Table 1 Summary of investigations
Investigation | Results | Differential diagnosis |
|---|---|---|
Peripheral blood investigations | Pancytopenia: Hemoglobin 86 g/L, mean cell volume 86 fL, white cell count 0.1 × 109/L (neutrophil count 0.00 × 109/L, lymphocyte count 0.17 × 109/L), platelets 18 × 109/L, low natural killer cell levels (at 6% detected in an HIV immunology screen) Raised ferritin: 127,985 μg/L Raised C-reactive protein: 123 mg/L Abnormal liver function: Bilirubin 22 μmol/L, alkaline phosphatase 219 U/L, alanine aminotransferase 27 U/L, γ-glutamyl transferase 356 U/L Raised lactate dehydrogenase: 2567 U/L Normal renal function: Sodium 143 mmol/L, potassium 4.3 mmol/L, urea 4.0 mmol/L, creatinine 52 μmol/L Normal clotting: Prothrombin time 14 seconds, activated partial thromboplastin time 29 seconds, fibrinogen 2.4 g/L Negative HIV test Positive antinuclear antibody and positive anti-Ro (> 100.0 U/mL), negative anti-LA/Sm/Scl70/Jo1 | Hemophagocytic lymphohistiocytosis Autoimmune disease (for example, systemic lupus erythematosus or Sjögren’s syndrome, which may cause macrophage activation syndrome) Infection/sepsis Aplastic anemia (for example, idiopathic) Marrow infiltration (for example, acute leukemias) Thrombotic thrombocytopenic purpura, hemolytic uremic syndrome |
X-ray | Chest x-ray (Fig. 1): Bilateral perihilar opacification | Pneumocystis pneumonia Atypical pneumonia Hypersensitivity pneumonitis Pulmonary tuberculosis |
Computed tomography | CT of the chest, abdomen, and pelvis with contrast: Abnormal lungs with widespread acinar ground glass opacification, intralobular thickening, and nodular change in a predominantly perihilar distribution. A moderate-sized right pleural effusion was noted. There were no enlarged axillary, supraclavicular, or mediastinal lymph nodes. There was no evidence of pulmonary embolism. Acalculous cholecystitis was noted. | Pulmonary tuberculosis Lymphoma Sarcoidosis |
Lumbar puncture | LP opening pressure not recorded; routine CSF was unremarkable with protein of 0.62 g/L, no white cells, and glucose 3.0 mmol/L (paired serum glucose not recorded). | Nondiagnostic routine CSF biochemistry and cell counts |
Microbiology | Routine cultures (blood, urine, sputum, CSF): No growth Pneumocystis jirovecii PCR negative, Legionella antigen and PCR negative, respiratory mycology negative, routine respiratory culture negative Mycobacterial cultures positive (blood, urine, sputum, CSF): Mycobacterium tuberculosis | Disseminated Mycobacterium tuberculosis Note: Acellular CSF in CNS tuberculosis is possible and well-described [11] |