Managing a Pneumothorax – The Fear is Mostly in the Mind

Two weeks ago, in Beirut, I was speaking on the impact of modern imaging in pulmonary medicine, to a group of chest physicians from Egypt. The moment I started speaking on CT guided lung biopsies, a physician got up and started talking about the dreaded risk of pneumothorax. I have had similar reactions in other towns in India, including tier I cities like Delhi.

I explained to him that while a pneumothorax is not uncommon during CT guided biopsies, there are many ways to mitigate its seriousness; single puncture, minimal trauma, bleeding along the tract during withdrawal and arguably puncture side down for a few minutes are measures that reduce the severity and incidence of or prevent the occurrence of pneumothorax.

But even if a pneumothorax does occur, it is a slow event that takes its own time to increase, if it does. If a pneumothorax occurs during the procedure, it can be aspirated at the same time and more often than not, that cares of the problem and we can even continue with the procedure (Figure 1). In case the pneumothorax occurs after we have washed out as a delayed complication, then we can still aspirate it using an over the needle catheter. A recent video describing this procedure has been posted on The New England Journal of Medicine site. While this video shows the technique to be used in patients with spontaneous pneumothorax and describes a blind approach, we can use this simple procedure to aspirate under CT guidance as well and then check the status immediately on the CT scan table.

A and B show the start of a CT guided core biopsy of a subpleural nodule using a coaxial system. Since the nodule is immediately subpleural, the risk of pneumothorax is slightly higher than for a deeper nodule and C shows the developing pneumothorax. In D, the canula has been withdrawn into the pleural space and the pneumothorax was aspirated. E shows the biopsy continuing after the pneumothorax has been aspirated. It did not recur. Five minutes after the procedure, a scan in the supine position (G) shows a thin residual pneumothorax that was non-progressive.

A and B show the start of a CT guided core biopsy of a subpleural nodule using a coaxial system. Since the nodule is immediately subpleural, the risk of pneumothorax is slightly higher than for a deeper nodule and C shows the developing pneumothorax. In D, the canula has been withdrawn into the pleural space and the pneumothorax was aspirated. E shows the biopsy continuing after the pneumothorax has been aspirated. It did not recur. Five minutes after the procedure, a scan in the supine position (G) shows a thin residual pneumothorax that was non-progressive.

In the worst case scenario, an interventional radiologist should be able to put a tube in as well, despite the fact that the need to do this would be very low in experienced hands.

Brittle Bones, Late Diagnosis

I received a call about 4 months ago from a family physician, who wanted me to perform a USG or CT guided biopsy for a mass in the anterior compartment of the right thigh in a 47-years old woman. He did not give me any more details and said the patient would get in touch with me.

I forgot about this, until a month later, when I was going through some histopathology reports of biopsies done by my ultrasonologist and chanced upon a report that described a hemangiopericytoma in the thigh with a comment saying that this was consistent with a phospaturic mesenchymal tumor.

Image

Fig. 1: Ultrasound shows the mass in the anterior compartment of the right thigh (red arrow) with the biopsy needle (blue arrow)

I called for more details and then realized that this was the same patient that the family physician, a month ago, had called about. Different people in our department do ultrasound and CT-guided biopsies and the patient went straight to the ultrasonologist, who in turn, went ahead and performed a core biopsy of the mass in the anterior compartment of the thigh (Fig. 1).

A phosphaturic mesenchymal tumor is a rare condition and typically secretes FGF-23 (fibroblastic growth factor) that produces osteomalacia. This combination is called oncogenic osteomalacia or tumor-induced osteomalacia (TIO).

I then asked the patient to get all the reports and details.

Image

Fig. 2: Radiograph shows an insufficiency fracture (arrow) of the base of the proximal right 3rd metatarsal bone.

Image

Fig. 3: Radiograph shows an insufficiency fracture (arrow) of the mid-left 5th metatarsal bone.

It had taken 5 years to get to this diagnosis. She started with an insufficiency fracture, five years ago, in the right 3rd metatarsal bone (Fig. 2), followed a month later by another fracture in the left 5th metatarsal bone (Fig. 3). She received symptomatic treatment and went from doctor to doctor with variable diagnoses of osteoporosis and perhaps osteomalacia.

This went on for 4 years, until one day, she was unable to get up from bed. She was admitted to a hospital and a skeletal survey showed fractures of the necks of both humeri (Fig. 5) and femurs (Fig. 6) with biconcave vertebrae (Fig. 7). Finally she received a diagnosis of osteomalacia and was worked up.

Her serum calcium was normal, vitamin D was normal, serum phosphorus was very low and her 24-hours urine phosphorus was elevated with a normal serum parathormone level and a raised serum alkaline phosphatase level. She did not fit into vitamin D related causes or phosphate deficiency conditions and what was left was a potential diagnosis of oncogenic osteomalacia.

Fig 4

Fig. 4: Radiographs of both shoulders show fractures (red arrows) of the necks of both humeri

Fig 5

Fig. 5: Radiograph of the bones of the pelvis and both hips show fractures (red arrows) of the necks of both femurs.

Lateral radiograph of the spine shows biconcave vertebrae

Fig. 6: Lateral radiograph of the spine shows biconcave vertebrae

Thus started the search for an FGF-secreting tumor that produces phosphaturia, hypophosphatemia and osteomalacia. A PET/CT then showed a mass with low FDG uptake in the anterior compartment of the thigh (Fig. 7), which was then biopsied. The common tumors that produce FGF are hemangiopericytoma, hemangioma, giant cell tumor and non-ossifying fibroma.

Contrast enhanced CT scan shows a hypervascular lesion (arrow) in the anterior compartment of right thigh, with mild FDG uptake (arrow) on the PET study.

Fig. 7: Contrast enhanced CT scan shows a hypervascular lesion (arrow) in the anterior compartment of right thigh, with mild FDG uptake (arrow) on the PET study.

She was operated and the tumor removed. Most patients show dramatic recovery of their phosphorus levels, but the skeletal changes and fractures take time to heal. The patient is slowly getting better symptomatically.

The most common reason for delayed diagnosis (in her case 5 years with an average time of 4.7 years from start of symptoms to final diagnosis) is due to lack of awareness and the inability to find the tumor.

This case was recently presented by our DNB resident Dr. Parang Sanghavi in the Teaching Files Case Presentation meeting in Mumbai, where it won the first prize in the 3rd year residents’ category.

%d bloggers like this: