Background
Miliary tuberculosis (MTB) makes up only 1.5% of tuberculosis (TB). It is uncommon in pregnancy and diagnosis is often delayed as its manifestations are varied including pyrexia of unknown origin (PUO). From 2003 to 2011, USA TB incidence in pregnancy increased significantly from 1.92 to 4.06/100,000 births most of which was non-pulmonary 1. MTB has been associated with adverse materno-fetal outcomes including meningitis, pre term labour, low birth weight, congenital TB and fetal loss.
Clinical History
A 28 year old primigravida presented at 31 weeks with fever and dry cough of one month’s duration. She completed a six month course of anti-tuberculous medication two years previously after contact tracing had detected latent TB. She had no other high risk factors. Investigations revealed a leucocytosis, high CRP and subtle patchy changes in the right upper zone on chest X-ray. Screens for influenza, atypical pneumonia and HIV were negative as were blood cultures. Despite escalation of antibiotics her fever persisted and a non-contrast CT chest showed minimal ground glass attenuation in both lower lobes. Further septic work up including vasculitis, connective tissue and neoplastic screens were unremarkable. TB sputum smear and PCR x3 were negative. At 35+6 weeks gestation she underwent scheduled Caesarean section for breech presentation, persistent fever, weight loss and intermittent fetal tachycardia. The baby was born in good condition but went to special care for prematurity. At operation a thickened peritoneum covered with pale fibrinous lesions and pockets of loculated fluid was noted. Placental and peritoneal biopsies were sent for culture and PCR and subsequently found to be positive for TB. The baby was not infected but was treated prophylactically for TB. The patient received standard TB medications postnatally. Both have since done well.
Conclusion
Despite a suggestive history, the diagnosis of MTB eluded us as relevant initial investigations into PUO were unhelpful and only became clear after surgical delivery revealed typical findings and specimens provided definitive culture.