How is COVID-19 causing Bone Death in people?

COVID-19 is unlike anything the world has seen before; the rapid moderations make it very hard for us to make assumptions about the future. The second wave of the COVID-19 took the whole country by storm and resulted in mass grief and loss. At present, India is at risk of a third wave of COVID-19, and we must take every measure to maintain social distance and health and hygiene around us.
 
We’re now also looking at the post-Covid complications in cases across the country. Earlier, the Black Fungus infection and now, three new cases of bone death in COVID-19 survivors have got the medical community worried about the ill-effects of COVID-19 post-recovery.
 
What is bone death?
 
Bone death or Avascular necrosis (AVN) is a painful condition due to reduced or interrupted blood supply to a bone, ultimately resulting in the death of the bone tissues. Thus, the bone tissues start deteriorating and becoming weak, eventually breaking the bone or the joint.
 
It commonly affects long bones and joints like the femur (thigh bone) and hip joints. Avascular necrosis is also associated with long term steroids medication or alcohol intake among the age group 30-50.
 
What do we know so far about Bone death and the risks involved for COVID-19 survivors?
 
Major Cause for Avascular necrosis
 
As we have discussed earlier, AVN is caused due to interrupted blood flow to the bone tissues. The blood flow may be interrupted due to the following reasons:
 

• Serious trauma or injury (joint dislocation or fracture) that may damage nearby blood vessels.
• Long-term use of corticosteroid medications (prednisone, cortisone, or methylprednisolone)
• Alcoholism
• Chronic medical conditions
• Cancer treatments that utilize radiation can also weaken the bone and harm the blood vessels.
• Fatty deposits (lipids) in the blood vessels interrupt the flow. Fatty deposits in a blood vessel to the heart would cause a heart attack and a stroke in the brain. In the bones, it results in AVN.
• Specific medical conditions that reduce the blood flow to the bone, like sickle cell anemia and Gaucher's disease.

 
Symptoms of AVN or bone death
 
It is hard to detect AVN at the beginning stage, as the patient may not exhibit any symptoms. However, as the case worsens, the patient may develop some of these symptoms:
 

• Initially, the patient may experience joint pain when exerting weight on the affected joint, and later they may feel pain even while resting.
• Breaking of the joint bone or surrounding structures collapsing.
• Reduced range of motion in the joint.
• Pain especially around the hip, thigh, and knee area (buttock region, lower back, outer side of the hip, mid-thigh, or knee)
• Pain in the groin while walking
• Sudden inability to sit cross-legged.
• Change in the manner of walking or developing limp with or without pain.

Since these symptoms are common to most bone-related issues, it is prescribed that you must consult a doctor and get the necessary tests done.
 
Who is at a major risk of developing AVN?
 
The factors that may contribute to developing AVN are listed as follows:
 

• Excessive use of steroids
• Diabetes Mellitus
• Pancreatitis (inflammation of the pancreas)
• Gaucher disease (building up of fatty substances in the liver/ spleen)
• Hyperlipidemia (high-fat levels in the blood)
• Alcohol abuse
• Decompression disease or the formation of gas bubbles in the body due to a change in pressure
• Blood disorders
• HIV infection
• Radiation therapy used for cancer treatment
• Long term use of bisphosphonates
• Organ transplants (especially kidney transplants)
• Autoimmune disorders such as systemic lupus erythematosus.

 
These factors may increase the chance of the patient developing AVN but are not prerequisites for developing the disease. According to recent reports, COVID-19 survivors are also at a high risk of contracting AVN as a post-Covid complication.
 
New risks involved for COVID-19 survivors
 
The new cases of AVN in COVID-19 survivors have created much buzz in the medical legion. There is a possibility of increased AVN cases as a post-Covid complication like the black fungus infection that was considered a major complication post-COVID-19.
 
Though mild Covid cases do not require a steroid medication, the severe cases have shown major improvement and proved life-saving with controlled steroid medication, as prescribed by the doctor. The COVID-19 infection itself makes the body weak and more perceptible to diseases and infections. Thus, putting the COVID-19 survivors at a major risk of developing AVN.
 
Even though the cases are fairly low and new at this point, nothing can be said for sure but according to a report in BMJ journals, studying three cases of AVN in Covid patients found out that the patients developed AVN on an average of 58 days after COVID-19 diagnosis, but according to the previous data it generally takes six months to a year to develop AVN after steroid exposure in a patient.
 
At this point, we can only hope that these AVN cases are resolved with minimal intervention like medication and core decompression. The key is to detect AVN at an early stage and get proper treatment.


Diagnosis of AVN
 
The doctor will ask for the patient’s complete medical history, and after a physical exam, they may prescribe specific tests to confirm the AVN diagnosis.
The specific tests are:
 

• Imaging tests: An x-ray, a CT scan, or an MRI to identify the detailed images of the affected bones.
• Radionuclide bone scan is a nuclear imaging technique where small amounts of radioactive material are injected into the blood to determine the cell activity and blood flow.
• Biopsy: biopsy involves a small sample of diseased tissue or bone removed by a needle or surgically to find out cancerous/ abnormal cells present in the affected bone.
• A functional evaluation of the bone to determine the pressure.

 
Taking care post COVID-19
 
AVN can be extremely painful and may lead to permanent bone damage and disability. Many reports suggest that the corticosteroids used in the COVID-19 treatment increase the chance of AVN in COVID-19 survivors. Thus, we recommend, the COVID-19 survivors take proper measures even after recovering from the disease and look out for any of the symptoms stated above.