Postgrad Med J 2003;79:359–362 359

to 10 years. The mode of spread of intramed- Postgrad Med J: first published as 10.1136/pmj.79.932.359 on 1 June 2003. Downloaded from SELF ASSESSMENT ANSWERS ullary cysticercosis is either haematogenous or ventriculoependymal.2 MRI studies help in diagnosing and correctly correlating the Congenital renal anomaly number of cases the band of renal tissue may 4 pathological diagnosis of neurocysticercosis evade ultrasonic detection. Computed tom- 3 in a patient with situs ography may be necessary to confirm the (including intramedullary cysticercosis). inversus diagnosis. Treatment modalities like drug therapy Intervention is required because of obstruc- (cysticidal drug)/surgery, or both, can be Q1: Name the congenital renal tion or calculi. The combination of horseshoe planned according to the pathological stage kidney with an aortic aneurysm presents a and location of the cyst as seen on MRI. Since anomaly identified in fig 1 (see p 355) the cysticidal drugs albendazole and Horseshoe kidney. The lower poles of the kid- diagnostic and therapeutic challenge to the vascular surgeon.5 praziquental were shown to be effective in ney being displaced towards the midline, parenchymal brain cysticercosis, these drugs joined by either functioning renal tissue or a Final diagnosis have been considered potentially useful in fibrous band. patients with intramedullary cysticercosis. Horseshoe kidney with situs inversus. Successful management of intramedullary Q2: What is the incidence and sex cysticercosis by cysticidal drugs alone has also ratio of this anomaly? References been reported in the literature.4 Incidence is one in 400. It is more commonly 1 Bauer SB, Perlmutter AD, Retik AB. Anomalies In the present case when the diagnosis of found in males at a ratio of 2:1. of the upper urinary tract. Campbell’s urology. intramedullary cysticercosis was established 6th Ed. Philadelphia: WB Saunders, 1992: 1376–81. on MRI, surgery was undertaken due to its Q3: What complications occur with 2 Matsusshita K, Veda S, Kegami K. location in cervical segment, and this was fol- this condition? Horseshoe kidney in a patient with situs lowed by albendazole therapy (15 mg/kg × 28 Thirty percent of cases are asymptomatic and inversus totalis. J Urol 1982;128:604–5. days). The patient showed complete neuro- are identified incidentally. Stasis of urine due 3 Krishnan B, Troung LD, Saleh G, et al. logical improvement with resolution of the to the malrotation of the kidneys, and Horseshoe kidney is associated with an intramedullary lesion. increases relative risk of primary renal It is concluded that with present generation impaired ureteric drainage result in infection 157 – carcinoid tumor. J Urol 1997; :2059 66. MRI and also successful surgical/drug man- and stone formation. 4 Banerjee B, Brett I. Ultrasound diagnosis of horseshoe kidney. Br J Radiol agement, the outcome of intramedullary cyst- Q4: Name three other genitourinary 1991;64:898–900. icercosis is not as dismal as was reported ear- anomalies that can be associated with 5 Stroosma OB, Kootstra G, Schurink GWH. lier, and patients with paraplegia also have a Management of aortic aneurysm in the favourable outcome. this condition presence of a horseshoe kidney. Br J Surg These are: (1) hypospadiasis; (2) undescended 2001;88:500–9. Final diagnosis testis; (3) ureteral duplication. Vaginal septa- Spinal (cervical) intramedullary cysticercosis. tion and bicornuate uterus can also be associ- ated with this condition. A man with numbness and References 1 Corral I, Quereda C, Moreno A, et al. Discussion limb weakness Intramedullary cysticercosis cured with drug Horseshoe kidney was first recognised during treatment. A case report. Spine a necropsy by DeCarpi in 1521, but Botallo in Q1: What is the diagnosis? 1996;21:2284–7. 1564 provided the first description and illus- The diagnosis is spinal (cervical) intramedul- 2 Mathuriya SN, Khosla VK, Vasishta RK, et al. tration of a horseshoe kidney.1 Horseshoe kid- lary cysticercosis. The MRI scan (fig 1; see Intramedullary cysticercosis: MRI diagnosis. Neurology India 2001;49:72–4. neys are believed to result from the median p 355) shows a cyst located in the intramedul- lary region. Cervical laminectomy with re- 3 Mohanty A, Venkatrama SK, Das S, et al. fusion of metanephric tissue due to mechani- Spinal intramedullary cysticercosis. cal forces. However studies have suggested moval of the cyst was done. Histopathology Neurosurgery 1997;40:82–7. http://pmj.bmj.com/ that abnormal fusion of tissue associated with examination (fig 2; see p 355) proved the 4 Sotelo J, Guerreo V, Rubio F. the parenchymatous isthmus of horseshoe lesion to be a cysticercus cyst with scolex (lar- Neurocysticercosis. A new classification kidney is the result of a teratogenic event val cyst). based on active and inactive forms—a study involving the abnormal migration of posterior of 753 cases. Arch Intern Med 145 – nephrogenic cells. Q2: What are the treatment options? 1985; :442 5. In most cases the kidneys are linked at the The treatment of spinal intramedullary cyst- lower poles by a parenchymatous or fibrous icercosis could be surgical, medical (that is, An interesting case of isthmus that crosses the midline of the body. cysticidal therapy) or both, based on location In general isthmus lies anterior to aorta and and stage of the cyst as also on the experience hemiparesis on September 26, 2021 by guest. Protected copyright. vena cava. Because kidneys fail to rotate, the of the physician. Surgical treatment includes calyces point posteriorly. The ureter inserts laminectomy with removal of the cyst. Cysti- Q1: What is the differential diagnosis higher on the renal pelvis and lies laterally cidal drugs given are albendazole in a dose of in this patient? and crosses over and anterior to isthmus. The 15 mg/kg body weight for 14–30 days or The differential diagnosis of HIV patients pre- blood supply can be quite variable.1 praziquantel 50 mg/kg body weight for 15 senting with focal neurological deficits should The horseshoe kidney is frequently found in days along with steroids to reduce the perile- include disorders such as toxoplasmosis, other congenital anomalies, some of which sional oedema and to prevent neurological primary central nervous system lymphoma, are incompatible with long term survival. deterioration during the course of cysticidal cerebral Chagas’ disease, progressive multifo- Most common congenital anomalies involved drugs. Administration of cysticidal drugs cal leucoencephalopathy (PML), central nerv- include skeletal, cardiovascular, and central before or after surgery is a point of personal ous system tuberculosis, and cryptococcosis.1 nervous systems. There is increased occur- preference for the individual doctor as no sys- rence of other genitourinary anomalies. Fe- tematic evaluation has been possible due to Q2: What are the computed males with Turner’s syndrome have a high the rarity of the disease. tomography and MRI findings? incidence of horseshoe kidney. Horseshoe Computed tomography of the head (fig 1; see kidney with situs inversus is a rare and inter- Discussion p 356) shows well defined hypodense areas in esting association.2 Intramedullary cysticercosis is a rare manifes- the white matter in bilateral posterior parietal One third of all patients remain asympto- tation of neurocysticercosis,1 and fewer than regions and in the right temporoparieto- matic. Others present with vague abdominal 50 cases have been reported. The cysts are frontal region without areas of enhancement pain resulting from hydronephrosis, infection, commonly located in spinal subarachnoid or mass effect. Figure 2A (see p 356) shows or calculus formation. Horseshoe kidney is space and rarely at intramedullary locations. the gadolinium enhanced T1 sagittal MRI of associated with an increased relative risk of The majority of reported cases have cysts in the brain showing non-enhancing white mat- Wilms’ tumour, transitional cell carcinoma, the dorsal cord, which is in accordance with ter changes. Figure 2B (see p 356) shows the and renal carcinoid.3 the regional blood flow to the spinal cord. In T2 weighted coronal MRI showing white mat- Ultrasound or an excretory urogram readily 90% of reported cases of intramedullary cyst- ter changes without mass effect. The findings makes the diagnosis. Ultrasound diagnosis icercosis due to neurocysticercosis the pa- of non-enhancing white matter lesions with depends on the demonstration of an isthmus tients were between 20 and 45 years of age. typical increased T2 and decreased T1 signals or band of renal tissue across the midline. In a The duration of symptoms varied from a week on MRI head are highly suggestive of PML.2

www.postgradmedj.com 360 Self assessment answers

3

Q3: How is the diagnosis confirmed? to make the clinical diagnosis of PML. the limb in the abducted positions (fig 3; see p Postgrad Med J: first published as 10.1136/pmj.79.932.359 on 1 June 2003. Downloaded from Though the definitive diagnosis of PML Recently polymerase chain reaction amplifi- XXX) virtual occlusion of the subclavian depends on identification of characteristic cation of JC virus DNA from the cerebrospinal artery can be seen. Venography demonstrated neuropathological abnormalities on brain fluid has become the favoured diagnostic similar positional compression of the subcla- biopsy, it is not necessary to confirm the modality to confirm the diagnosis.4 vian vein. The vascular compression accounts diagnosis.3 Neuroimaging is most helpful in Currently, outlook for patients with PML is for the limb colour changes and lack of pulses diagnosis with typical computed tomography poor and there is no effective treatment. Few during abduction and for the symptoms when and MRI findings as described above, MRI authors have reported promising results with working overhead. being more sensitive than computed tomogra- HAART treatment.89Recently treatment with phy. Recently polymerase chain reaction am- cidofovir has been tried in such patients with Q3: How should be injury have been plification of JC virus DNA from the cerebro- varying results.10 Mean survival time after managed upon initial presentation? spinal fluid has become the favoured diagnosis is about six months. This patient presented after a fall onto his diagnostic modality to confirm the shoulder with pain and swelling in his neck diagnosis.4 Final diagnosis and left medial end of clavicle, symptoms and Progressive multifocal leucoencephalopathy signs of neurovascular compromise of his left Discussion in AIDS. upper limb, and asymmetry between the The neurological infections commonly pre- medial end of his clavicles. This history 1 senting in HIV are toxoplasmosis, cryptococ- References strongly suggests posterior sternoclavicular cal meningitis, PML, while the less common 1 Mamidi A, DeSimone JA, Pomerantz RJ. joint dislocation with mediastinal structure ones are central nervous system tuberculosis, Central nervous system infections in compromise, but this diagnosis was not made individuals with HIV-1 infection. J Neurovirol syphilis, cytomegalovirus, HTLV, acan- post-injury as the plain radiographs appeared thamoeba, or naeglaria. Among the neo- 2002;8:158–67. 2 Wilson BG. CT assessment of CNS normal. This injury is often not demonstrated plasms, primary central nervous system complications of AIDS. Radiol Technol by plain radiographs and therefore computed lymphoma is the more common entity in HIV 2002;73:424–37. tomography should have been performed at positive individuals. 3 Yan Geisan HT, Neuen Jacob E, Dorriea K. initial presentation, and would have demon- Toxoplasmosis is one of the most common Diagnostic criteria and clinical procedures in strated the injury. The fracture dislocation secondary central nervous system infections HIV-1 associated progressive multifocal should then have been reduced, thereby in AIDS presenting late at CD4+ counts leukoencephalopathy. J Neurol Sci resolving symptoms both from the dislocation µ 1997;147:63–72. <200/ l. The most common clinical presenta- and from compression of nearby structures. It tion is fever, headache, with focal neurological 4 Antinori A, Ammassari A, De Luca A, et al. - is important not to miss posterior sternocla- deficits. The diagnosis is suspected on finding Diagnosis of AIDS related focal brain lesions: a decision-making analysis based on clinical vicular joint dislocations as injury to the multiple ring enhancing lesions on MRI head and neuroradiologic characteristics combined upper mediastinal structures can cause seri- and positive serology for Toxoplasma gondii. with polymerase chain reaction assays in CSF. ous complications including death. Definite diagnosis is by brain biopsy. Trypano- Neurology 1997;48:687–94. somiasis or Chagas’ disease may present in 5 Clavo Sanchez A, Garcia-Gil D, Sasian Q4: What are the management HIV patients as acute meningoencephalitis Martinez S, et al. Progressive multifocal options nine years after injury? with fever, vomiting, seizures, and focal leukoencephalopathy in acquired The options available to the patient are to live neurological signs. Lesions appear on MRI as immunodeficiency. Rev Clin Esp 194 – with his disability or to undergo surgery to single or multiple hypodense ring enhancing 1994; :13 6. 6 Sanchez Herrero J, Lopez Facal S, Arnal prevent the medial clavicle compressing me- lesions mainly in the subcortical areas. Cryp- Monreal F, et al. Progressive multifocal diastinal structures. tococcal meningitis is one of the leading leukoencephalopathy as the initial The patient chose to proceed to surgery due neurological complications in HIV patients manifestation of acquired immunologic to the severity of his symptoms. At operation a and generally occurs in patients with CD4+ T deficiency syndrome. Med Clin (Barc) fracture dislocation of the clavicle 1 cm from cell counts <100/µl. The diagnosis is con- 1988;90:416–8. the medial end was noted and as reconstruc- Berger JR firmed by identifying organisms in the 7 , Kaszovitz B, Post MJ, et al. tion of the fracture-dislocation was not possi-

Progressive multifocal leukoencephalopathy http://pmj.bmj.com/ cerebrospinal fluid on India ink examination ble the medial 2 cm of the clavicle was or by detection of cryptococcal antigen. associated with human immunodeficiency virus infection. A review of the literature with a resected subperiosteally leaving the costocla- Central nervous system tuberculosis in the report of sixteen cases. Ann Intern Med vicular ligament intact. At review six weeks form of tubercular meningitis or tuberculo- 1987;107:78–87. postoperatively symptoms had resolved, the mas is common in HIV patients and may 8 Simpson D. HIV rounds at Cornell: selected medial clavicle was stable and he had present with focal deficits. Computed tomog- neurologic complications of HIV disease. AIDS returned to work. At six and 12 months post- raphy findings show prominent leptomenin- Patient Care STDS 1998;12:209–15. operatively the patient felt that both his upper Clifford DB geal and basal cistern enhancement or rim 9 , Yiannoutsos C, Glicksman M, et limbs were normal and on examination his al. HAART improves prognosis in HIV- enhancing granulomas. Cerebrospinal fluid shoulders and upper limbs were functionally analysis often helps in establishing the associated progressive multifocal on September 26, 2021 by guest. Protected copyright. leukoencephalopathy. Neurology normal with full power, normal range of joint diagnosis. 1999;52:623–5. movements and normal pulses in all limb PML, caused by JC virus, a human papil- 10 1Wilcox RD. Cidofovir: progress in the positions. loma virus, is an important neurological treatment of progressive multifocal manifestation in patients with AIDS. It is a encephalopathy (PML)? HIV Clin Discussion subacute demyelinating disease of the central 2002;14:1–2. Posterior sternoclavicular dislocation is a rare nervous system and is caused by reactivation injury.1 It is nearly always a result of trauma of the latent JC virus in presence of under- A misdiagnosed potentially and is rare after the age of 25 years.2 It can lying immunosupression. Since the onset of result in significant morbidity or death due to AIDS epidemic, HIV infection has become, by dangerous shoulder injury the proximity of the superior mediastinal far, the most common risk factor for the contents, which may be compressed or injured disease and currently more than 60% cases of Q1: What is the diagnosis? by the medial end of the clavicle.3 PML occur in patients with AIDS. It com- The patient has sustained a posterior fracture Early diagnosis can often be difficult due to monly occurs in the setting of advanced dislocation of the left sternoclavicular joint extensive local swelling and bruising,4 diffi- immunosuppression and only infrequently with compression of the upper mediastinal culties in assessment using plain heralds AIDS.5–7 However in this patient, PML structures, including the oesophagus. The radiographs,5 and as this injury is rare it is was the initial and the only manifestation of fracture dislocation can be visualised on the often overlooked. Computed tomography is AIDS. computed tomogram (fig 1; see p 357) where the best method of demonstrating the anat- Patients most often present with visual the difference between the left and right ster- omy of the sternoclavicular joint and its deficits, motor weakness, or other focal noclavicular joints can be clearly seen. It is surroundings structures.5 In most cases the neurological deficits with or without changes also possible the patient suffered from a tran- dislocation can be reduced by closed methods in sensorium. Neuroimaging is most helpful sient brachial plexus palsy after injury. within 48 hours of injury and after 48 hours in diagnosis with MRI typically revealing open reduction is more likely to be required.2 multiple non-enhancing white matter lesions, Q2: What do the angiograms It is therefore important to maintain a high predominantly in the occipitoparietal areas. demonstrate? level of suspicion of this injury as early Yan Geisen et al have laid down diagnostic cri- Arteriography when performed with the limb diagnosis improves the success of closed teria on the basis of epidemiological, neurora- in the resting position (fig 2; see p 357) dem- treatment and reduces complications. Our diological, and cerebrospinal fluid parameters onstrates a patent subclavian artery but with patient’s injury was missed due to poor

www.postgradmedj.com Self assessment answers 361

awareness and inadequate imaging after the association with a high urinary pH, indicating Q3: What are the treatment options Postgrad Med J: first published as 10.1136/pmj.79.932.359 on 1 June 2003. Downloaded from injury. At presentation nine years later, the distal renal tubular acidosis. The diagnosis is and prognosis of this disorder? diagnosis was confirmed using computed carbonic anhydrase II (CA II) deficiency syn- Bicarbonate supplementation is the mainstay tomography and angiography. drome, which is characterised by the triad of of treatment, but the long term outcome of Our patient suffered from dysphagia due to osteopetrosis, intracranial calcification, and 1 therapy is not known. Bone marrow trans- compression of the oesophagus, which is the renal tubular acidosis. Intracranial calcifica- plantation may improve the skeletal most common mediastinal symptom from tion and renal tubular acidosis distinguish CA 4 1 4 disorder, but not the renal defect. A low cal- posterior sternoclavicular joint dislocation. II deficiency from classical varieties of osteo- cium, high phosphate diet may be useful in The positional vascular symptoms experi- petrosis. Also, severe anaemia, a common 6 this disorder. CA II deficiency is reportedly enced by our patient are rare. finding in classical osteopetrosis, is absent or compatible with long life. Due to the length of time that had elapsed very mild in CA II deficiency.1 since the fracture, scarring between the CA II deficiency is a rare autosomal Final diagnosis medial end of clavicle and the great vessels recessive disorder attributed to mutations of Carbonic anhydrase II deficiency syndrome. was anticipated and therefore the operation the CA II isoenzyme gene (chromosome 8).12 was performed jointly by orthopaedic and CA II is the most catalytically active as well as References vascular surgeons. Fortunately, the medial the most widely distributed isoenzyme of the 1 White MP. Skeletal disorders characterized end of clavicle was mobilised easily, without CA series. CA II is important for acid-base by osteosclerosis and hyperostosis. In: Avioli damage to the great vessels. regulation as well as bone resorption.3 The LV, Krane SM, eds. Metabolic bone disease There is conflicting advice from previous latter function is mediated by its effects on and clinically related disorders. 3rd Ed. San authors regarding the surgical approach for osteoclast function: it enables H+ pump activ- Diego: Academic Press, 1998: 697–738. chronic posterior sternoclavicular dislocation. ity, which helps the osteoclast in secreting 2 Felix R, Hofstetter W, Cecchini MG. Recent developments in the understanding of the Rockwood et al recommend resection of the acid that helps to dissolve bone mineral as pathophysiology of osteopetrosis. Eur J medial clavicle and retention of the costocla- well as digest bone matrix. Therefore, in CA II Endocrinol 1996;134:143–56. 7 vicular ligament for support. Other authors deficiency, bone resorption is markedly af- 3 Blair HC, Schlesinger PH, Ross FP, et al. suggest that reconstruction of the joint fected, leading to osteopetrosis. The raised Recent advances toward understanding provides better results.89 In this patient serum acid phosphatase levels are attributed osteoclast physiology. Clin Orthop reconstruction would not have produced nor- to defective osteoclast activity. A similar defi- 1993;294:7–22. mal joint function due to the degree of joint ciency in acid excretion by the kidney may 4 McMahon C, Will A, Hu P, Shah GN, et al. damage and thus resection was performed. explain renal tubular acidosis. The reason for Bone marrow transplantation corrects osteopetrosis in the carbonic anhydrase II Medical practitioners should maintain a cerebral calcification is presently unclear. deficiency syndrome. Blood high index of suspicion of posterior sternocla- Children usually present with mental subnor- 2001;97:1947–50. vicular joint dislocation in patients complain- mality, short stature, and involvement of ing of pain near the joint after direct or lower cranial nerves (due to sclerosis of skull indirect trauma to the neck or shoulder as this base). As this is an inherited condition, family Multiorgan involvement in injury is easily missed. Also radiographs members also need to be investigated if should not be relied upon to exclude sterno- molecular studies are readily available. thalassaemia major clavicular dislocation and further imaging, Q1: What are the findings on the MRI usually a computed tomogram, is indicated. Q2: What are the radiological features of this disorder? images? Final diagnosis Skeletal radiography in CA II deficiency MRI scans of the sella (fig 1 in questions; see Posterior fracture dislocation of the left reveals findings indistinguishable from classi- p 358) show markedly decreased signal inten- sternoclavicular joint with compression of the cal osteopetrosis—that is, a generalised in- sity in the anterior lobe of the pituitary gland upper mediastinal structures. crease in bone density; hence the term “mar- in all the sequences, though best seen on gradient echo images. Hypointense signal is References ble bone disease”. Skull radiographs typically show a thick dense cranium with basal osteo- also seen in bilateral basal ganglia. Nettles JL http://pmj.bmj.com/ 1 , Linscheid RL. Sternoclavicular sclerosis and under-pneumatisation of the dislocations. J Trauma 1968;8:158. Q2: What is the diagnosis? 2 Buckerfield CT, Castle ME. Acute traumatic paranasal and mastoid sinuses. Another well described radiological feature of osteopetrosis The diagnosis is secondary (erythropoietic) retrosternal dislocation of the clavicle. J Bone haemochromatosis with hypogonadotropic Joint Surg Am 1984;66:379–85. is the appearance of alternating dense and 3 Stankler L. Posterior dislocation of the lucent bands in the long bones and skull, hypogonadism developing in a patient with β clavicle: a report of two cases. Br J Surg which occurs due to a fluctuating skeletal -thalassaemia major. 1962;50:164–8. growth.1 However, in CA II deficiency, osteo- The child had been diagnosed as having 4 Gangahar DM, Flogaites T. Retrosternal sclerosis can spontaneously diminish. Cer- thalassaemia major at the age of 5 months Dislocation of the clavicle producing thoracic ebral calcification involving the cortex and the and had received numerous blood transfu- outlet syndrome. J Trauma 1978;18:369–72. sions since. She had also been treated with on September 26, 2021 by guest. Protected copyright. 5 Cope R. Dislocations of the sternoclavicular basal ganglia on computed tomography may 1 desferrioxamine B. Her serum ferritin level 22 – appear at about 2–5 years of age. joint. Skeletal Radiol 1992; :233 8. was 8672 µg/l, luteinising hormone was zero, 6 Noda M, Shiraishi H, Mizuno K. Chronic posterior sternoclavicular dislocation causing and follicle stimulating hormone level was compression of a subclavian artery. J Shoulder 0.20 U/l. Elbow Surg 1997;6:564–9. Learning points MRI the of abdomen and chest (fig 1, next 7 Rockwood CA, Groh GI, Wirth MA, et al. page), done at the same sitting, demonstrates Resection arthroplasty of the sternoclavicular • CA II deficiency is an atypical variant of low signal intensity, equal to that of back- – joint. J Bone Joint Surg Am 1997;79:387 93. - ground, in liver, spleen, pancreas and myocar- 8 Booth CM, Roper BA. Chronic dislocation of classical osteopetrosis and is character ised by renal tubular acidosis and dium, indicating iron deposition in these the sternoclavicular joint. Clin Orthop organs also. 1979;140:17–20. cerebral calcification. 9 Eskola A, Vainionpaa S, Vastamaki M, et al. • Radiological features of osteopetrosis Operation for old sternoclavicular dislocation. Discussion J Bone Joint Surg Br 1989;71:63–5. include uniformly dense, sclerotic Haemochromatosis refers to a group of disor- bones; alternating dark and lucent ders in which there is a progressive increase in bands have also been described. total body iron stores with deposition of iron A child with growth failure • Children with CA II deficiency syndrome in the liver, heart, pancreas, and other organs.1 Q1: What are the radiological and present with growth failure, asympto- - Two generalised categories of iron deposi- biochemical features and the matic cerebral calcification, and osteo petrosis. tion in iron overload have been described: diagnosis of this case? (1) Parenchymal cell iron deposition (see • The disorder is compatible with long The computed tomogram shows extensive box 1)—this is seen in idiopathic (primary cerebral calcification (fig 1; see p 358), and the life. haemochromatosis), secondary to anaemia radiograph shows the dense osteosclerosis • Bone marrow transplantation may im- and ineffective erythropoiesis, intravascular (fig 2; see p 358) that is characteristic of prove osteopetrosis, but does not re- haemolysis, cirrhosis, after portocaval anasto- osteopetrosis. Biochemical investigations verse acidosis; hence alkali supplemen- moses, and secondary to high intake. show hypokalaemia, hyperchloraemia, low tation is required. (2) Reticuloendothelial cell iron deposition bicarbonate levels, and a low arterial pH in (see box 2)—this is seen most commonly in

www.postgradmedj.com 362 Self assessment answers

dium. Furthermore, cardiac iron deposition is Postgrad Med J: first published as 10.1136/pmj.79.932.359 on 1 June 2003. Downloaded from exclusively sarcoplasmic and not interstitial; therefore, wall thickness in haemochromato- sis is usually normal.5 At MRI, the marked signal intensity reduc- tion is due to decreased T2 relaxation time and magnetic field inhomogeneties created by the excess intracellular iron. Ferritin and haemosiderin, being para magnetic substances, cause a proton relaxa- tion effect on neighbouring hydrogen nuclei; T1 and T2 relaxation time decreases. Since both T1 and T2 are shortened, intensity may either increase or decrease depending on which relaxation effect, T1 or T2, dominates. Figure 1 (A) Coronal gradient echo image at the level of the heart shows hypointense For relatively low concentration of iron, as signal in the myocardium indicating iron deposition and (B) axial gradient echo MRI scan seen in organs like muscle and kidney which through the upper abdomen showing hypointense signal in the liver, spleen, and the do not accumulate iron in high concentra- pancreas. tion, T1 is considerably shortened and T2 values only slightly shortened leading to increased signal intensity of these tissues. Box 1: Parenchymal cell iron Box 2: Reticuloendothelial cell iron With increasing concentrations of iron, as in deposition deposition liver etc, T2 shortening becomes dominant leading to decreased signal intensity in these organs.6 • Idiopathic (primary haemochromatosis), • Secondary to multiple transfusions, in GRE T2*-weighted sequence is regarded secondary to ineffective erythropoiesis, patients with rhabdomyolysis. as the most sensitive technique for the intravascular haemolysis, etc. • Organs involved: liver (Kupffer cells), detection of parenchymal iron deposition. • Organs involved: liver (hepatocytes), spleen (reticuloendothelial cells), bone This is likely due to the lack of a 180° refocus- pancreas (acinar cells), heart, endocrine marrow, lymph nodes. ing pulse that partially recovers signal loss from the field in homogeneity in spin echo glands (anterior pituitary etc). • No significant organ dysfunction. imaging.4 • May lead to cellular damage and organ dysfunction. Final diagnosis beyond the iron storage capacity of the reticu- Secondary (erythropoietic) haemochromato- loendothelial cell system (10 g), which is the sis with hypogonadotropic hypogonadism in a patients who have received multiple transfu- amount of iron in 40 units of blood.3 patient with β-thalassaemia major. sions and also in patients with rhabdomyolysis. Reticuloendothelial iron deposition does not Parenchymal cell iron deposition occurs produce any significant organ dysfunction. References primarily in liver (hepatocytes), pancreas Thalassaemia major, characterised by inef- 1 Powell LW, Bassett ML, Halliday JW. (acinar cells), heart, and other endocrine fective erythropoiesis and hypercellular bone Hemochromatosis: 1980 update. glands (anterior lobe of pituitary gland). The marrow, results in secondary erythropoietic Gastroentrology 1980;78:374–81. spleen is usually spared. However, there have haemochromatosis. These patients also absorb 2 Seigelman ES, Mitchell DG, Rubin R, et al. been few reports of low signal intensity in the iron inappropriately and can develop severe Parenchymal versus reticuloendothelial iron spleen without any history of blood transfu- parenchymal cell overload. Also, iron accumu- overload in the liver: distinction with MR 2 imaging. Radiology 1991;179:361–6.

sion, the cause of which is unknown. Paren- lation of the reticuloendothelial system may http://pmj.bmj.com/ 3 Yoon DY, Choi BI, Han JK, et al. MR findings chymal cell iron deposition leads to cellular develop due to repeated transfusions for the of secondary hemochromatosis: transfusional damage and organ dysfunction unless anaemia, accounting for the decreased splenic vs erythropoietic. J Comput Assist Tomogr treated. signal intensity. Thus, this group of patients 1994;18:416–19. In transfusional iron overload, haemosi- share MRI features of both reticuloendothe- 4 Sparacia G, Iaia A, Banco A, et al. derin is deposited in the reticuloendothelial lial and parenchymal cell iron overload, as Transfusional hemochromatosis: quantitative system, such as the Kupffer cells of the liver seen in our case. relation of MR imaging pituitary signal intensity reduction to hypogonadotropic and the reticuloendothelial cells of the spleen Excess iron deposition in the anterior hypogonadism. Radiology 2000;215:818– and bone marrow. This iron is derived from pituitary leads to degranulation of theadeno- 23. the extravascular haemolysis of intact red hypophysis and decreased hormone storage 5 Blankenberg F, Eisenberg S, Scheinman on September 26, 2021 by guest. Protected copyright. blood cells by the reticuloendothelial cells, with ensuing hypogonadism due to pituitary MN, et al. Use of cine gradient echo (GRE) which occurs during the metabolism of hyporesponsiveness to gonadotrophin releas- MR in the imaging of cardiac senescent native and transfused erythrocytes. ing hormone.4 Iron deposition in the posterior hemochromatosis. J Comput Assist Tomogr The pancreas is spared because it is not a lobe and diabetes insipidus usually do not 1994;18:136–8. 6 Brasch RC, Wesbey GE, Gooding CA, et al. reticuloendothelial organ. However, pancre- occur. Magnetic resonance imaging of transfusional atic iron deposition in transfusional iron over- Cardiac iron deposition occurs in the hemosiderosis complicating thalassemia load may result from massive transfusion ventricular myocardium before atrial myocar- major. Radiology 1984;150:767–71.

www.postgradmedj.com