I. Radiological Findings

Based on the provided X-ray and CT images, the following main features can be observed:

• Overall increased bone density, blurred trabecular structures, and a “bone-in-bone” appearance.
• Increased density of the vertebral bodies; the boundary between the lamina and vertebral bodies is unclear, presenting a diffuse high-density shadow.
• Abnormal morphology at the metaphysis of long bones, with some showing “Erlenmeyer flask” expansion.
• Thickening of the skull plates and increased skull density, possibly restricting the cranial cavity, with potential compression of the bony canals for cranial nerves.
• Abdominal CT indicating splenomegaly, consistent with clinically observed enlarged spleen.

These imaging findings of markedly increased bone density often suggest a sclerotic bone disease. Considering the patient’s hearing and vision impairments, along with hematological abnormalities, a congenital bone metabolic disorder should be strongly suspected.

II. Potential Diagnoses

Based on the patient’s history (persistent fever, anemia, thrombocytopenia, splenomegaly, vision and hearing impairments) and the imaging presentations (generalized increased bone density, thickened skull, spinal and long bone changes), the following potential diagnoses can be listed:

1. Infantile Malignant Osteopetrosis (Autosomal Recessive Osteopetrosis)
   Cause: Failure of normal bone marrow cavity resorption, leading to abnormally increased bone density. Genetic mutations (e.g., in genes related to H⁺ pump vATPase) result in dysfunctional osteoclast activity.
   Features: Generalized bone sclerosis, pathological fractures, cranial nerve compression (e.g., optic nerve, auditory nerve), and impaired hematopoiesis (anemia, thrombocytopenia, splenomegaly as compensatory extramedullary hematopoiesis). Radiologically, “bone-in-bone” appearance and “Erlenmeyer flask” deformities can be observed.
2. Other Sclerosing Bone Diseases (e.g., sclerosing bone dysplasias or other rare congenital bone disorders)
   Cause: Relatively rare, some are associated with metabolism and genetics, often presenting with increased bone density and sclerosis.
   Features: Clinical manifestations can include bone pain and pathological fractures. However, they usually do not cause such extensive cranial nerve involvement or severe hematopoietic dysfunction.

In summary, infantile malignant osteopetrosis (autosomal recessive osteopetrosis) most closely matches the clinical and radiological features.

III. Final Diagnosis

Considering the patient’s age (4 months), clinical symptoms (anemia, thrombocytopenia, splenomegaly, visual and auditory impairment), and the radiological findings of diffuse increased bone density and pathological changes, the most likely diagnosis is:

Infantile Malignant Osteopetrosis (Autosomal Recessive Osteopetrosis).

For further confirmation, genetic testing can be performed to identify common mutations in the H⁺ pump vATPase a3 subunit (Chromosome 11q12-13), which is valuable for disease classification and genetic counseling.

IV. Treatment Plan and Rehabilitation Program

1. Overview of Treatment Strategies
Currently, the main treatment approaches for infantile malignant osteopetrosis include:

• Bone Marrow Transplantation (Hematopoietic Stem Cell Transplantation): Recognized as a fundamental therapy that can extend life and partially correct the pathological process.
• Pharmacological Support: Such as glucocorticoids, interferon-γ, calcitriol (active vitamin D), and parathyroid hormone to improve hematopoiesis and reduce abnormal bone overgrowth.
• Symptomatic Supportive Care: Including blood transfusions, infection control, and correction of electrolyte imbalances.
• Prevention and Management of Complications: Promptly addressing fractures, protecting visual and auditory nerve functions, etc.

2. Rehabilitation and Exercise Prescription
Because patients with osteopetrosis have abnormal bone structure, increased bone fragility, and are at the infant stage, caution is required during exercise and rehabilitation. It is recommended to proceed under the guidance of a specialized medical team:

1. Initial Care and Passive Movements
   • Primarily passive joint movements, assisted by parents or rehabilitation therapists with gentle limb mobilization, avoiding rough handling or large range-of-motion stretches.
   • Frequency is recommended several times daily, each lasting 2-3 minutes, with careful application of force to avoid discomfort.
2. Assistive Devices and Positioning Management
   • When necessary, use appropriate orthoses or protective gear to safeguard areas at high risk of fracture (e.g., spine, long bones of the limbs).
   • Ensure the infant’s skeletal stability during daily handling, feeding, and sleeping to reduce concentrated stresses.
3. Gradual Increase in Active Movement
   • As the patient’s condition stabilizes after bone marrow transplantation or pharmacological treatment, begin incrementally introducing active exercises, such as prone head-lifting or voluntary limb movements, under professional assessment.
   • Monitor the infant’s tolerance; sessions should be short and gradually extended.
4. Respiratory Training and Overall Health Management
   • Because skeletal abnormalities may affect thoracic development, provide infant respiratory training if necessary to maintain lung ventilation.
   • Enhance nutritional support, especially ensuring adequate intake of calcium, phosphorus, and vitamin D, to support skeletal and overall development.

The rehabilitation plan emphasizes individualization and gradual progression, with continuous assessment of the patient’s skeletal condition and hematopoietic function. Exercise safety must be ensured, and any abnormal signs, pain, or discomfort should prompt immediate medical attention.

V. Disclaimer

This report is a reference analysis based on the current available data and does not replace an in-person consultation or professional medical advice. If you have any questions or if the condition changes, please seek medical care or consult a professional physician promptly.