Natural history of non-functioning pituitary microadenomas - results from the UK NFPA consortium

OBJECTIVE

The optimal approach to the surveillance of non-functioning pituitary microadenomas (micro-NFPAs) is not clearly established. Our aim was to generate evidence on the natural history of micro-NFPAs to support patient care.

DESIGN

Multi-centre, retrospective, cohort study involving 23 endocrine departments (UK NFPA consortium).

METHODS

Clinical, imaging, and hormonal data of micro-NFPA cases between 1/1/2008 and 21/12/2021 were analysed.

RESULTS

Data for 459 patients were retrieved [median age at detection 44 years [interquartile range (IQR) 31-57) - 152 males/307 females]. 419 patients had more than two MRIs [median imaging monitoring 3.5 years (IQR 1.71-6.1)]. One case developed apoplexy. Cumulative probability of micro-NFPA growth was 7.8% (95%CI 4.9%-8.1%) and 14.5% (95%CI 10.2%-18.8%) at 3 and 5 years, respectively, and of reduction 14.1% (95%CI 10.4-17.8%) and 21.3% (95%CI 16.4-26.2%) at 3 and 5 years, respectively. Median tumour enlargement was 2 mm (IQR 1-3) and 49% of micro-NFPAs that grew became macroadenomas (nearly all >5 mm at detection). Eight (1.9%) patients received surgery (only one had visual compromise with surgery required >3 years after micro-NFPA detection). Sex, age, size at baseline were not predictors of enlargement/reduction. At time of detection, 7.2%, 1.7% and 1.5% patients had secondary hypogonadism, hypothyroidism and hypoadrenalism, respectively. Two (0.6%) developed hypopituitarism during follow-up (after progression to macroadenoma).

CONCLUSIONS

Probability of micro-NFPA growth is low and development of new hypopituitarism is rare. Delaying first follow-up MRI to three years and avoiding hormonal re-evaluation in absence of tumour growth or clinical manifestations is a safe approach for micro-NFPA surveillance.

Isolated splenic sarcoidosis: a rare cause of hypercalcaemia in a patient with type 1 diabetes

A 30-year-old man was admitted to Intensive Therapy Unit (ITU) with status epilepticus secondary to severe hypoglycaemia on a background of type 1 diabetes. CT of the brain showed generalised cerebral oedema. He was successfully stepped down to a medical ward after 2 weeks. He was noted to have persistently high calcium, which required multiple doses of pamidronate. Parathyroid hormone level was appropriately low. CT of the thorax, abdomen and pelvis showed mild hepatosplenomegaly with small pathological lymph nodes throughout the abdomen. Bone marrow biopsy was unremarkable. Lymph node biopsy was difficult to achieve, and therefore a positron emission tomography scan was arranged. This showed an enlarged and hypermetabolic spleen. Differential diagnoses at this point included lymphoma and sarcoidosis. He underwent diagnostic splenectomy, and the diagnosis of sarcoidosis was confirmed histologically. Calcium level remained normal 17 months after splenectomy.

Pituitary infundibular epidermoid cyst: a rare cause of hypopituitarism

A 53-year-old man presented with 6 months history of weight loss associated with nausea, fatigue, dizziness and headache. On arrival he was in adrenal crisis. Biochemistry revealed anterior hypopituitarism with low cortisol, thyroxine, testosterone and a slightly raised prolactin. He was commenced on steroids, thyroxine and testosterone. MRI pituitary gland was reported to have a 9.4 mm microadenoma. Cabergoline was started for a possible microprolactinoma. Follow-up MRI showed increase in the size of complex cystic lesion causing chiasmal compression raising a possibility of craniopharyngioma. Visual fields assessment was normal. In view of the rapid enlargement, to protect vision and obtain a tissue diagnosis he underwent endoscopic trans-sphenoidal surgery. A cystic lesion was noted intraoperatively originating from pituitary stalk with intrasellar and suprasellar extension. It was filled with white caseous material and fluid. Histology revealed epidermoid cyst. His headache resolved postoperatively.

Estimation of subnational tuberculosis burden: generation and application of a new tool in Indonesia

SETTING: In many high tuberculosis (TB) burden countries, there is substantial geographical heterogeneity in TB burden. In addition, decisions on TB funding and policy are highly decentralised. Subnational estimates of burden, however, are usually unavailable for planning and target setting.OBJECTIVE and DESIGN: We developed a statistical model termed SUBsET to estimate the distribution of the national TB incidence through a weighted score using selected variables, and applied the model to the 514 districts in Indonesia, which have substantial policy and budgetary autonomy in TB. Estimated incidence was compared to reported facility and domicile-based notifications to estimate the case detection rate (CDR). Local stakeholders led model development and dissemination.RESULTS: The final SUBsET model included district population size, level of urbanisation, socio-economic indicators (living floor space and high school completion), human immunodeficiency virus prevalence and air pollution. We estimated district-level TB incidence to be between 201 and 2,485/100 000/year. The facility-based CDR varied between 0 and 190%, with high variation between neighbouring districts, suggesting strong cross-district health utilisation, which was confirmed by domicile-based CDR estimation. SUBsET results informed district-level TB action plans across Indonesia.CONCLUSION: The SUBsET model could be used to estimate the subnational burden in high-burden countries and inform TB policymaking at the relevant decentralised administrative level.

GRANULOMATOUS DISEASE OF UNUSUAL SITES CAUSING HYPERCALCEMIA: TWO CASE REPORTS

Objective

Hypercalcemia with suppressed parathyroid hormone (PTH) levels is mostly due to granulomatous disease (GD) or neoplastic disease. In GD, autonomous activity of extra-renal 1α-hydroxylase enzyme is usually the underlying cause. We describe a pair of cases where hypercalcemia resulted from GD of unusual sites posing significant diagnostic challenges.

Methods

We describe 2 cases of PTH-independent hypercalcemia due to GD of the prostate gland and the stomach.

Results

Both cases presented with marked hypercalcemia and suppressed PTH levels. Case 1 is an elderly male who presented with marked symptomatic hypercalcemia on multiple occasions. Investigations revealed elevated levels of 1,25-dihydroxyvitamin D3 and prostate-specific antigen but normal PTH-related protein. Transrectal biopsy of the prostate gland confirmed the presence of chronic granulomatous prostatitis. The patient responded very well to steroids which entirely normalized his calcium level. Case 2 is a male who presented similarly with significant hypercalcemia but had upper gastrointestinal symptoms and anemia at onset. Endoscopy and biopsy established the presence of granulomatous gastritis likely due to Crohn disease which responded to steroids resulting in normalization of calcium levels within a short span of time.

Conclusion

While the majority of PTH-independent hypercalcemia cases are due to GDs of lymph nodes or malignancy, our cases indicate that in uncertain cases, granulomatous processes involving unusual sites should be considered in the evaluation of hypercalcemia with suppressed PTH.

Cinacalcet: A Viable Therapeutic Option for Primary Hyperparathyroidism in the Elderly

OBJECTIVE

Parathyroidectomy is usually curative in primary hyperparathyroidism (PHPT), but its utility would be limited if patients are elderly who may either refuse surgery or may have advanced frailty and multimorbidity. We evaluated the effectiveness of cinacalcet, an allosteric modulator of calcium-sensing receptor in PHPT in an elderly cohort of patients.

METHODS

A prospective analysis of 29 patients who had PHPT and despite fulfilling criteria for surgery were unable to undergo parathyroidectomy either due to self-refusal (n = 12) or due to advanced multimorbidity (n = 17). All patients completed treatment with cinacalcet for at least for 6 months. Analysis were performed as per age (<75 and ≥75 years) and Charlson comorbidity index (CCI) score (≤5 and >5).

RESULTS

Our patients were the elderly (77 ± 12.7 years). In the whole group, complete normocalcemia was observed in 72.4% of patients (mean reduction: -0.55 mmol/l [confidence interval (CI) 0.4--0.7; P < 0.0001]) and parathormone (PTH) normalized (≤6.9 pmol/l) in 33.4% of patients [mean reduction: -5.5 pmol/l (CI -11.6-0.6; P = 0.0015)]. In subgroup analysis, the severity of hypercalcemia was found to be higher patients with age <75 years and also in patients with CCI score >5. Cinacalcet lowered adjusted calcium in both age groups (P < 0.0001) with a greater reduction (20.5% vs. 16.2%; P < 0.0001 for both) in patients with CCI score >5. PTH fell in both age groups but significantly (-6.7 pmol/l [CI -14.9-1.5]; P = 0.008) in ≥ 75 years category and likewise, the drop was greater in patients with higher CCI scores (-7.1 pmol/l [CI -15.8-1.6); P = 0.009] vs. [-4.5 pmol/l [CI -3.9--5.10]; P = 0.001). Patients with age <75 years and with CCI score ≤5 needed higher doses of cinacalcet to achieve biochemical targets.

CONCLUSION

Cinacalcet is a viable and valuable treatment strategy for elderly patients with multiple comorbidities who suffer from PHPT but either cannot or refuse to undergo parathyroidectomy.

An insidious case of hepatic artery pseudoaneurysm secondary to acalculus cholecystitis

A 68-year-old man with expressive dysphasia presented with upper gastrointestinal haemorrhage, jaundice and abdominal pain. He was unable to tolerate ultrasound tranducer pressure. His oesophagogastroduodenoscopy (OGD) showed large blood clots in the stomach with blood trickling from the ampulla. An urgent CT angiogram demonstrated a 32 mm pseudoaneurysm within the gallbladder fossa. The patient subsequently underwent an endovascular embolisation of the pseudoaneurysm performed by the interventional radiology team.

Light-dependent activation of rod transducin by pineal opsin

The pineal gland expresses a unique member of the opsin family (P-opsin; Max, M., McKinnon, P. J., Seidenman, K. J., Barrett, R. K., Applebury, M. L., Takahashi, J. S., and Margolskee, R. F. (1995) Science 267, 1502-1506) that may play a role in circadian entrainment and photo-regulation of melatonin synthesis. To study the function of this protein, an epitope-tagged P-opsin was stably expressed in an embryonic chicken pineal cell line. When incubated with 11-cis-retinal, a light-sensitive pigment was formed with a lambdamax at 462 +/- 2 nm. P-opsin bleached slowly in the dark (t1/2 = 2 h) in the presence of 50 mM hydroxylamine. Purified P-opsin in dodecyl maltoside activated rod transducin in a light-dependent manner, catalyzing the exchange of more than 300 mol of GTPgammaS (guanosine 5'-O-(3-thiotriphosphate))/mol of P-opsin. The initial rate for activation (75 mol of GTPgammaS bound/mol of P-opsin/min at 7 microM) increased with increasing concentrations of transducin. The addition of egg phosphatidylcholine to P-opsin had little effect on the activation kinetics; however, the intrinsic rate of decay in the absence of transducin was accelerated. These results demonstrate that P-opsin is an efficient catalyst for activation of rod transducin and suggest that the pineal gland may contain a rodlike phototransduction cascade.

Enhancement of opsin activity by all-trans-retinal

The rod cell photoreceptor apoprotein, opsin, activates the G-protein, transducin, although at a much reduced level than light-activated rhodopsin. The ability of all-trans-retinal to enhance opsin apoprotein activity was investigated using a guanyl nucleotide exchange assay on transducin. All-trans-retinal enhanced opsin activity in a concentration-dependent manner. At high concentrations of all-trans-retinal, the activity of the all-trans-retinal-opsin complex was comparable to that from an equimolar amount of metarhodopsin(II). However, in contrast to metarhodopsin(II), the active all-trans-retinalopsin complex did not require a stable Schiff base linkage between opsin and all-trans-retinal. The lack of a stable Schiff base and differences in activity at high pH imply that opsin and all-trans-retinal form a complex that is distinct from metarhodopsin(II). The ability of all-trans-retinal to stimulate the transduction cascade may be a source of post-bleach noise in photoreceptors.

Modulation of opsin apoprotein activity by retinal. Dark activity of rhodopsin formed at low temperature

The bovine opsin apoprotein activates transducin, although at a much reduced level than light-activated rhodopsin (Surya, A., Foster, K., and Knox, B. (1995) J. Biol. Chem. 270, 5024-5031). The ability of retinal to modulate opsin apoprotein activity was investigated using a guanyl nucleotide exchange assay on transducin. 11-cis-Retinal reacted with opsin at 22 degrees C to (a) reform pigment having maximal absorbance at 500 nm and (b) reduce opsin activity by >80%. Pigment formation also occurred at 0 degrees C with a t1/2 of 260 min. However, unlike rhodopsin formed at 22 degrees C (R22), the rhodopsin formed at 0 degrees C (R0) activated transducin with the same half-saturating concentration as opsin in an exhaustive binding assay. Thus, the formation of a protonated Schiff base associated with 500 nm absorbance does not by itself lead to the inactivation of opsin. The R0 conformation was partially inactivated by incubation at 22 degrees C (t1/2 = 61 +/- 9 min), suggesting that it may be an intermediate conformation in the regeneration of rhodopsin.

Transducin activation by the bovine opsin apoprotein

The interaction of the bovine opsin apoprotein with transducin in rod outer segment membranes was investigated using a guanyl nucleotide exchange assay. In exhaustive binding experiments, opsin activates transducin, with half-maximal exchange activity occurring at 0.8 mol of opsin/mol of transducin. The opsin activity was light-insensitive, hydroxylamine-resistant, unaffected by stoichiometric concentrations of retinaloxime, and more heat-labile than rhodopsin. The t1/2 of transducin activation in the presence of excess opsin was 8.5 min, compared with 0.7 min for metarhodopsin (II). The second-order rate constants were determined to be 0.012 pmol of guanosine 5'-(gamma-thio)triphosphate (GTP gamma S) bound per min/nM opsin and 0.35 pmol of GTP gamma S bound per min/nM metarhodopsin (II). Opsin was able to activate more than one transducin, although there appeared to be a turnover-dependent inactivation of the apoprotein. Opsin showed a broad pH range (5.8-7.4) for optimal activity, with no activity in buffers of pH > 9, whereas metarhodopsin (II) exhibited activity at pH > 9. Regulation of opsin activity by stoichiometric amounts of retinal was observed, with inhibition by 11-cis-retinal and stimulation by all-trans-retinal. A model for opsin activity is proposed.