Metabolic bone diseases are a group of disorders that affect the skeletal system and result in changes to bone structure and function. These diseases can be challenging to diagnose and manage, making them a crucial topic in radiology.
In the case of metabolic bone diseases, radiology plays a critical role in diagnosing and monitoring these diseases.
Let’s learn more about metabolic bone diseases and how radiology allows doctors to diagnose and manage these conditions effectively.
Hyperparathyroidism (Primary)
Pathognomonic Features
At 2nd& 3rd proximal / mid phalanges on Radial aspect: Subperiostealresorption
In skull :Salt & pepper skull appearance
Loss of lamina duraNormal lamina dura
Multifocal irregular lytic lesions scattered throughout body in metaphysis k/a “Brown tumors/Osteitis cystica fibrosa”
Important Information
Brown tumors : Bleeding occurs within them resulting in hemosiderin deposition
Secondary hyperparathyroidism
Chronic kidney disease →↓Ca2+, ↑PO3 → HPT (2°)
Hallmark finding : Sclerosis
Alternative bands of sclerosis & osteopenia: Ruggerjerseyspine
Knee & wrist : Calcification of meniscus k/a chondrocalcinosis
Important Information
Chondrocalcinosis
2°HPT
Pseudo gout (due to calcium pyrophosphate deposition)
Wrist : Triangular fibrocartilage calcification
Knee: Meniscus calcification
Paget’s Disease
May have visual loss, hearing loss (because cranial nerves getting compressed)
Sclerotic phase
Skull markedly enlarged with multiple sclerotic spots :Cottonwoolskull
↑Hat size: Tam O’ Shanter sign
Lytic phase
Osteoporosiscircumscripta
In long bones
Lysis with advancing edge :Bladeofgrass/ candle flame sign
Spinal manifestation
Peripheral sclerosis, central osteopenia: Picture framevertebra
Ivory vertebra
Important Information
Ivory vertebra
Lymphoma
Hodgkin
Sclerotic metastasis
Prostate : male
Breast : female
Paget’s disease
In case of treated TB
In bone scan
Tc99m with MDP (Methyl Diphosphonate)
“Mickey Mouse sign” in vertebra
“Lincoln sign” in mandible
Mickey Mouse Sign
USG LL → Sapheno femoral junction
USG Antenatal→ Anencephaly
Bone scan → Paget’s disease
Brain MRI → Midbrain atrophy in case of PSNP
Acromegaly
Due to increased growth hormone (after growth plate fusion)
Over growth in distal phalanges : “Spadephalanx”
Gross increase in heel pad thickness
> 23 mm in female
> 25 mm in male
In skull
Widened sella
Prognathism
Enlarged sinuses
Thick bones, PNS
Langerhans Cell Histiocytosis
Multisystemic disorder
Child with multiple bone swelling, multiple lymph nodes, multiple skin lesions
In skull
Lytic lesion: Geographical with beveled margin (differential destruction of outer & inner table)
Spine
One of the Vertebra completely destroyed :“Vertebra plana”
Important Information
LCH : MC cause of vertebra plana in children
Ewing sarcoma, lymphoma, leukemia can also cause vertebra plana
Mandible
“Floating teeth sign” (due to multiple erosion in mandible)
Multiple punched out lesion Aka Raindrop appearance
Sturge – Weber syndrome
Complete cerebral atrophy with tram track calcification which leads to refractory seizure
Port wine stain
MC affected: Ophthalmic branch of Trigeminal nerve
Congenital glaucoma (+)
Hemolytic Anemia
Sickle cell anemia, Thalassemia
Hair on end / Crew cut appearance
Raised ICP
Copper beaten sign
Earliest sign on X-ray
Children: Sutural diastasis (Sutural widening )
Adults : Dorsum sella erosion
Osteopetrosis
Congenital dysplasia
Child with hepatosplenomegaly having pancytopenia
Diffuse ↑ density
Bone within Bone appearance / Sandwich sign
Osteoporosis
Diffuse ↓ density
End plates compressed :“Codfishappearance ” [due to weak bone & weight of the body]
Important Information
Codfish appearance also seen in Osteomalacia (Vit D def. in adults)
IOC: DexaScan (Dual energy X-ray absorptiometry)
If we compare the bone mineral density of the patient with young adult : T score
If we compare the bone mineral density of the patient with the same aged person : Z-score
WHO scoring used T-score
+2 to -1 : Normal
-1 to -2.5 : Osteopenia
< -2.5 SD : Osteoporosis
Rickets
Child with widening of joints predominantly wrist, ankle
Vit D deficiency
Earliest finding: Increased growth plate / Zone of provisional calcification
Due to decreased vitamin D →↓Ca2+
Unmineralized osteoid accumulates near growth plate
Seen in Metaphysis: Cupping, Splaying, Fraying (irregularities)
Sign of healing rickets
White metaphyseal line
Important Information
White metaphyseal line
Healing rickets
Lead poisoning
Treated Leukemia
Scurvy
Scurvy
Vitamin C deficiency
Bone density decreased
Frenkel’s white line
Wimberger sign [Epiphyseal sharp margin]
Pelkan spur (metaphyseal projection)
Trummerfeld zone (Translucent zone above white line)
Subperiosteal hemorrhage
Very painful [Scurvy is known as Pseudo paralysis state]
Chronic Osteomyelitis
Central white dead bone (no demineralization) → Sclerotic k/a Sequestrum
Surrounding translucent granulation → Involucrum
Defect through which the pus comes out → Cloaca(thenwillhavedrainingsinus)
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