Bone And Arthritis - Pt.2

Post menopausal state is a primary cause of osteoporosis because during menopause, the body's production of estrogen decreases significantly. Estrogen plays a crucial role in maintaining bone density, so the decline in estrogen levels can lead to accelerated bone loss and increased risk of osteoporosis. This is why postmenopausal women are particularly vulnerable to developing osteoporosis.

The given clinical presentation of a 55-year-old man with painful hips bilaterally, along with radiographic findings of joint space narrowing, osteophyte formation, and round radiolucent cystic zones in the subchondral bone of both femoral heads, is consistent with the diagnosis of osteoarthritis. Osteoarthritis is a degenerative joint disease characterized by the breakdown of cartilage, leading to joint pain and stiffness. The radiographic findings mentioned are typical features of osteoarthritis, supporting this as the best diagnosis for the joint condition in this patient.

The correct answer is Gonococcal. Gonococcal arthritis is caused by the bacteria Neisseria gonorrhoeae, which is sexually transmitted. The symptoms of gonococcal arthritis include a sore, red, hot, and swollen joint. The joint fluid analysis typically shows a thin and cloudy fluid with many neutrophils, indicating an acute inflammatory response. Additionally, the joint fluid may spontaneously clot. These findings are consistent with the presentation described in the question.

The histologic examination of the vertebral bone in a 79-year-old woman with chronic back pain and a compression fracture of the vertebral body of T2 would most likely reveal thinned bony trabeculae. This is because as individuals age, there is a natural process of bone loss and thinning of the bony trabeculae, which can lead to fractures and chronic back pain.

The rapidly progressive dementia, myoclonus, ataxia, and spongiform degeneration seen in the cerebral and cerebellar cortices and basal ganglia are all characteristic features of Creutzfeldt Jakob Disease (CJD). Huntington Disease typically presents with chorea and behavioral changes, Alzheimer Disease with gradual cognitive decline, Parkinson Disease with bradykinesia and rigidity, and Progressive Multifocal Leukoencephalopathy with focal neurological deficits. Therefore, CJD is the most likely diagnosis in this case.

Based on the clinical presentation of increasing pain and tenderness in the wrist joints, metacarpophalangeal joints, and proximal interphalangeal joints, along with stiffness that improves as the day progresses, the primary pathology is likely to involve the synovial membranes. Synovial membranes line the joint cavities and produce synovial fluid, which lubricates and nourishes the joints. In conditions such as rheumatoid arthritis, inflammation of the synovial membranes can lead to pain, swelling, and stiffness in the affected joints.

A patient with osteolytic bony metastases is likely to demonstrate increased radiolucency. Osteolytic bony metastases refer to the spread of cancer cells to the bones, leading to the destruction of bone tissue. This results in areas of increased radiolucency on X-rays, indicating a loss of bone density. The cancer cells cause the bone to become weaker and more porous, leading to the increased radiolucency. This is in contrast to osteoblastic bony metastases, which would show increased bone density. Involvement of a single bone only, absence of pain at the site of metastasis, and the presence of "Codman's triangle" on X-ray are not characteristic findings of osteolytic bony metastases.

In Duchenne muscular dystrophy, there is a mutation in the dystrophin gene, leading to the absence or significant reduction of dystrophin protein. Therefore, electrophoresis (Western blot) performed on skeletal muscle preparations from a patient with Duchenne muscular dystrophy would most likely exhibit no detectable dystrophin.

Most bone tumors are benign, meaning they are not cancerous and do not spread to other parts of the body. Benign bone tumors are typically slow-growing and do not invade surrounding tissues. They can cause symptoms such as pain, swelling, and fractures, but they are generally not life-threatening. Malignant bone tumors, on the other hand, are cancerous and have the potential to spread to other parts of the body.

This patient is presenting with symptoms consistent with subacute combined degeneration of the spinal cord, which is most commonly caused by vitamin B12 deficiency. The decreased proprioceptive sense and numbness in the lower extremities are early signs of this condition, followed by the development of spastic weakness in the lower extremities. Over time, this can progress to a spastic paraplegia. The normal CSF findings without an increase in gamma globulins rule out other conditions such as multiple sclerosis. Amyotrophic lateral sclerosis, tabes dorsalis, and Wilson's disease are not typically associated with these symptoms.

The term "sequestrum" refers to a fragment of dead bone that becomes isolated by an infection. In this case, the woman developed severe pain and sinus tracts over the lower leg, and the material identified by the pathologist as sequestrum confirms the presence of dead bone. This suggests that the infection has caused a portion of the bone to die and become separated from the surrounding healthy bone.

All of the mentioned diseases have in common that their pathogenesis appears to be related to the aggregation of a protein within neurons. This means that in all of these diseases, there is an abnormal accumulation of proteins within the neurons, which leads to the characteristic symptoms and degeneration of brain function.

In the development of osteoarthritis, a decrease in cartilaginous proteoglycans and an increase in water content in the cartilage occur. This change in the composition of the cartilage leads to its degeneration and loss of its ability to cushion and protect the joints. This early event is significant in the pathogenesis of osteoarthritis as it sets the stage for further damage and progression of the disease.

This tetrad of symptoms, including lens dislocation, nerve deafness, corneal dystrophy, and posterior cataracts, is known to result from a mutation of type IV collagen. Type IV collagen is a major component of basement membranes, which are found in various tissues including the lens, inner ear, cornea, and kidney. Mutations in type IV collagen can lead to structural abnormalities in these tissues, causing the symptoms observed in the patient.

Rapidly progressive glomerulonephritis (RPGN) is a syndrome of the kidney that is characterized by a rapid loss of renal function, (usually a 50% decline in the glomerular filtration rate (GFR) within 3 months) with glomerular crescent formation seen in at least 50% or 75% of glomeruli seen on kidney biopsies. If left untreated, it rapidly progresses into acute renal failure and death within months. In 50% of cases, RPGN is associated with an underlying disease such as Goodpasture syndrome, systemic lupus erythematosus, or Wegener granulomatosis; the remaining cases are idiopathic. Regardless of the underlying cause, RPGN involves severe injury to the kidneys' glomeruli, with many of the glomeruli containing characteristic glomerular crescents (crescent-shaped scars). Because of this microscopic feature, RPGN is also called crescentic glomerulonephritis

The presentation of generalized CNS signs and symptoms, along with a lymphocytic pleocytosis in the lumbar puncture, suggests an inflammatory process involving the central nervous system. Perivascular lymphocytic infiltrates and microglial nodules are commonly seen in viral encephalitis, which is characterized by inflammation of the brain tissue. This is the most likely finding on histologic sections taken from the brain at autopsy in this case.

Minimal change glomerulonephritis is a kidney disorder characterized by the loss of podocyte pedicels. Podocytes are specialized cells in the kidneys that help filter waste and excess fluid from the blood. Nephrin is a protein found in the renal glomerulus, which is part of the filtration system in the kidneys. A mutation in the renal glomerular protein nephrin can lead to the abnormality seen in minimal change glomerulonephritis. This mutation may affect the structure or function of nephrin, disrupting the filtration process and causing the symptoms associated with this condition.

The patient developed CNS symptoms secondary to global cerebral ischemia, which suggests that there was a lack of blood flow to the brain. This would lead to ischemic injury and subsequent necrosis of various brain cells. A watershed infarct in the parasagittal region of one of the cerebral hemispheres is expected because this region is particularly vulnerable to ischemia. Laminar necrosis of the cerebral cortex is also expected as it is a characteristic finding in global cerebral ischemia. Necrosis of pyramidal neurons in Sommers' sector of the hippocampus is also expected as this region is highly susceptible to ischemic injury. Necrosis of Purkinje cells in the cerebellum is expected because the cerebellum can also be affected by global cerebral ischemia. However, subarachnoid hemorrhage is not expected in this case as it is not directly related to global cerebral ischemia.

The correct answer is Thymus gland. This is because the patient's symptoms, including weakness of the extraocular muscles, ptosis, and generalized muscle weakness, along with the improvement after administration of Tensilon, suggest a diagnosis of myasthenia gravis. In myasthenia gravis, there is a decrease in the number of acetylcholine receptors, which are responsible for transmitting nerve signals to the muscles. The thymus gland is often associated with this condition, as it plays a role in the development of the immune system and can be involved in the autoimmune process that leads to myasthenia gravis.

Type III Rapidly Progressive Glomerulonephritis is not a type of glomerulonephritis that LE (lupus erythematosus) patients may present with. The other options listed (Mesangial glomerulonephritis, Diffuse proliferative glomerulonephritis, Diffuse membranous glomerulonephritis, and Focal glomerulonephritis) are all types of glomerulonephritis that can be seen in LE patients.

The most likely diagnosis in this case is Progressive Multifocal Leukoencephalopathy (PML). This is indicated by the presence of discrete patches of demyelination scattered throughout the white matter, which is a characteristic finding in PML. Additionally, the patient's deteriorating neurologic status and eventual death are consistent with the progressive nature of PML. The absence of other specific findings or symptoms associated with other diseases mentioned in the options further supports the diagnosis of PML.

The autopsy findings of acute infarction in the right occipital lobe and Duret hemorrhages in the pons and midbrain suggest that the patient experienced increased intracranial pressure. Uncal herniation occurs when there is a mass effect in the brain, causing displacement of the uncus (part of the temporal lobe) through the tentorial notch. This can lead to compression of the oculomotor nerve, resulting in a dilated pupil and paralysis of ocular movements. The rapid deterioration in mental status and subsequent death further support the diagnosis of right uncal herniation.

The patient's presentation of fever, headache, stiff neck, confusion, and positive Brudzinski sign is consistent with meningitis. The lumbar puncture findings of mild increase in protein, normal glucose, and moderate lymphocytic pleocytosis are also indicative of viral meningitis. Enteroviruses are a common cause of viral meningitis, especially in young adults. Therefore, the most likely causative organism in this case is an enterovirus.