upper arm. There was no known antecedent trauma. Three days later the arm was hot and swollen, marked tenderness was localized over the proximal humerus, but the shoulder could be moved passively throughout its range. On the fifth day of the illness a radiograph of the shoulder (Fig. 1 A) indicated slight increase in soft tissue density over the area and blurring of fat planes but the bone structure was entirely normal. A bone scan (Fig. 2) performed on the following day, two hours following an intravenous injection of 10 mCi " T c m pyrophosphate, showed only a very slight increase in accumulation of radionuclide in the shaft of the right humerus compared with the left and the increase was somewhat more apparent in the distal portion. There was no soft tissue accumulation of the isotope. These findings were interpreted as unlike those of acute osteomyelitis but the clinical picture was so compelling the arm was explored under general anaesthesia immediately after the scan. A collection of pus had elevated the metaphyseal periosteum from the shaft and more pus was released from the medullary cavity when the metaphysis itself was drilled. Staphylococcus aureus was isolated from this pus with a phage type the same as that of staphylococci grown from
757
VOL.
50, NO. 598 Case reports
FIG.1.
(A) Right shoulder radiograph at time of admission—no osseous abnormality, (B) At three weeks there is evidence of extensive periosteal new bone in upper two thirds of shaft, combined with diffuse areas of bone destruction. blood cultures. The staphylococci were sensitive to cloxa- disclosed patchy bone destruction extending from the cillin. The medullary cavity of the proximal humerus was growth plate throughout the upper third of the humerus. irrigated for two weeks with cloxacillin and the same anti- More significantly the periosteum could be seen to be elebiotic was given intravenously for six weeks, during which vated from the surgical neck as far down the shaft as the time the child slowly recovered. junction of the intermediate and lower third. A second bone scan (Fig. 3) was done on the eighth day of The fulminating clinical course of the osteomyelitis in this the illness. There was now a modest and generalized in- boy had raised the possibility of an abnormality of phagocrease in the accumulation of pyrophosphate in the shaft of cytic function or a coagulation defect but no evidence for the humerus with a more obvious accumulation in the distal either was detected. epiphyseal region. Although the difference between the diseased and normal side was obvious the changes were not DISCUSSION those expected from acute osteomyelitis of the proximal There is no doubt that our patient had acute humeral shaft. A third scan (Fig. 4) was done on the 19th day of the osteomyelitis of the proximal humeral metaphysis. illness. An intense accumulation of isotope was seen in the mid shaft with an abnormal but less intense accumulation in The development of radiographic changes from nonthe proximal shaft. A radiograph three days later (Fig. 1B) specific soft tissue alteration to a progressive series of
758
Case reports
FIG. 2. %;,'. Anterior "Tcm-Sn-pyrophosphate scan showing minimal *•'' increase in accumulation of radioactivity in distal end of right humerus. wt FIG. 4. Anterior "Tc m -Sn-pyrophosphate scan showing marked increase in accumulation of radioactivity in middle and upper thirds of shaft of right humerus.
9jan
FIG. 3. Anterior "Tcm-Sn-pyrophosphate scan showing moderate uniform increase in accumulation of radioactivity in shaft of right humerus and more marked accumulation in distal epiphyseal region.
changes extending from the metaphysis into the diaphysis with bone destruction, displacement of the periosteum and repair is classical. The vascular factors in the development of osteomyelitis have been emphasized (Waldvogel et al., 1970). The classical juxtametaphyseal focus of bone destruction is considered to have originated from a small focus in one of the metaphyseal vascular loops. Whether these loops are occluded by thrombosis as part of a local inflammatory process, or whether they are occluded as a consequence of pressure changes following the hyperaemia and occlusion of the vascular sinuses within the marrow cavity is controversial. What is known is that hyperaemia occurs early and affects initially nutrient vessels and perhaps some of the metaphyseal perforating vessels. The inflammatory response implies hyperaemia with an increased supply of radiopharmaceutical and an increased leakiness of vessels. The product of these factors accounts for the usual increased accumulation of isotope as an early sign of osteomyelitis. In the present case this did not happen. The blood flow through the metaphysis must already have been compromised when the first scan was done. Further, the reduced accumulation of isotope in the right shoulder (Fig. 2) suggests that the blood supply to
759
VOL.
50, No. 598 Case reports
the humeral head was also compromised. The reduction in metaphyseal blood flow may have resulted from a rise in marrow cavity pressure resulting in venous compression, thrombosis of the nutrient vessels, or a combination of both. A similar and extensive impairment of diaphyseal blood flow has been invoked to explain the massive diaphyseal sequestra that were not uncommon before penicillin. LeVeuf (1948) went further and suggested that massive diaphyseal involvement results from early occlusion of the nutrient artery itself close to its point of entry into the medullary cavity. It is interesting that the soft tissues around the humerus as well as the humerus itself accumulated only fractionally more radionuclide than the contralateral normal side. Gilday et al. (1975) has shown that accumulation of bone-seeking radiopharmaceutical in the inflamed soft tissues adjacent to an area of osteomyelitis is fairly common. The fact that there was minimal soft tissue accumulation of radioactivity and only a slight increase in uptake in the distal humerus suggests that very little blood and hence very little pharmaceutical could get to the bone. By the same token presumably very little antibiotic could reach the affected area. Sometimes a focus of osteomyelitis may show little local accumulation of isotope but in this instance it is usual to see an area of increased accumulation of isotope in the area immediately surrounding the lesion, as well as an increased uptake in the more distal part of the bone. The lack of these findings in our patient indicates a fairly massive vascular deprivation. The true extent of the disease that we were able to observe in late radiographs after a latent period was therefore not surprising. During the process of repair blood flow must have been restored. This presumably resulted in part from medullary decompression and in part from the growth of new vessels from the elevated periosteum. In the light of the natural history of the vascular
alterations in osteomyelitis it is perhaps surprising that the pattern of events recorded here is not seen more often. As the emphasis in the literature to date has been on the sensitivity of bone scanning as an aid in coming to an early diagnosis of acute osteomyelitis, this experience should introduce a cautionary note to the interpretation of a "negative" scan at an early phase in the evolution and development of osteomyelitis. This obviously has significant therapeutic implications and indicates that high levels of antibiotic cannot be achieved locally unless treatment directed at improving the circulation is carried out. The truism that clinical judgment is the best guide to management is strikingly reinforced by this case. If appropriate therapy had been withheld based on the "negative" isotope scan, the progression of bone destruction would probably have been even more severe. REFERENCES DUSZYNSKI, D. O., KUHN, J. P., AFSHANI, E., and RIDDLES-
BERGER, M. M., 1975. Early radionuclide diagnosis of acute osteomyelitis. Radiology, 117, 337—340. GARNETT, E. S., BOWEN, B. M., COATES, G., and NAHMIAS,
C , 1975. An analysis of factors which influence the local accumulation of bone seeking radiopharmaceuticals. Investigative Radiology, 10, 465-568. GILDAY, D. L., PAUL, D. J., and PATERSON, J.,
1975.
Diagnosis of osteomyelitis in children by combined blood pool and bone imaging. Radiology, 117, 331—335. LEVEUF, J., 1948. Treatment of osteomyelitis—anatomical and physiological basis. Journal of Bone and Joint Surgery, 30B, 207. MAJD, M., and FRANKEL, R. S., 1976. Radionuclide imaging
in skeletal inflammatory and ischaemic disease in children. American Journal of Roentgenology, 126, 832-841. TREVES, S., KHETTRY, J., BROKER, F. H., WILKINSON, R. H.,
and WATTS, H., 1976. Osteomyelitis: early scintigraphic detection in children. Paediatrics, 57, 173—186. VAN DYKE, D., ANGER, H. O., PARKER, H., MCCREA, J., DOBSON, E. L., YANO, Y., NAETZ, J. P., and LINEFOOT, J.,
1965. Bone blood flow shown with 18 F and the Positron camera. American Journal of Physiology, 209, 65-70.
WALDVOGEL, F. A., MEDOFF, G., and SWARTZ, M. N., 1970.
760
Osteomyelitis: a review of clinical features, therapeutic considerations and unusual aspects. New England Journal of Medicine, 282, 198-206.
OCTOBER 1977
Case reports
containing contrast medium is used. Water soluble contrast opacifies the amniotic fluid and this may be detected on early films. Myodil coats the skin on delayed films (the fetogram) because it is taken up by the vernix and will not coat before 32 weeks or in lesions which are covered by meninges only. In this case, the thin layer of Myodil covering the lesion suggested that the defect was covered by skin and this was in fact so. The covering of the meninges by skin may account for the fact that the alpha-fetoprotein was normal.
anomaly is 1:20 and increases to 1:10 if two previous siblings had the defect. Amniocentesis early in the second trimester with the detection of raised levels of alpha-fetoprotein would be an indication to terminate pregnancy.
CONCLUSION
LODGE, T., SAMUEL, R. G., and HEAP, S. W., 1965. Cranio-
The value of early antenatal diagnosis does not radically change the obstetrical management, but enables early surgical consultation and a prepared approach to the post-natal infant care. The risk of a subsequent child having a neural tube defect after the birth of a child with this
REFERENCES MATSON, D. D., 1969. Neurosurgery of Infancy and Childhood, 2nd edn, p. 65. SHAUB, M., WILSON, R., and COLLEA, J., 1976. Fetal cystic
lymphangioma (cystic hygroma)—prepartum ultrasonic findings. Radiology, 121, 449-450. MACRAE, D. L., 1966. Observation on craniolacunae. Acta Radiologica, 5, 55-64. lacunae in relation to hydrocephalus and spinal dysraphism. Proceedings of the Xlth International Congress of Radiology, London. Excerpta Medica, 640-645. RUSSELL, J. G. B., 1969. Radiology in the diagnosis of fetal abnormalities. Journal of Obstetrics and Gynaecology of the British Commonwealth, 76, 345-350. RUSSELL, J. G. B., 1973. Radiology in Obstetrics and Antenatal Paediatrics, p. 14 (Butterworths).
Classical acute osteomyelitis with a negative bone scan By E. S. Garnett, M.B., B.S., F.R.C.P., F.R.C.P.(C), W. P. Cockshott, M.B., Ch.B., M.D., M.R.C.P., F.R.C.P.(C), F.R.C.R., and J. Jacobs, M.R.C.S., M.B., B.S., D.C.H., M.D., M.R.C.P., F.R.C.P.(C) Departments of Radiology and Paediatrics, McMaster University Medical Centre, Hamilton, Ontario, Canada {Received January, 1977 and in revised form April, 1977)
Clinically and pathologically acute haematogenous osteomyelitis displays the characteristics of a typical inflammatory reaction. Local blood flow is increased, the capillaries are dilated and become leaky. These vascular features favour the development of a positive scintiscan following the introduction of a boneseeking radiopharmaceutical (Van Dyke et al., 1965; Garnett et al., 1975). Clearly, the vascular changes will precede any radiologically detectable alterations in bone structure. Accordingly, skeletal scintigraphy is now recommended as a sensitive test to help in the early diagnosis of osteomyelitis (Duszynski et al., 1975; Gilday et al, 1975; Majd and Frankel, 1976; Treves et al., 1976). The purpose of this report is to draw attention to the fact that proven severe acute osteomyelitis in a major long bone need not be associated at a preradiographic stage with a greater than normal accumulation of bone-seeking radiopharmaceutical either in the bone itself or in the surrounding soft tissue.
CASE REPORT
Clinical findings A previously healthy, 11 -year-old boy developed a "flu"like illness with malaise, diarrhoea and fever. On the second day of his illness he complained of throbbing pain in his right upper arm. There was no known antecedent trauma. Three days later the arm was hot and swollen, marked tenderness was localized over the proximal humerus, but the shoulder could be moved passively throughout its range. On the fifth day of the illness a radiograph of the shoulder (Fig. 1 A) indicated slight increase in soft tissue density over the area and blurring of fat planes but the bone structure was entirely normal. A bone scan (Fig. 2) performed on the following day, two hours following an intravenous injection of 10 mCi " T c m pyrophosphate, showed only a very slight increase in accumulation of radionuclide in the shaft of the right humerus compared with the left and the increase was somewhat more apparent in the distal portion. There was no soft tissue accumulation of the isotope. These findings were interpreted as unlike those of acute osteomyelitis but the clinical picture was so compelling the arm was explored under general anaesthesia immediately after the scan. A collection of pus had elevated the metaphyseal periosteum from the shaft and more pus was released from the medullary cavity when the metaphysis itself was drilled. Staphylococcus aureus was isolated from this pus with a phage type the same as that of staphylococci grown from
757
VOL.
50, NO. 598 Case reports
FIG.1.
(A) Right shoulder radiograph at time of admission—no osseous abnormality, (B) At three weeks there is evidence of extensive periosteal new bone in upper two thirds of shaft, combined with diffuse areas of bone destruction. blood cultures. The staphylococci were sensitive to cloxa- disclosed patchy bone destruction extending from the cillin. The medullary cavity of the proximal humerus was growth plate throughout the upper third of the humerus. irrigated for two weeks with cloxacillin and the same anti- More significantly the periosteum could be seen to be elebiotic was given intravenously for six weeks, during which vated from the surgical neck as far down the shaft as the time the child slowly recovered. junction of the intermediate and lower third. A second bone scan (Fig. 3) was done on the eighth day of The fulminating clinical course of the osteomyelitis in this the illness. There was now a modest and generalized in- boy had raised the possibility of an abnormality of phagocrease in the accumulation of pyrophosphate in the shaft of cytic function or a coagulation defect but no evidence for the humerus with a more obvious accumulation in the distal either was detected. epiphyseal region. Although the difference between the diseased and normal side was obvious the changes were not DISCUSSION those expected from acute osteomyelitis of the proximal There is no doubt that our patient had acute humeral shaft. A third scan (Fig. 4) was done on the 19th day of the osteomyelitis of the proximal humeral metaphysis. illness. An intense accumulation of isotope was seen in the mid shaft with an abnormal but less intense accumulation in The development of radiographic changes from nonthe proximal shaft. A radiograph three days later (Fig. 1B) specific soft tissue alteration to a progressive series of
758
Case reports
FIG. 2. %;,'. Anterior "Tcm-Sn-pyrophosphate scan showing minimal *•'' increase in accumulation of radioactivity in distal end of right humerus. wt FIG. 4. Anterior "Tc m -Sn-pyrophosphate scan showing marked increase in accumulation of radioactivity in middle and upper thirds of shaft of right humerus.
9jan
FIG. 3. Anterior "Tcm-Sn-pyrophosphate scan showing moderate uniform increase in accumulation of radioactivity in shaft of right humerus and more marked accumulation in distal epiphyseal region.
changes extending from the metaphysis into the diaphysis with bone destruction, displacement of the periosteum and repair is classical. The vascular factors in the development of osteomyelitis have been emphasized (Waldvogel et al., 1970). The classical juxtametaphyseal focus of bone destruction is considered to have originated from a small focus in one of the metaphyseal vascular loops. Whether these loops are occluded by thrombosis as part of a local inflammatory process, or whether they are occluded as a consequence of pressure changes following the hyperaemia and occlusion of the vascular sinuses within the marrow cavity is controversial. What is known is that hyperaemia occurs early and affects initially nutrient vessels and perhaps some of the metaphyseal perforating vessels. The inflammatory response implies hyperaemia with an increased supply of radiopharmaceutical and an increased leakiness of vessels. The product of these factors accounts for the usual increased accumulation of isotope as an early sign of osteomyelitis. In the present case this did not happen. The blood flow through the metaphysis must already have been compromised when the first scan was done. Further, the reduced accumulation of isotope in the right shoulder (Fig. 2) suggests that the blood supply to
759
VOL.
50, No. 598 Case reports
the humeral head was also compromised. The reduction in metaphyseal blood flow may have resulted from a rise in marrow cavity pressure resulting in venous compression, thrombosis of the nutrient vessels, or a combination of both. A similar and extensive impairment of diaphyseal blood flow has been invoked to explain the massive diaphyseal sequestra that were not uncommon before penicillin. LeVeuf (1948) went further and suggested that massive diaphyseal involvement results from early occlusion of the nutrient artery itself close to its point of entry into the medullary cavity. It is interesting that the soft tissues around the humerus as well as the humerus itself accumulated only fractionally more radionuclide than the contralateral normal side. Gilday et al. (1975) has shown that accumulation of bone-seeking radiopharmaceutical in the inflamed soft tissues adjacent to an area of osteomyelitis is fairly common. The fact that there was minimal soft tissue accumulation of radioactivity and only a slight increase in uptake in the distal humerus suggests that very little blood and hence very little pharmaceutical could get to the bone. By the same token presumably very little antibiotic could reach the affected area. Sometimes a focus of osteomyelitis may show little local accumulation of isotope but in this instance it is usual to see an area of increased accumulation of isotope in the area immediately surrounding the lesion, as well as an increased uptake in the more distal part of the bone. The lack of these findings in our patient indicates a fairly massive vascular deprivation. The true extent of the disease that we were able to observe in late radiographs after a latent period was therefore not surprising. During the process of repair blood flow must have been restored. This presumably resulted in part from medullary decompression and in part from the growth of new vessels from the elevated periosteum. In the light of the natural history of the vascular
alterations in osteomyelitis it is perhaps surprising that the pattern of events recorded here is not seen more often. As the emphasis in the literature to date has been on the sensitivity of bone scanning as an aid in coming to an early diagnosis of acute osteomyelitis, this experience should introduce a cautionary note to the interpretation of a "negative" scan at an early phase in the evolution and development of osteomyelitis. This obviously has significant therapeutic implications and indicates that high levels of antibiotic cannot be achieved locally unless treatment directed at improving the circulation is carried out. The truism that clinical judgment is the best guide to management is strikingly reinforced by this case. If appropriate therapy had been withheld based on the "negative" isotope scan, the progression of bone destruction would probably have been even more severe. REFERENCES DUSZYNSKI, D. O., KUHN, J. P., AFSHANI, E., and RIDDLES-
BERGER, M. M., 1975. Early radionuclide diagnosis of acute osteomyelitis. Radiology, 117, 337—340. GARNETT, E. S., BOWEN, B. M., COATES, G., and NAHMIAS,
C , 1975. An analysis of factors which influence the local accumulation of bone seeking radiopharmaceuticals. Investigative Radiology, 10, 465-568. GILDAY, D. L., PAUL, D. J., and PATERSON, J.,
1975.
Diagnosis of osteomyelitis in children by combined blood pool and bone imaging. Radiology, 117, 331—335. LEVEUF, J., 1948. Treatment of osteomyelitis—anatomical and physiological basis. Journal of Bone and Joint Surgery, 30B, 207. MAJD, M., and FRANKEL, R. S., 1976. Radionuclide imaging
in skeletal inflammatory and ischaemic disease in children. American Journal of Roentgenology, 126, 832-841. TREVES, S., KHETTRY, J., BROKER, F. H., WILKINSON, R. H.,
and WATTS, H., 1976. Osteomyelitis: early scintigraphic detection in children. Paediatrics, 57, 173—186. VAN DYKE, D., ANGER, H. O., PARKER, H., MCCREA, J., DOBSON, E. L., YANO, Y., NAETZ, J. P., and LINEFOOT, J.,
1965. Bone blood flow shown with 18 F and the Positron camera. American Journal of Physiology, 209, 65-70.
WALDVOGEL, F. A., MEDOFF, G., and SWARTZ, M. N., 1970.
760
Osteomyelitis: a review of clinical features, therapeutic considerations and unusual aspects. New England Journal of Medicine, 282, 198-206.
